cornishflyer

I used some silicone sealant in the inner vent holes, waited for it to dry and then held in with a large washer.

Thanks to all of the replies. I ended up sealing the cap off, the fork feels much better now as well, more progressive even.

Thanks Graham, excellent information

HI guys, Quick question. I have a fork cap that's shooting oil everywhere whenever the fork is compressed. Do these look like normal caps? It looks like there is a screw in the middle that has been shaved. I can't really see how these are serviced, can they be and do they look standard? Cheers

I was in the same boat as you chappo, my bike came with some lovely looking falcons, with 80 pound springs.. Too heavy for me on my bike, which really needed 50 pound springs. I couldn't afford to get the falcons rebuilt, it would have been cheaper to get some new shocks, so I went for a pair of the OZO experts last week. They don't have any adjustments but the damping and progression is very nice, I'm happy with them. I found next to nothing on the net about these shocks, once I've taken my bike around a few sections I might write up a quick review. I would offer my falcons up to you for use on yours but I think they will be too heavy.

What a great idea, I hadn't thought of doing it that way. Similarly I have no actual plans to ride at dark, or even dusk. How long do you expect to get out of that 1800.Ah battery?

Hi all, I'm going to register my M158 so I can ride it to local bush land for practice, and hopefully get it ready in time for the Sydney Distinguished Gentleman’s Ride at the end of Sept. I'm in the process of getting the electrical parts together. I wonder if anyone knows, or could measure the diameter of the front headlamp? Would it be around 5"? Cheers

Gosh, it does look lovely like that, almost too good to paint

Mine is M158. I just checked my photo album, my old M159 had one too.

Going along with the theory that there's no such thing as a silly question, what is the bolt behind the seat loop on the Sherpa? Is it to secure some sort of a rear light?

Well I tracked the source of the noise, but I still don't really know what the cause is. The tensioner bush is quite warn but the inner surface is pretty smooth. The rubber wheel is well aligned to the chain and round. The rubber is quite hard but I suppose it they are supposed to be? I don't think it's the additional tension putting pressure on the clutch bearing, all of the bearings in the engine are new, as are the seals. I'm pretty certain I've put the clutch and flywheel on correctly. I'm running 300ml of ATF, but that doesn't dull the noise. Has anyone seen this before? I could run it with the tensioner I guess, or just ignore it.

Welcome Cribbs74, Like you, I started my Bultaco resto project about months ago, and I'm almost at the point when I can start to enjoy the riding (I've enjoyed the building immensely). My initial budget was way off though, I've spent far more than I expected, but I do consider it worth it, to have a go at many of the things I hadn't done before. Lots of great people on this forum. In terms of parts, I think the Sherpa parts are one of the most readily available due I think to the bikes popularity. There isn't anything I haven't been able to source eventually (although original pistons are tricky). In addition to Hughes Bultaco in NY check out http://www.bultacoaustralia.com (who I have got used parts from in the past) I'm sure there are many other shops that are not english speaking, I get a lot of Spanish results in my searches, and there is a pretty good Spanish Facebook page. Cheers,

Ouch, did you have to split the cases?

Thanks scot taco. The bearing is new but I'll certainly keep that in mind. I checked in a couple of positions but agree it's worth checking again. I'm also concerned that the alloy clutch basket teeth might be worn enough to cause this as the chain I removed was really past it's best, with over 20mm play. I'll have a closer look but can't think of any obvious way to check the wear of the teeth, they aren't "sawtoothed" for example.

Just wrapping this topic off (I hope). I installed the new wood-ruff with with Loctite 660 and did it up nice and tight and the engine sounds great now. Funnily enough the piston slap isn't that bad at all, even with 7 thou clearance (this is in my garage which always makes it sounds nosier than outside). Thank you to everyone who offered advice. I also installed a new primary drive chain and there is a (not unpleasant) whirring sound from the RHS flywheel side. You can hear it in the video when the revs come down after I rev it. I'm assuming this it the new chain on the tension wheel as the chain had around 10mm freeplay before I put the tensioner on. Do they usually do that?

Thanks for the link Peter, I'll look into those washers. For the enlarged keyway, I'm going to look at Loctite 660, which from this video looks to be my best shot. However reading the forums the stuff looks difficult to remove, which will probably come back to bite me. Asking someone that has done this before, do think 660 is overkill?

You were spot on Peter, there was noticeable play of the RHS flywheel on the crank shaft. As soon as I put some force on it "that noise" was clear as a bell. Now I have to work out why the bolt came loose, even though it was tight. The key way is quite enlarged from some previous owners mischief but when the engine was recently assembled it was tight and there was no play. One thing I have noticed is that when the seal bobbin is fully inserted there is 4mm of shaft before the shoulder, however there is 6mm recessed into the flywheel. I wonder if the flywheel is supposed to sit hard against that shoulder of the shaft. When the bobbin expands and contracts it might be loosening the bolt. Or do I just need to get another woodruff key and jam a whole load loctite in there?

From memory the piston clearance is 7 thou, baggy for sure but I was expecting some noise. I did think this sounds different though. I did wonder about the primary chain as the bad sound comes and goes riding around at walking pace, sort of like the chain is getting caught up. You can feel a bit of chain slap rolling the throttle on and off as well. I thought the tensioner was stuffed and I took the cover off to have a look but it looked ok, as did the flywheel feel tight. I didn't try to tighten anything while I was in there though. The clutch basket is alloy which I don't think is a standard for the sherpa, perhaps Pursang? Also, it has a flywheel on one side of the chain. I think I read somewhere they came with one each side?

Hi all, Has anyone used, or heard anything about the coated italkit pistons from feked off? Cheers. EDIT: Just saw there is another post here on the same topic, pls ignore.

Thanks experts, looks like I'm at least looking for a new piston. I was hoping to get away with the one I had until I could afford to get a new one but it looks like it's behold that. feetupfun- we checked the crank when we rebuilt it, so I really hope it isn't the big end, but anything is possible. You might remember that this is the engine with the crank from another model (my previous post - twin bearings, stuck seal bobbin) so anything is possible. That was part of the reason for posting this as I've been worried it could be something other than the piston slap. Guess there is only one way to find out. Cheers

Funnily enough the slap goes get a lot better when I rev it, it's worse when it's idling. It's worse when the engine warms up as well.

Hi All, I''ve almost completed the build of my M158, and took it for it's first spin today. We put the engine together fully expecting piston slap as the clearance was well over service limits and sure enough it sounds like it's got a bad case of it. It's going well enough, first time I've ridden a Sherpa 250, very different power to my old 350. It picks up quite nicely at higher revs when you give it the gas, and the engine is turbine smooth. Anyway, I just wanted confirmation on the piston slap diagnosis from the experts on here. Cheers

Hi all, I just wanted to update this thread as I have pretty much finished my tank and side covers. I ended up getting the large Bultaco name and small round Sherpa stickers from Rob at Motoresto. I wish I had got them all from him as I had real issues getting the 2K clear coat to stick to the other vinyl stickers I got as part of a kit, it sort of pooled up and started to run off. I'll probably end up lightly taking some P2000 wet to sand the blobs over those and see if I can make it any better but obviously I want to go easy. So, if any one else reads this in years to come, a big thumbs up from me for Motoresto. Overall the paint is millions times better then before so I'm happy to move onto the seat next Cheers

Sounds lean. The first thing I would do is turn the mixture screw out a couple of turns and see if it solves the problem. If it's more than 2.5 turns out and you don't see any difference check the jets are the right size as copemech said. The check for air leaks. Start by squirting soapy water around the inlet manifold while it's running. There are billions of results on the web about steps after that but as you say it runs well so to me it sounds like idle mixture screw.