longstroke crank with a stock cylinder

[pasner]

Could someone advice me about this combo? I will need a base gasket but no idea about thickness. Do I need to rework the head? I will use stock carb but no Idea about the exhaust. Any advice wellcome :fb:

[cezeta]

eden, whats your combo like to ride? is it a rattler or smooth and hows the power delivery. im soon to rebuild the mrs p2 motor and was going to use a harry barlow stage 4 with a 60 stroke........but bigger and shinier always sounds better

she wont rev anything so the power needs to be low.

(sorry to hijack)

[buttontobutton]

I used a 1.5mm packer at the base (crank was a Mazz 60mm, gives the piston 1.5mm further travel up and down the barrel). This was with a stock cylinder, head, carb and exhaust and it gave a very noticable improvement over stock. I opened the transfers in the piston a bit to make sure it all lined up OK at BDC.

I aslo had a Polini upgear kit fitted and it pulled this as well, although only with the stock pipe.

I'm in the process of building up a similar engine now and I'm going for the MEC 60 mm forged crank from SIP (the Mazz ones are poor quality, last one I had destructed my casings) and I will be again packing it 1.5mm at the base.

If I was to go for the upgear option as well now I would pack it at the head to get more torque. Not that I've put on weight or anything...

With different thicknesses of gaskets you can try different combinatons as well and see what works best for you and your style of riding.

I love 60mm cranks and putting one in a standard P2 engine with a packing gasket is a cheap and cheerful way to get more usable power at moderate expense. I often wonder why more people don't cotton on to this and instead go for the old 'Malossi 210 with a carb and pipe' route, only to find that it's not what they were really after at all.

[pasner]

I used a 1.5mm packer at the base (crank was a Mazz 60mm, gives the piston 1.5mm further travel up and down the barrel). This was with a stock cylinder, head, carb and exhaust and it gave a very noticable improvement over stock. I opened the transfers in the piston a bit to make sure it all lined up OK at BDC.

I aslo had a Polini upgear kit fitted and it pulled this as well, although only with the stock pipe.

I'm in the process of building up a similar engine now and I'm going for the MEC 60 mm forged crank from SIP (the Mazz ones are poor quality, last one I had destructed my casings) and I will be again packing it 1.5mm at the base.

If I was to go for the upgear option as well now I would pack it at the head to get more torque. Not that I've put on weight or anything...

With different thicknesses of gaskets you can try different combinatons as well and see what works best for you and your style of riding.

I love 60mm cranks and putting one in a standard P2 engine with a packing gasket is a cheap and cheerful way to get more usable power at moderate expense. I often wonder why more people don't cotton on to this and instead go for the old 'Malossi 210 with a carb and pipe' route, only to find that it's not what they were really after at all.

Thanks for all your input I stock a Mazz long stroke crank so lets see if it can cope with what Im building. I will probably buy a new BGM 200 cylinder wich is 0,7mm shorter than standard Piaggios one, not sure if packing it 1,5mm at the base would be enough will try and see what happens.. I will also try a short four gear that is liying in my shed and a Sip Road exhaust. will see....

[buttontobutton]

I would stick with the stock 4th myself, the set up you've described should pull it no problems. If it doesn't, just switch the packer from the base to the head (order both).

[pasner]

thanks buttontobutton