R100gs Transmission 'jump'.

[jeeperz0]

Hi Everyone. I have a problem with my 91 paralever. Grateful for any help, I know a bit but not a lot about mechanics.
When given some throttle in 1st the transmission jumps like a bike with a knackered chain jumping a tooth., its not a clutch slip, but a more definite jerk and then carries on ok. Seems to be happening more often. Would like to carry on using it til the weather goes and then strip down over the winter as I'm planning to go to the Isle of Man in in June so was gong to give it a good check over, (I'm in SE uk).
Is it likely to be self fixable for a novice? I know its diff to diagnose from a ditance but any help would be gratefully recieved !!

 

[Rob Farmer]

It could be the shock absorber on the input shaft. There was an issue with the "ears" wearing or breaking off. Do you get flakes of metal in the gearbox oil? have you been using GL5 spec oil? It could simply be the spring loosing it's tension though so don't panic yet, unfortunatly the only way you will find out whats wrong is to have the gearbox apart.

It's not self fixable I'm afraid unless you have the tools for the job.

obviously this is an extreme example but it's this part :-

I took that photograph from Anton Largiadiers excellent site. Lots more info on it - http://www.largiader.com/

 

[jeeperz0]

Thanks Rob, I will have the oil out tonight if I have time and have a look. But you think its going to be a box out job anyway?

 

[Rob Farmer]

Thanks Rob, I will have the oil out tonight if I have time and have a look. But you think its going to be a box out job anyway?

I do. It's not a difficult job but if your new to spannering on airheads or haven't got a lot of experience I'd have somebody look at it. If you could get it to London Steptoes probably the best bet.

 

[Rob Farmer]

jeeperz0,

I should of asked this initially. Is it when you let the clutch out or has the clutch been let out when the bike snatches? It may simply be the clutch release bearing sticking in the tunnel if it happens while letting the clutch out.

 

[jeeperz0]

Jumping

Hi, never got a chance to let the oil out last night, the joy of being self employed!!

The jump happens when the clutch is fully engaged, ie in first gear giving some throttle uphill when revs get higher after about 25 yards.

Appreciate your help, thank you.
Jimmy

 

[jeeperz0]

Oil out

Well I dropped the oil out today. It did not look too bad. I bought the bike from fleabay about a year ago, have not done a lot of miles on it since and the PO provided loads of history old Mots etc. He said he had just serviced it himself and looked like it, oil and filters looked new then, no idea if GL5 was used or not tho.
Oil that came out looked good, about 12 pieces of metal about the size of a grain of sugar came out, nothing else. So think I might have to take out box and look. Have done a bit over the years but not much on bikes or boxers. Did take the engine out of my MT500 tho!!!

 

[jeeperz0]

looks like the problem is found.

Well it looks like the problem is solved, if not sorted.
Took out the gearbox and took it to Brian Giles in Pembury, he had the box apart in 15 mins. Looked at the dogs on first and second gears and said he had never seen such s------ dogs. The bearings were good but the rest had had it.
So its off to James S to see if there is a secondhand one about.