Big engines in little bikes
 

This is Truckinducs fault by the way, when he posted pics of his latest project.
I thought I'd show pics of a couple of bikes that I built.

The first one is an '86 250 Ninja with a 600cc Rotax motor shoehorned in.
Works performance rear shock and EX500 forks with a mix and match of Yamaha and GSXR brake parts.
I built it back in '89, put 20,000 miles on it and sold it about 3-4 years ago to buy my XR650R/SM. (That makes that bike the same age as truckinduc, kinda ironic)

The second one is a work in progress.
It's a 1989 CB400 aka CB1 that has a built CBR600 F3 motor for power. It was started by a friend of mine and I mechanically finished it about 4-5 months ago and put about 3000 miles on it since.
I was supposed to take it apart, once I knew it worked, and powdercoat the frame/swingarm black and paint the tank/fender and cowl in pearl white, too much fun riding it.
Speaking of which, any recommendations for affordable paint and powder coaters in So Cal ?

Kai Ju

The CB1 looks like tons of fun.... it'd have to awfully cold outside for me to want to tear it down for paint.

I''ve always wanted to stuff a KX450F or KX500 motor into a new EX250.

kai ju, you don't post all that often, but when you do you steal the show. Nice work as always.

I've seen an old vintage Mustang with a big modern Harley engine in it. Looked pretty good too.

Love that CB1. Is the engine a direct fit?

Nice work kai ju!

What great work. The Ninja looks like it could have come from the factory. Must be a LOT of fun to ride.
I put a Yamaha 600 single in a Bultaco Astro. Quite a track bike.

i love the cb

How is 60hp going to move a mustang???? :eek:

VERY sweet bikes! I would love that Rotax/Ninja, and the CB looks like a Hawk GT. :)
I just am finishing restoring a nice old XR350 trail bike. But now I'd REALLY like to have that motor in a CR frame. :)

I had a CB1 and i wanted to put a F3 motor into it. All the CB1 guys said it couldn't be done... Liars. I had dreams of a sub-400# 100hp streetfighter. I'd love to hear more about it.

The vintage Mustang refered to, is a small motorcycle (think Cushman)

Thanks guys,

The Rotax powered Ninja was a fun bike to build and a real hoot in the canyons.
But man was it a pain around town, it would sometimes die just as the light turned green and with the kickstarter on the left it was a real pleasure to get going again.
It weighed only 315 lbs with a full tank of fuel, did killer stoppies and wheelies and could hold it's own against much bigger bikes. I do miss it.

The CB1, or CB1.5 as I call it, on the other hand feels just like a typical Japanese bike. Fires right up, doesn't stall or leak and is wicked fast, twisties or straight line.
I had it on a frineds dyno and it showed 94 hp at the rear wheel. There were files for three other F3's which were all in the mid 80's.
A good friend of mine started the project ten years ago but never finished it. He did all the hard work, like getting the engine lined up in the frame and fabricating the front motor mount, machining the rear sprocket carrier to line up the chain run etc.
When I asked him whether he ever finished the bike he said no and asked if I wanted it.
I couldn't say no to that, could I now ?
I finished the rest of the mounts, modified the F3 airbox to fit under the tank, installed a 599 radiator, CBR600RR gauges and a whole bunch of other stuff.
Like the flyscreen that is an upside down helmet faceshield.........

I'm glad you guys like them.
As always questions are welcome.

Kai Ju

There you go, I knew someone would know what I meant.

Like this
http://img138.imageshack.us/img138/3...llion02xr8.jpg

Do it! cant be any harder than what im doing

Brilliant work kai ju!

Chris.

No, but your skill can be a lot better than mine. (guaranteed) ;)

https://www.superhawkforum.com/forum...ad.php?t=16937

chk out Slot's YSR! 600-400 = 200cc / 400 = 50% increase, try 250 - 80 = 170 / 80 = 212% increase

I WIN

Ha ha, how about a Husaberg 470 in a ZB50 frame?

Attachment 30075

Attachment 30076

I'm not trying for anyone to win. As a forum member if you built what is in the pics, that "kicks ass" quite literally.

I was just playing around. I just found that bike, its pretty radical.

I'm currently building a YSR80 which i have now fitted with a 250cc 4 stroke :)

http://i34.tinypic.com/ad2t69.jpg

damn good luck trying to keep the front wheel on the ground on that thing. but it is super cool...:shock:

YSR80 +
 

Hey Slot,

Keep the pics coming, that looks really clean so far.
What's the donor bike for the forks, or is that what YSR80's come with in the UK ?

Kai Ju