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carb info and tunning guide!

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Category: Nitro
Forum Name: Nitro Trucks
Forum Discription: Menace 21, XTR's and others
URL: http://www.racing-cars.com/forum/forum_posts.asp?TID=4285
Printed Date: 16 July 2019 at 11:47am
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Topic: carb info and tunning guide!
Posted By: lincsrc
Subject: carb info and tunning guide!
Date Posted: 23 March 2006 at 10:44pm

STICKY THIS ONE PLS!

hope it helps new and old r/c peeps out.

The question seems to keep popping up about Carb adjustments- what does it do, which do I adjust first, etc.. Here a basic guide explaining the internal carb components, what they're responsible for, and how to tune it properly.

Assuming you're at the manufacturers recommended starting point with the idle opening gap already set and the engine running- the first thing that must be set is the HSN. The HSN (main needle) controls the maximum amount of fuel flow through the fuel inlet/spray bar. Since it does control total fuel flow- the HSN setting WILL AFFECT the LSN setting. Therefore, you MUST adjust this setting 1st before finalizing your LSN adjustment. Setting your LSN 1st will only cause you to have to reset it again once you alter you HSN adjustments. You must typically match this maximum fuel flow through the carb with the maximum amount of air flow through the carb. Maximum airflow through the carb can only be achieved with the carb at WOT and the engine at max RPM. It doesn't matter how fast you accellerate at this point- just get the engine to maximum RPM's doing several high speed passes and make a judgement based on maximum speed and smoke trail. Adjustments should be made at hourly incriments. Once you get to a point where top speed is no longer improving, richen the HSN between 1/8-1/4 of a turn out just to ensure adequate lubrication at that maximum speed.
*If the engine suddenly cuts out at high RPM's - you too lean

*If the engine lacks high RPM response with excessive smoke- your too rich

If your engine's is starting to run excessively hot even while your fuel mixture is excessively rich...try switching to a cooler glow plug, one step cooler than the one your using. ( If your using Dynamite plugs like an MC-59, switch to an MC8, then to an MC9 if necc- if your using OS plugs and using an OS8, switch to an OSA5, and then to an OSR5 if neccesary. DO NOT JUMP FROM ONE MANUFACTURER TO ANOTHER WHEN EXPERIMENTING WITH GLOW PLUG HEAT RANGE. THERE IS NO INDUSTRY STANDARD FOR THEM TO COMPLY WITH SO KNOWING WHICH PLUG IS HOTTER THAN THE OTHER BASED ON IT'S GIVEN RATING IS NOT SOMETHING THAT CAN BE DONE BETWEEN 2 MANUFACTURERS)


When the throttle is anywhere between 1/2 open to fully closed, the LSN enters the fuel inlet/spray bar and restricts the amount of fuel that can flow through it. Less fuel is required at this point since the smaller carb opening is also restricting the amount of air that can flow through the carb. The deeper the LSN enters the fuel inlet, the more it restricts fuel flow- to match the restricted air flow.

There are many methods people use to set their LSN. For me- I typically clear out the engine by doing a high speed run, bring the truck in and allow it to idle, then watch and see how it responds at idle speeds. If the idle speed drops right away or slowly drops within a few seconds ( or if temperatures start to drop too fast) = the LSN is too rich allowing too much fuel through which is loading up the engine lowering it's RPM. If it starts to climb in RPM ( or if temperatures also start to climb) then it's set too lean. Adjustments should be made at hourly incriments with a high speed run in between each adjustment to clear out the engine. Once I get the engine to idle for at least 20 seconds or so without excessive load up, once again, I'll clear out the engine, bring it in and idle the engine for 5-10 seconds- then hit the throttle to watch how it accellerates. It should accellerate smoothly and powerfully from idle all the way to max RPM's with a nice healthy smoke trail leaving the exhaust. Even finer LSN adjustments can made in even smaller incriments to fine tune this setting. Once your satisfied with your overall performance- you can adjust the idle speed ( if neccesary) by using the Idle stop screw. This basically adjusts how far the carb's slide barrel will close. The LSN will affect the idle speed/quality if it's not set correctly- so it is important you're able to achieve and hold a steady idle at the manufactures suggested setting (usually at around 2mm) before making it's final adjustment. Remember- you're not entering a contest which engine can hold the lowest idle speed so just set it to where it's comfortably below clutch engagement to prevent premature clutch wear.

Note: the ability to hold a prolonged and reliable idle is greatly affected by the heat range of the glow plug.. the hotter the better as far as idle quality. As far as high speed/max RPM running- the heat range of the glow plug will affect overall timing advance in which a hot plug might overadvance the timing causing detonation and/or reduced power output- the key is to experiment with something that will give you the perfect balance for overall bashing- cold plugs for tracks with long straightaways and extended high RPM use, and med/hot plugs in tight tracks where lots of decelerating at closed throttle followed by WOT acceleration is performed.

The Midrange adjustment does NOT control an actual needle- nor can it be set rich or lean (LSN shape and design has more of an impact as to how much more gradual fuel flow is allowed through the fuel inlet at mid throttle). It actually controls at what point of the carb opening, the LSN fully leaves the fuel inlet. Since the HSN should typically be set slightly on the rich side- the point at which the LSN leaves the fuel inlet will create a sudden small rush of fuel. This sudden richness can be beneficial to expert tuners by manipulating at what point it occurs in the throttle opening. To adjust the Midrange point, both the Mid and the LSN need to be rotated TOGETHER in opposite directions. In the picture below, this transition point takes place at 1/2 carb opening. If you want the transition point to happen at a later throttle opening- you'll need to adjust the mid range clockwise (deeper) into the carb body while adjusting the LSN counterclockwise in the same amount of turns. If you fail to adjust the LSN at the same time- you will affect your Low speed setting. The opposite holds true if you want the transition to occur at an earlier throttle opening. The affect of the Midrange adjustment is very minimal and is better off being left at the manufacturers base settings.

Remember- there are other factors involved in maintaining and regulating operating temperatures of your engine- while a excessively lean or rich mixtures will affect your overall operating temps- it is NOT the only factor involved. If your engine is approaching excessively hot temperatures while still spewing out lots of raw fuel/oil out of the exhaust due to an excessively rich fuel mixture, there is likely to be another problem with your engine (air leak, too high or too low compression ratio, wrong glow plug heat range, etc). Engines are set up and shimmed at the factory to work in most/average operating enviroments. If you live in an area that is always excessively hot (95F +), it may be neccesary to ADD an addition shim to reduce the compression of the engine to keep everything in safe operating range. If you live in area that are excessively cold year around...you might even want to consider removing the thinnest shim (.1mm) to INCREASE compression or even consider using higher nitromethane content to keep temperatures up where they need to be.

Good Luck!

below is t2boats own guide to tuning.

hiya, i thought we may aswell keep all the tuning info together so here's the other lot:

it's best to tune an engine when it's warm. so start it and let it run for a few minutes (they don't take long to heat up).

the carb settings are unique for each engine, yes, in more or less the same region (number of turns on the screw) but there might be a little difference. i run a few cars, one in particular i can compare as there's another fella on here who has the same truck but uses different settings on his carb and they're the same engine too. for example his truck doesn't run as rich as mine...

if you're having probs trying to set the engine up revert back to the factory settings which are (or should be) written in the instructions somewhere. the engine will still run on a rich setting! not touching the bottom end (really you shouldn't have to touch this needle) gradually screw in the high speed needle by 1/8th of a turn each time

when u hear the car bog down and possibly cut out, it's running too rich

when the car just cuts out, it's too lean

there are a few other points to remember n all:

outside temperature, if it's hot: use a cold plug, if it's mild: use a cool plug, if it's cold: use a warm plug.

now depending on what fuel u are using will depend on what plug you'll need to put in.

using a high nitro content, like 25% fuel would require a cooler plug in order to keep the running temp down, as it burns very hot..however, u also need to consider the outside temp you're running the car in. it's a compromise

once you've finished setting the high speed needle (as you lean the engine out you'll notice the revs are capable of getting higher, but be careful not to go too high) it's time to do the low speed setting.

if there's 2 needles which are opposite one another on the side of the carb, they are low speed settings and only 1 should be adjusted... it's usually the larger brass screw.

leave the truck to idle for about 10seconds then suddenly blip the throttle to full. if the engine bogs down with a delay then it is running too rich. the transition from low speed to high is not good enough. screw in the low end needle 1/8th of a turn and repeat the blip!

should the engine cut out when you blip it, it's too lean, so unscrew the bottom end 1/8th turn and repeat the process

when the engine is capable of being quickly accelerated without any bogging or cutting out then the bottom end is fine, you can then again fiddle with the high speed screw for a better top speed if you wish

little tip for racing: raise the idle speed to just below where the clutch bites, this reduces the time on the starting grid, just a slight rise in rpm and it's away! good take offs..

pls feel free to add any other bits of info you feel may help others out or any problems youve had and how you have solved them. 



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Replies:
Posted By: ultrapeter
Date Posted: 09 April 2006 at 9:20pm
very good instructions,i have just run my havocs engine in but in still revs very high when sitting ilde.what do you suggest.

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http://imageshack.us"> nice one peter


Posted By: lincsrc
Date Posted: 09 April 2006 at 9:30pm

this may be a stupid question but have you adjusted the idle screw to try and lower it or maybe the trim on your controller is set high



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Posted By: ultrapeter
Date Posted: 09 April 2006 at 9:47pm
trim set low have idle screwn set out.if i set it out more it does not fire up

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http://imageshack.us"> nice one peter


Posted By: lincsrc
Date Posted: 09 April 2006 at 10:04pm

at this time of year nitros are harder to start but if you need the wider idle gap for starting then use the trim on the comtroller to open the throttle a little to get it running and then back it off when it is nice and warm and then you can set your idle right.

dont try and get the idle as low as it will go just get it low enough to not engage the clutch and move the truck with the brakes off.once youve got your idle set right you can start to tune for performance.



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Posted By: newboyaustin
Date Posted: 25 April 2006 at 6:24pm

i got a fusion and when it is idle it spits out a load of fuel, i know coz the ground was wet and now i got a fuel patches on the road, is this normal or does it need tweeking, i've made several adjusts ment but it still seems to spit out quite a bit of petrol,wot should i do



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lets roll


Posted By: markjordan
Date Posted: 30 April 2006 at 11:33am
I have a schumacher havoc and it cuts out at nearly high speed what is the reason for this happening 


Posted By: newboyaustin
Date Posted: 30 April 2006 at 12:58pm
high speed mixtur needs tweeking a bit, u need to unsrew the high speed mixture!! 1/8 of a turn untill its good!!!

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lets roll


Posted By: GBDUO
Date Posted: 30 April 2006 at 7:31pm

Do you have the new exhaust restrictors in your exhaust?  Contact Schumacher as it sounds like you need them!

Graham



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Menace
XTr


Posted By: xtr 3e
Date Posted: 30 April 2006 at 9:15pm

I have got the xtr and i have a small problem the engine was set and some one has fiddled with it at my cousins.I need to know the setting to get it running again it runs but then when i give it full throttle it loses power and starts to splutter and not work then cut out.If i only give it 1/10th of power then it works really well wot is happening. can anyone help me?

 

gary



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r/c madness


Posted By: newboyaustin
Date Posted: 30 April 2006 at 10:25pm
yeah as i said, high speed mixture needs sorting and the low 1 maybe!!!!!!!!!

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lets roll


Posted By: GBDUO
Date Posted: 30 April 2006 at 11:24pm

HSN: 2 1/2 to 2 3/4 from fully screwed in 

LSN: 2-3 mm from flush

Idle: 2mm gap

I could have sworn this was answered in the OP...

Graham



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Menace
XTr


Posted By: lincsrc
Date Posted: 01 May 2006 at 1:21am
your right mate all the info needed to get your engine running sweet and problem solving is up there to read but is a lot to read at once.

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Posted By: MATT 06
Date Posted: 02 May 2006 at 11:28am
WHAT IS THE RIGHT PEAK TO TUNE TO

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MATT


Posted By: GBDUO
Date Posted: 02 May 2006 at 12:51pm

Say what!?

Right peak???

Graham



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Menace
XTr


Posted By: blade954
Date Posted: 21 June 2006 at 1:43pm

Hey guys i just put a picco carb on the TTr .21 with low & high end adjustments, with the option of changing throats in the carby, Its composite and is a direct change over and really helped crispen and liven the TTr .21 up... An easy to tune carb as well..

I was a bit sceptical on the picco due to hearing they are hard to tune and so on but really they are easy to tune, just no as big movments as the ttr carb even 1/2 a mm will make a difference and it holds its tune quiet well...



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Posted By: mrmaggoo
Date Posted: 26 July 2006 at 7:10am

Hi, I'm new to all this.  Does anyone have a picture of a Thunder Tiger .21 with the screws that need adjusting labled.  I tried setting my car (XTR-3e) to standard last night and now it won't start so I have obviously done something wrong,

cheers

 



Posted By: GBDUO
Date Posted: 26 July 2006 at 10:48pm

Hi mate,

These are the best i could find i am afraid!  Most of my pics are with the carbs of for some reason!

http://photo-origin.tickle.com/image/130/7/5/O/130754727O019056455.jpg - http://photo-origin.tickle.com/image/130/7/5/O/130754727O019 056455.jpg

http://photo-origin.tickle.com/image/130/7/5/O/130754785O830793483.jpg - http://photo-origin.tickle.com/image/130/7/5/O/130754785O830 793483.jpg

Sorry about the small size and crapness of the photos!  Basically the screw with the brass surround is the HSN, the one which is huge and perpendicular to the carb slightly below the HSN is the idle and the tiny black screw below the idle is the LSN.

If you scroll up, i have posted the factory settings, do this on each of the needles and it should fire into life.  If it doesn't it is probably something else!  Is your glowheater warm, does your glow plug work, have you primed the engine properly?

Graham



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Menace
XTr


Posted By: mrmaggoo
Date Posted: 27 July 2006 at 7:23am

thanks for that mate.  Made the adjustments last night, but I tihnk it was an air bubble in the fuel line that was stopping it starting.  I squeezed it a few time a it started fine.  Where did you get that filter and the aluminium hop-ups from?  Does it make much difference?

cheers



Posted By: mrmaggoo
Date Posted: 27 July 2006 at 8:40am
Also, in your description of how the screws are set you said that the LSN should be set 2-3mm from flush.  I can't set mine like this as there is a spring there that stops it going this far in??


Posted By: GBDUO
Date Posted: 27 July 2006 at 8:35pm

Yah, the LSN note should actually be the idle screw setting.  Sorry!

The LSN should be like 7 turns i think...although that one is trial and error as i can't remember how many turns it is! lol!

The hops ups i got from Apex Models in Crowthorne, Berks ( http://www.apexmodels.co.uk - www.apexmodels.co.uk ) Apex are the largest supplier of Schumacher bits and bobs and are just awesome, thourghly recommended!

The air filter is just for show (look at me, i have a K&N filter on my RC car! lol!) , but the alloy hop ups add a huge amount of strength to the car, it does not break that much anymore...

Graham



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Menace
XTr


Posted By: mrmaggoo
Date Posted: 28 July 2006 at 9:03am
cheers


Posted By: NilSatis
Date Posted: 21 September 2006 at 10:42pm

Ooooh Look wot I found...hope it helps someone. I thought it was quite well laid out and simple to understand for noobs.

" Rather than tell you to tune your engine to a specific temperature or number of turns out, your best off tuning your engine based on how it is behaving. Even if this is your second engine, most people have an understanding of how the top end needle affects the vehicles performance. Richening (backing the needle out) makes the vehicle travel slower, leaning makes the car faster. Getting the ideal setting and correct balance of top end and bottom end is simple task through a few simple rules of engine tuning.

To begin, we have 2 main needles to adjust, the top end and the bottom end. They adjust each end of the end of the rpm spectrum. The two needles are independent from one another, but they can be mistaken for affecting one another. What is sometimes misunderstood with regard to a top end is the need for the engine to “clear out” of the lower rpm range to get to the top speed. Meaning the bottom end is so rich it needs to overcome the flood of fuel just to get to the maximum rpm. The point here is when adjusting the top end; make sure you have a large enough area to reach the top end.

The bottom end is much more elusive to most tuners. The deception lies with the belief that the bottom will do just what the top end did. Yes, leaning the bottom end does give more power, to a point. You want your vehicle to pull wheelies and flip over backwards from the power. But, much like a real engine, a glow engine has a powerband. The engine can’t overcome an incorrectly setup clutch that is engaging just above idle. (The clutch is whole other article).

Much can be known about the low end mixture just by looking at how far the carburetor is opened for idle. Understanding the relationship between the bottom end needle and the idle stop screw (opening of the carb) is important for adjusting these 2 needles. If you followed our break-in procedure, you found yourself adjusting the idle with the low end needle, not necessarily the so named idle screw. This was to insure a rich idle setting. Assuming the engine idles appropriately, and there is large opening for idle (set at 1.5-2mm 15% opened), the idle/low end mixture is quite rich. If there is a hairline crack of an opening for idle (.2mm 2% opened), and the engine idles appropriately, the mixture would be considered lean. It’s important to understand the relationship between these two needles to know how to adjust these two in tandem. If you richen the low end, anticipate the idle to drop (slower less rpm). Sometimes the drop will be to low for the engine to keep running, so adjust the idle stop screw accordingly (turning it in [more open] to compensate). As you lean the bottom end, anticipate the idle to rise, back out the idle stop screw.

Generally, if you lean the engine down and gain power, all is ok. Which brings me to the golden rule, “when in doubt, richen it”. A common and detrimental mistake is leaning the engine unnecessarily. If you’re not sure of which way to to turn a needle, always make sure to richen it (counter-clockwise). Richening should make the vehicle loose power. If you do not see a loss of power, or question if there is even a loss, richen the engine until you see it. Only then, after going to rich, can one decide where the engine operated ideally. This is true of the top end, and of the bottom end. Top end of course is just that, maximum speed. The bottom end is acceleration. If you lean the bottom and there is a gain in acceleration, so be it. The same is true of the top end. Just check yourself occasionally by richening it.

If you perform the above check, with the top end and the bottom end, there will not be a need for a pyrometer. Temperature devices sample heat differently, some read by means of reflected heat, others are infrared, or even a remote probe. Each method yields different results. The important point about temperature is that it is relative to your device, in your climate and environment. A cold day will result in a cold reading and hot reading on a hot day. Don’t lean your engine down for the sake of temperature, lean it down because it makes your engine go faster. If there’s a gain, go for it, but make sure your right. A few times at a track I’ve heard, “Hey Eric, my engine is slow at 240 degrees, what’s the deal?” “When I lean it down the temperature spikes up to 290 and then it’s a rocket”. What is usually the cause is an extremely lean bottom end and a very rich top end (if it’s not a bearing going bad internally). As soon as the low end needle pulls out of the spray bar, fuel is dumped in the engine and it goes rich. When the top is leaned, the speed comes back. The issue of course is the bottom being too lean; this is where the temperature comes from. Richening the bottom would bring the temperature back down. Again, check your engines setting periodically.

When in doubt, richen it. "

From Werks Racing.  Cheers.



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Involuntary Nitro snorting. Good clean fast fun without breakin' the law.......


Posted By: danniuk
Date Posted: 02 April 2007 at 8:23pm

my mt2 revs too high and moves a lil forward when idling... but when i have the car idling any lower it cuts out, ive tried everything i could think of.

cheers



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Posted By: Winfield
Date Posted: 01 May 2007 at 12:04pm
Originally posted by danniuk danniuk wrote:

my mt2 revs too high and moves a lil forward when idling... but when i have the car idling any lower it cuts out, ive tried everything i could think of.

cheers

If you have tried all the mixture settings and still cant get the revs low enough without cutting out.

It may be the centrifugal clutch enagaging and putting load on the engine.

My clutch got bunged up with dirt and the above happened. The clutch bell shouldn't really move much when you pull the starter cord.

Or if you are electric start spin the clutch bell it should run freely and sound nice not gritty.

Hope this helps

 



Posted By: teddy1981
Date Posted: 27 February 2008 at 12:16pm
Hello all, sorry if this has been asked before, if I remove the carb restrictor from my Rascal, is it going to go NUTS on me? or should I just play it safe and go for the 2-speed gears instead? or both?

Any opinions considered.

Thanks.


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A.C.


Posted By: teddy1981
Date Posted: 03 March 2008 at 2:04pm
No need to worry about the carb restrictor question now.

Once removed, the Rascal went like S**t of the proverbial shovel ....until I lost it in a 6 inch deep puddle and killed it.

Think it needs a little TLC after that.


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A.C.


Posted By: menacemike
Date Posted: 14 May 2008 at 10:58pm
hi i am new to all of this and have got a menace fitted with a venom speed meter on the front drive shaft it is set up correctly but am only getting top speeds of about 50 mph and yes that is f,ing fast.Wher is my other 20ish mph if i screw the hsn in any more it is to lean and dies at top end i think the wheel bearings are a bit worn but any other help would be a help


Posted By: Paul M
Date Posted: 14 June 2008 at 8:39pm

The Menace will only hit those kind of speeds under optimal conditions; your tuning, belt tensioning, mesh, lubrication, even body-shell design (affecting your aerodynamics), everything has to be pretty spot-on usually.  I've had mine in 3rd gear plenty of times, courtesy of the fact that I've had a few monster carparks and the odd runway to let her loose on, but once she gets into 3rd, you'll probably be a long-time waiting to hit the maximum.  I can't honestly say that I think I've ever hit 70mph.  Maybe downhill with a trailing wind...

It may well be your bearings sapping power though; I had not run my Menace for about 4 months and could not persuade her out of 2nd, I thought my tuning was off, or perhaps the fuel was a little bit old, but nothing I did was making much of an effect, but changing all the wheel bearings, diff bearings, and diff balls freed everything up again.  Incidently, now (18 months later) they are all shot to sh** again, and she's back to sulking in 2nd, so now I'm upgrading to ceramics all-round, I'll let you know in a couple of months how much of a difference (if any) it's made.

One thing you didn't mention though is how old or used your Menace is; if it is second-hand, it may be that your engine is worn, or may just not have been run-in properly.  If it is brand-new, it could be that not everything has freed-off yet.  Did you follow the tuning guide?  Also, how much does the speed meter weigh?  If you're putting stuff like that on, it may be the weight that you're adding.



Posted By: Mofi
Date Posted: 12 November 2008 at 11:13pm
Can someone unstick this thread or explain what 'tunning' is please?

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I'm English so only type and reply to messages in my language.


Posted By: La La
Date Posted: 14 November 2008 at 10:16am

i now where y6our coming from mofi this thread had been hear for flipin ages!

UNSTICK it



Posted By: Mofi
Date Posted: 19 November 2008 at 11:24pm

I've no idea what "tunning" is?



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I'm English so only type and reply to messages in my language.


Posted By: La La
Date Posted: 20 November 2008 at 4:24pm
its getting the carb settings right, but i don't see the point in having a stick post about it. its a wasted stuck post


Posted By: topbuzz
Date Posted: 17 January 2009 at 7:13pm
Originally posted by newboyaustin newboyaustin wrote:

high speed mixtur needs tweeking a bit, u need to unsrew the high speed mixture!! 1/8 of a turn untill its good!!!
is this the same on a rascal as mine does the same cuts out at high speed.


Posted By: GBDUO
Date Posted: 29 September 2009 at 12:28pm
How could you say such a thing!

This took hours to compose and I am sure it has helped many people. Carb
tuning is tricky when you are new to the sport, and hopefully by reading this
first it should get new and old guys alike up and running quickly.

I don't think it should be unstuck, it is useful.

Graham

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Menace
XTr


Posted By: GBDUO
Date Posted: 29 September 2009 at 12:29pm
Originally posted by topbuzz topbuzz wrote:


Originally posted by newboyaustin newboyaustin wrote:

high speed mixtur needs tweeking a bit, u need to
unsrew the high speed mixture!! 1/8 of a turn untill its good!!!
is
this the same on a rascal as mine does the same cuts out at high
speed.


You are running lean, unscrew it, only a small amount though.

Mind you looking at the date, you probably worked this out! lol!

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Menace
XTr


Posted By: alkistsamb
Date Posted: 11 October 2009 at 5:37pm
Hello, i have the menace 21 for about 5 years, it operated a few times on the first year, and now after 5 years i thought i would get involved again, my first question is about the fuel.Does it matter to have it 5 years in the box?Anyway i ask that because it was really difficult for me to start the engine again. once i managed to start the engine i noticed that when ever i took of the glow starter the engine shut of institaneously.Why does that happen? If i left it on for a few seconds it works fine but once i take the glow starter off it switches off.Also, i managed to melt the first gear (plastic)without running at high speeds.I was in the process of trying to make the proper tunning.Finally, for the LSN most say it should be 2-3mm from flush. What does that mean?From flush meaning that is should be 2-3mm off? Any help for my questions?

__________________
menace 21 LSN 2-3 mm from Flush

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menace 21


Posted By: Newbie
Date Posted: 13 October 2009 at 10:47pm
What does "tunning" mean?


Posted By: GBDUO
Date Posted: 14 October 2009 at 1:16pm
Tuning.

make more sense?


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Menace
XTr


Posted By: Newbie
Date Posted: 14 October 2009 at 7:23pm
That makes more sense - thanks.


Posted By: Lavaman
Date Posted: 30 November 2009 at 1:08pm
I had quite a serious crash yesterday and i think i've knackered the carb, the engine is out but i'm constantly putting it back in to test new settings.

seems to me like the rubber thing on the throttle is opening it and making it rev very high where it should just tick over nicely. should this happen?

should i only try and tune it with it attached to the throttle servo (i'm thinking that will keep it closed)

i can push the throttle back then it opens again by itself leaving about a 3mm gap.#

can't get my head around it, any and all help very appreciated. cheers


Posted By: GBDUO
Date Posted: 02 December 2009 at 11:53am
No, I can't get my head round it either!

Take the air filter off and look down the carb with the servos on (and TX on) and check the gap first and make sure it is 3mm and then we could go from there. 

Unless the car inverted and landed on the carb, I think it is pretty rare to damage them, they are fairly simple devices with one moving part!


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Menace
XTr


Posted By: Lavaman
Date Posted: 02 December 2009 at 12:32pm
Yea i don't reckon it's the carb after all :) it appears that i have fried the clutch shoes.... well at least they look nothing like the new parts, (all black with white powder residue and very warped) the gears have been shreaded too.
New parts are on the way so i guess by process of elimination i'll figure what's wrong with it.
This is a steep learning curve, but from everything i've got out of it so far i like!

when i get the beast back up and running i'm going to consider selling it on ebay and picking up a spanker.

my reasoning for this, some parts are a little grubby and worn and i'm looking to buy all the upgrade parts... nice new shiny wishbones, hubs,  etc etc won't look good next to rusted / tarnished old turnbuckles and driveshafts.

thanks for all the help so far :)


Posted By: GBDUO
Date Posted: 02 December 2009 at 5:27pm
Just get some wet n dry and you can get rid of the rust, then use hammerite to repaint and treat.  MUCH CHEAPER!!

Yeh clutch normally goes brown due to heat, black is definitely gone. 


-------------
Menace
XTr


Posted By: slippyjim
Date Posted: 15 August 2010 at 9:23pm
Hiya,

I am a bit confused with this tuning....
Ive got a Nitro 21 Extreme thats about 10 years old, I havent used it for at least 5 years....

Managed to get it to start and idle Ok now, but as soon as I accelerate hard it stalls. Ive tried fiddling with the settings but decided its time to get some help!!

According to the schumacher instructions that came with my car
HSN - 1 1/4 turns out
LSN - 0.4mm below flush
idle - 0.5mm slide open

but...
According to the thunder tiger instructions that came with my car
HSN - 2 to 2 1/2 turns out
LSN - no mention
idle - no mention

which are both different to what is mentioned earlier in this post
HSN: 2 1/2 to 2 3/4 from fully screwed in
LSN: 2-3 mm from flush
Idle: 2mm gap

My LSN only goes in about 1 -1.5mm anyway

Any help is much appreciated


Posted By: Anthoop
Date Posted: 18 August 2010 at 11:48pm

Here is a link to Schumachers base settings for the TTr.21-  http://www.racing-cars.com/images/Technical_Info/Schumacher/Old%20Cars/21%20XTR%203E/Instruction%20Manual/xp14.jpg - here

I would start with-

 Idle gap at 0.5mm from open at least, adjusted by removing the air filter and vary the gap between the slide and the carb body using the screw with the spring on it.

 LSN adjusted to 0.4mm from flush, make the head of the screw on the end of the carb flush and then turn screw anti-clockwise untill the head of the screw is 0.4mm from surround.

 HSN adjusted to 2.5 turns from closed, turn the screw with the brass surround in gently untill it stops then anti-clock 2.5 times.

 



-------------
http://video.google.co.uk/videoplay?docid=-1521400473217460978&q=derek+and+clive&total=120&start=10&num=10&so=0&type=search&plindex=4 - D&C


Posted By: slippyjim
Date Posted: 25 August 2010 at 1:34pm
Hiya,

I got my new OS no8 plug today so will be trying that out with the recommended settings.

cheers


Posted By: slippyjim
Date Posted: 11 September 2010 at 3:38pm
I finally got round to trying everything out and eventually got it going OK after replacing the fuel pipe it had come loose and was letting air in.

Thanks for your help


Posted By: sid8
Date Posted: 30 October 2012 at 5:33am
very good insrtuctions. I need to know the setting of my nitro car when i give it full throttle it loses power and starts to splutter and not work then cut out.

Regards
Sid
http://www.nitrotek.co.uk/rc-cars/1-5-petrol-cars.html%20" rel="nofollow - Nitrotek


Posted By: Anthoop
Date Posted: 30 October 2012 at 5:25pm
If there is a lot of smoke/oil coming out of the exhaust then it is too rich (HSN)...



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