S&S 3 5/8" EVO piston?

[oneuptom]

That should be fun. I snagged a good running but cosmetically nasty 89" conversion and it's torquey fun to ride. This thread is useful in case I need to go inside it.

Is your 89" a 5spd?

There's a few extra challenges in building up a 4spd but I feel up to it and plan to do it right. Hopefully it can turn out something I'm proud of. Good learning experience either way.

[JBinNC]

S&S cylinder spigot 0.175" longer

[ATTACH=CONFIG]109476[/ATTACH]

Cylinder spigots are longer, because on the stroker motors for which the cylinders are made, the pistons go down further, as well as up further. (Something that some will overlook when planning a stroker motor.)

Jim

[oneuptom]

Something to help with the big combustion hits and high rpm crank harmonics. Also sightly raises gearing by way of one additional tooth

[farmall]

Is your 89" a 5spd?

Yes. No four speed Evos for me because I dislike the "clutchernator" and trap door issues (xlforum goes into ample detail on trap door/bearings/fixes). I'll take four-speed frames since the sidestand mount is easy to slice off then replace with something cleaner (or even save the removed mount).

BTW S&S axed a lot of old material they should have left on their website (it's not as if it would hurt the hosting bill). When you touch base with them best to ask for someone technically clueful because their drone was useless when I emailed them. Granted, it's hard to find people who know their products who would work for secretarial money so I understand but it's unfortunate given their long history. Dunno if things are better this year.

The frame mods for the extra cylinder height are pretty basic downtube stretching and while you're in there anyway would be a good time to alter the rake if you wish.

[flatman]

maybe its just the pics, or maybe me, but that cylinder on the right looks shorter from the basegasket surface to the top of the cylinder head gasket surface.

[oneuptom]

maybe its just the pics, or maybe me, but that cylinder on the right looks shorter from the basegasket surface to the top of the cylinder head gasket surface.

Ha, good eye!.. It's sitting up and cockeyed because a single alignment dowel still attached. They are the same length.

[oneuptom]

The frame mods for the extra cylinder height are pretty basic downtube stretching and while you're in there anyway would be a good time to alter the rake if you wish.

Me and this 4spd Evo go way back so lots of sentimental value attached to it.

I'm piecing together a Irionhead style frame from OEM forgings for it. (anybody doing this, the first thing you need to do is move the swingarm pivot point if you don't want to go nuts) The cylinders have been shortened to stock length so as to use the stock stroke and rods. I could use the stock frame untouched if I wanted.

Almost everything everywhere is pretty much like McDonalds these days so I never expect too much from a phone person. On the other hand, individuals are still mostly reliable I think. Like the good folk here and over at XLFORUM & Sportsterpedia. Blows my mind how creative, borderline genius some of them are, especially related to the 86-90 4spd fixes they've come up with. Between the vast amount of knowledge available on the internet and my own efforts I feel pretty confident I won't be overlooking very much.