I've been messing with my suzuki rg for a little while now. I got a decent expansion chamber and had mild port work done on the barrel; standard jet 180, chucked a 230 in; mega rich, put a 200 in, nice at top end, bottom end struggling; dropped needle 2 notches. Runs quite nice, pretty good on pull away, nice top end. Power band starts at 7000 rpm and goes to 11000 and does it cleanly. However, mid-high throttle at about 5000-6000 rpm, it splutters; main jet still too big or drop needle again?
mid range would be needle was the engine warm ? my nsr bogs at about that rev range if it hasnt been warmed up properley also the powervalve timing might need to adjusted too open later
yup.. probably the valve setting or the needle profile just wont allow for correct ajustment.. they make hundreads of needles for a reason
it's only on the middle of the needle at the moment; worth raising the clip even more? Powervalve is blanked off for top end power with a piece of tube so that's non adjustable
check the plug colour first if its lean drop it , if its reach raise it depends how mild the port work was then just keep playing with the main jet till the plugs a nice shit brown colour do you mean youve bodged it to have the valve constantly open lol ?
no not at all, gammas didnt come with powervalves as standard; they're £200 from suzuki. I would never spend that when that's nearly as much as the bike cost, so a cheap and easy way is to put a tube in as it gives good top end power or leave it out for all bottom end power. yeah the problem with the plug chop is that the plug IS a nice colour but with a plug chop, you're only likely to get a top end reading, I'm guessing that the splutter is maybe just before I get onto the main jet or as i'm entering the main jet so it's hard to pin point the problem; basically, the plug was coffee brown before I even adjusted the neddle, which makes me think top end is good. However, it was bogging low down, hence me adjusting the needle. Just didnt know whether it was worth dropping it another notch or not as it's a mission to get to the carb!
the splutter is the port m8.... its having the valve open at the wrong rpm hence there will never be the right power there an the flat spot will remain.
so not alot I can do about it then? (thanks for the advice by the way everyone;definately handy to get a show of opinions)
you could fit a servo to open the powervalve ? that would stop the splutter and it wont cost anywhere near 200pounds , you could probly bodge the servo unit of a nsr/tzr to fit and that would have roughly the correct timings, you can pick one up for a bout 30-40 quid of ebay
or find the correct one your options are; buy the proper valve set the thing closed and save your piston/conrod throwing a wobbely every time you try and pull away
i did a search of ebay before i posted and couldnt find any servos for rg powervalves so i just suggested tyring to use another one
wont work right, an by the time you bought it all you might aswell have scorced a proper one.. not just buying the bits, its mounting them, finding the cable/crescents are diff lengths, the controller opens the wrong time.. allsorts find the proper one or just leave it closed. its REALLY NOT a good idea setting them open as the low power pull off really hits the big end bearing..,
well with the rg, it's like a separate chamber; basically, blocking it off closes the chamber off so it has no effect. I got told by a work collegue and the bloke who ported my barrel to block it off with a tube as apparently it's quite commonplace; didnt realise that it effects the engine that much in terms of extra strain, etc. I will be on the look out for the bits on ebay
