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gear clunck
honda69_85 - 2/6/14 at 05:01 PM

i have a stuart taylor fireblade kitcar
big clunck when changing gear and off and on throttle
is this normal first kitcar
i can turn prop 1/4 turn each way when car is in gear

any help thanks jon


mark chandler - 2/6/14 at 05:09 PM

Perfectly normal, with practise you can change quietly.

When changing up, foot off the gas and knock into the next gear without using the clutch, changing down always use the clutch.

You will also find when cruising it will rattle at lot, this is especially bad if the carbs are not well synced and dialled in, you can fit a TRT prop which helps.


adithorp - 2/6/14 at 05:49 PM

Clunking is a common complaint when not used to a BEC... but 1/4 turn of free play in the prop isn't normal. In gear and with the engine off you should have hardly any play in the prop' and in neutral there would be just a few degrees normally.


jwhatley - 2/6/14 at 09:17 PM

Surely the free play wil depend on the number of engagement dogs in the gearbox?

My busa box, with it in gear I can rock the car forwards and backwards about half a meter before it locks up against the engine.

Clunking, vibration and general noise is all common with bike engines.


matt_gsxr - 3/6/14 at 08:49 AM

Doesn't free play in the prop indicate a diff that needs adjustment.

A bit of clunking is normal, but like Adi says 1/4 of a turn is much more than normal at the diff end.


adithorp - 3/6/14 at 09:25 AM

quote:
Originally posted by jwhatley
Surely the free play wil depend on the number of engagement dogs in the gearbox?

My busa box, with it in gear I can rock the car forwards and backwards about half a meter before it locks up against the engine.

Clunking, vibration and general noise is all common with bike engines.


Untill the dogs engage? I was meaning once they (the dogs) have engaged.

OP... How much play is there in the prop' in neutral?


Slimy38 - 3/6/14 at 09:49 AM

quote:
Originally posted by jwhatley
Surely the free play wil depend on the number of engagement dogs in the gearbox?

My busa box, with it in gear I can rock the car forwards and backwards about half a meter before it locks up against the engine.



True, but the box will be moving for that half a metre, it'll be locking up against the cylinder compression which will depend on what gear you're in. You should be able to move it further in sixth than you would in first (for example).

Movement against the diff should be virtually zero.