Efe 'thumping'

[Sheep]

Guys,took my bike out of the shed today to start her up to make sure everything is ok before i get my paintwork back soon and ready for the road.

What i have noticed now i have it running on idle nicely is a noise which i described in the title as a thumping noise from what i think is around the main gearbox area.I tried recording it but its not clear enough to post on here.I can compare the noise to a missing cylinder which it isn't before you ask lol.I can feel it through the frame but an old fashioned screwdriver stethoscope to the ear doesn't really enhance a particular area.Pulling the clutch in helps considerably as does raising the revs whether it be through the throttle or by tweaking the tickover.Slowing the revs down really low only increases the noise.

My first thought was wear/play somewhere in the motor or due to bad timing yet it seems to rev pretty freely.The history on the motor is unknown and i have yet to put it through its paces.The previous owner did say he would stand by the good motor but i bought it as a non runner due to carb problems.The motor i standard except for Mikunis,flowed head,complete exhaust,and uprated chain tensioner

This noise has always been there but i,m close to getting it on the road and its playing on my mind.Sorry for my lack of knowledge but this is my first big aircooled Jap in my long list of bikes..shame on me

[Captain Chaos]

Clutch basket has some play in it. Nothing serious, just annoying.

Adjust / balance the carbs and there's a good chance the noise will disappear.

[Sheep]

Really,that woud be cool.I have seen a few vids on hootoobe showing a basket problem.I have bench synched the carbs but yet to really use them.Thanks bud

[johnr]

also, if the petrol in your tank is more than a month old it might have gone off and be making it run lumpy, wear in the clutch basket always sounds worse if the carbs are out of balance, but run fresh fuel through it before you balance them.

[Sheep]

Okey doke....i am using fresh fuel through an auxillery tank as i am still waiting on my tank to come back from the painters but i will get a better idea how the carbs are when i get it on the road....hopefully sooner rather than later.

[johnr]

check that your flywheel isnt loose either, but tbh clutch rattle caused by out of synch carbs is a pretty common gs/gsx issue.

 

[Captain Chaos]

he said pulling the clutch in helps considerably so I'm 99% sure it's a transmission issue.

[johnr]

not sure, rattly clutch is usually just a symptom of out of balance carbs.

 

[Captain Chaos]

I agree John but it's not a loose flywheel as you suggested earlier.

[Sheep]

Well today i have mostly been replacing clutches.....

A big thanks for all your help guys,it turns out the clutch hub was slightly loose and a new APE heavy duty nut and clutch kit has tightened everything up and no more thumping.

It wasn't a bad job either apart from the moment i had just about finished packing the tools away when i remembered i had forgot to knock over the tab washer..D'oh....

[Captain Chaos]

9 hours ago, Sheep said:

 i had just about finished packing the tools away when i remembered i had forgot to knock over the tab washer..D'oh....

[busa ash]

11 hours ago, Sheep said:

Well today i have mostly been replacing clutches.....

A big thanks for all your help guys,it turns out the clutch hub was slightly loose and a new APE heavy duty nut and clutch kit has tightened everything up and no more thumping.

It wasn't a bad job either apart from the moment i had just about finished packing the tools away when i remembered i had forgot to knock over the tab washer..D'oh....

at least you remembered