Putting a different motor in a frame?

[nudemetalz]

I've seen several rgv50's with honda 100's in them
and even a lonchin 150

Granted, but it's still a bastard of a job !!

[DEATH_INC.]

As said previously, what are ya putting in what? Most things are possible, it just comes down to how far you're willing to go.....

[Buckets4Me]

aha has anyone put an rg50 in a fxr frame ?????

[Buckets4Me]

Granted, but it's still a bastard of a job !!

thats why I got someone els to do mine lol
but it wasn't hard just needed checking and re welding lol

[SHELRACING]

I've done a few replants, great fun. Before you spend any money measure up, plan it out in your head especially the engine mounts, and exhaust if it's a 2 stroke the exhaust is really important.

As said before alignment of rear wheel sprocket and engine sprocket is probably the most critical consideration.

Tell us what you want to fit into what, someones almost certain to have tried it.

[Rick 52]

I'm doing a ER125 in a CR85 frame and the swinging arm bolt is the same diameter as the engine that makes it very easy to mount but lowering the bike could be tricky, has anyone cut upside down forkes ?

[glice]

Right. I guess I should have mentiond that at first. I'm looking at putting an fxr motor into an rg250 frame, so I'm pretty sure it would fit.
I dont have a welder. has anyone payed to have it done?

[gav]

Is it an early RG250? Good luck, you'll need to cut and modify the frame to fit, the motor doesn't appear to fit without cutting the frame.

[glice]

Is it an early RG250? Good luck, you'll need to cut and modify the frame to fit, the motor doesn't appear to fit without cutting the frame.

Oh ok, its an 85 I think. Havnt got it yet, was just wondering how hard it might be.

[nudemetalz]

One thing you want to look at is being able to strip the top end and barrel with the crankcase still in the frame.
We had to machine some of the cylinder fins off the top end of the Luncheon engine to slide it out the top. Not really ideal !!

[vifferman]

Sometimes you will be lucky and some engines from the same manufacturer will use common crankcases. For an example (stepping outside of buckets here), Honda used the same bottom end for some of their road and trail bikes. I had a XBR500RS Mutant which was a CB250RS with an XL or XR 500 donk. The lower mounts all lined up, but obviously the barrel was much bigger, so the top mount had to be cut off the engine (better than cutting the upper frame tube!) and the gas tank had to be "cut'n'shut". It meant though that there was precious little room around the engine, so the carb was rather squished and had to run a different intake manifold (shorter) and airfilter.

As for lining the sprockets up: while it's the ideal, sometimes it's better to get the engine sitting in the right place and use spacers to line the sprockets up (if they're only a few mm off being in line).

[gav]

Oh ok, its an 85 I think. Havnt got it yet, was just wondering how hard it might be.

The rocker cover of the FXR is rather large for a single and was going to be a struggle to fit. In the end I swapped the RG frame for another frame that was a perfect fit.

[SHELRACING]

Right. I guess I should have mentiond that at first. I'm looking at putting an fxr motor into an rg250 frame, so I'm pretty sure it would fit.
I dont have a welder. has anyone payed to have it done?

Is your RG frame aluminium or steel. Easy to weld brackets and mounts to steel, bit harder if the frame is aluminium.

I fitted a FXR motor into a Yamaha Deltabox frame which worked very nicely. I don't know about anyone else but it takes me quite a while to design, fabricate and fit engine mounts, to pay someone may be rather costly. Got any welder mates who can help ??

[Rick 52]

Right. I guess I should have mentiond that at first. I'm looking at putting an fxr motor into an rg250 frame, so I'm pretty sure it would fit.
I dont have a welder. has anyone payed to have it done?

Is your fxr frame bent ? The fxr isn,t a bad frame just a little heavy how heavy will the new bike be when its finnished .I got my fxr down to 103kg wet and I think I could get it down well under 100kg .

[gav]

The RG250 frame is aluminium, and being a two stroke twin, the upper area is alot more cramped than a deltabox frame designed for a four cylinder four stroke. Also is it the RG250 rolling chassis you are bidding on, on Trade Me? The 16" front wheel isnt ideal either, may struggle to find some decent rubber.