Bike Running Horribly

  • Thread starter Bike running horribly
  • Start date
Your running lean I'm pretty sure
You come to that conclusion after watching vudeo right. Thats what i thought too is that its running lean honestly i have no pull after 3/4 throttle so i was thinking my main jet is too lean.
I could go one more notch down on the needle to the richest setting but that wont affect the main jet. So i do need a richer main jet to get the full potential?
 
<SOME SNIPPED> I also did a WOT plug chop heres what the plug looks likeView attachment 72097<MORE SNIPPED>

Jeffrey, you missed the part where you need to install a new plug for the plug chop.
You don't need a BPR8HIX for the chop, use a BP8HS or BR8HS, they are cheaper.
Based on what your present plug looks like, I'd move the heat range to 7 or so.

Frankfort, do you really think that plug looks like it has been running lean?
I'd say rich and/or cold, but hard to be sure on a well fouled plug.
Need to do a new plug chop.

Testing for vacuum leaks is best done by plugging the intake and exhaust and pumping up the system to 7psi.
Any more will blow out the crank seals. You watch the gauge for how long it holds and listen or soap for leaks.
image002.jpg


image006.jpg


2825884_orig.jpg


leakdownck2.jpg


Far more accurate than the propane or carb cleaner tests.

Steve
 
Ok so first off did you watch the video on youtube that i posted. How did it sound as far as the idle thats the best that i could get it. If you want i can do a ride on video i think she might be 4 stroking at or close to 3/4 throttle.

Secondly i was thinking of going to a hotter plug was thinking b5hs spark plug.
Would that be too hot?

Third you think its running rich based on the plug. Yes i know i need a fresh plug to do a plug chop money really tight lost my job a week ago.

Forth what is that tool that is used for the crankcase pressure test?

Please steve if you havent watched the video that i posted please watch it i see you on alot of threads here and you seem to give really good advice

Much appreciated Jeff
 
So if the plug was too cold could that be a possibility as why it cuts out a 3/4 throttle or is it completely unrelated? ive been working on my build for the past 10 or so months so im still fairly new to this stuff but hey ive gotten this far after 3 engines. lol no they didnt seize or anything like that, 2 of them had casing defects.
 
I did watch the video on Youtube. It should drop back to an idle better than that.
Something is off, I really don't know what from here (brain fade from hard day).

Go hotter but a 5 might be too much. The B7HS sounds good and price is great.
Yes, it looked rich and cold to me, but you have to look at a new plug to be sure.
Solve any leaks, get the main jet right with a plug chop, then worry about your idle.

The crankcase pressure test tool is homemade.
Exhaust plug of a plate or rubber expanding engine frost plug.
Plug the intake, schrader valve to fill it and low pressure gauge.

I'd go back to the NT carb for a while if it were me.
Step back, regroup, enjoy success, move forward again. Often my tactic.

Steve
 
Im actually puting nt carb back on as i type this and i will be picking up that plug tomorrow as well as a micro drill bit set. If nt works better which im sure it does would mean i need a richer main jet as the jet for nt carb is slightly larger then this keihin carburetor clone which i have had nothing but problems with.
 
Ok so all these plug chops where done on the nt carburetor each run was 5 minutes here are the 3 plugs from the lowest 3 settings on a 4 grove needle.

2nd from top
20160516_135412.jpg

3rd from top
20160516_141342.jpg

And bottom of needle
20160516_142712.jpg

So every plug is white and kept getting whiter as i would lower the c-clip. Has anyone ever had to rejet nt carburetor richer. Im at a loss right now.
 
Jeffrey, you missed the part where you need to install a new plug for the plug chop.
You don't need a BPR8HIX for the chop, use a BP8HS or BR8HS, they are cheaper.
Based on what your present plug looks like, I'd move the heat range to 7 or so.

Frankfort, do you really think that plug looks like it has been running lean?
I'd say rich and/or cold, but hard to be sure on a well fouled plug.
Need to do a new plug chop.

Testing for vacuum leaks is best done by plugging the intake and exhaust and pumping up the system to 7psi.
Any more will blow out the crank seals. You watch the gauge for how long it holds and listen or soap for leaks.
image002.jpg


image006.jpg


2825884_orig.jpg


leakdownck2.jpg


Far more accurate than the propane or carb cleaner tests.

Steve

I meant it sounded like it was running lean based off the video, have you tried adjusting the screw on the side of the carb?
 
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