372 X-torq Mod Discussion Final Woods Port Video Posted

[RIDE-RED 350r]

You couldn't slap the grin off my face.... still!

On your XT... I wonder if some 372 OE porting numbers might be useful on your XT??

 

[fordf150]

I wouldn't run 50:1 in a stock husky. There's been too many crank bearing failures in them.

Stihl is no better. Plenty of big end bearing failures on stock saws.

 

[XP_Slinger]

I doubt it. I think I need to just find my way by experimenting. I'll get there, or I'll trade in on a 390.

 

[XP_Slinger]

Ok fellas...tuning got it going. Initial cuts with the tac showed it holding 11.5k in the cut. An improvement over the previous 11.2k. Did a few cuts then did a plug chop to check tune, it was rich. So I started leaning it out 1/8 of a turn at a time, then doing five cuts then a plug chop. The plug started to turn a dark grey at 12.5k. It got too grey for my liking at 12.7k! It had great power at 12.7k but since it's not a race saw I dialed the tune back to 12k +/- 100 in the cut for longevity sake. It runs great! I made all my cuts in 15" (measured) very hard seasoned white ash. My chain is a near new stihl RS, the only cuts on it were the ones I did for the video in this thread and a couple last night. I am now very pleased with the advances in performance I've made. And lesson learned, don't jump to conclusions before a proper tune. I should know better but we all make impulsive mistakes. I'll get a video up later when my brother shows up to be my camera man. And I'm sure he'll want to post a video of his rabid XPW...

 

[XP_Slinger]

The last recorded cut...

 

[XP_Slinger]

Here's the plug tuned to 12k in the cut...success!!!!

 

[XP_Slinger]

Post woods port video, same log as the next video but on the butt end.

 

[XP_Slinger]

For comparison

 

[RIDE-RED 350r]

Next on the bench: 357, times 2!

 

[Mattyo]

So...what cha do to the xpw?

Heres my xpw transfers...

 

[RIDE-RED 350r]

My XPW work..I'd have to dig out my notebook for timing numbers....

 

[Mattyo]

Looks good to me....basically same as what I do.

 

[Mattyo]

Your transfers dip forward more towards the intake than mine....I think

 

[RIDE-RED 350r]

I did not widen the transfers or alter their angle. Just raised em.

I did however widen the exhaust to just under 70% of bore, 35mm if memory serves.

And I did square up the intake, no change to intake timing though other than what change occurred from running no base gasket

It seems to be a pretty capable setup though. Since I posted in this thread, I was able to tune it to 14.6k no load RPM and still retain slight 4-stroking. But I tuned it back to high 13s for work.

 

[Spike60]

I really don't think the bottom end would last too long at 14,700. High 13's is pushing it too.

 

[T.Roller]

13, 800 is what mine is tuned to now

 

[Spike60]

You guys are probably already doing this, but 40:1 would be a good idea when winding these saws up beyond 13,000.

 

[T.Roller]

You guys are probably already doing this, but 40:1 would be a good idea when winding these saws up beyond 13,000.

Yes sir I sure am.

 

[RIDE-RED 350r]

You guys are probably already doing this, but 40:1 would be a good idea when winding these saws up beyond 13,000.

I'm actually running mine at 32:1 for the exact reasons you mentioned.

Tuning to 14.6k was simply for testing purposes to see what my work made the engine capable of compared to stock config. At that RPM there is still a touch of 4-stroking but not a copious amount... For work I dialed it back to high 13's, 13.7k if memory serves. There, it 4-strokes readily and needs to be in the cut to clean up. When my saws were stock, I always ran 50:1 as per Husky's recommendation. But since I'm learning how to make them spool higher and one of my saws now does spool significantly higher, I switched to 32:1 in an attempt to help the moving components deal with the higher RPMs better.

And I'm sure you already know this, but the stock coil on my XPW was limited at 13.3k. So I might assume that in stock config and properly tuned it was capable of that??

FWIW, 32:1 is the ratio most frequently recommended by the best 250r builders in the biz for hot-rodded 250r's and that's also what I run those at.

 

[mdavlee]

Some of the ones I sent to Canada are mid 14s running 33 and 36" bars. They 4 stroke past 16k easily.