Charlie

Ok excellent cheers for that, going start looking for an alternative 36mm set of headers now.. Got a b12 sump pan and pick up now also so few more options..

Does anyone know what the optimum header diameter is for these motors 36mm or 38mm?? The custom made system that's on it has 42mm headers which I'm pretty sure is what's causing it to be down on power..

The bikes going to be a hillclimb race bike all round power is key, so 4-2-1 and 36's will be my best bet then..

No, the underside of the slabbie tank is in pretty bad shape and the bike is going to be mainly used as a hillclimb race bike..

Nope clip on's are going, just put them on for ease of moving it around for now.. Will be a cnc top yoke c/w risers and flat bars on it soon.. Subframe will be getting made later down the line along with a small alloy fuel tank, the slabbie tank will be just a cover on a hinge eventually..

Ok cheers for that, did you have to change your sump to over to fit your yoshimura system on your slabbie..

Currently making slow progress with another project, a 85 slabbie frame with a B12 motor and VFR750 swingarm (swingarm conversion originally done by speed fab).. Had the B12 motor refreshed by Nikki Kennedy new rings higher compression ratio dialled in cams. What carbs work best? 38 BST's?.. Also exhaust options what works best 4-2-1 or 4-1, have got some delkevic B12 headers..

Very nicely done like it, the yoshi exhaust is beautiful.

Totally agree, said powerscreen engine is actually in a 1982 Gurls blouse cb750 frame with bandit running gear brakes etc.. Mainly used for hill climbs hence not wanting to lose any low/mid range, does however have a day time MOT so occasionally used on the road..

Ah yes it could well be the headers that are robbing some of the power, the full 4-2-1 system was made by nrp in Newark.. In comparison to some b12 delkevic 4-1 headers I have on a other project, the nrp headers are much bigger diameter maybe to big?

Oh ok interesting.. Currently has a 60mm diameter link pipe and end can on it which I don't think is helping (going to drop down to a 50mm end can & put the bst36's on and set up with a jet kit etc etc see if that helps.

Ok excellent cheers guys thanks for that, will give the 36's ago for now as already have them.. Its currently running a custom 4-2-1 exhaust velocity stacks with fine mesh gauze (due to space, powerscreen engine in the wrong frame ;-) ) stage 3 jet kit bst34's, compression ratio upped to 13:1 with dialled in cams... Currently making 117 rwhp & 75ft/lbs.. Any idea on gains with 36's???

Has anyone fitted b12 bst36's on to a 1127 powerscreen and with what results? Any loses in low/midrange? Any dyno results before and after? Cheers