toddo
Weekend rider
Posts: 75
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Post by toddo on May 19, 2022 17:27:43 GMT 1
Hello
After a consistant coolant leak into my left hand bore when running I measured a slight lip at the front of the cylinder liner closest to the exhaust. I think this may be causing my leak.
I measured my squish clearance at 1.6mm. It should not need much skimmed off the cylinders to correct but I was wondering what is the minimum squish clearance before I will have a problem.
I read somewhere on this site that people go as low as 1mm but my searches can not find the thread and I think they were talking about an another engine. I think one or two tenths of a mm should sort it out but thought someone might have some expirience.
Thank You!
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Post by midlifecrisisrd on May 19, 2022 17:55:22 GMT 1
On a road bike I'd be aiming for 1.1mm to 1.2mm so you have plenty to play with
Steve
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Post by muttsnuts on May 19, 2022 18:21:30 GMT 1
1.2mm for road use is fine
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Post by JonW on May 20, 2022 8:14:39 GMT 1
What they said: just dont go under 1mm
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toddo
Weekend rider
Posts: 75
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Post by toddo on May 20, 2022 8:40:15 GMT 1
On a road bike I'd be aiming for 1.1mm to 1.2mm so you have plenty to play with Steve Thanks Steve! |
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toddo
Weekend rider
Posts: 75
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Post by toddo on May 20, 2022 8:40:55 GMT 1
1.2mm for road use is fine Thanks Muttsnuts! |
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toddo
Weekend rider
Posts: 75
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Post by toddo on May 20, 2022 8:41:33 GMT 1
What they said: just dont go under 1mm Thanks Jon! |
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Post by vectisitch on May 20, 2022 16:12:34 GMT 1
Oopps. Mine is around 0.9mm on my 31k
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Post by bare on May 20, 2022 16:59:40 GMT 1
Running 0.9 mm for years. Happily.
It's getting close though.. So be sure it actually IS 0.9 !
There is small room for error as the Mechanical bits can/do stretch under heavy use and eat up any safety margin quickly.
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Post by vectisitch on May 20, 2022 22:41:33 GMT 1
Running 0.9 mm for years. Happily. It's getting close though.. So be sure it actually IS 0.9 ! There is small room for error as the Mechanical bits can/do stretch under heavy use and eat up any safety margin quickly. It's between 1mm and 0.9mm. It's certainly not less than 0.9mm |
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Post by JonW on May 21, 2022 0:32:30 GMT 1
horses for courses naturally, just rules of thumb for longevity. Each to his own  |
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Post by bigdork on May 21, 2022 4:38:18 GMT 1
At a certain distance or if there is a significant difference in angles between the piston crown and the head it's not really squish anymore.
But as always with two strokes YMMV. Particularly with 40 yr old cases, cranks that may be well past due for rebuild and parts that over the years my have been mismatched to each other.
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Post by 4l04ever on May 21, 2022 8:14:10 GMT 1
Remember if you skim the head, you are reducing the squish but also increasing the compression ratio, and you can only go so far before it will blow up. Maybe worth measuring to make sure you are still safe.
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toddo
Weekend rider
Posts: 75
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Post by toddo on May 22, 2022 18:51:25 GMT 1
Remember if you skim the head, you are reducing the squish but also increasing the compression ratio, and you can only go so far before it will blow up. Maybe worth measuring to make sure you are still safe. Thanks 4l04ever I mesured each cylinder a few times each using solder and got a fairly consistant 1.6mm. Hopefull 1 or 2 tenths of a mm will true it up and I will not have to go lower then about 1.4mm. |
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Post by bare on May 24, 2022 16:49:02 GMT 1
IMO .. ANY shop that is worth handing over your hard earned Coin to... For headwork.. 'Should' reprofile the squish band to match the pistons being used.
Band Width as well.. if they are seriously reputable.
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toddo
Weekend rider
Posts: 75
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Post by toddo on May 25, 2022 9:14:28 GMT 1
IMO .. ANY shop that is worth handing over your hard earned Coin to... For headwork.. 'Should' reprofile the squish band to match the pistons being used. Band Width as well.. if they are seriously reputable. . Thanks bare I am actually getting the tops of the cyliders skimmed. When it is done it will only be a tenth or two of a mm less then stock. |
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