My first race bike build!!!
- Thread starter deonsrace
- Start date
Davezilla
New Member
Sounds like you still need to jet up another size if you can feel it speeding up when you back off the throttle, at full throttle the main jet is wide open so it can only flow the amount of fuel it was drilled for. If you have a set of small drill bits you can run the bits thru to see which one fits it exactly then drill it out with the next smaller Number bit which is the next larger size. I prefer to just buy more jets and keep a few sizes bigger and smaller to make future adjustments quick and easy, but you can also drill them if you got the right bits.
The CVT may eat a belt or 3 while it's breaking in as well because those surfaces need to be really really smooth that the belt rides on and as the belt polishes the sides of the sheaves it'll stop eating belts... I used to buy 3 or 4 belts at a time for my go kart when I had it because it can eat belts, but shouldn't eat a belt in just a few rides. make sure you don't have any burrs or deep gouges or scratches in the belt sheaves where they contact the belt and polish out any imperfections on the riding surfaces, and also make sure the flat sides of both sheaves are lined up as perfectly as possible.
The CVT may eat a belt or 3 while it's breaking in as well because those surfaces need to be really really smooth that the belt rides on and as the belt polishes the sides of the sheaves it'll stop eating belts... I used to buy 3 or 4 belts at a time for my go kart when I had it because it can eat belts, but shouldn't eat a belt in just a few rides. make sure you don't have any burrs or deep gouges or scratches in the belt sheaves where they contact the belt and polish out any imperfections on the riding surfaces, and also make sure the flat sides of both sheaves are lined up as perfectly as possible.
Davezilla
New Member
Keep playing with your top end fuel mixture, you'll feel it go faster as you jet bigger, then it'll reach a point where it feels dull and not quite as quick on top, that's where you back off one size with the main jet, you may also feel a slight hesitation before the engine responds when the main jet is too rich.
From what it sounds like you got the jetting close, maybe one or 2 sizes up on the main and it'll be there... you'll still need to play with the needle settings tho so when you go up in jet size, put the needle back in the middle until you get the top end to do what you want, then adjust the needle if needed after you get the top end dialed in.
From what it sounds like you got the jetting close, maybe one or 2 sizes up on the main and it'll be there... you'll still need to play with the needle settings tho so when you go up in jet size, put the needle back in the middle until you get the top end to do what you want, then adjust the needle if needed after you get the top end dialed in.
Davezilla
New Member
Before you order that head, contact rogerdendron1 who is also a member in here that knows a lot about these type engines, he may have the head you need as well as other goodies that can save you a few bucks. He's told me in some other posts that he knows these engines really well so it might be worth asking him both for advice and for parts he might have left over...
Davezilla
New Member
This may look like a bandaid fix, or you could look at it as a tuning aid for varying weather and track conditions, but I use one of these on my Harley and it does help to keep me out of the inside of the carb... http://www.thunderproducts.com/dial_a_jet.htm
The way these work is by feeding the extra fuel only when needed by sensing engine load and controlled by a small dial with small air bleeds in different sizes, but the way it works is you jet the carb a size or 2 lean then set up the dial a jet so it lets you change settings pretty much on the fly, or at least without the need to open up the carb and it basically takes over where the main jet leaves off, even as simple as these are, they are really good at keeping the air fuel mix spot on.
Mikuni makes one similar called the power jet which works about the same way but to make adjustments it requires changing the internal jet and it just feeds raw fuel at a predetermined rate with no air bleed to compensate or keep the fuel metered accurately by it's self.
I'm thinking this may help you once you get the tuning close since it allows you to adjust without removing the carb or float bowl, you'll still have to do that to get the carb dialed in initially, but these will help afterwards.
For now, I'd say go up at least one more main jet size and it should pull better at higher rpm.
The way these work is by feeding the extra fuel only when needed by sensing engine load and controlled by a small dial with small air bleeds in different sizes, but the way it works is you jet the carb a size or 2 lean then set up the dial a jet so it lets you change settings pretty much on the fly, or at least without the need to open up the carb and it basically takes over where the main jet leaves off, even as simple as these are, they are really good at keeping the air fuel mix spot on.
Mikuni makes one similar called the power jet which works about the same way but to make adjustments it requires changing the internal jet and it just feeds raw fuel at a predetermined rate with no air bleed to compensate or keep the fuel metered accurately by it's self.
I'm thinking this may help you once you get the tuning close since it allows you to adjust without removing the carb or float bowl, you'll still have to do that to get the carb dialed in initially, but these will help afterwards.
For now, I'd say go up at least one more main jet size and it should pull better at higher rpm.
