372XP Rebuild and mod.

[Mastermind]

Bout the same principal....just never did it that way before I've done it this way so much Im used to it I guess.

I run a ring up in the bore like you......then measure from the squish band down with a machinist's rule and cut a piece of card stock that size. I stick it in the bore and cut till I hit it......

 

[blsnelling]

Same here. But can you really pin the whole problem on high compression?

Not with just one failure. It is cause for concern though.

 

[parrisw]

That's why I run 32:1, especially in the winter.



I do that all the time and then forget. D'oh.

Well Will, great sounding saw so far, seems really tight on the acceleration. Now I'm gonna need you to build me a XPW.

I've been running about 45:1.

I'll build you a saw anytime JJ. Just say the word. You better let me figure out the XPW on my own cylinder first though!! Can't imagine its much different in porting then a 71cc 372.

 

[Mastermind]

Same here. But can you really pin the whole problem on high compression?

I get talked into stuff at times.......I built one 372 with a cut squish and a popup. It's still running in a work setting with real high compression....

 

[Mastermind]

32:1 for me too JJ....

 

[Jacob J.]

I knew the 372 had some big end rod bearing issues in the past, but was surprised to hear that the wrist pin bearing went bad.

That's why I use new wrist pin bearings on any saw I modify. I only go OEM if at all possible- on custom applications I'll use a different size OEM from another model.

 

[blsnelling]

I get talked into stuff at times.......I built one 372 with a cut squish and a popup. It's still running in a work setting with real high compression....

Someone's got to push those boundaries

 

[parrisw]

Not with just one failure. It is cause for concern though.

Sure, I'm not really worried though. You guys will be the first to find out if she blows up, it will be put to the test tomorrow, I will be running it rich though for the first few tanks.

 

[parrisw]

I get talked into stuff at times.......I built one 372 with a cut squish and a popup. It's still running in a work setting with real high compression....

Someone's got to push those boundaries

Sure, as long as they know you're pushing the limits.

 

[Mastermind]

Sure, as long as they know you're pushing the limits.

I ask a lot of questions on certain saws.......I also like to get an idea on how well the owner can tune and sharpen.....

 

[parrisw]

I ask a lot of questions on certain saws.......I also like to get an idea on how well the owner can tune and sharpen.....

Yep, and that's the biggest thing I worry about when selling someone a modded saw, tune tune tune.

 

[Tree Sling'r]

I ask a lot of questions on certain saws.......I also like to get an idea on how well the owner can tune and sharpen.....

Yep, upside down spoons don't cut any faster at 14k.

 

[parrisw]

Yep, upside down spoons don't cut any faster at 14k.

ha ha ha. LOL, haven't heard that one before.

 

[Jacob J.]

Yep, upside down spoons don't cut any faster at 14k.

That's why everyone should have a Ziegelmeyer grinder in their shop. The one grinder that can do everything and do it well.

 

[srcarr52]

Will, I don't know how much you cut out of the squish band but I cut 0.030" out of a BB kit so it should be interesting to see what I come up with. My 394 is still running strong it's it was above 200 after the first tank. I should put the gauge on it to see where it settled at.

 

[parrisw]

Will, I don't know how much you cut out of the squish band but I cut 0.030" out of a BB kit so it should be interesting to see what I come up with. My 394 is still running strong it's it was above 200 after the first tank. I should put the gauge on it to see where it settled at.

Well, honestly I kinda screwed up and lost a little track of it, was the first one I did with using the mandrel as a cutter, so to keep track of my progress I used a digital depth gauge, but the plate I used across the bottom of the bore to sit the depth gauge on had a burr which I didn't see so my first measurement got all messed up, I was shooting for .050" out of the chamber, but I think I ended up taking out .060". So next one, I think I wouldn't go for more then .050". But for you with the BB, the bigger bore if the CC was the same size as stock you'd have more comp then a stock bore, so I'd say your on track with starting with .030", you may want more, what's you're intake at? Do you have room to take more out and drop the cylinder some?

 

[Tree Sling'r]

That's why everyone should have a Ziegelmeyer grinder in their shop. The one grinder that can do everything and do it well.

Few and far between machines.

 

[parrisw]

That's why everyone should have a Ziegelmeyer grinder in their shop. The one grinder that can do everything and do it well.

Few and far between machines.

Never heard of one.

 

[Tree Sling'r]

Never heard of one.

The best square grinder evermade. They have a raker machine also. A friend of mine had both, he sold them out from under me, so I got the Silvey Pro Sharp and their raker machine. Happy with what I have, but the Zieglemeyer was my first choice.

 

[Jacob J.]

Few and far between machines.

They are- my dad bought one used in 1987 and paid $1700 at the time. New they were over $4k. I just got one this summer but it cost me $300 and two full days of labor.