I will mention it to John but I'm sure he already checked that.jensey wrote:If the piston pin pushes against one side check your conrod for being straight. In 4 out of 5 times this the case. Tapered bearing can cause this, but very unlikely.
Japan Meets Britain
John's been testing the bike and most everything looks great. New rings seated just fine, compression is at 185 and 190 respectively, and it's pretty much ready to go. Pretty much except for one thing.....the clutch!
The clutch has been slipping, and it seems to be getting worse and worse. We thought it might have been that newly-formulated Rotella T4 (and it's been reported that the new formula does not play nice with our clutches), so he cleaned everything out and switched to Castrol 4T Motorcycle Oil. Interesting with this oil (10w40) is that it's almost clear, but after only a couple hundred miles it's almost black. Plus he's seeing very fine aluminum particles in the oil (not sure if that Castrol oil has superior detergent qualities or if something else is going on). John checked the plates and the springs and they seem fine, but we're wondering if it's possible for that Rotella to have impregnated itself into the plates. He cleaned out the engine, and cleaned the plates twice. No difference. Another thing he was also wondering about was if the clutch basket itself could wear -- if you grab hold of the sprocket that's mounted behind the clutch basket, and if you keep that sprocket from moving, and if he grabs the outer basket he's able to rotate the outer basket somewhat (like from 11:00 to 1:00). Could this be the source of the slippage or is this normal? I'm willing to replace the plates and springs (the plates are Barnett and springs are CB750) as I think Tim McDowell has Barnett plates and springs for $67 and about $14 respectively, but we're concerned that replacing those parts might not fix the slippage problem if the basket itself could be the culprit. Any ideas??? I think these Barnett clutch plates/ CB750 springs have about 20,000 miles on them, and the basket is original. Oh Jensen BTW I asked John about the connecting rods and he's 100% sure that is not the issue -- he's pretty convinced the bores are a little offset, and that is why the wrist pins were doing what they were doing. They were both going to the left, so he thought it would be rather unusual for both rods to be bent and going in the same direction. Same with the bearings.
Oh what a difference a clutch makes! I finally -- finally! -- picked up the bike today from its many 'adjustments', and I do believe it's about the strongest that it's ever been. The new clutch is a revelation -- it just goes bang bang bang from one gear to the next. Strong, precise and rock-solid.
John was following me in his car on the way back to my place from his, and he said that once he reached 90mph and saw me pulling away, he backed off. So this bike is raring to go go go. I am hoping that this will do it for a good while -- I'm going to take the bike for a nice long ride this weekend. It definitely deserves it. Here's one more thing to lose sleep over:
If you take your cylinder to a typical automotive machine shop for boring, they're going to register their boring tool off the existing bore. If the cylinder bore is not perpendicular to the cylinder base, the new bore will be crooked also. A machine shop that understands motorcycles will mount the cylinder on its base-gasket surface for boring. Bore Tech in Ohio is one place that does this. Do what you've always done and you'll get what you've always had.
Good point. I was corresponding with Bill Silver last night, and he said it sounded like they didn't machine the clip grooves deep enough. So honestly I don't know that we'll ever find out what was causing the issue, since there seem to be multiple possibilities flying about. He said that wrist pin holes in the Honda cranks was an issue, but he didn't think that would be the cause. I asked Bill about the teflon buttons as well, and he didn't recall any real issues with them when they were used. So really time will tell. One thing that I did discover yesterday morning was my right carb weeping gas -- turns out it was the plastic drain plug at the bottom of the bowl. At some point Amal switched from brass drain plugs with a fiber washer to a plastic plug with a plastic washer (maybe a cost-cutting measure?). Anyhow, I found out that the right drain plug had a crack in the threads, so I found a set of brass drain plugs online. For the moment I'm using a temporary replacement that John gave me. Yeah, the plastic drain plugs for the Amals are junk. If you have them, no tighter than finger tight and use Yamabond.
In 'Tuning for Speed' by Phil Irving (the designer of the Vincent engine), he explains many engine building techniques, such as how to determine if the piston is running true in the bore, how to prepare pistons, balance cranks, etc. He also suggested to Triumph way back when that they use a 270° crank instead of the 360. They finally got around to it with the Hinkley bikes! Well worth reading. Do what you've always done and you'll get what you've always had.
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