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Discussion Starter #1 (Edited)
Hello
Not long ago, I replaced the cylinder with the piston (Arisal 125ccm) after flooding with coolant and starting the motorcycle, after 10 minutes, coolant began to leak from under the head. The head is tightened with a torque wrench. At the beginning, when I bought the Arisal set, I noticed that its upper part is slightly rough (the old cylinder is perfectly smooth). Is it a manufacturing defect? is it supposed to be like this? The problem is that there is a leak between the head and the cylinder.

I will give photos in a moment.

sorry for my english ;)
 

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photos ideally :).

The mating surfaces like where the head gasket etc go need to be smooth and it should all fit together quite exactly, not like "ok well it nearly fits" or chunks missing, or you'd get weird coolant leaks

Could be you got one with a defect? Interesting given someone was asking about replacement pistons just the other day and airsal was one of the options.

I've got a fresh 180cc cylinder here and this is how it looks in case it helps:

IMG_20210107_020828.jpg
 

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Discussion Starter #5 (Edited)
Disassembled engine.
the place of the leak.
20210107_155637.jpg

comparison of cylinder surfaces on the left Airsal on the right old.
Why does Airsal use such a rough surface?
or maybe the cylinder is defective? Maybe you need to tighten more Nm? I don't know anymore.
20210107_171626duze.jpg
20210107_171725.jpg

Airsal
feel the rough surface on your fingernail
20210107_171538.jpg


Old cyinder
20210107_171541.jpg

it is probably not normal right?

The cylinder head
20210107_171014.jpg

20210107_171033.jpg


I think I will write directly to Airsal in Spain.
20210107_170216.jpg
 

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hmm interesting. that does look a bit rougher than you'd expect. I just re-checked the 180cc one and whilst the finish is matt, it is very smooth, there's no roughness or texture like in your pics.

it doesn't really look like it shold cause a problem though .. once the gaskets are on.. surely, or?
 

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Discussion Starter #7
Well, I will write @ to the manufacturer Airsal and show these photos interesting what they will write back.
 

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I couldn't remember what the 180 i have on now looked like but I just found a pic for comparison..it's smooth and matt like the other one I have here (they're supposed to be the same though). Idk if this pic will come out but..

P1060190.JPG
 

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Discussion Starter #9
So I think something is wrong with my cylinder, we'll see what they write back from Airsal ... if they write back at all.
 

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Gasket ? on head/cylinder ? , I did ask you for specific photos ! , however looking @ first photo your head is bent like banana (or head tightening was done VERY WRONG WAY ) in a place of leak it goes down touching cylinder squasing iregularly gasket and further more touching cylinder preventing proper gasket seal. Need photos from my firts post !
 

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Discussion Starter #11 (Edited)
Here you are
I personally tightened the head correctly. I even tightened in three stages, 8Nm 16Nm and 22 Nm crosswise. Unless it was already badly tightened, but there was no leakage before.
I also unscrewed in three stages.
20210108_150926.jpg
20210108_150942.jpg
20210108_151014.jpg
20210108_151024.jpg
20210108_151203.jpg
20210108_151216.jpg
20210108_151226.jpg
20210108_151233.jpg
20210108_151251.jpg
 

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have you perhaps got a straight edge or a metal ruler or something you can lay across the cylinder and the head surface to see if there's any deformation?

It's very difficult to get a pic which shows stuff like that accurately.
 

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After examination those photos ( sounds good is it :D ) do this: take glass about 40x40cm more less put it flat on something so you can see uner glass spill on it bit (few drops) of kerosine and put head on it and check if fluid tension distibuted kerosine across whole flat surface of head that touches glass, if any side is not touching head is bend like banana do same with cylinder, if you put to much kerosine all will be floating and no result will be visible, so bit of experimentation is needed about amout fluid needed, same can be done with watter however water have tendency to make metal rust ;) . You can clearly see that one corner of gasket was squased badly question is whether it was bend head or wrong assembly and tightening ;) . What brand is head ?
 

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Keep in mind glass aint perfect either, this should work perfect, one last test put them together holding in heands so they touch where gasket goes (both Head/cylinder clean and dry) touch them and look throu where gasket goes to bright light if there is bend you will see light. Hoewer looking on videos you are to blame as there was fault when tigheting from my point of view, bend head have issues touching all corners in fluid test ;) it is irregular shape.
 

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also sometimes you do everything right and the fucker still chucks coolant everywhere.

how much is another head gasket? is it possible to get another one (or two) to test?

did you remember to put oil on the threads of the head bolts. 25nm+oil is quite different from 25nm without oil and if miz is right then there's a problem with the tightening and top of the list of things to forget is oil on the threads.
 

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Discussion Starter #18
I think this gasket is to compensate for these little unevenness.

I have two more new head gaskets.

I did not lubricate the threads of the screws, only the heads and washers of the head pins. This time, he will also apply grease to the threads. And tighten to 25 Nm, not 22Nm.

I will check the adhesion under the light of the head and cylinder dry as it writes
misiozol
 

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Under NO CIRCUMSTANCE do more than 22Nm, as this 22Nm is on edge of thread pulling from alloy block, just use bit of oil on thread and use copper washers ! Now do NOT use to much oil as it will not compress under thread and will damage block . I can tell you that doing even 20Nm is quite sufficient for proper seal, all must be clean and dry as gasket have adhesion layer and is 1 time use only. Best solution for this would be to have pins instead of bolts to be sure not to damage block against thread pulling but thats whole diferent story ;)
 

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Discussion Starter #20 (Edited)
Copper washers are standard. OK I will not give more than 22Nm. Everything was clean and dry washed 100 times before reassembling.

also sometimes you do everything right and the fucker still chucks coolant everywhere.
According to what you wrote, I will check the head one more time and try to put it all together again. If there are leaks again, I will either give the heads to the grinding or buy a Chinese set and try on it.

The Airsal company wrote back like this:

Good morning,


Firs of all we want to thank you very much for purchasing Airsal cylinders.


Concerning your problem, roughness shouldn’t be a problem since the gasket set is enough to close. Have you check the head flatness? Because normally, almost 100% of leaking problems are caused by a deformed head.


Let us know.


With best regards,
 
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