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M72 - overheating right cylinder


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#1 englishdealhunter

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Posted 28 October 2017 - 01:26 PM

Hi Guys - started her up after some months and the right cylinder is hot, very hot, around 230 degrees c/w left at around 150. I can't get rid of this symptom. I've replaced points, checked plugs (NGK 6's) and points gap, checked advance / retard mechanism, fitted new carb gaskets, checked fuel getting to carbs, cleaned carbs, checked compression at around 75 psi on both sides, checked valve clearances.

I believe the right cylinder is generating more power, as when you take off the plug caps when running, the right cylinder is more responsive.

I'm thinking of; replacing the distributor cap and rotor arm, cleaning the carb again on left side, checking exact timing for both sides with distance of piston from TDC, but am running out of ideas.

Can anyone help???

Thanks

Greg

#2 Daveyl

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Posted 28 October 2017 - 02:56 PM

i can only guess that the carb is running too 'lean'. if the plug colour is pale or white, it will run hot.

#3 Ratso88

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Posted 28 October 2017 - 11:45 PM

Try swapping the carbs side to side, if that's possible, see if the problem follows.

I had a very similar problem on my Dnepr, turned out to be a vacuum leak. Never hurts to double and triple check. Simple things first.

#4 racepres

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Posted 29 October 2017 - 08:34 AM

View PostRatso88, on 28 October 2017 - 11:45 PM, said:

Try swapping the carbs side to side, if that's possible, see if the problem follows.

I had a very similar problem on my Dnepr, turned out to be a vacuum leak. Never hurts to double and triple check. Simple things first.
What I would do...

#5 haj

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Posted 30 October 2017 - 07:04 AM

Did you balance the carbs? wasn't mentioned.
--
Dnepr K750 1956 (it says on the polish papers, damn lies! must be from the 60's)
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#6 dowey

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Posted 30 October 2017 - 12:33 PM

Yeah, like said above, it sounds more like a carb problem ..swopping them around would tell you for sure if you move the problem ..but balancing them properly would help no end. I know people use all sorts of gadgets for doin it but i always found just stickin my fingers in will tell me when they are lifting together ..then playin about with the idle setting and mixture to find the optimum
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1992 dnepr mt11
2015 ural

#7 racepres

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Posted 30 October 2017 - 07:11 PM

Been using my Finger, and ears, since I got my 1970 BSA...
Longer ago than I care to try to recall!!!

Haven't re-done the MT-11 since I wrote this
http://www.russianir...topic=14044&hl=




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