January 28, 20224 yr Wheel bearings just knock out from the inside with a drift but you need to dislodge the spacer tube in order to get a contact with the bearing inner race. If the tube is held tight between the bearings then and won't move then yes, it becomes difficult. Once out you can cut a slot into one or both ends of the spacer so that next time you can get at the innder race through the slot with a thin bar. Or, use a blind bearing puller to pull one out, much easier and quicker. then drift the other one out
January 31, 20224 yr Author Another question for the experts...My piston is a MAHL with markings: 85k5-1 and W1, is that the standard size? I think It will clean up with whatever the next size up is.
February 1, 20224 yr 6 hours ago, slowrider said: Another question for the experts...My piston is a MAHL with markings: 85k5-1 and W1, is that the standard size? I think It will clean up with whatever the next size up is. Neither of those are oversize markings so if that's all there is on the crown, then it is likely to be on the standard bore. The safest bet is to have whoever is going to rebore the cylinder measure the bore to advise what the minimum size piston kit is you should get.
February 1, 20224 yr Author I see the aftermarket pistons dont have the holes drilled in the side, do I look for the correct piston or are the holes no big deal? Also my forks do not have the hat shaped sheet metal cap, is that needed or did mine not come with them? Edited February 1, 20224 yr by slowrider
February 1, 20224 yr 1 hour ago, slowrider said: I see the aftermarket pistons dont have the holes drilled in the side, do I look for the correct piston or are the holes no big deal? Also my forks do not have the hat shaped sheet metal cap, is that needed or did mine not come with them? Those hat shaped caps are spacers for adjusting the fork spring preload. Springs come in different lengths and those spacers allow you to set the bike up to have the right suspension sag. If the bike was being ridden without them, you may not need to adjust the preload. If you are fitting new springs you will probably need to adjust the preload.
February 2, 20224 yr Slowrider - Holes in the pistons are one part of the booster ports, the other part being the slots in the cylinder liner. You need these if your engine is to perform as Bultaco intended. First o/size Mahle piston :- www.francetrialclassic.com/en/pistons-and-con-rods/4403-bultaco-350-piston-with-clips-pin-and-rings-diam-8525-mm.html The hat shaped sheet metal caps you refer to are oil baffles/deflectors (Bultaco called them "oil breakers") ; AIUI their purpose was to influence the amount of oil coming out the top of the damper tube. You appear to have non-standard dampers, and I can't see how the caps would fit, but who knows ?. Edited February 2, 20224 yr by lorenzo broken link
February 2, 20224 yr Author 19 hours ago, feetupfun said: Those hat shaped caps are spacers for adjusting the fork spring preload. Springs come in different lengths and those spacers allow you to set the bike up to have the right suspension sag. If the bike was being ridden without them, you may not need to adjust the preload. If you are fitting new springs you will probably need to adjust the preload. Any idea how they work or where they go?
February 2, 20224 yr Author 7 hours ago, lorenzo said: Slowrider - Holes in the pistons are one part of the booster ports, the other part being the slots in the cylinder liner. You need these if your engine is to perform as Bultaco intended. First o/size Mahle piston :- www.francetrialclassic.com/en/pistons-and-con-rods/4403-bultaco-350-piston-with-clips-pin-and-rings-diam-8525-mm.html The hat shaped sheet metal caps you refer to are oil baffles/deflectors (Bultaco called them "oil breakers") ; AIUI their purpose was to influence the amount of oil coming out the top of the damper tube. You appear to have non-standard dampers, and I can't see how the caps would fit, but who knows ?. Many Thanks!
February 2, 20224 yr Sounds as though you have a bike that was at some time owned by a knowledgable rider, hence the mods you have found. When I needed new cases I spoke with In Motion who supplied me with some s/h items that were nigh on perfect. If you have any cracks and get them welded be sure to check internal clearance as weld penetration can interfere with the flywheel and lock the crank when the case is tightened. As the forks from what I can see are not rusty where the sliders travel over and it is the exposed area between the yokes, try cleaning with wire wool or careful use of 600/1200 wet and dry with light oil. Not an ideal fix but that lets you get on with restoration/rebuild. If you use Ethanol free Aspen or similar then you will not need to worry about lining any fuel tank, plastic is better than glass reinforced plastic or fibre glass if you will. The plastic tank will take a few knocks if you use the bike in anger, again talk to In Motion who can advise you accordingly. Keep us updated on your progress.
February 3, 20224 yr 6 hours ago, slowrider said: Any idea how they work or where they go? You need to put a picture of the part you're referring to as from your description it could be a preload spacer or an oil deflector. Preload spacers are alloy and sit on top of the fork spring under the cap. The oil deflector is steel and pushes up into the bottom of the spring and sits over the top of the damper rod. I'd guess it's the deflector you're asking about Your damper rod is certainly different from any other Sherpa rod I've seen
February 3, 20224 yr 6 hours ago, slowrider said: Any idea how they work or where they go? Most people fit preload spacers between the top end of the fork spring and the fork cap. They work by pre-loading the spring so that the neutral position of the forks in their travel is right while you are riding. The more of those preload spacers you put in the forks, the higher the bike rides at the front.
February 3, 20224 yr Slowrider - Oil breaker :- https://www.inmotiontrials.com/product/betor-fork-damper-top-tin-oil-breaker-each-136-02-105/ Works as I explained in my last post. Preload spacer :- https://www.inmotiontrials.com/product/front-fork-spring-pre-load-spacers-10mm/ Works as explained by feetupfun. HTH Edited February 3, 20224 yr by lorenzo
February 3, 20224 yr Author 18 hours ago, woody said: You need to put a picture of the part you're referring to as from your description it could be a preload spacer or an oil deflector. Preload spacers are alloy and sit on top of the fork spring under the cap. The oil deflector is steel and pushes up into the bottom of the spring and sits over the top of the damper rod. I'd guess it's the deflector you're asking about Your damper rod is certainly different from any other Sherpa rod I've seen Was talking about the oil deflector which is missing on mine
February 3, 20224 yr Author 7 hours ago, lorenzo said: Slowrider - Oil breaker :- https://www.inmotiontrials.com/product/betor-fork-damper-top-tin-oil-breaker-each-136-02-105/ Works as I explained in my last post. Preload spacer :- https://www.inmotiontrials.com/product/front-fork-spring-pre-load-spacers-10mm/ Works as explained by feetupfun. HTH Have the spacer, no deflector installed, can I skip the deflector? where does it go if I install it?
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