[quote=Damocles;691303]The geometry's obviously difficult to grasp, but . . . stock wrist-pin-to-piston-top distance is OK for re-ground stroked crankshafts (given shorter rods). /QUOTE]
Yes, itís safe to use a shorter rod if it still remains in the cylinder skirt at its minimum rotation, but the compression would drop as the piston dome would not reach the top of the cylinder. Thatís not quite what I was thinking about.
Stroking by installing a longer connecting rod only?
No. I still plan to relocate the crankshaft pivot pin. I found out last night that EM stared the stock connecting rod is 138mm from center to center. This is from postings on another forum. EMís was a direct measurement vs. a printed 139mm measurement. Iím not 100% sure itís correct, but it does give me some numbers to crunch.
So, depending on how far a custom rod could be relocated on the crankshaft will determine how long a rod I can install. EM used a modified stock rod which is pressed vertically. Iím going to use a custom rod by Crank Works Inc. that would use a more conventional bolt on lower cap. If I can. Got to talk to them. But, I was hoping I could relocate the crank pin 6mm. If that works it would give a 89mm stroke. So, a new rod should be 150mm from center to center to match the new stroke. Could go more in both measurements possibly. I donít know the limits yet as I donít have a crank to measure. So, itís all guess work at this point.
I asked about piston heights because. Want to keep the piston in the cylinder skirt. If the 719 piston is not as tall as the stock piston then it might fit. Generally, a long stroker moves the wrist pin location closer to the piston dome. The ring pack is condensed I think this relocation is more to increase torque - longer rod = longer leverage. Itís not a requirement though to just increase displacement. Basically, what Iím saying is if I can get it to all fit in the cylinder top and bottom it should work.
EMís kit is/was based on the 685cc kit I believe from references. A 102.5mm/103mm bore and 92mm stroke is 759.15/766.57 cc. If these numbers are correct and I could push the rod length to 156mm, pin relocated 9mm, and a stroke of 92mm then it would be a 796.63cc engine. Numbers are great, but real world is something else. I donít have the parts in front of me to measure. Ugh. Kind of drives me crazy just not knowing what would fit.
Maybe you mentioned earlier, ILove2; missed it if you What bike(s) do you ride today? Just curious!
Just the KLR right now. Iíve got room for two motorcycles after I sell the two scooters my wife & I bought for local transportation when we hit the road in our RV, but that didnít quite work out and sheís decided not to ever ride two wheels. So really I only have room for one motorcycle as the other space will go for a Can-Am Spyder - 3 wheels - if sheís ever going to ride with me.
Anyway, one motorcycle to do it all. So, thatís a big part of my motivation to maximize the KLRís potential.
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