Well.. I started replacing base gaskets on my 89" 4 5/8 stroker EVO and found a pretty deep gouge in one of the cylinders. The piston actually has a mark on it also. My dillema is that it was already bored .20 over. I know that the EVO cylinders shouldnt be bored more than .040 over, but im not sure this will be enough to get rid of the gouge. Should I just buy new std bore cylinders and new stroker pistons or should I go the extra and have the cases bored now and go 96", 106"? The motor runs strong now with a 585 cam, ported polished heads, etc..So I can get away with just cylinder and piston upgrade...any thoughts?

 

Good way to see this is to bore, just untill it cleans up, then measure, and go to the next appropriate oversize.
A lot of times they look way worse than they really are.
Scott

 

You don't say what year your bike is. I also had an 89" stroker and looked into boring it out further, but all the advice I got was my 1990 crankcases were not suitable. Be warned, the itch got so bad I bought an S&S 107 instead! Follow Scott's advice.

 

sorry forgot to mention the bike is a 97 so the cases shouldnt be a problem. Im just throwing around the possibilities..for me it does not make sense to to go with a different motor, I already have the components to make either a 106 or bigger.4 5/8 stroke by say a 4 inch bore??..for the price of some maching, some pistons and jugs this thing would rip up most purchased after market engines. Im just asking advise..Thanks

 

I here you! Been down the same road. As I recall Sputhe and Axtell do suitable cylinders. JIMS advertised them for a while (I had a JIMS stroker kit in mine), but never produced them. So it is worth checking what is actually available. Theoretically it is possible to install larger diameter liners in stock cylinders, but I'm not sure if anyone actually does that.

Do not under-estimate what you are talking about! I had exactly the same approach about three years ago, but the costs keep mounting when I looked into it in detail. It is all do-able, but I concluded the down-time, plus costs were too expensive. My after-market S&S has ripped up pretty well every Harley it has met yet! Don't under-estimate them either!

Amongst the things to consider are a total rebuild of crankshaft with new bearings, to deal with a significant increase in performance, other new bearings, as well as a thorough top-end overhaul plus gas-flow, etc. That can involve a lot of new parts, plus labour, to make a 106/7 Evo work well.

An alternative to consider is that these days there are shops like HDF sponsor Hillside Cycle who can work a lot of magic on Evos without the expense of bigger bores. Might be worth looking into, even a phone call to them!

 

3 13/16" bore is as large as you can go without a set of raised deck cases.
Reason is, that the scallop on the pistons, to avoid contact at BDC, would be so large, it'd be into the ring lands.
114" is the limit with an OE case,( 5" arm, 3 13/16" hole) and even then, an aftermarket case of 356-T6 aluminum would be strongly advised, as the power of a well built 114" could very well, overcome the strength of an OE Evo case.
Scott