I hate my late model 371

[SawGarage]

You'll need a right angle for doing the uppper transfers.

OHH! I get to buy new tools!

I figured a right angle would be necessary...

as far as general technique, just general porting stuff ( I have not done many 2 strokes, but MANY 4 strokes..) smoothing, blending, rounding sharp radii, etc..??

Thanks

 

[parrisw]

OHH! I get to buy new tools!

I figured a right angle would be necessary...

as far as general technique, just general porting stuff ( I have not done many 2 strokes, but MANY 4 strokes..) smoothing, blending, rounding sharp radii, etc..??

Thanks

Yes all that is good. Just have to be very careful with port timing, the raising lowering of ports, you can really screw a saw up good of you go too far, best to leave that alone until you have a good understanding of it.

Have a read through this thread I just did on a 371 rebuild.

http://www.arboristsite.com/showthread.php?t=131911

 

[SawGarage]

Yes all that is good. Just have to be very careful with port timing, the raising lowering of ports, you can really screw a saw up good of you go too far, best to leave that alone until you have a good understanding of it.
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of course..I have a fair understanding...not good enough for me yet...

did you make 'adjustments' to the port timing, raising or lowering the ports?

if you lower a jug, it would make sense to raise the ports, correct? (assuming same slug...) to keep the timing the same of course....

I have ALOT more reading to do before I do ANYTHING, besides.

Have a read through this thread I just did on a 371 rebuild.

http://www.arboristsite.com/showthread.php?t=131911

Very familiar with THAT thread!! good stuff!

do you have another pic of your splitter?

thanks!

Jay

 

[parrisw]

of course..I have a fair understanding...not good enough for me yet...

did you make 'adjustments' to the port timing, raising or lowering the ports?

if you lower a jug, it would make sense to raise the ports, correct? (assuming same slug...) to keep the timing the same of course....

I have ALOT more reading to do before I do ANYTHING, besides.





Very familiar with THAT thread!! good stuff!

do you have another pic of your splitter?

thanks!

Jay

Yes I altered port timing. I think I posted my numbers in that thread somewhere.

When you lower the cylinder, you lower the intake increasing intake duration, you can't take that back, but don't worry, that's good. Exhaust, yes you can raise the amount you lowered, but its better to have a degree wheel to check your numbers, as apposed to just raising it a certain amount, you'll still never know timing unless you check.

Sorry I guess I was going to take a pic of that splitter. I forgot, I'll go do it now.

 

[parrisw]

Here ya go.

 

[SawGarage]

Here ya go.

Oh cool....super simple... I'll have to do some measurements and see if I can make a universal for big/small huskys and Stihl as well...

(just planning for the next bearing failure... )

How do you like the AMSoil sabre?

do you actually mix it @ 100:1??? :jawdrop:

 

[parrisw]

Oh cool....super simple... I'll have to do some measurements and see if I can make a universal for big/small huskys and Stihl as well...

(just planning for the next bearing failure... )

How do you like the AMSoil sabre?

do you actually mix it @ 100:1??? :jawdrop:

Very easy to make it universal, those 2 holes I have there, just make a big slot, that's all you need to do.

I love Sabre Professional! I mix at 40:1 since a good portion of my saws are ported.

 

[SawGarage]

Very easy to make it universal, those 2 holes I have there, just make a big slot, that's all you need to do.

I love Sabre Professional! I mix at 40:1 since a good portion of my saws are ported.

cool..

I NEVER run 50:1 like husky suggests. (not to fire up this discussion into a 'how-you-mix-your-oil-ratio' thead..:monkey

I'm about 40:1 also. safer that way.

 

[parrisw]

cool..

I NEVER run 50:1 like husky suggests. (not to fire up this discussion into a 'how-you-mix-your-oil-ratio' thead..:monkey

I'm about 40:1 also. safer that way.

I've only just switched to 40:1, I've run 50:1 for years with no problems.

 

[SawGarage]

I've only just switched to 40:1, I've run 50:1 for years with no problems.

Good to know...I was leary..

J

 

[nhlogga]

The bearings on the 371 are a very standard 6202 C3, I believe. Many other chainsaws have them, so this failure doesn't have much to do with this particular saw. Is it possible that someone rebuilt the saw with cheap bearings? The gasket thingy might indicate that someone went through the saw a bit too quickly. The one thing I have noticed in particular about the 371/371 is that I see more big end bearing failures that would expect. I believe that this failure is more common in the 371/2 because this saw is capable of pulling hard at low RPMS, a good thing, really. I do believe this transfers a lot of stress to the crankshaft bearing, though. For me, the message is clear, try not to lug your 371 just because you can.

Anyhoo, the problems you're having aren't typical of the saw, but may be brought on by the previous owner.

I'll give a hundred for it. :hmm3grin2orange:

Every 371/372/jred 2171/2165 I have owned has eventually lost the big end bearing. Same with my cousin and grandfather. So much for fixing them on the tailgate in the woods:bang:

 

[Brmorgan]

When I tore my 371 down last year, I found that the base gasket had deformed and was leaking, which I had suspected, but it was an intermittent problem like it was for you so I wasn't sure at first. If the gasket had swollen from moisture (washing the saw out in your case, maybe) it could have sealed a small leak off for a while only to manifest the problem now. Your compression is a tad high from anything I've seen here for a stock 371/2; is the base gasket even in there? Mine, with new rings and no gasket, only pushes 150 PSI, which by all accounts is fairly average, and I still have room to deck the cylinder down lower if I wanted to (or had the equipment to do so).

As for the bearings, you didn't happen to whack the end of the crankshaft with a hammer etc. in order to pull the flywheel or something, did you? This can side-load the bearings and make them rough or hard to turn over until they're re-set with a blow in the opposite direction.

 

[andrethegiant70]

When I tore my 371 down last year, I found that the base gasket had deformed and was leaking, which I had suspected, but it was an intermittent problem like it was for you so I wasn't sure at first. If the gasket had swollen from moisture (washing the saw out in your case, maybe) it could have sealed a small leak off for a while only to manifest the problem now. Your compression is a tad high from anything I've seen here for a stock 371/2; is the base gasket even in there? Mine, with new rings and no gasket, only pushes 150 PSI, which by all accounts is fairly average, and I still have room to deck the cylinder down lower if I wanted to (or had the equipment to do so).

As for the bearings, you didn't happen to whack the end of the crankshaft with a hammer etc. in order to pull the flywheel or something, did you? This can side-load the bearings and make them rough or hard to turn over until they're re-set with a blow in the opposite direction.

I believe that gasket was redesigned (wider) so that the really thin part wouldn't be tempted to slip off the inside of the case. I had always assumed that the two I've seen that have done this were simply assembled wrong, but now I'm getting the feeling that heat cycles and vaccum pulled the gasket inwards. This saw might be a good one to use a torque wrench on, at least on the top end.

The original poster said his saw was pushing 165psi, which is unbelievably good for a 371/372. That alone would cause me to keep that saw.

 

[TRI955]

anyone out there able to take the base down a bit?? I wanna go all out if it's coming apart :hmm3grin2orange:

jay

I can do this for you, just have to tell me how much you want to take off.

 

[TRI955]

Hell, might as well send the piston too, you need a pop-up don't ya?!?! You WILL have to put the degree wheel on it then....

 

[SawGarage]

Hell, might as well send the piston too, you need a pop-up don't ya?!?! You WILL have to put the degree wheel on it then....

WOW! that is an awesome gesture...thank you Mike.

degree wheel it would be.

a 371 that outruns a 385 would be cool

saw is disassembled... finishing one other project this week, then on to this...

 

[AUSSIE1]

WOW! that is an awesome gesture...thank you Mike.

degree wheel it would be.

a 371 that outruns a 385 would be cool

saw is disassembled... finishing one other project this week, then on to this...

A nicely ported 371/2 will whip a stock 385's butt in over 2ft hardwood.

 

[AUSSIE1]

Every 371/372/jred 2171/2165 I have owned has eventually lost the big end bearing. Same with my cousin and grandfather. So much for fixing them on the tailgate in the woods:bang:

Interesting how so many aren't having these same issues.

 

[AUSSIE1]

You won't have to degree the saw till after the barrel and piston machining but do check your squish prior.

 

[parrisw]

A nicely ported 371/2 will whip a stock 385's butt in over 2ft hardwood.

:agree2: