83-88mm block

[Nigel]

My first post. Hello all !
I'm currently rebuilding my 850 Le Mans 2. the engine is fully stripped and I'm pondering options as to what to repair and what to upgrade etc.
The barrels and pistons aren't bad but are close to their tolerance limit on spec however it ran fine before, so I 'm toying with the idea of a 950 kit which'll provide new round barrels as well as pistons etc.
I understand there seem to be 2 ways of doing this, to turn down the OD of the barrel sleeve so if fits the standard block - or to open out the block to suit the OD of the standard barrels.
I'd appreciate any comment-suggestions-tech advice etc on this. Do it /Dont do it.
Also regarding cams, My cam is pitted & needs replacing, if I keep to 83mm is there a recommended slightly more exciting cam I could get & if I go the 88mm route - same question.
I plan on probably lightening the flywheel a bit & maybe upgrading carbs. But that's all, I don't want to tune the engine just get it running sweetly.

[jacksonracingcomau]

Good timing I just  saw Phil Joy first time in 25 years, he reground many many cams for me in 80's
He'll still have spec for cam, tell him Martin Harvey sent you. Exactly what you need, not for peak rpm just broad torque curve, discuss with him if you think you want more. Same cam for we always used 83mm , 88mm or 90mm ,
Joy Engineering, in Hatfield Heath Essex.

950 barrels--either way works fine but with empty cases I'd open holes up

Do lighten flywheel or fit alloy one, Phil didn't do mine but possibly would. I had a firm CNC mill them but connection long lost

[Dukedesmo]

I bought 950 barrels/pistons from HMB in Germany, they were a straight fit into the 850 block as he supplies them turned down.

http://hmb-guzzi.de/Cylinder-Kit-88mm-LM-1-LM-2

[Furbo]

I've done it both ways. If you can get the kit turned down and it has good reviews, that's easiest.

For Cams, the B10 was the 'race cam' for 850 engines and stock in the LM 1000's. The P3 was the next bump after that.

These are undercarburated IMHO, a bump to a larger 40' Del would not be bad with the larger bores and more cam.

Lighter flywheel is great, but as your changing a lot of engine mass I STRONGLY...VERY infact, suggest you take the relevant parts to a competent machine shop for balancing. If they do it right, it will be smoother than a stock motor.