372 xp and 372 xpw

[The beginner...]

Thank you fur your in put...is this a common thing do you no....thanks...

 

[gomoto69]

I've only seen it once, happened to my son's kx 125, fully race ported by pro circuit, but we ran maxima 927/vp c-12 in that engine, and the castor oil is notorious for gumming things up. The bike sat for a while after arenacross season but before he could ride outdoors here in bc, maybe 2 months. Went to kick it over and had zero compression. Pulled the jug off and rings were simply stuck in the grooves, cleaned up no prob. If your saw had been run with cheap and or too much mix oil then sat, it could have stuck the rings enough to have low compression but look fine. Worn rings could cause it too.

 

[The beginner...]

Thank you fur your input gomoto...how did you clean the pistion up and with what..thank you...

 

[71dart]

That piston looks pretty worn out to me. Compression is measured while your piston is at top dead center so those transfer covers aren't effecting your compression.

 

[The beginner...]

Thank you fur your in put 71dart....OK..wasn't sure...is there a way to clean up the jug with out buyin another one...thank you...

 

[The beginner...]

Up date...I took the jug,pisition and carb off the 372xp x-torq...it had no compression...then I took the jug,pisition and carb off the 372xp and put it on the body of the 372xp x-torq...I had to use the rings from the x-torq and put the on the pisition of the 372xp...I had the coil out...but didn't have a feeler gauge to set the coil...so I used a match book cover...I put it in between the coil and the fly wheel...let it pull itself together...then tightend it up...pulled out the match cover...put every thing together...primed it and it fired on third pull...I put gas in it and choked it a few pulls...it fired up and runs good ...I need to retune the carb...it needs more top end...I'll kit the carb at the end of my season...I do still have a little problem tho...where the dogs are attached to the block...some one let them get lose and it knock the threads out...so the dogs are only held on by the mount bolt...can I Healy coil those two spots and if so...what size would they be...and since i used old rings on an old pistion...how long do you think it will last...should i buy anothere jug and pistion...and if i did that...should i go big bore...thank you every body fur helpin me with this project...I learn a lot...

 

[dozerdan]

Regarding the XPW, there were 3 basic versions of them in the US - 71cc (up to 2006 or so), 75cc (about 2006 - 2009) and 71cc strato/xtorq (from 2009 or so).

The 75cc topend was from the 375 cutoff saw, and had much inferior porting compared to the original 71cc one. That can be corrected by someone that knows what he is doing though - but properly porting it is much more work than on the original 71cc one..

It does take more work when porting the 75cc cyl but not as much work as a 346. There is also more room to get your tools inside the 375 cyl.

If I had to pick my favorite cyl to port on the 372 it would be the 75cc, the end results are well worth the little extra work. The bad part is I cant find any good quality after market pistons for the 75cc cly.

Later
Dan

 

[The beginner...]

Up date...I took the jug,pisition and carb off the 372xp x-torq...it had no compression...then I took the jug,pisition and carb off the 372xp and put it on the body of the 372xp x-torq...I had to use the rings from the x-torq and put the on the pisition of the 372xp...I had the coil out...but didn't have a feeler gauge to set the coil...so I used a match book cover...I put it in between the coil and the fly wheel...let it pull itself together...then tightend it up...pulled out the match cover...put every thing together...primed it and it fired on third pull...I put gas in it and choked it a few pulls...it fired up and runs View attachment 430319 View attachment 430320 goodView attachment 430319 View attachment 430320 View attachment 430321 View attachment 430322 View attachment 430323 View attachment 430324 View attachment 430325 View attachment 430326 View attachment 430327 ...I need to retune the carb...it needs more top end...I'll kit the carb at the end of my season...I do still have a little problem tho...where the dogs are attached to the block...some one let them get lose and it knock the threads out...so the dogs are only held on by the mount bolt...can I Healy coil those two spots and if so...what size would they be...and since i used old rings on an old pistion...how long do you think it will last...should i buy anothere jug and pistion...and if i did that...should i go big bore...thank you every body fur helpin me with this project...I learn a lot...

It does take more work when porting the 75cc cyl but not as muck work as a 346. There is also more room to get your tools inside the 375 cyl.

If I had to pick my favorite cyl to port on the 372 it would be the 75cc, the end results are well worth the little extra work. The bad part is I can find no good quality after market pistons for the 75cc cly.

Later
Dan

It does take more work when porting the 75cc cyl but not as muck work as a 346. There is also more room to get your tools inside the 375 cyl.

If I had to pick my favorite cyl to port on the 372 it would be the 75cc, the end results are well worth the little extra work. The bad part is I can find no good quality after market pistons for the 75cc cly.

Later
Dan

Thank you fur your input Dan....do you have pictures of portin of know of a web sight where I can read up on how to port...I am very interested in learnin how to port and polish...thank you...

 

[SawTroll]

It does take more work when porting the 75cc cyl but not as muck work as a 346. There is also more room to get your tools inside the 375 cyl.

If I had to pick my favorite cyl to port on the 372 it would be the 75cc, the end results are well worth the little extra work. The bad part is I can find no good quality after market pistons for the 75cc cly.

Later
Dan

Nice to see you posting again!

 

[The beginner...]

Thanks saw troll...

 

[dozerdan]

Thank you fur your input Dan....do you have pictures of portin of know of a web sight where I can read up on how to port...I am very interested in learnin how to port and polish...thank you...

Read and reread and then read again the Two Stroke Tuners Handbook. http://www.amrca.com/tech/tuners.pdf

The lower transfer ports should look like this on a 346,357,365 or 372. http://www.sunlink.net/~dozerdan/372hiltbarrel.jpg The rest you should be able to figure out.

Later
Dan

 

[dozerdan]

Nice to see you posting again!

Thanks Troll

 

[The beginner...]

OK...I pulled this pistion out of the 372xpw...one of the 3 saws I bought fur a hundred bucks....all 3 being the 372xp series...what a pain it was to get the jug off..the pistion has a few hits on it...the Lowest one to the bottom of the pistion and the longest one looks like maybe a piece come from the crank case...maybe ...both rings look still intact....the crank don't feel smooth nether when you turn it over...should the crank be OK fur rebuilin the saw....thanks...

 

[Gypo Logger]

Not trying to highjack the thread, but my friends new 372xt is doing this.
Hoping it isnt a crank seal.

 

[The beginner...]

Read and reread and then read again the Two Stroke Tuners Handbook. http://www.amrca.com/tech/tuners.pdf

The lower transfer ports should look like this on a 346,357,365 or 372. http://www.sunlink.net/~dozerdan/372hiltbarrel.jpg The rest you should be able to figure out.

Later
Dan

Thanks fur your input Dan...awesome...thank you...I will check it out...I want to learn...

 

[The beginner...]

Not trying to highjack the thread, but my friends new 372xt is doing this.
Hoping it isnt a crank seal.

No worries...I can't see the link...

 

[The beginner...]

Not trying to highjack the thread, but my friends new 372xt is doing this.
Hoping it isnt a crank seal.[/QUOT



I just watch the video...I think it is a air leak of some kind...if its new...is it under warranty... Take it to the dealer...when did it start doing that...

 

[dozerdan]

Not trying to highjack the thread, but my friends new 372xt is doing this.
Hoping it isnt a crank seal.

John
I don't have any sound on your video. I have seen a lot of crank side bearing failure on the 365 and the 372xt. I have heard the cause to be various from faults. I think that it is a Husky design error. The 365 or 372 case is a proven design and it worked for years until they added the strato top end. That cylinder uses way less fuel then the old cyl did. Less fuel means less oil, hence the problem. I have rebuilt and ported and de-strato many of the new xt saws and they hold up fine. They also use more fuel.

Later
Dan

 

[The beginner...]

John
I don't have any sound on your video. I have seen a lot of crank side bearing failure on the 365 and the 372xt. I have heard the cause to be various from faults. I think that it is a Husky design error. The 365 or 372 case is a proven design and it worked for years until they added the strato top end. That cylinder uses way less fuel then the old cyl did. Less fuel means less oil, hence the problem. I have rebuilt and ported and de-strato many of the new xt saws and they hold up fine. They also use more fuel.

Later
Dan

How do you de-strato the saw...

 

[dozerdan]

Remove the strato, grind and cut. LOL

Later
Dan