top end miss on apex 90

[dewutfan]

need some help here i got apex 90 with malossi big bore kit trackside pipe 28mm pwk carb with 38 pilot and 135 main on the top end its cutting out. the plug in is nice brown color but i think i am running out of fuel... can anyone give me there 2 cents please .. also got overrange kit in it also and it has 4.5gm weights belt only running up 3/4 way up got 19th front and 30 t rear i think i need to go up on back sprocket any help there.. its running about 13000rpm but its not going anywhere .... we have more motor then we are showing on the track just not getting the power to the ground.. please give me your guys 2 cents here i need it .. thanks guys

[mmsoup]

Try 5 gram weights and check to see if your fuel hose is pinched coming out of the tank. Do you run the stock tank or oversized?

Do you run a Haggerty? Asking cause it means a relocation of the carb and can cause issues with pinching the fuel line.

You can stiffen the rear spring to help with belt travel but too much and you get heat, we get travel to within 1/8 of the top of the driven plate.

[dewutfan]

I dont have oversize tank run stcok and no haggerty i run a 1/2 spacer on the intake .... i will try some 5 gram weights ty for that info

[chunky0071]

I agree i would try the 5's a half a gram makes alot of difference

[heepers]

adjust float in carb
make sure vent hose is routed correctly(not in the steering stem)
add 6.5 gram rollers and reduce weight accordingly

[selbygirl]

we had a simaler problem it had a weak shoe spring . and it was a overange set up. it almost felt like carb problem and on our 90 2 fast motor the belt doesnt travel all the way to the top eather .biut its has all kinds of power for mx tracks

[CRBOGGAN]

Just had a top end miss with a setup close to yours it was the light blue wire on the PVL it was not snaped together good. Acted just like jetting was off.

[dewutfan]

Hey Thanks guys for the feed back on this i will check those things out and see ....

[Logan #34's Dad]

Check and clean all your ground wires. Always run a separate ground wire/strap from the engine to the frame.

[dewutfan]

Yes i got a ground wire to the frame but i am gonna go and get the wires to make sure all is clean and tight .. i use a powerwasher to clean it i might have got one loose or wet inside so i will pull them all apart tonight and reconnect them all thaks for that heads up....

[heepers]

so what did you figure out?

[dewutfan]

i got the bad miss fixed.. it was either a loose wire connect from power washer... learned a lesson there .. but i still have a small miss on top end and i am gonna start tonight by rejetting .. i have a 38 pilot and 135 main in my 28 mm carb i am gonna try 50 pilot and start moving up on my main to see if i cant get it fixed.. it acts like its running out of fuel on very top end and i have check for air leaks all good there... so i will keep trying untill i get it ...

[selbygirl]

try running the fuel line from the tank strait to the carb. we get rid of the cockpit and shut off the reserve line . makes for less fuel line travel. check your spark plug cap. some times they get dirty and lose .. i zip tie mine to the spark plug real tight . check your kill switch sometimes they will make the bike run funny. and check all your factory conections . i hard wire all mine or use a pvl. 2strokes viberate a lot at top speed ...so it still could be electrical

[dewutfan]

I changed the piolt jet last night from a 38 to a 50 and adjusted the air screw its out now 1 3/4 turns and WOW no more miss and smooth sound all the way tho the throttle ... little things make a huge differnce... thanks guys for all the help too..