Evo rebuild for performance
Club Member
Joined: Jun 2007
Posts: 45,429
Likes: 2,898
From: Bedford UK
You've mentioned a very significant name there! Phone Scott and talk through your project and discuss all the various options. Use CR, any headwork and cam to a proven combination and let the expert do the recommending!
As for your bottom end, I have owned my 1990 bike from new. After a few years and around 40k miles I had the engine rebuilt with a stroker crankshaft by a top engine man (since retired). He told me that the con rod bushings tend to go out of round and that, if necessary, he would hone them and fit oversize rollers. I don't recall the figures he measured, but mine were indeed out of round, so don't be surprised if someone like Scott recommends stripping and rebuilding your crankshaft. That engine was just remarkably smooth as, I'm pleased to report, is my S&S 107", the stoker's successor!
As for your bottom end, I have owned my 1990 bike from new. After a few years and around 40k miles I had the engine rebuilt with a stroker crankshaft by a top engine man (since retired). He told me that the con rod bushings tend to go out of round and that, if necessary, he would hone them and fit oversize rollers. I don't recall the figures he measured, but mine were indeed out of round, so don't be surprised if someone like Scott recommends stripping and rebuilding your crankshaft. That engine was just remarkably smooth as, I'm pleased to report, is my S&S 107", the stoker's successor!
Last edited by grbrown; Jul 20, 2014 at 10:02 AM.
Road Master
Joined: Feb 2014
Posts: 913
Likes: 5
From: indiana
it depends on the cam and the base circle. the only cam I was referring to was the W-9 witch is only a .580 lift and the rollers hit the blocks on my stock blocks
Road Master
Joined: Oct 2011
Posts: 957
Likes: 2
From: Carlsbad Springs Ontario
Bottom end.
You've mentioned a very significant name there! Phone Scott and talk through your project and discuss all the various options. Use CR, any headwork and cam to a proven combination and let the expert do the recommending!
As for your bottom end, I have owned my 1990 bike from new. After a few years and around 40k miles I had the engine rebuilt with a stroker crankshaft by a top engine man (since retired). He told me that the con rod bushings tend to go out of round and that, if necessary, he would hone them and fit oversize rollers. I don't recall the figures he measured, but mine were indeed out of round, so don't be surprised if someone like Scott recommends stripping and rebuilding your crankshaft. That engine was just remarkably smooth as, I'm pleased to report, is my S&S 107", the stoker's successor!
As for your bottom end, I have owned my 1990 bike from new. After a few years and around 40k miles I had the engine rebuilt with a stroker crankshaft by a top engine man (since retired). He told me that the con rod bushings tend to go out of round and that, if necessary, he would hone them and fit oversize rollers. I don't recall the figures he measured, but mine were indeed out of round, so don't be surprised if someone like Scott recommends stripping and rebuilding your crankshaft. That engine was just remarkably smooth as, I'm pleased to report, is my S&S 107", the stoker's successor!
He advised that the cases be split and a thorough check out of the bottom end would be a smart thing to do considering the age , model and miles etc. and i agreed. The result was ... the con rod work described by grbrown , replaced crank pin due to normal wear and also this little surprise ., the left side case crank bearing was beginning to move in the case boss and i was advised that this is not uncommon for this year and model etc. The fix was a sublet to a machine shop and an extra $500.00 .
Road Captain
Joined: Aug 2009
Posts: 691
Likes: 4
From: H-TOWN TEXAS
As Machine said. The cost for rod bearings, balance, parts, and labor is minimal cost vs. tearing it down sooner then needed because the extra stress from the higher comp ratio beat the old rod bearings to *****.
Just went through the same issue on my brothers bike. 15k miles on a 89" evo tore down to replace the infamous 89 model cracked cases. Long story short rod bearing had a cracked cage and needed a new crank pin.
Just went through the same issue on my brothers bike. 15k miles on a 89" evo tore down to replace the infamous 89 model cracked cases. Long story short rod bearing had a cracked cage and needed a new crank pin.
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