Honda xl sideport motor into '79 390 CR frame?

[vmxrider]

I've got a 79 CR 390 with a motor making some funny and expensive clunky noises. A also have a spare XL 250 sideport motor that has a few mods to improve performance. While I save up to fix the CR motor I'm contemplating doing a bit of a Hondavarna hybrid just for a bit of fun. I've seen these motors fitted to the earlier husky frames but not the later ones. Before I start pulling motors out and making a few measurements has anyone seen this done. Being a sideport motor I'd say the carby may come very close or even foul the rear down tube.

[albrid-3]

Do the hybrid thing, you will enjoy it more, and cheaper

[husky61]

I have a 74 model that has the XL-250 side port implant.

Alot of work and frame mod's are required to fit the engine.

The original honda airbox is retained.

Having said that the 79 frame is different to the 74 frame.

It would be a shame to chop a good 390 frame and when you consider the time and affort required for the transplant it would be far more cost effective to repair the 390 engine.

[firko]

My take on building these engine swap bikes is to avoid destroying a complete bike. Using a wrecking yard hulk or someones discarded frame is great but to chop up a complete Husky just because the motor needs a rebuild is a bit sad. If the thought of building a hot rod gives you a woody go find an old piece of crap that's past being restored and fit the Honda to it  and fix the motor in your '79 390. Going by your email you seem to think that you can plonk a Honda engine in there and go racing until you've finished the Husky rebuild and then pull the Honda and just put the Husky motor back where it once lived.
Unfortunately that isn't viable. To fit the Honda you have to make difficult to reverse frame mods so, like Shoey and I have said..........fix the Husky motor.

[Marc.com]

My take on building these engine swap bikes is to avoid destroying a complete bike.

yeah ditto, bitsa bikes should just be a way of finding a use for parts nobody else wants. 390 CR is definitely worth rebuilding, or sell it as a project to a Husky freak and buy another bike....or CR250 frame.

[vmxrider]

Yeah you are right guys, fixing the 390 motor is the best course of action, but i just like the thought of doing something a bit different with the bits I have at hand without excessive outlay, not looking at making a race winner or show pony.
I guess I'm dreaming a bit thinking it would almost be a plug and play sort of thing. Just jump on the CNC, mill up a few engine plates, turn a couple of wheel spacers to fit the XL wheel, get a pipe bent up, a pod filter and away I go.
Talk to me in 2 years time and I'll still most likely be thinking about it. Still, once the Husky motor is out I wont be able to resist just sitting that XL motor in there and having a think.......but if involves using a hacksaw then it will be over before it starts. 

[jimspac]

If you had a Yamaha TT/XT/SR500 engine on hand it would be just a matter of fabbing motor mounts and fitting a rear wheel or such to the Husqvarna swingarm. I have a 78 Husqvarna ML frame that I have loose fitted the engine into the frame with no cutting what so ever and simply have to fab the motor mounts and fit running gear and exhaust

[TT5 Matt]

ask coljay500 he's done a 500 yam conversion

[grouty]

I had the same idea a few years ago ! But stopped short of destroying my beloved 390 for ever. So I went and found a complete bike minus motor and modified that. Mine has a Triumph Daytona 500 twin shoehorned in. Took ages to get the fit right as I did not want to cut the frame.
Rebuilding the 390 motor is easy and not overly expensive. All parts are available from specialists.