Calling all Factory Pipe gurus

[gabe_k]

Another 650 vs 701 topic…. Sorry

From what I gather, the manifold and chamber are both smaller. Are the head pipes identical for the 650 and 701?

I have a lead on a 650 setup. I have a wax manifold on the shelf that I can use so essentially all that would be different is the chamber. This will all be bolted to a ported 61x/61x set up.

Any help is appreciated

 

[VXSXH20]

I had a 650 chamber on a stock 701 for awhile, it ran ok and didn’t choke seat of the pants performance down much if at all. I believe the 650 B pipes were approx 47mm diameter At the gasket flange, which were carried over to the later model production manifolds. If I recall that 650 era headpipe had 2 water adjustment screws as opposed to the later style 3 screw that the limited and mods came with.

 

[fastgtfairlane]

Wouldn't hurt to bore the headpipe and manifold to 49-50mm if your engine is ported. Might see a little gain with the 701 chamber but no need to pay top dollar for one. The 2 screw headpipe has a 3rd bleed hole at the bottom that I'd recommend plugging so you can use the top and middle screws to adjust your water injection into the exhaust.

 

[TheBuzzard]

The 650 manifold has square ports that match the 650 cylinders. Same manifold used on the Polaris Octane. The first head pipes only had 2 screws and just engraved factory pipe. Ive heard them called the A pipe but whatever. Same head pipe used for old kawi 650 and it uses the longer bolts like a kawi head pipe, when the b head pipe uses shorter bolts since that flange is thinner. It's been many years since I've had an old headpipe , but supposedly the ports are smaller. Not sure I'd get in there and open it up and weaken that area for insignificant performance gains on some turd.