Engine Problems

D

DEVCOL4

New Member
The bike was running just fine for a couple months after the build. I changed the head to an angle fire and got some more power- no problem. In the last few days, it started popping and jerking under a load and it backfired out the carb a few times. Any Ideas?
 
Check your plug; is it clean?
What plug are you using? might need a colder plug with the new higher compression??
& re-mix your gas.
 
On my second batch of fuel I used an inferior 2-stroke oil. I drained it and used the good stuff again at a 32-1 mix as I guessed that it was probably broke-in by now. I put in a new NGK B7HS-10. Same problem. I played with the needle setting and found it to run best on the lowest notch. Still, same problem. I found a bad exhaust gasket and changed it out with a metal gasket. No change. I've even cganged out the carb for a new one. Still popping and jerking at speed. Head bolts are tight and intake gasket seems to be OK. HELP!
 
DEVCOL4 said:
No discoloration around the head gasket.
Click to expand...
Hi DEVCOL4,sounds like your sparkplug,i put a new sparkplug in went for a ride about two mile,half way it started to miss and backfire and then finally packed it in,replaced sparkplug and started straight away,goodluck,yendorrodney88
 
What else could it possibly be!? I've tried everything. New fuel, new plug, new carb, new exhaust gasket, I've checked the wiring and it seems to be OK. Would a chain thats too tight cause these problems? Should I take it out and shoot it, and buy a new engine?
 
ok changed the plug and the carb and had to lower the needle in the carb(I am guessing lowered it in both carbs and the same results),,had power after the head swap,,is the plug wire in the kit a solid metal wire or a carbon fiber one(?),that can get a break along the wire inside causing weak spark?,,,could the ground attatched wire in/on the magnito be rusted or loose, or possibly even the small soldered wire broken but still touching breaking contact w/viabration
 
Low needle or raised needle,,,,I read the above as lower needle and that is less gas/oil in the motor,less lube,jet unscrewing in the fuel bowl(Flooding),dirt in the float needle valve(flooding),in-line filter?,
 
I just found this too,..........................
gebhardm
Motorized Bicycle Member Join Date: Jul 2010
Location: Illinois
Posts: 21

Re: Totally Stumped!

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This sounds like a problem I had when my motor was still new. I tried everything you said and also got no power. I then, tried to start the engine with no muffler connected and it had all the power in the world. My engine probably had less than 150 miles on it so I just couldn't believe the catalytic converter was already clogged but it was. I had been using 1:16 mixture of oil:gas. I would not run it long without a muffler though because the engine needs somw kind of back pressure. Hope this helps
 
FOUND IT!! I removed the magneto cover and all of the magneto screws were loose. Runs like new again! Thanks guys, for the help. Thanks corgi for your time and effort!
 
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