Very cool!!
What you going to do with the old 1250 kit?

 

Please keep us updated.

 

I bet you can fit two of my 883cc pistons in one of the 90cu cylinders ..hahaaa

question... besides the 90cu kit / case boring .. which cams/heads do you recommend for the 90cu kit?... also... is the 90cu kit meant to be a rideable/reliable daily street motorcycle?.. or is it meant just for the track? thanks for the info!!

 

That's a good question ??? Might go under the bench like my oem 1200 jugs & pistons or I might sell them, 40 or 50 cents on the dollar. They are the 10 degree dome pistons too so I don't know it there's much of a demand for that type.

 

My bike see's both, it's been down the track hundred's of times and me and the wife are always going on afternoon rides. Put over 5,000 mile on it in 3 months so nothing going to change when it a 90" soon so will see ??

The pistons are shorter to clear each other and the rods too so you do give up some piston stability and wear but since the torque comes in early in the RPM you don't have to rev the hell out of it so it might just be a good trade off.

I think it will just as reliable as my 1250 kit, the only issue might be tire wear. You might want have a few spare tire's laying around.

I got 536 cams now and will still use them, they only seem to give up about 5hp compared to the 575's from what I've seen on the webb. If I do change cams I'm leaning towards SS 600, with my stage II on old SE heads that should work good. The heads flow around 147 CFM at .600 lift now so I know I'll find more power if I do.

As for heads at least some 1200 heads and XB one's would be the ticket, plus it all depends on the chamber CC's and how much negative CC dome is required for the compression you want. The CP piston's I got have been machine to lower compression with my 64cc heads, Pistons have negative 9.5 CC's and with a .040 head gasket compression is 10-1

No one piston is just a drop in and go situation, whoever you go with you'll need to work out a game plan for your build like, heads, cams, pistons even a good exhaust. If you have stock heads it should still run strong but alittle headwork will really wake it up.

That's my 2 cent's ??

 

RacingJake... thanks much for all the info.. I imagine that if I go the 90cu kit way with cams and heads + case boring I am talking probably around $ 4K I am close? thanks again!

 

Yeah it cost some bucks. Once I paided off the loan it was alot easier to start upgrading.

90" kit $900
1250 kit $700
536 cams $300
headwork $700
ignition $300
42mm Carb $300
bore cases $300
Old 2-1 supertrapp $125

And it's still not as fast as my 82 GS1100 when it was stock. But who care's !! I enjoy the hell out of it. Only another gearhead would understand

You take what you got and make it faster

 

Amen...

 

Sounds like the long way of saying, "Speed costs. How fast do you want to spend?"

I like faster! Just have to figure what I want to do to it, and how much faster I want to spend. I'm thinking I'd like about 110-120 hp that will survive daily use. I'd love some thoughts on that. I could always go with the S&S 100" engine, but damn, I don't want to spend $9,500 on a Sportster engine. Hell, that's more than I spent on my whole bike!

 

I think it's stroked too and you have to keep the revs down.

I've seen the Youtube vid of that guy's 100" sportster and he always hitting the rev-limit plus he had to rebuild it for some reason too. I think the stock stroke and big bore is the best way to go IMO.

I'd like to see it run the 1/8 or 1/4 cause that would be the best way to tell what that 100" motor can do ??