Engine cutting out at high rpm By dozer187 (Read 7,864 times)

[Alleyoop]

What kind of cone filter do you have on there take a picture of the carb area. You may need a UNI filter those cone filters are not the greatest they are usually made of aliuminum mesh.

[dozer187]

It is a mesh i believe got it for free from a friend, metal cap on the end...
www.amazon.com/gp/aw/d/B00AM6JXE6/ref=mp_s_a_1_fkmr3_1?qid=1454206954&sr=8-1-fkmr3&pi=AC_SX236_SY340_QL65&keywords=gy6+50cc+uni+filter

[Alleyoop]

I figured it was one of those, that is why asked for a pic of the carb area, they are crap bud, get a uni. Also a piece of tubing between the filter and the carb works good to control the flow of air.
Alleyoop

[dozer187]

Problem fixed, ran the old flow tube from the stock airbox to my filter and it runs flawlessly with a 92 jet...thanks for all the help

[dozer187]

i hate to bump this thread but im having issues with the bike again, low end issues this time, bike is hesitating at low rpms then seems to rev out just fine after like 5k roughly, ive tried retuning the a/f screw and nothing is making a difference, spark plug is new and i havent found any air leaks all the gaskets are new as well, compression is in the 140ish range. carb is running a 92 main jet still and has been cleaned out. oh and the diaphragm is new as well

[Alleyoop]

Does it bog and or does the motor make a different sound, pay attention to the sound it makes. Different sounds emitting from the muffler helps determine what is wrong.

Just like you did when it was acting up on the top end do the same when it acts up on the low end.
BACK OFF THE THROTTLE 1/8-1/4 of an INCH AND HOLD IT THERE.
Now pay Close Attention to what the motor does:
A. Does it speed up?
B. Does it stop the stuttering and settles down?
Alleyoop

Could be your Air Filter is dirty and needs cleaning which would cause it to run rich, also check your fuel filter.

[dozer187]

the sound is almost like a gurgling type stutter then it levels out after 5k, airfilter is brand new so its clean, i pulled the fuel filter off b4 and it was still doing it cuz i thought the filter was clogged. ill try to get a video tomorrow as its to late now to be running my bike(its not quiet lol)

[Alleyoop]

Sound like to much fuel BUD, did you mess and with the needle and lowered the clip? You may have to be a pilot jet in what size is it and what size carb?

[dozer187]

I believe the pilot is a 32 same one ive had since sept, low end was never a problem before the diaphragm went out and i replaced it and the clip is still in the same spot its always been

[Alleyoop]

Last time you said the Pilot is a #35 which is way to big for a 50 even with a BBK on it. So if you have the old carb or jets put a smaller pilot jet in. You "GOTS" to know what you have this guessing sh!t is not going to get it because then we will be diagnosing wrong.

[dozer187]

its a 32 i just looked, the 35 was the extra the carb came with thats why i thought it was a 35 previously, carb is a 32 pilot 92 main, 18mm carb. 50mm top end free flow exhaust and intake, c7rhix spark plug emissions deleted on the motor all vacuum lines plugged that needed to be, petcock delete, installed lines direct with a manual fuel shutoff valve, shes also been harder to start lately as well

[Alleyoop]

Ah, harder to start good and since it was running good before this it is probably the valves have tigthen up, So adjust them INTAKE .003 inchs EXHAUST .004 inchs that should make it flow better.
Alleyoop

[dozer187]

did that already too, all the basic troubleshooting i went through last time i did again. those are my exact valve settings. thats why i cant figure out what the problem is, the bike was running flawlessly till the diaphragm went out on the carb, i have since replaced it and its running better than it did with the torn diaphragm but the low end is trash now. needle settings are the same, tried tuning to no avail and tore down the motor to check the rings and internals, theyre all good, replaced all gaskets while i was at it. im about ready to be done with this thing and just buy a brand new 150

[dozer187]

So today it was cooler in the morning and the bike fired right up, now my top end surging is back, seems to rich on the top, shouldnt u need more fuel in the heat to keep the engine cool?

[Alleyoop]

NO, motor need LESS FUEL IN HOT WEATHER and MORE fuel in COLD WEATHER.
Alleyoop