Gear Box help needed

[Rangy65]

HELP!! I am trying to build up my gear box. It all seem fine until i tighten the six bolts then the output shaft and clutch shaft lock solid. Slack off the screws the box turns freely. i know there must be something binding but can't see anything obvious. This is my first attempt to re-build one of these and i didn't have a complete gearbox to start with.

Firstly any suggestion to the binding issue?

Secondly is there any lightweight owners who would be willing to meet up and show me how do do these box's correctly.

Third i'll be happy to pay someone to fix this is either of the other two options does not work out.

Exasperated

Steve

[Les Howard]

http://archives.jampot.dk/Technical/Tra ... ebuild.pdf

This might be of some help?....only if you have not already seen it of course

ATB

Les

[Rangy65]

Thanks Les i have got the actual magazine but the pictures in the archive article are much clearer so its a help. I have discovered that i had missed the condition of the bearing under the clutch operating mechanism pt no 012545 its really stiff. So ordered new part & gaskets from the club this PM.

[Ozmadman]

HELP!! I am trying to build up my gear box. It all seem fine until i tighten the six bolts then the output shaft and clutch shaft lock solid. Slack off the screws the box turns freely. i know there must be something binding but can't see anything obvious. This is my first attempt to re-build one of these and i didn't have a complete gearbox to start with.Firstly any suggestion to the binding issue?
Secondly is there any lightweight owners who would be willing to meet up and show me how do do these box's correctly.Third i'll be happy to pay someone to fix this is either of the other two options does not work out.Exasperated
Steve

Have you replaced anything, particularly bushes? are they tight at all? I would have thought that the small mainshaft bearing you mention, as it is knackered, would cause it the be tight even before you tighten the screws up which pulls the casings together. Do both parts lock solid or is it just the output gear on the mainshaft? In neutral the mainshaft should be able to be rotated independently of the output gear and should be free and rotate easily. Do they lock solid or are they just tight to turn? Does it free up if you hold the kick start down as this is indirectly linked to one end of the lay shaft. The top gear on the lay shaft and the output gear on the mainshaft are in constant mesh so if the mainshaft has a slight bend or the lay shaft is a bit tight in the bushes or something is out of line there then the out put gear would be stiff to turn even in neutral. To be honest I had the same problem recently with my rebuilt box, the main shaft turned really easily but the output gear was stiff to turn even in neutral as mentioned above. I took it apart about 5 times, I checked the lay shaft end float as I thought that it was locking up there when I tightened up the screws but that was fine when I just put the lay shaft in the box on it's own as was the mainshaft on it's own as well. A kind member even checked the straightness of the mainshaft on his lathe and confirmed it was fine. All bushes were new and ran freely and I even bought a new output gear large main bearing at great cost and replaced the two bushes in the output gear yet STILL the output gear was very tight to turn once the case was bolted up, all gears are in good condition with no apparent wear and I could honestly find nothing wrong at all and it's not exactly a complicated box is it?. Finally I just accepted that it was just a bit tight, maybe being caused by a bush or casing machining being very slightly out of line once everything was working together(this was a spare box in bits given to me with the bike so I don't know its history or whether it ever was an original box that ran properly in the first place) and that once filled with oil and on the bike it will be ok. The box was fitted to the bike a few days ago and so far when he bike is stationary all gears select fine with the engine running and the back wheel off the ground. In a few days I will get the chance to take it for a spin and hopefully despite being a bit tight at first all will be fine. BTW the box I took out because of a badly leaking gearbox main seal is very loose and easy to turn probably because all the bushes are a bit worn, will find out when I get round to taking that apart...hope some of this helps?
Paul

[Ozmadman]

If you need someone to rebuild your box try here

WORKSHOP 14 - We offer sympathetic repairs to your motorcycle. Frame repairs, welding, brazing, cycle parts, engine and gearbox rebuilds, electrical repairs, blasting and paint service. For good old fashioned service call John Bolton 07802 740672 or Mick Clarke 07910 17978
Paul

[Ozmadman]

The box was fitted to the bike a few days ago and so far when he bike is stationary all gears select fine with the engine running and the back wheel off the ground. In a few days I will get the chance to take it for a spin and hopefully despite being a bit tight at first all will be fine.
Paul

Been out for a spin today, just a nice steady plod around town and the box seems fine, changes ok, no oil leaks and no 3rd gear whine or other horrible noises
hopefully that's it now?? BTW fit a 19 tooth gearbox sprocket, makes a big difference and you don't go looking for that extra gear thinking you are still in third when you are already in top!!!

Paul

[Rangy65]

Hi Paul, got all the bearings,gaskets and seals through today so Saturday its re- rebuild time.

Thanks for the advice let you know how it goes.

Cheers
Steve

[Rangy65]

Still struggling with this.Does anyone know which gear selector fork goes on first i.e nearest to the rear of the gear box. The selectors are distinctive with one being a bronze colour. I cant determine which is which from any of the pictures in the parts book or the mechanics magazine article.

Thanks

[cbranni]

Hi Steve, I'll assemble a gearbox, take some photos and email them to you, can't do it today as there is the little matter of a rugby match to watch

Colin

[Rangy65]

Thanks Colin,appreciate the Rugby match

many thanks again!!