Topic: Swap a 550 for a 650

[fdbrat]

Hello all. I have a question. I have a 74 cb550. The engine now needs a full rebuild. Until I get the 550 rebuilt id like to know if I could slap a 1980 cb650 engine into my cb550 frame?

This hopefully will get me by until I can rebuild my 550.

I did see the thread about the 550/650 Hybrid. looks awesome. But for now could I do this as a straight swap?

Thanx in advance. Mr Brat

[Triffecpa]

It is my understanding that you can swap a 650 directly into a 550 frame.  However, only the first year or two of the 650 had similar carbs to the 550.  then they went to CV carbs and the heads were changed, so your 550 carbs will not bolt up.  Also, in my experience, you can't bolt a 550 exhaust system to a 650 head.  The pipe angles are different.

TR

[fdbrat]

Woooo. Awesome. Thank you Triffecpa, this is the info I needed. Yeah I do have a complete 650 bike. Pipes carbs and all.

here is another question. When I took the 650 out, the lower frame bar was removeable. Made it easy enough to remove the engine. Now my 550 frame dosnot have this. Is there any advice on putting the 650 in. I know laying the bike over helps.

Any help is appreciated,

[Triffecpa]

the 550 engines go in from the same right side as the 650.  remove the oil filter housing first.  might want to remove the cam breather on top of the engine as well.  Most of the time you lift the back of the engine to clear the motor mounts (rotate the engine forward) and it will come out the right side without too much problem. 

Tracy