trialsbits.co.uk supply a range of lenghts and bends but you have to roll the threads youself. (however they also sell thread rolling equipment if your pockets are deep enough )
on the subject of engine breathing - might as well think of that while I wait for the bearing - I have been toying with the idea mentioned in Ruperts book re:B50 breathing with 2 x 10mm holes drilled from the drive side into the lower crankase. These holes are supposed to be drilled at a height which will act as a weir and hold "engine oil" in the primary case. The primary gear and the engine would therefore share an oil supply. I like the idea of a single oil level to monitor but I have been unable to find out any more details or get sight of a B50 casing to have a look. I think it may provide "too much" breathing for the engine but I would be interested in anyones input. Rgds Nigel
I thought long and hard about that and decided against it for the drive side bearing and removed both to provide continuous oil feed. Could have left the outermost but was concerned about crankcase pressure.
The sleeve gear bearing I did leave the outermost to help the oilseal keep the muck out. When I stripped engine there was 1/4 inch of what could only be described as MUD in the sump well. I have allowed for gearbox pressure by venting the filler cap with a .8mm hole drilled to vent at the side of the bolt and not the top.
I drilled a hole in one of the tappet covers on my B40, it breathes pretty hard through that. Did this several years ago and without tempting fate, reduces oil leakes elsewhere.
I think the 6004 bearing is common in the modern bikes and can take a pounding. Hopefully you can find an off the shelf axle long enough to work as I do believe these are hardened alloys. The Sherco uses a straight shaft for example. The assembly is fairly wide to accomodate the disk and such. One could cut one down if needed and rethread! At a quick measure, the shaft seems just over 9 inches including the threads.
Thanks Copemech, I'm not concerned about the bearings so much as the axle, I have since spoken to a machine shop who also think a 15mm axle would be strong enough, as long as it was quality steel. The 20mm option is more for using an alloy axle, but would require widening the slot on the swinging arm, which may be just moving the problem somewhere else.
I'm in the process of building new wheels and my dilema is axle diameter. The hubs dictate that I can use either a 20mm dia axle or 15mm dia axle, (bearing size 6004 2rs or 6302 2rs). I'm quite happy to run with a 15 mm axle in the front, but not so sure about the back. When the axle is turned up for the rear I won't have a spacer, just increase the dia to approx 23mm x 100mm between the bearings (ie a stepped axle) I would rather go for a 15mm axle, and am looking for re-assurance that it would be strong enough.
Its for a B40 and I am approx 13 stone in weight. (I will have conventional spacer between the bearing in the front.)
Most of these treatments work best when your boots are still damp, stuff them with paper, treatment on, leave and the treatment is drawn through. Job done. ( for this week anyway)
I for one think Lewis should win... END OF STORY.... lalalalalalalalalalalalalalalalalalalalalalalalala .... I not listening to anybody that does not agree with me ... lalalalalalalalalalalalalalalalalalalalalalalalalalalalalalala
You remind me of my brother, when he was three, thirteen, twenty three etc etc
Yes I found the bearing on Simply Bearings Last night. I have spoken with my Machinist mate today, and he said it would probably be better to grind the races, and use phospher bronze for the two washer/spacers. that hold the oil presure in.
I will order a bearing along with the drivside main and gearbox etc , tomorrow.
Another tip I have found out is to use double rubber sealed bearings, and just remove one for the drive side main, keep both in for the rest, and this stops most of the oil leaks. And for the amount of work that a trials bike does,they will be fine with there own lubrication.
Will let you know how we get on mate. Good luck with yours in the mean time.
Regard's Charlie.
If you ever pick out the rubber seal on a new bearing you will be shocked at the tiny amount of grease in there, probably worth adding some.
Jings, he mings.
Bsa B40 Gearing
in General Trials Talk
Posted
Is a B40WD ?