Hitchcocks Forum

May I request your help please. My Bullet 4 speed gearbox is spiting out grease through the output oil seal. New seal and sealed bearings a few years before, without any leaks, then all of sudden the dreaded drip, after a long run. ( The seal has been removed and found to be in good order, still flexible and no sign of ware). The gearbox temp has been raised along with internal pressure, which I assume is pushing the grease out. Which leads me to the question, through ware should the gear box breath. I am thinking of drilling a hole in the filler bolt, about 0.5mm, to come out in the middle of a flat of the bolt head, facing backwards, to keep the rain etc out.. Any suggestions …. Martin

hi martin ,i would advise you not to drill the filler plug as they are made of bellmetal i have tried to drill these and the drill always breaks halfway through!i cut a fine slot up the thread with a hacksaw then drilled to the slot under the head of the bolt atb paul p.s hows life on the other side of the hill?is the south lancs branch still in existance?i note theyve never penned a centre report in the gun.

I've taken this from pete snidals manual, remove outer cover and follow instructions below.


Gearbox Vent: As shipped, the Bullet has no venting for the gearbox. This is a good time to drill a small hole 13/64" - 2mm into the outside of the Filler Passage - the bump on the outside of the cover just below the filler hole - so that any buildup of foam or gasses will dissipate into the unsealed cavity between the covers. Hole should be about 1/4" - 6mm distance from the underside of the top face of the cover.


regards gwilly.

Here is something I haven't tried but it seems like a good idea. There are gearbox sprocket nuts appearing on ebay etc that at first glance appear to be made the wrong way around, couldn't work it out when I came across the first one but I later worked it out (I think) They have a recess in them and I believe that in that recess you fit an oilseal and that then seals the mainshaft but uses an oilseal rather than the original nut which has a felt washer that nobody ever replaces. Oil/grease travels down between the mainshaft and the mainshaft sleve, making you think it it coming from the gearbox seal because it drips off the sprocket

hi norm i have a 2002 bullet gearbox with the said gearbox nut i think they junked the felt seal around 2000 gwilly has the best venting idea it sounds simular to the 5 speed box venting i noticed the hole when playing with my HELLECTRA atb paul.i may sign write that on the tank sounds very AC/DC inspired while i,m on the subject the members of AC/DC havn,t posted on here since mr h did his secure log in don,t tell me someone used bonn scott as a psuedonym?

Norm, That sounds like the same nut/seal that I've just replaced on my Bullet. Came from Price Parts, a recommended, later upgrade. As you say, doe's away with the felt type seal and a conventional type, rubber, spring loaded seal, push fits into the nut centre. Seems to work a treat. I put some tape over the mainshaft splines to get it over damage free. BT