Hi Again

[Suzuki_Don]

Check this link, the power comes from the head change more than the extra capacity. Tell your friend to use the 650 head.

http://i226.photobucket.com/albums/dd105/donclifton/GS650TechnicalP15.jpg

He would also have to get around the fact that the two motors have different sealing setups between the cylinders and head.

The links i have are not much use to you as they are bike specific. For instance my cam timing numbers will be of no interest to you. You will have do do your own cam degreeing and each setup is unique. I will pass stuff on as needed if you run into trouble with the conversion.

Cheers

[mlinder]

Ah, thanks for the heads up on differences between head and jug mating on the 550 and 650.

Yes, I was pretty excited by the head design on the 650. Really very, very nice. Big flat-floored straight intakes with giant pockets behind the valves, and very little valve-tunnel material in the intake.

Also interested in the combustion chamber design, with the compression focusing shape.

Did you time your cams differently than stock 650?

Sorry for asking, but wading through lots of different threads on your build is difficult to find stuff sometimes.

[Suzuki_Don]

Ah,
Sorry for asking, but wading through lots of different threads on your build is difficult to find stuff sometimes.

Yeh I should have been more organised.

[mlinder]

Yeh I should have been more organised.

From reading more of your posts, I surmise that you are using the cams from your '77 550.

A bit of a hotter cam, I suppose?

I have cams from my 78. Should I use those?

[Suzuki_Don]

From reading more of your posts, I surmise that you are using the cams from your '77 550.

A bit of a hotter cam, I suppose?

I have cams from my 78. Should I use those?

Have you read this thread on 550 vs 650 camshafts. The 550 has an extra 8 degrees duration, but .500mm less lift.

I went with the 650 cams. If you use the 650 cams don't forget to change the sprockets to suit the 550 crank.

[mlinder]

Have you read this thread on 550 vs 650 camshafts. The 550 has an extra 8 degrees duration, but .500mm less lift.

I went with the 650 cams. If you use the 650 cams don't forget to change the sprockets to suit the 550 crank.

Nope, I haven't read it, I don't think. I read something on that though, where 550 and 650 cam had same lift, but different duration :/

[Suzuki_Don]

Nope, I haven't read it, I don't think. I read something on that though, where 550 and 650 cam had same lift, but different duration :/

Sorry fogot to put the link in:

http://www.thegsresources.com/_forum/showthread.php?t=154785&highlight=camshaft

[mlinder]

Sorry fogot to put the link in:

http://www.thegsresources.com/_forum...light=camshaft

Ah, yes, I read that, but it conflicted with a statement you made in another thread, which was that they had the same lift.

I also read that the early 550's and the later 550's were different.

I haven't completely made up my mind on what characteristics I want this engine to have. I have all three cam sets, so....

[mlinder]

That said, it appears I'm going to go with the 650 intake cam, and the 550 exhaust cam, with just a bit of cam-timing adjustment.

Will keep ya'all updated.