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Compression and electrical problem solving


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On 8/28/2019 at 3:02 PM, gusto said:

I just refile the metal on the frame and re-install.  Throw on your old harness and see if that is the cause.  If the old harness when installed still doesn't fire up I would start looking at the carbs.

Have you checked the compression after the non start issues?

gotcha. I dont see a grounding strap other than the one toward the back of the frame near the voltage regulator. Im assuming if a have a nice blue spark than my ground is adequate?

Ill get into the carbs tomorrow, though I dont think thats the case; Ill post my findings...

the old harness was rotten and had been spliced a dozen times. So, I replaced it with a 2004 OEM Yamaha harness and have ridden the bike a number of times since the install.

Btw, the compression comes in a 125~ for both cylinders. Its low, but should be more than enough for the bike to run. Additionally, I ran a crankcase pressure test prior to reinstalling the engine. It held 7psi for 8 hours. So...thats not the issue.

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gotcha. I dont see a grounding strap other than the one toward the back of the frame near the voltage regulator. Im assuming if a have a nice blue spark than my ground is adequate?
Ill get into the carbs tomorrow, though I dont think thats the case; Ill post my findings...
the old harness was rotten and had been spliced a dozen times. So, I replaced it with a 2004 OEM Yamaha harness and have ridden the bike a number of times since the install.
Btw, the compression comes in a 125~ for both cylinders. Its low, but should be more than enough for the bike to run. Additionally, I ran a crankcase pressure test prior to reinstalling the engine. It held 7psi for 8 hours. So...thats not the issue.
125 psi is more than enough, it should be purring with that compression,when it drops under 110 is when it starts to play up.

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2 hours ago, the boris said:

125 psi is more than enough, it should be purring with that compression,when it drops under 110 is when it starts to play up.

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I had it running great. I put the bike in the garage before going out of town on business for a week and when I came back, no joy. I started the afternoon before I left, after a wash job as a sanity check to ensure  the wash didnt mess with anything.

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2 hours ago, the boris said:

Check the slides, I had them other way around and my bike would only start at half open throttle and would run rich as.

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no carburator configuration changes have been made since the last ride. Im runing mikuni tm34's, one cannot install the slides backward as the carb design will not allow it.

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Just now, the boris said:

What timing advice are you running?

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its np.

+1 on a billet timing plate.

I had these same symptoms 2 weeks ago; I installed a new generator and it cranked right up. I understand that new doesnt mean good. but, the likelihood that a brand new oem stator failed after one right has got to be very small....this is frustrating as hell. 

when I get into the carbs Ill post my findings, though i doubt Ill find anything out of place 

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its np.
+1 on a billet timing plate.
I had these same symptoms 2 weeks ago; I installed a new generator and it cranked right up. I understand that new doesnt mean good. but, the likelihood that a brand new oem stator failed after one right has got to be very small....this is frustrating as hell. 
when I get into the carbs Ill post my findings, though i doubt Ill find anything out of place 
Fuck mate, I don't know what to tell you.
If it was working fine and you turned it off and won't start again, I would think it's something electrical,but considering you checked everything, I really don't know.
I'm perplexed and bamboozled by your boke

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7 hours ago, the boris said:

Fuck mate, I don't know what to tell you.
If it was working fine and you turned it off and won't start again, I would think it's something electrical,but considering you checked everything, I really don't know.
I'm perplexed and bamboozled by your boke

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me too. 

The first time I replaced the stator my thought was this: The original stator fell within Ohmic limits but was on the low end of the spectrum at 113ohms. Could it be possible to have an internal short across a winding that reduced resistance but not out of limit? ie the stator originally wouldve had 130ohms and now it reads 133ohms, or something like that.

so, I but an oem stator after examining everything else. the bike started right up.

now its exhibiting the same symptoms. my thinking is that my odds of getting 2 bad stators in a row have got to be slim.

idk bro, Im at a loss as well....

ill continue to post any finding / results

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