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two stroke complexities...?


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nickvr

 
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two stroke complexities...?

Mon Mar 19, 2007 8:12 pm » Post: #1 » Download Post

Hi. Tonight I again realized how complex yet simple an engine can be... I have (had) this problem with the NSR MC18 where one cylinder would completely stop running and then the other. Started with basics e.g. spark on plugs, fuel in carbs etc. etc. I was finding and 'fixing' potential problems everywhere e.g. compression checks, value checks, replaced plugs, set float levels, polishing the float needle seats, adjusting, re-routing fuel lines etc etc. Instead of doing all of this in one go, I ended up doing something and test, doing something and test. This resulted in weeks of stripping, 'fixing', testing, stripping, fixing testing... Tonight I again adjusted the float levels a little and when done, the one side was still dead. Removed the plug, cleaned and dried the electrodes and replaced. Kicked it once and boy we had stereo, both sides smoked like a charm! Moral of this long story, there is no shortcuts here boy, check and fix EVERYTHING at once and spare yourself the agony or stripping, replacing, testing, stripping, replacing, testing... Laughing
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Dave Ett
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Tue Mar 20, 2007 2:03 pm » Post: #2 » Download Post

Yep, no point doing it in little steps. As Stephens strap line says:

If I have to remove the carbs once more...
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nickvr

 
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Tue Mar 20, 2007 5:46 pm » Post: #3 » Download Post

Thank you to this forum for all the advice everywhere! Have one last question, the carb is all stock e.g. 125 & 128 . How can I get the airscrews close to perfect without dyno and gas analyzers? I would assume the top cylinder would require little less air. I also feel when closing the throttle the revs would sit at 3000 for 2 or 3 seconds and then drop to +-1500. I think one of the cylinders may be to lean?
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Dave Ett
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Wed Mar 21, 2007 4:16 pm » Post: #4 » Download Post

Without a dyno, all you can do is go by feel and spark plug colour.

A nice tan and all's well in the world. White and it's on the verge of going bang, black and it's safe, but too rich and not giving you all the power it can.
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Andy
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Wed Mar 21, 2007 9:04 pm » Post: #5 » Download Post

Dave Ett wrote:
A nice tan and all's well in the world.

Yeah, I'll second that! Cool
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StephenRC45
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Wed Mar 21, 2007 11:43 pm » Post: #6 » Download Post

Youre never really going to get any sort of nice plug colour on tick over. The best you can do is set it to stock then adjust it by feel.

On the subject of colour I like white but I seem to of ended up with tan... ho hum.
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If I have to take the carbs off once more...
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Matt@TYGA
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Thu Mar 22, 2007 1:20 am » Post: #7 » Download Post

I know where you're coming from Steve. Very Happy

No matter how lean I run mine she'll never go white. Does make a funny noise though....a sort of permanent whining!! Know what I mean?

I believe that Andy has the same trouble, only when his starts making funny noises he changes countries Wink
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Andy
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Thu Mar 22, 2007 9:44 am » Post: #8 » Download Post

I had to go a little darker last night!
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Dave Ett
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Thu Mar 22, 2007 6:13 pm » Post: #9 » Download Post

Laughing
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