Honda GB400 now GB650

[koba]

ive been through one of those things that say how fast youre going, and at 4000rpm im doing 100km/ph but my speedo reads 90km/ph so wouldn't 170km/ph be around the 7000rpm mark?

www.gearingcommander.com

[ICE180]

Looking at putting one of the Cycleworks pipes on my GB as part of the "tidy up" project (a restoration of sorts but replacing sub-par parts with near-enough identical looking better replacements). I've stripped the carb, giving it a good clean and replacing the float valve which oddly had corrosion on it, it still splutters at low revs so think there's an air leak somewhere I need to sort out first, but you reckon that it'll run ok with the standard jets with one of these pipes like Damon @ Cycleworks reckons? The thing is so economical that I'm not too worried about losing a bit of the economy if it gains an hp or two and/or improves reliability.

the standard Jetting on the GB400 is slightly rich from factory so it should be fine I think i went up 2 jet sizes on the pilot jet but it was too rich it stopped the popping on deceleration but i could see unburnt fuel coming out of the exhaust and the fuel economy was crap round town. that was with the GB400 engine and the open pipe like the one you are looking at

[ICE180]

My 600 runs outta puff after 5k, pulls hard between 3k and 4k. gb400 bottom end xr500 head and xr600 barrel. gb500 carb with manifold for the twin inlets on the xr head. Thinking about changing it to twin carb though......

the CRF Carbs work really well with the GB engines see if you can get 2 small ones of an old CRF

[ICE180]

Well its now been 13 years since the 650 install and the bike is still going great just have had no issues use it mostly in summer for rides of up to 250km as after that I have a vaibration in my hands for a while after longer rides than this

[F5 Dave]

Glad you've had so much use out of it.