1982 GS550 With Snow Machine Engine

[Guest]

I have someone at work trying to give me a 1980 GS550 that has been sitting and doesn't run. I already have a 1982 gs550 so I really don't want another stock bike.

I have a junk sled at home with a good engine, clutch and carbs. It runs great but the rest of the sled is junk. So I was thinking maybe just put the snow machine engine in the gs550. Run it off the clutch and just have the cvt.

Im not sure if I want to do this or not yet, but I think it will be fun.

BTW the engine I want to put in is a 1991 Ski Doo Formula Plus 521. So its a twin cylinder liquid cooled rotary valve 500cc. puts out about 75HP.

What do you think?

DO it or not.

Curtis

[JEEPRUSTY]

hell yes do it.

[tkent02]

Do it now.

[JEEPRUSTY]

how are you going to transmit power to the rear wheel?

Or are you using the track as well?

[curtie94]

i was planning on running the belt to a pulley and on the other end of the pulley have a sprocket. Im not really sure yet but that is what I have in mind.

So it would have to have a bracket then have a rod through it what spins so the pulley can spin the sprocket, unless there is another easier way.

[BigD_83]

Excellent...a mad hatter project!

I want to see this one happen.

[gsrick]

I have someone at work trying to give me a 1980 GS550 that has been sitting and doesn't run. I already have a 1982 gs550 so I really don't want another stock bike.

I have a junk sled at home with a good engine, clutch and carbs. It runs great but the rest of the sled is junk. So I was thinking maybe just put the snow machine engine in the gs550. Run it off the clutch and just have the cvt.

Im not sure if I want to do this or not yet, but I think it will be fun.

BTW the engine I want to put in is a 1991 Ski Doo Formula Plus 521. So its a twin cylinder liquid cooled rotary valve 500cc. puts out about 75HP.

What do you think?

DO it or not.

Curtis

Sounds cool, why not. You may be able to get some ideas from these snowmobile engine powered bikes.
blob:https%3A//www.youtube.com/af74d70d-f270-43ed-8bec-964ce4a245ff

https://youtu.be/nQiHWtoBYFM

[curtie94]

I've been thinking and I'm stumped on exhaust. I would want expansion chambers, but it doesn't look like I could buy some.

I would have to make my own. Has anyone done this?

[Grimly]

I've been thinking and I'm stumped on exhaust. I would want expansion chambers, but it doesn't look like I could buy some.

I would have to make my own. Has anyone done this?

Plenty of knowledge to be found regarding expansion chambers for the likes of Yamaha RD250 / 350 etc, out there. I've no doubt you could tailor one for your needs, but be prepared for a bit of trial and error.

[curtie94]

So I finally go around to starting the project. I actually found some Yamaha rd400 expansion chambers, i picked up a project rd400 and it came with both stock pipes and aftermarket. So the rd will keep the stock pipes and tje gs will get the chambers. it looks like I have some pipes.

Now its just making everything fit. I'm not sure how the pipes will fit I may need to modify them a bit but at least its a starting point.

I'm actually going to use both clutches from the snow machine. And the jackshaft. Well at least a portion of the jackshaft. I'm going to weld the sprocket to the jackshaft and have the jackshaft run on bearings.

It sounds easy in my head but I guess I'll have to wait and see.

I still need to pull the engines and strip what I need from the sled.

BTW does anyone need any 1991 ski doo formula plus 521 parts. Lol

Any input on the project would be appreciated.

Curtis

[barnbiketom]

The only input I have is:
WE WANT PICTURES

[curtie94]

OK. Will do. Once I start assembling I'll get some pictures.

[curtie94]

IMG_20151017_140659.jpg
I used the jack shaft from the snow machine. We had to cut it down so it fit win the frame. As you can see I machined the end down in order to fit a bearing on the end. I also used bearing stops in front of the bearing. We are going to weld the sprocket to the shaft so hopefully the gearing is good.

[curtie94]

KIMG0081.jpg
In this picture the jack shaft is mounted and the brackets are welded into place. The engine is mocked up with 2x4s so we could see how it is going to fit.

[curtie94]

KIMG0085.jpg
Here you can see the jack shaft is mounted and the chain is on. You can also see why we have to have the engine lifted off the frame otherwise the carbs would hit the jack shaft.