Stihl 026 Top End Rebuild Compression Problem

Wesspur
Rugged made
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Bob Hedgecutter said:
Don't know what all the cryptic questions are for, but do what @rupedoggy says and measure the stoke.
Or list the serial number up here and maybe someone with the access to the US data base can tell you the information logged on to records when it was first sold.
Click to expand...
A previous poster asked those question accouple days ago. I think based on the answers he can tell 024 vs 026.
 
Confusing.

Very early 026 could have rails without the oil pump adjustment notch. Later all have notch, regardless of the type of oil pump they came with.

Never saw an 024 with a side adjust case. Every one I’ve had, including supers, were front adjust.

Is it at all possible that you have a 44mm piston in a 44.7 bore jug? What’s the clearance between the piston skirt and bore ? Makes no sense cause it’s with both kits, right?

Something fishy with whole thing. Did you check actual squish?
 
drf255 said:
Confusing.

Very early 026 could have rails without the oil pump adjustment notch. Later all have notch, regardless of the type of oil pump they came with.

Never saw an 024 with a side adjust case. Every one I’ve had, including supers, were front adjust.

Is it at all possible that you have a 44mm piston in a 44.7 bore jug? What’s the clearance between the piston skirt and bore ? Makes no sense cause it’s with both kits, right?

Something fishy with whole thing. Did you check actual squish?
Click to expand...
I tried to check squish but its too large and over .030 inches so my solder isn't thick enough. This saw is the old ass 026 I'm 99% sure. Also I'm not going to lie I left the base gasket that was on their because there are no tears and it seemed super hard to remove. I was thinking I could get some chemicals to help remove that base gasket then check compression with the gasket deleted. Then if that wasn't enough sand down the cylinder. The piston seems sized correctly diameter wise and yes came with the cylinders.
 
RabbitFarmer said:
I tried to check squish but its too large and over .030 inches so my solder isn't thick enough. This saw is the old ass 026 I'm 99% sure. Also I'm not going to lie I left the base gasket that was on their because there are no tears and it seemed super hard to remove. I was thinking I could get some chemicals to help remove that base gasket then check compression with the gasket deleted. Then if that wasn't enough sand down the cylinder. The piston seems sized correctly diameter wise and yes came with the cylinders.
Click to expand...
Well, use the old playschool plasti-gauge method. Take the cylinder off put a rolled snake of plasticine that measures around 1/8 to a 1/4 inch diameter (ie: more than the 2mm you are short), put the cylinder back on, roll the engine over a couple of times to squish the plasticine, take the cylinder off and measure the thickness of the crushed plasticine.
You did install rings on the piston eh?
 
Bob Hedgecutter said:
Well, use the old playschool plasti-gauge method. Take the cylinder off put a rolled snake of plasticine that measures around 1/8 to a 1/4 inch diameter (ie: more than the 2mm you are short), put the cylinder back on, roll the engine over a couple of times to squish the plasticine, take the cylinder off and measure the thickness of the crushed plasticine.
You did install rings on the piston eh?
Click to expand...
LOL yes I installed the rings. This isn't my first top end its just my first 2 stroke. I promise I'm not completely retarted. I've measured piston/valve clearance on 4 strokes with model clay before I just don't have any around right now and the two stroke guys I saw on YouTube seem to use solder for some reason which I did have. I can get some and measure but it will just be a day or so.
 
RabbitFarmer said:
LOL yes I installed the rings. This isn't my first top end its just my first 2 stroke. I promise I'm not completely retarted. I've measured piston/valve clearance on 4 strokes with model clay before I just don't have any around right now and the two stroke guys I saw on YouTube seem to use solder for some reason which I did have. I can get some and measure but it will just be a day or so.
Click to expand...
Generally we use solder because if the cylinder is correct to the stroke- that is all that is required.
You mentioned earlier you were stacking solder 3 high to get contact.
You could still take the cylinder off and measure the stroke from BDC to TDC.
 
RabbitFarmer said:
I tried to check squish but its too large and over .030 inches so my solder isn't thick enough. This saw is the old ass 026 I'm 99% sure. Also I'm not going to lie I left the base gasket that was on their because there are no tears and it seemed super hard to remove. I was thinking I could get some chemicals to help remove that base gasket then check compression with the gasket deleted. Then if that wasn't enough sand down the cylinder. The piston seems sized correctly diameter wise and yes came with the cylinders.
Click to expand...
Fold and twist up the end of your solder and give her a go. Usually stock 026 cylinders are too tight to delete the gasket I believe. The AM cylinders usually have looser squish
 
Ok I've come to the conclusion that the squish band is way to big with both of these after market cylinders its not even close to .02 inches, the modelling clay hasn't come in yet. I gave up and dug through my HOA dumpster and got the original piston cylinder and slapped that back on and it ran perfect immediately. IDK if my 026 is just on the super super low end of crank height tolerance or if both of these AM cylinders suck or if my 026 is actually some rare Frankenstein creature. Either way its running and if the top end goes out in the future and requires anything besides new rings I'll just get a new saw.
 
I could get my calipers out and measure the stroke but I have to use the saw right now so that's going to have to wait.
 
You could have used a ruler to measure the stroke between the AM cylinder coming off and the so called trashed old OEM cylinder (that runs perfectly!) going back on.
Hell, you could have used a stick and marked it.
You could have measured from the cylinder flange to the squish band of your AM cylinders and done the same to the OEM and compared the 2mm differences. :omg:
 
Bob Hedgecutter said:
You could have used a ruler to measure the stroke between the AM cylinder coming off and the so called trashed old OEM cylinder (that runs perfectly!) going back on.
Hell, you could have used a stick and marked it.
You could have measured from the cylinder flange to the squish band of your AM cylinders and done the same to the OEM and compared the 2mm differences. :omg:
Click to expand...
Its not inoperable, but it has some scoring and I would have preferred to just replace it. Don't worry some day I'll get around to measuring it. Its just I have 5 or so big trees down on my property I've been needing to take care off so that's first.
 
I purchased an American made jug and piston as well and had the exact same problem, so I don't think it was a problem with the china jug.
 
RabbitFarmer said:
I purchased an American made jug and piston as well and had the exact same problem, so I don't think it was a problem with the china jug.
Click to expand...
I'm almost positive there are no "American made" piston and cylinder kits. Meteor is made in Italy, Farmertec is China and Hyway is Taiwan.
 

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