372XP X-Torq Modding

[XP_Slinger]

I'll second that.  I haven't been a participating member on this forum for very long but it's easy to see that Spike60 is one of the guys that is eager to share his knowledge in a productive manner.  That goes for weimedog also.  I've learned a lot over these couple days. Thanks fellas

[ehp]

Spike, gut everything , first thing you will notice is the saw will run a lot better and be far better to adjust on the carb compared to stock , the idle is far better than stock , You should blend the 2 intake air ports so no major restriction for the air/fuel mixture to get into the cylinder . Every XT that I have built is still running strong and I have only built these saws for guys that cut timber so most have a lot of hours on them , Most guys ran 385/390's and parked them . I never sent a XT to the USA only in Ontario . I have heard lots about the bore lining coming off after porting and stories like that but in most cases that's not the cylinders fault , that's the guy running the porting tools fault , Using way to coarse of a porting burr does that, the 7900 will do the same . I have seen pictures but never had a cylinder lining lift on me 

[ehp]

Now I have heard some of the XT's come with a different carb , I have never seen that here , all came with same carb so far

[weimedog]

Home from work .. wow! A lot has gone on! Pretty much any Sunday the farm road isn't snowed in works. I have a set of J-red 2166 cases that need a purpose, maybe that will be a test bed for XT top ends with EHP inspired mods. I see the suggestion on gutting all plastic dividers from air filter to cylinder AND raising transfers & exhaust. Any idea on the ending blow down & exhaust opening? Any surgery to the intake port/casting on the cylinder? Looks like there is a fair amount of "meat" around that intake should working those make sense. Thanks for both the research and defining a direction to forge ahead with on these.

[49er]

I kinda like the fuel mileage of my XT, well really not having to go to my gas can as often.Cost of the fuel is not important.
A rubber intake manifold and plastic intake is all that would be needed to go back to strato. But the saw may not like it what with the changes in port timing.
Running the saw each way would be an interesting experiment.

[49er]

   I removed the black coil and reinstalled the original blue coil. I think it runs better with the retarded ignition at idle and a good advance at high rpm.
   I have heard the compression release is too great on this saw. I believe it is because on restarts while using the "CR" it does not like to start unless ya give it a good windup. So I am thinking of trying a "CR" from another saw like my 2253.
   Has anyone else tried this? 

[weimedog]

Just put a "plug" in it. Solves the issue.

[Spike60]

Spike, gut everything , first thing you will notice is the saw will run a lot better and be far better to adjust on the carb compared to stock , the idle is far better than stock , You should blend the 2 intake air ports so no major restriction for the air/fuel mixture to get into the cylinder.

Thanks for the advice Ed! Did just what you said, and the saw really runs nice. Doesn't mind being leaned on. You're right on the idle settling down too. Carb needed a fair amount of adjustment from where it was to adapt to the changes.

[ehp]

Spike not a problem , the xt motor is a very good design just needs a hack to make it run abit better  ;D. I'm to the point I donot like running a stock xt just because of how they idle and throttle response compared to modded

[ehp]

play with the flywheel to Spike, advance the flywheel timing say even 1/4 width of the key way helps as well , makes them come alive when you nail the gas  ;D

[RIDE-RED 350r]

In my experience, a little more timing within reason is a plus with alot of different things.

This may or may not apply to the specific application we are discussing (372XT) But I would only caution that between the bump in compression with the gasket delete, and advance of ignition timing, it may bring your fuel octane requirements up a little higher than pump gas can provide.

[XP_Slinger]

Spike, gut everything , first thing you will notice is the saw will run a lot better and be far better to adjust on the carb compared to stock , the idle is far better than stock , You should blend the 2 intake air ports so no major restriction for the air/fuel mixture to get into the cylinder.

Thanks for the advice Ed! Did just what you said, and the saw really runs nice. Doesn't mind being leaned on. You're right on the idle settling down too. Carb needed a fair amount of adjustment from where it was to adapt to the changes.

Think I just found a project for this afternoon.  Did you gut the intake and blend the dual intake ports as Ed suggested?

[XP_Slinger]

   I removed the black coil and reinstalled the original blue coil. I think it runs better with the retarded ignition at idle and a good advance at high rpm.
   I have heard the compression release is too great on this saw. I believe it is because on restarts while using the "CR" it does not like to start unless ya give it a good windup. So I am thinking of trying a "CR" from another saw like my 2253.
   Has anyone else tried this?

My XT absolutely refused to start using the decomp until I removed the base gasket and bumped compression to 180psi.  Now it works as it should somewhat indicating that the decomp is a bit too tight as you suggested.  Compression was 145psi prior to the gasket delete.

[49er]

My XT absolutely refused to start using the decomp until I removed the base gasket and bumped compression to 180psi.  Now it works as it should somewhat indicating that the decomp is a bit too tight as you suggested.  Compression was 145psi prior to the gasket delete.
[/quote]

My desire is to have an super easy start, on hot restarts. I want to try 
a smaller decomp from another saw. Right now it does not like hot restarts when using the decomp. It will do it if ya spin it fast enough.

[XP_Slinger]

/quote]

My desire is to have an super easy start, on hot restarts. I want to try 
a smaller decomp from another saw. Right now it does not like hot restarts when using the decomp. It will do it if ya spin it fast enough. :o
[/quote]

Don't blame you, mine frustrated me a little when the decomp wouldn't reset.

[weimedog]

A question. .. I have a bone stock 2172. Not quite a shelf queen but one I want to keep nice... should I tweak it? Or leave it be.

[49er]

A question. .. I have a bone stock 2172. Not quite a shelf queen but one I want to keep nice... should I tweak it? Or leave it be.

I say tweak it. Try it. Report back. And then, I'll know what to do to mine. 8)

[XP_Slinger]

A question. .. I have a bone stock 2172. Not quite a shelf queen but one I want to keep nice... should I tweak it? Or leave it be.

I know the feeling, my 357XP is near new and I had reservations about "tweaking" it because it's so nice.  Needless to say, that reservation went away after running my brothers tweaked 357.  Mods done right will only make your saw nicer IMO.  What are you going to do?

[Spike60]

Think I just found a project for this afternoon.  Did you gut the intake and blend the dual intake ports as Ed suggested?

Yes I did, and it worked nice.    Think of it in 4 steps. Filter holder, carb divider plate, intake boot, and then the blending of the top and bottom intake ports. One look at the carb side of the filter holder and you'll see why that has to get cleaned out! The carb divider slides out easy by removing the throttle shaft. This may allow the choke plate to go a little overcenter, but the choke lever will keep it where it needs to be.

Plan to do his suggestion on the timing advance today, but probably won't run it til the weekend.

[XP_Slinger]

Think I just found a project for this afternoon.  Did you gut the intake and blend the dual intake ports as Ed suggested?

Yes I did, and it worked nice. :)   Think of it in 4 steps. Filter holder, carb divider plate, intake boot, and then the blending of the top and bottom intake ports. One look at the carb side of the filter holder and you'll see why that has to get cleaned out! The carb divider slides out easy by removing the throttle shaft. This may allow the choke plate to go a little overcenter, but the choke lever will keep it where it needs to be.

Plan to do his suggestion on the timing advance today, but probably won't run it til the weekend.

Thanks for the response Spike.  I took the air filter divider out when I deleted the base gasket.  I'll get into mine this weekend and remove the carb divider and blend the intake.  And by blend I assume we are putting knife edges on them to smooth out the flow.  Correct?  Cant wait to hear your report on how she runs.  Left field question:  is it true that to turn a 2166 x-torq into a 2172 all that has to be done is removing the transfer restrictors?  Thanks

[Spike60]

Yes on both the knife edge and transfer cover points.

However, I'm afraid I've detected a little baloney in this thread.    A certain individual has tossed out the thought of going into his mint 2172 and doing these mods to it. There's NO WAY he's going to be doing that right yet; given how well I know said individual. I'm sure that a proven recipe will have to be documented and tested on some other ugly carcass before he messes with that nice 2172.  ;D 

[XP_Slinger]

Yes on both the knife edge and transfer cover points.

However, I'm afraid I've detected a little baloney in this thread.    A certain individual has tossed out the thought of going into his mint 2172 and doing these mods to it. There's NO WAY he's going to be doing that right yet; given how well I know said individual. I'm sure that a proven recipe will have to be documented and tested on some other ugly carcass before he messes with that nice 2172.  ;D

:D  The problem with an itch is you eventually have to scratch it   I get the feeling Weimedog wanted to diversify the thread with some Red n' Black.   Just so happens that I am, for some reason, REALLY wanting a JRed.  A friend of mine is getting a smoking deal on a new 2166 from a dealer for $549 (Hence the transfer restrictor question).  As to why I want it?  Still haven't figured that one out :  Might be because of my dads 87' 455 that both me and Ride-Red cut our teeth on as kids.

[49er]

Yes on both the knife edge and transfer cover points.

However, I'm afraid I've detected a little baloney in this thread.    A certain individual has tossed out the thought of going into his mint 2172 and doing these mods to it. There's NO WAY he's going to be doing that right yet; given how well I know said individual. I'm sure that a proven recipe will have to be documented and tested on some other ugly carcass before he messes with that nice 2172.  ;D

I like some baloney. There is nothing wrong with being conservative.  :D
I still don't know if I want to go non-strato with this saw. A faster saw is desirable but a saw is not fast when your pouring fuel in it.

[weimedog]

That was Spike's way of saying... leave it stock for now. BUT he is right. Have two bloody carcasses to try things out on first.. One red and one Orange. ( Need another new top end though.... ) ALSO this gives a reason for those older boots to avoid the trash can. And on the "knife" edge, that's not actually hogging out the entire dividers, just making a more aero dynamic shape for the mixture to work around to get to the intake ports.... does it make sense to "favor" the traditional port (lower one)?? How about widening that lower port a bit after blending the divider to favor it vs. the strato ports? Inquiring minds want to know... That along with an offset key and a "no base gasket build" sounds like a start.. Has anyone figured out what timing works best for these? Exhaust/Blow down numbers after that intake tweak?

(Still want to do a "simple mans" old style 365 build )

[XP_Slinger]

Yes on both the knife edge and transfer cover points.

However, I'm afraid I've detected a little baloney in this thread.  :)  A certain individual has tossed out the thought of going into his mint 2172 and doing these mods to it. There's NO WAY he's going to be doing that right yet; given how well I know said individual. I'm sure that a proven recipe will have to be documented and tested on some other ugly carcass before he messes with that nice 2172.  ;D

I like some baloney. There is nothing wrong with being conservative.  :D
I still don't know if I want to go non-strato with this saw. A faster saw is desirable but a saw is not fast when your pouring fuel in it.

Sounds like we need to test the fuel mileage.  I would be surprised if it were any worse than a traditional 372xp, bit that is purely speculation.  I bet Ed or Spike could offer some info on the strato vs de-stratofied fuel economy.