What the heck?

3489 Views 36 Replies 8 Participants Last post by zx12ryder, Jun 6, 2009

Chris Garrett

Discussion Starter · May 9, 2009

Okay, let me begin by reminding you guys that I'm new to tuning bikes. So many variables for a new guy. Anyway, I got the bike running pretty good, but it is still backfiring on the right side and idles all over the place and then just dies. It will be idling at 1100rpms and abruptly die.
Also there is a tapping noise in the engine. When I put my stethescope on the right side lower engine, near the oil filter, it is a distinct rapping noise.
So just for fun, I pulled the right side plug wire, which I noticed looked worn. The engine did miss a beat. It runs the same way with the plug wire on as it does with it off. Rpms don't change at all. What is going on? :?:

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66Sprint

· #2 · May 9, 2009

Chris....Sounds like your "backfires" are when the right side actually/occaisionally fires the plug.... You are running on one cylinder, the left one....
Find out why.... right points, right coil, right HT lead and/or cap....something is BAD!
might even be the feed wire to the points on the right side....

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66Sprint

· #10 · May 10, 2009

Not necessarily enough fuel into the bowl......IT will always flow when the float is down (such as when the bowl is off)......You set the float height to keep the supply just high enough to feed the jets, but not so high as to flood into the venturi.....

Spritz some ether at that carb while the engine is running...IF it picks up and both pipes show heat, it's a fuel supply problem....
If it doesn't, something else is wrong...

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66Sprint

· #12 · May 10, 2009

If the fuel does not cover the jets, it does not get drawn into the cylinders .....without fuel, what is there to fire?.... Try the spritz test.....

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66Sprint

· #13 · May 10, 2009

Or, you could manually fill the bowl about 1/2 way and reinstall it.....

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66Sprint

· #16 · May 10, 2009

If the bowl was full (enough), YES, the jets could be clogged......TRY THE SPRITZ TEST....IT PROVIDES FUEL AND WILL VERIFY IF THE CARB IS THE PROBLEM, or at least that the problem is within the carb.............Let us eliminate that possibility before going anywhere else!

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66Sprint

· #18 · May 10, 2009

Well, an engine only needs three things to run... Fuel-air mixture, compression, and a spark at the right time.....
The ether provided the fuel-air mixture, ( a spritz behind the carb will gather in enough air as it gets sucked into the carb)
You claim to have spark....(You DO realize that just because a plug will fire in open air does NOT mean it's firing under compression..... Did you try new plugs?)
You either have a lack of compression,(What were your compression readings?) OR the spark is mis-timed ........

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66Sprint

· #20 · May 10, 2009

Bill, I thought that was the engine you re-ringed, so I now KNOW three things....
IT HAS COMPRESSION......(and the crank/cam is timed properly, valves adjusted properly...)
A spritz of ether shot behind the carb will provide a fuel mixture adaquate to fire 100% of the time.......(You didn't spray a lot, or directly into the carb did you Chris?)
The ONLY thing left is "Spark at the correct time"....
Either it's not getting spark, Or the spark isn't happening at the right time.....

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66Sprint

· #22 · May 10, 2009

Yes, I remembered that...We are pretty much down to spark and spark timing......This could end up as simply as a disconnected wire to a coil......or misadjusted point.... or bad plug.....

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