Author Topic: Left hand cylinder running hotter  (Read 177 times)

gordie36

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Left hand cylinder running hotter
« on: July 26, 2020, 09:43:34 PM »
Hello All
I have just put together a 3MA1 which i bought in box's of parts! All went together well with all new bearings & seals along the way.
Rebuilt the motor, crank, new pistons bearings, seals etc, had a slight issue with a bit of corrosion in the left hand carb, but had them ultrasonic cleaned & all looked good, fired up 3-4 kick but i noticed that the left hand exhaust temp is much higher than the R/H side & also less smoke.
The restrictor rings in the pipes have been removed & snorkels had been shortened.
The carbs have the following jets, mains 210, pilots 20, Q4 needle valve, 6L02-63-2 needles, pj 20
& floats set at 20mm, also the carb heating pipes blanked off.
Is there something wrong here? or normal for a 3ma?
Thanks gordon

no smoke no poke

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Re: Left hand cylinder running hotter
« Reply #1 on: July 26, 2020, 11:38:30 PM »
personally i would check that its getting enough oil b4 anything else less smoke means less lube for the piston and bearing costly blow up may ensue i would eliminate that its not running lean on the cylinder

mellorp

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Re: Left hand cylinder running hotter
« Reply #2 on: July 26, 2020, 11:57:57 PM »
All 3MA's smoke more on one cylinder

http://pure2strokespirit.net/redandblueftp/tech_data/3ma_service.html

Your jetting is wrong for a std motor
Mellion say If it ain't broke thrash it until it breaks

mellorp

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Re: Left hand cylinder running hotter
« Reply #3 on: July 27, 2020, 12:23:30 AM »
You can set the 3MA tickover same as this procedure http://pure2strokespirit.net/forums/index.php?topic=6656.msg65761#msg65761
Mellion say If it ain't broke thrash it until it breaks

gordie36

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Re: Left hand cylinder running hotter
« Reply #4 on: July 27, 2020, 09:45:26 AM »
Thanks for the help, will check it all out & let you know how i get on

Goober

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Re: Left hand cylinder running hotter
« Reply #5 on: August 01, 2020, 10:15:06 PM »
Hi Gordon,

I am experiencing the same issue. I have exhaust temp senors 100mm away from the piston crown and the LHC will almost always be 100 - 115 degrees Celsius hotter - regardless of RPM. I have swapped out all the usual suspects and it has made no difference. I have backed this up with using one on those heat temp 'guns' similar to what authorities have been using to test peoples temperature for covid-19 - this shows a similar difference - obviously not when going down the road :o
I am working through and idling issue that I cannot help thinking might be related... The only way I can bring up the temp of the RHC is to adjust the balance screw between the carbs. Interestingly to bring it up to a similar temp, the RH carb slide needs to be a good 5mm higher than the LHC. This is miles out of course, however I have changed everything and the carbs are spotless - She has new pistons and rings so I don't believe it is a cylinder issue ether.
The weird thing is the bike runs very well indeed, right through the rev range with some serious poke up top and you just would not know there was an issue other than not idling well and the senors showing the difference.
I am interested to see how you get on and whether you too have any problems with idling.
Greg. (-P)
If in doubt, bore it out.

jools

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Re: Left hand cylinder running hotter
« Reply #6 on: August 01, 2020, 11:09:05 PM »
Hi Goober,

one thing to double check is the type of EGT you are using. Thermocouples generally have 2 different conductor materials in the wiring. any bad or inconsistent connection can cause a "cold" junction which could lead to the symptoms you are describing. This also includes the type of joint between sensor and cabling.

The other starting point would be to determine which temperature is correct so you are not chasing your tail. I only ever used cylinder head temps, which are fitted under the spark plugs and there was around 25 deg C difference, but I know my fueling was out.

Are you still using the air jets ?
Plus ce la change, plus ce la memchose