Just looking for a quick yes or no answer, I got a standard 12mm carb if I fit a 17.5 and tune it correctly, will I need to change my rollers due to the power increase? Thanks
Really and truly there won't be much of a power increase. What there will be is better torque and a motor which does other things besides 'on' and 'off'. You'll spend more time at mid- throttle than simply mashing it open all the time, and your fuel economy will generally be better as a result- even with a bigger jet. More importantly, the engine will have more of everything - and will run cooler and last longer.
That ain't odd, that's absolutely screwy. I;m surprised it's even starting with a jet that big. Whats the full set-up?
Yeah. Sounds like an air leak. Admission stack, crank seaks, base of the cylinder etc. The usual suspects. How is the idle? Is it high/ fluctuating?
Is a standard 50cc with a foam open air filter, pollini variator, stage 6 belt, just put in a mix of 4g and 3.3 rollers, dellorto 17.5mm carb, my rubber inlet manifold is really really perished, just came back from a ride and It feels like it goes faster at half throttle and sounds really deep on full throttle, almost feels like I need to up jet again
I think it's probs the manifold, I got a new one but can't put it on because one of the 4 bolts holding it on is rounded :'(
Undoubtedly the manifold leaking! If you reomove the good three bolts and dremel off the head of the fourth, you can then replace the manifold. You will find that the shaft will unscrew easilly once the manifold is off. I have done this more than once. Go to it!
Flat dremel carbon disc. You could even buy one and put it in a normal drill if you don't have a dremel. Electric, mind. Not battery drill. You need the speed.
Agree the turbo, massive air leakage somewhere. Sort the manifold out first, that'll stop it sucking excessive air, then you'll find you have to down jet massively. General rule of thumb is: from standard setup, add sports exhaust (leo vince, gianelli etc) up jet by about 5 points over standard add an open filter as well, up jet by a further 10 to 12 points. Check your plug colour to make sure it is not running too rich, if it is drop a size at a time until you get a nice ginger biscuit colour. I reckon an 80 jet should suit, but only once you get the rest sorted out.
I ended up drilling it out and replacing it, still runs even on choke, also when I put my new carb on I might have an air lock in my oil pipe because it doesn't really smoke, I've put a pre mix in atm but don't want to keep doing that, how do I check that I've got oil going into it? I can't bleed it because I can't get the water pump case off
You'd know if it was not working because your engine would seize. The oil pump on a rox is pretty reliable. If you make sure the oil pump hose is secured to the inlet nipple on the carb with a collar or a zip tie, you should be fine. If you see no leak, there is no leak. Just unplugging it from one carb and putting it on another is not enough to give you trouble, unless you empty the little pipe of oil at the same time. The oil forces any little gaps through and out pretty fast. The symptom of an oil pump on the way out with that engine is similar to the problem you get with an air leak. You can put any jet you like in the thing, you can't get the plug to turn black. It goes a funny pewter colour. But this won't happen to you.
I'm going to put some sealant around the intake manifold and see if that works, if not, time for a 70 kit
