Just asking if the 98 buell S3 motor will fit in a similar vintage Sportster chassis. I have a super light weight dirt track chassis with glass work from Mert, built to take a Sportster Iron Head, and a line on an inexpensive crashed '98 S3 thunderbolt. I thought this might be a low buck, fun project and a neat little ride when finished.

I know this has probably been covered in this forum somewhere, but also, I was wondering if the chain drive parts are available to convert the drive side to a chain. Anyway if someone can just give me the benefit of some hard earned knowledge, I'd appreciate it. Thanks! :doh

A friend did.
S3 engine in a 2000 rigid mount XL frame.
I put a complete SE ignition system for 1200 sportster.
The only problem is the speedo.
You don't have a speed sensor for electronic XL speedo on former S3 engine.
He put a cable model one.

there will be some problems with motor fitment. the xl was set up for a four speed which is skinnier than the five speed because the charging system. So ull need to move the side stand mount. the motor wont fit if left alone.

there will be some problems with motor fitment. the xl was set up for a four speed which is skinnier than the five speed because the charging system. So ull need to move the side stand mount. the motor wont fit if left alone.

What??? The four speed stopped being produced in 90, my man. So if he took any five speed motored frame, it will fit. He plainly asked if the S3 motor would fit a same vintage xl frame. So the answer is yes.

[QUOTE=He plainly asked if the S3 motor would fit a same vintage xl frame. [/QUOTE]

well, he also said the chassis was set up for an Iron Head.

go for it. the chain conversion should be easy enough.

You can make anything fit with welding and a grinder..............

It will fit, but you'll have to make a of mods as you go along. i tucked a 2000 x1 motor (with the efi) into my 2000 sporty frame. Ended up cutting off about half of the upper frame motor mount to fit the efi. You won't have to worry about that with a '98. There are a few other issues like the buell block wasn't tapped for a rear sprocket cover like a sporty block is. The front upper motor mount on the sporty motor is a stud coming out (on the left side only). The buell block is threaded for a bolt to go in. Just little differences like this.