Honda GX270 clutch slipping to much

[Kiwitruck J05]

Does anyone know of a way to get these clutches to hook up quicker? Has new clutch in it but had same prob with old clutch (both factory honda clutches), takes to long to hook up and i get left behind off the start and out of corners, i can make up 6-8 lengths through the fast corners and end up beside the dude that takes off quicker but lacks drive off the slow corners, his clutch is supposedly standard but i dont think so. Any tricks to hooking up quicker? We have put an extra plate in behind to limit the travel needed to clamp but didnt make any difference. Wondering if we get lighter springs for the clutch would that help. The class rules say standard but need to be able to keep up.If i can get more drive off the start and slow corners ill be able to kick his butt lol
Thanks for any help guys

 

[Kiwitruck J05]

After looking through some more i thought i should give some gearing info, sprocket off gearbox is 10 tooth, axle sprocket is either 45 or 50 tooth (have both setup as quick change) and rear tyres are 17 or 19" tall (again for quick gearing change to suit track and conditions).

 

[tazmannusa]

Not that familiar with the gear box . Is the gear box 2:1 ratio ?
The way you describe the situation it sounds like to high gearing for the track size .
lighter springs will help a little but also cause it to kick in sooner .
What kind of kart are you racing that has 17" tires ?

 

[mckutzy]

Can you post some pics of the kart in question?
This will help alot.

 

[justinlogue5_0]

I would like to see it as well.

 

[Young One With A Manco]

Check his profile... He's got an album... Here's a teaser

 

[landuse]

Sounds like you have a 10:1 ratio if you have a 50T axle sprocket.

 

[Kiwitruck J05]

Not sure what ratio the box is its the standard one that came with the GX270 i think 2:1maybe, the truck is an off road race truck, has 13" suspension travel in front and just over 18" travel in the rear, goes pretty much anywhere unless its to steep then depends on how much run up you get lol, best ive had is about 3' off the ground so far. I need to have between 50 and 70 kmh top speed to be competitive. Just had a look at the book and it says its a 2:1 reduction box if that helps, bit mystified as to what gearing i should be using

 

[tazmannusa]

I thought the Jr trucks ran the 20 series TC or is it a class that runs the 270 with gear box that you are running in ? If you are running against others that are running a torque converter they will pretty much blow you away on low end .
With what you have if rules allow heavier weights and springs in the clutch and a little lower gearing would get you better performance. If you can't mod the clutch then a little lower gearing and driver fineness at lower speed IE don't floor it till is rolling and the clutch kicks in . Without knowing the engine mods or top RPM I would say try a 9 tooth driver or a 55 on the axle

 

[Kiwitruck J05]

The class is supposed to be standard engine but they are sorta blown away as the guys that created the class removed the govenor and put the stage1 kit in from NRRacing so really it isnt standard lol
Weve been wondering if there are heavier weights and springs available for the pressure plate, havent been able to find anything in New Zealand yet lol.
Re the comment on not flooring it until its moving might have some value, currently we run on light starts, 1, then 2 then 3 red lights on , when they go out is the start. I have been waiting for the 3rd light to come on then gas and brake foot hard down and when lights go out side step the brake, this is proberbly making the clutch slip so when i get off the brake its already slipping, would i be better of with just light gas application and floor it when the lights go off. We have changed the rear sprocket to a 50th. Its running a 08b1 chain and sprockets and the 10th engine drive was the smallest we could get, we did try a 57th on the rear but its to large and hits on the swing arm and also doesnt have a lot of ground clearance. Looking at the possibilty of changing the chain type to something with more sprocket size range. Ive learnt a lot from you guys, originally i was thinking lighter springs on the the pressure plate to engage quicker but im now thinking heavier to allow more revs on before it engages.
Am going to chat with dad to see how heavu his wallet is feeling lol.
Thanks everyone for your help

 

[tazmannusa]

The class is supposed to be standard engine but they are sorta blown away as the guys that created the class removed the govenor and put the stage1 kit in from NRRacing so really it isnt standard lol
Weve been wondering if there are heavier weights and springs available for the pressure plate, havent been able to find anything in New Zealand yet lol.
Re the comment on not flooring it until its moving might have some value, currently we run on light starts, 1, then 2 then 3 red lights on , when they go out is the start. I have been waiting for the 3rd light to come on then gas and brake foot hard down and when lights go out side step the brake, this is proberbly making the clutch slip so when i get off the brake its already slipping, would i be better of with just light gas application and floor it when the lights go off. We have changed the rear sprocket to a 50th. Its running a 08b1 chain and sprockets and the 10th engine drive was the smallest we could get, we did try a 57th on the rear but its to large and hits on the swing arm and also doesnt have a lot of ground clearance. Looking at the possibilty of changing the chain type to something with more sprocket size range. Ive learnt a lot from you guys, originally i was thinking lighter springs on the the pressure plate to engage quicker but im now thinking heavier to allow more revs on before it engages.
Am going to chat with dad to see how heavu his wallet is feeling lol.
Thanks everyone for your help

That is the way it usually goes with a stock class unless there is a rule book and someone enforcing it .
As far as chain you have the 40 series 1/2" pitch only other options would be a #35 3/8" pitch to get more tooth count but I don't think it would hold up
Interesting that they would do a light start rather than rolling flag start but I guess it is easier on the race officials
The starts power braking is not good with CC clutch, the clutch will get hot instantly and glaze the disk and when that happens it will loose gripping power and slip more, Try no throttle till light turns green punch it giving 1/2 to 3/4 throttle till its moving , you will have to practice till you find the sweet spot of max acceleration with the least clutch slip