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Discussion Starter · #1 ·
Hi everyone, hoping to get some advice on what to do next. I'll recap my issue from the begin, this is from my Reddit post last month:

Bike has 35,000km/21,000miles
I've been riding for about 40 minutes on the high way around 9k rpm before i feel a sudden loss of power where keeping over 90kmh/55mph it struggled.
I noticed it had a deeper exhaust tone and idled lower. In neutral any revs and it was on the crisp of stalling when the idles came back down.
Around 4-6k rpm it would stutter badly, complete loss of power and i would need to shift into at-least 6th gear to go 50kmh/32mph.
Any throttle more than 25% and it stutter and accelerates slow. 6th gear is the best where it would only stutter 4-6k rpm and then be fine unless more than 25% throttle is applied.
Here's what I think it could be:
  • Bad Gas
  • Running on single cylinder/cylinder misfire
  • Bad clutch
  • Over heating causing limp mode?
I'm thinking it's likely to be a cylinder misfire based on the symptoms and am hoping to hear where I should start? I think spark plugs would be the easiest?
In short, the bike feels like it's in limp mode.
Later I took it out to the gas station and it rode fine on 2 cylinders for the first ~7 minutes. After the bike warmed up was when it the cylinder misfired and the same symptoms started. This confirmed to my that it's likely the coils.

Since then my buddy and I swapped out the stick coils and spark plugs with replacements. First thing we did was test the new coils outside of the engine grounded against it to see if there's spark. There was on both cylinders. One of the old spark plugs was black and burnt so I was further convinced we've resolved the issue. With the new plugs in and new coils inserted in, we cracked the bike and it ran fine for about 30 seconds before the idle became rough again and the engine light was thrown (couldn't get a code out of it this time, I turned it off then key to the on position-- ODO B and held down the left button and no code pops up) and the right header was cold.

Where i'm at now is we tested the coil spark plug and coil grounded against the engine. There's spark from the left cylinder, not from the right. Could this be a wiring issue? What would be my next steps to trouble shoot the wiring and where does it even run to? Are there any other parts in between that I can try to troubleshoot or replace?

Would really appreciate suggestions. All I can really think to do is take apart the bike and follow the wiring for the right coil connector with a volt meter to see why there's no power but want to make sure i'm on the right track.
 

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Another possibility may be the fuel injector on that side, where the plug is dark, is hanging open and giving a rich mixture. When the engine is cold it's not a big problem, but when it warms up it causes a misfire.

Check all the connectors and wires for corrosion/breaks as well.

Make sure the air filter is in good condition and the snorkel is clear.

A low battery will also send a cycle into "limp mode" so make sure it has adequate voltage before starting (over 12.7V) and when idling (over 13V).
 

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Discussion Starter · #3 ·
Another possibility may be the fuel injector on that side, where the plug is dark, is hanging open and giving a rich mixture. When the engine is cold it's not a big problem, but when it warms up it causes a misfire.

Check all the connectors and wires for corrosion/breaks as well.

Make sure the air filter is in good condition and the snorkel is clear.

A low battery will also send a cycle into "limp mode" so make sure it has adequate voltage before starting (over 12.7V) and when idling (over 13V).
Thanks for the reply!
I'll take a look at the fuel injector and it's connections next time. With the misfire I thought it was for sure a faulty coil that fails when warmed up but now that the connector for the right coil doesn't send any voltage i'll look elsewhere.

I'll check the battery also. I don't think it was an issue before as long the alternator worked but with the bike not running now and me constantly trying to crank it there might be a possibility that it's depleted anyways.


Still looking for suggestions on why the harness/connector for the left coil works but not for the right coil if anyone has encountered something similar!
Could it be related to the CDI electronic ignition? How would I troubleshoot that?
 

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(SNIP)
Still looking for suggestions on why the harness/connector for the left coil works but not for the right coil if anyone has encountered something similar!
Could it be related to the CDI electronic ignition? How would I troubleshoot that?
Tracing wires back, looking for damage, would be the first thing to try.

An Ohm Meter or test light would probably be what I would use.
 
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