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About cornishflyer

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    Sherco 250

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  1. Yeah I tried that but he insists that 500mm springs are what I need in this bike, even though it was solid as a rock All good now though, I shortened the new springs to 475mm and it feels a lot better. I will wait till I get the engine in and then set the sag properly, possibly by taking a little more off. Thanks everyone for your help.
  2. Hi OTF, yes I have, they run lovely and smooth with just the old spring in there, no binding at all. I've got some video I'll try to post so you can see what I mean. No probs about the eggs by the way, I'm all about the most obvious that I've probably missed.
  3. Oh and the selling that was in the bike was 150mm long, 59 coils, 3.7mm wire thickness. Different again. 🤨
  4. I'm 82kg, what's that? Around 12 stone? The engine is out but I've factored that in (I reckon that's another 25kg tops) still it's WAY too stiff. I can barely compress it by jumping all my weight on the bars. I think I'll just shorten the springs to around 475 and adjust from there, like the idea of the grinder, I hadn't thought of that. The seller has assured me he's sold thousands of 500mm springs with no issues so I don't know what the difference is in my bike. Perhaps Aussie bikes where shorter, less gravity down here, I dunno.
  5. Hi all, I have purchased some new fork springs for my #158 Sherpa T 250 which are just over 500mm long and are so stiff when I install them that I can hardly compress the front end. My bike only came with one spring so I can't compare compression but the one old spring I have is about 450mm (50mm shorter) and comes up to the top of the tube when I remove the top cap. These new ones stick right out and it's a real struggle to the get the top caps on. The reseller tells me these springs are correct for this bike and something else must be wrong with the fork. So, I took the fork apart and it all look ok, perhaps I have incorrect length damper rods. The top tubes are 550mm and the damping rod assembly is 100mm My old Sherpa had very plush forks, and I tried another over the weekend that was also plush. This thing is rock hard with these springs in. Any help appreciated, especially the length of the springs I need. Thanks
  6. I've just heard that around the time that this model came out the con rod was centered from the piston end using the small end spacers (which my bike has). Perhaps this isn't an issue at all (embarrassed).
  7. No, not stepped, just that the rod will then stick out both ends of the cranks webs.
  8. Quick update. I received my thrust washers today., they are each 0.5mm thick which is thinner than I was expecting because it's not going to solve this particilar issue. My conrod is 17mm wide, and there is 20mm between the crank webs so even after installing the thrust washers there is going to be 2mm axial play. This goes against what I have read on this forum and in the couple of general Bultaco books I have access to, all saying there should be around 0.25mm clearance. I can't see what is wrong at the moment. The big end pin won't allow the crank webs to close that side play down even more. Unfortunately I don't have anything else to measure up against. Could it be that the #158 sherpa did in fact have a lot more side play? Or perhaps that someone has installed the wrong size big end pin? Scratching head...
  9. Quick update. I measured the play in the conrod and sideplay at the top is only 1mm. When pulling on the gudgeon pin I can't feel any play at all so I'm thinking the conrod might be quite new and is OK. What I would like to do is get some of the crank pin washers and just get the crank rebuilt. I'm not sure if I can get those without the conrod, or what the measurements/material is? I also can see on the exploded diagram that there is supposed to be a washer that goes on the end of the kick starter shaft (that fits into the RHS engine case. Mine is missing. Any ideas what that washer thickness is? Cheers, Dylan
  10. Thanks. I keen on saving some money, a lot more since I've opened the cases and discovered what else needs to be done. Obviously not as keen as the skinflint that serviced the engine before me though. I can't "feel" and up and down play in the big bearing when I pull on the conrod but I can see corrosion in the small bearing area so should just replace the whole thing to be safe.
  11. Thanks bullylover, that might explain the slop. I thought the crank might have spread but when the pin is protrudes out of both sides. I can't see any markings on the conrod itself to say it's the correct part, but the pictures I can see on the net do look similar. Out of interest, why replace the whole conrod and not just the bearings? Surely the bearing would wear faster than the conrod?
  12. Took the crank out and used LOTS of heat on the seal sleeve and still can't get the thing off. I need to send this one for a crank rebuild anyway so hopefully they can get it off for me. Who knows what has happened here, but I don't think much of the previous owners rebuild work, the cases were sealed with bathroom silicon.
  13. Thanks feetupfun, once I split the cases I'll know, but I also fear that the crank webs have been pushed apart somehow. Either way I'm going to be needing new bearings, seals and con-rod kit at the very least. Once I get this seal sleeve off I'll report back.... cheers.
  14. Hi all, I'm just starting to tear into the engine I got with my #158 Sherpa basket case project. There has obviously been a pretty catastrophic failure at one point, the magneto side is full of corrosion, I guess it was full of water for a long time. The cases where completely void of any oil. The crank didn't turn. When I removed the clutch side cover I found that the nut holding the flywheel on was completely undone and floating around, there was no lock wire on that nut, nor the clutch nuts. The area around the woodruff key on the crank is a bit mangled, but I should be able to clean that up. 1) I have two questions. The primary side seal interfaces with what looks like a flanged collar that slides onto the crank. How does that come off? Is a small flywheel puller enough or do I need to use some heat? 2) What is the side play supposed to be on the con rod in the crank webs? Mine seems to be around 5mm which seems crazy big. Cheers
  15. Hi all, I've just taken delivery of a Sherpa T 250 (serial 158) which is about 80%. I want to treat as a slow project to perhaps do the odd twin shock comp, don't want to go mad polishing and that, want to ride it properly. First thing I need to look at is the bottom of the frame, and the clearance to the engine. the frame is in pretty good condition but the bottom rails are a bit squashed, I would imagine there should be more clearance to the engine that this shouldn't there? It feels like the engine is sitting on the rails at the moment. Cheers