Power Sports Tuning: Power Sports Tuning -> Project: War Pig

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Posted by David - WI , 06 March 2007 - 07:21 PM

Things didn't go very well for the old War Pig on our last trip out.

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I can't say enough good things about Midwest Crankshaft in Green Bay, WI... he fixed my broken crank while I went out to breakfast, so I could take it back home with me instead of driving 3 hours round trip, twice.

Filed in '98 Polaris XCR700

Plug Wires

Posted by David - WI , 25 January 2007 - 08:32 PM

I've always had trouble with Polaris plug wires coming loose from the plug... sooner or later a hard landing knocks one loose.

MSD makes a cool little plug wire "retainer" that works with their plug caps... but their wires are way too big to fit in the stock Polaris coils.

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My next attempt to fit them involves trimming a small amount of insulation off the plug wire where it screws into the coil... and then using heat shrink tubing to lock them in and seal them up.

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Filed in '98 Polaris XCR700

New Heads

Posted by David - WI , 15 January 2007 - 08:53 PM

Sled ran great for the first time out. The EGT's are still a little bit out of whack at part throttle, but not nearly as bad as they were with the Yost tubes in.

Still need to re-tune the primary clutch for the titanium spring. Seems to engage really smoothly but it's only pulling about 8300 rpm at WOT... and it needs to be up around 8800 - 9000 rpm.

I bought some lightly used "Thunder Dome" heads.

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I don't think too much of their chambers... but I think it will be cool to have interchangeable inserts so that I can try a couple different designs. The inserts are "round" so I can make them completely on the lathe... rather than having to mill the area around the bolts.

Filed in '98 Polaris XCR700

Bye-bye Yost Power Tubes

Posted by David - WI , 31 December 2006 - 06:54 PM

Today, the Yost Power Tubes are coming out for good... just too much trouble to tune with them in.

Yesterday I installed the titanium primary spring and adjusted the "Heavy-Hitter" weight system to get my engagement back up to 5k rpm (actually it's 4,999... but that close enough! laugh.gif )

I assembled a pair of Ni-MH battery packs so that I can run the wide-band oxygen sensor on the trail without wiring into the sled (for power). These packs should give 2 hours each... which better be plenty!

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I also ordered some hi-capacity Ni-MH "AA-cells" for our Collett Communicators... which should get us about twice or 2.5 times the running time on those.

As soon as my new hyfax arrives, I need to pull the suspension and find out how many of my lightweight track clips are bent... and tearing up my $120 hiperfax slides. sad.gif

Filed in '98 Polaris XCR700

Parts Is Parts.

Posted by David - WI , 27 May 2006 - 06:33 PM

I know what you're thinking. But, yeah, I do expect this to work! biggrin.gif

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Time To Get Serious!

Posted by David - WI , 27 May 2006 - 06:32 PM

This will be a separate "category" in my blog... building a low dollar, accurate chassis dyno. I'm going to try using different text colors for the varios sections here... not sure how that will work out! blush.gif

The plan is to have an inexpensive system that can be rapidly installed/removed... and gives good, repeatable results.

Initial requirements include recording speed, rpm, horsepower, EGT's... and the ability to graph them all and export them. Additionally, I would like to capture the A/F ratio, intake air temperature, and the belt temperature, if possible.

Being able to view the data in "real-time" during the test would be nice... but right now that's a "luxury" item. Being able to record a dyno run and analyze the data afterward would be fine.

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Last Chance To Run The Pig?

Posted by David - WI , 21 March 2006 - 09:24 PM

Despite our best efforts we cannot make the race tracks.

As of Saturday March 11, we had both the quarter mile and 660 lanes pretty well groomed, and we just needed them to freeze. Instead, Sunday temps hit near record highs, causing slush and Monday we got 24 of snow.

I'm really glad I decided not to drive 5 hours and stay overnight!

Filed in '98 Polaris XCR700

Too Many Aftermarket Parts!

Posted by David - WI , 23 February 2006 - 03:04 PM

It looks like the main problem was with the installation of the Yost Power Tubes... but the EGT's are still off by 100+ degrees compared to being within about 10 degrees of each other last year.

Unplugging the lines from the Tempa-flow unit brings them right in with about 20 degrees across all three cylinders... but I can't figure out why. I blew through the Tempa-flow lines and none are blocked or kinked... and none seem to be leaking vacuum either.

They all draw off a common manifold, so I don't understand how one carb can be different than another... unless the float heights were off or something (checked everything I could think of).

I'll run it up north this weekend (trails closed at 10 a.m. yesterday eliminating my chance to test run the thing before we go) and then decide what to get rid of.

It looks like either the Yost tubes or the Tempa-flow are going to have to go. They might each work independently but they sure don't seem to work very well together.

I'm actually pretty decent at carb tuning... but with the Tempa-flow constantly trying to adjust the mixture and no baseline with they Yost tubes installed; I feel like I've been chasing a ghost for two weeks.

Filed in '98 Polaris XCR700

Just Figures.

Posted by David - WI , 20 February 2006 - 12:15 AM

I screwed up the install on the Yost Power Tubes.

Actually, I followed the directions... but I misunderstood them! huh.gif

The directions said that the Yost tubes should have a large washer on the end and screw directly into the jet tube without any extensions or baffles. Well, I'm not sure what they're called but I left out the little brass cups that the main jets go through... so the jet tubes weren't completely seated even with the Yost tubes screwed in tight. blush.gif

I only got a chance to run it in the shop... but I think it will fix the wild mixture swings I was seeing.

Today I ended up removing the seat, gas tank, oil tank, airbox, carbs, and most of the wiring so I could replace the coolant overflow tank. The neck was starting to strip out and the cap wouldn't stay on or hold pressure.

Other peoples' junk... don't buy it! Don't buy it. Don't buy it. Too late! wink.gif

I also fixed the tunnel protectors that were coming loose and pressure washed the whole mess while the seat and tank were off... so I guess today was a good day.

Still have trouble with the recoil though... tackle that tomorrow night perhaps.

Filed in '98 Polaris XCR700

Finally... Some Snow.

Posted by David - WI , 17 February 2006 - 01:31 AM

Today was a bad day anyway... I should have known better than to work on the sled tonight! sad.gif

This things runs absolutely horribly! The belt de-laminated tonight and I really sort of expected the new belt to solve some of my problems... but no such luck. The new belt seems to be running too hot but I tightened up the secondary to try to get the motor to pull the rpm's I want... plus the hood vents are still blocked off which probably isn't helping.

The EGT's are all over the place... "warning lights are flashing down in quality control"... and there's no rhyme or reason to the readings. First the MAG side is way too hot at part throttle but it "comes in" closer to the other cylinders when you get up around 3/4 throttle.

Next pass down the trail... it starts out great and then spikes at about 3/4 throttle! sad.gif

I spoke to the tech support at Yost Performance... and he more or less blamed the Tempa-flow (even though it worked fine last year). He said the EGT's should be cooler than normal... but they're higher?

I guess on Saturday I will be pulling the Yost tubes out first and then the Tempa-flow... until I get back to a "stable" baseline again. I kind of suspect a vacuum leak in the Tempa-flow plumbing... but the Yost tubes are the only things that's really changed since last year. wacko.gif

Filed in '98 Polaris XCR700

Initial Testing

Posted by David - WI , 11 February 2006 - 08:53 PM

Below is a screenshot of the Digatron software showing a very short run across the yard here at the shop.

The data on the big screen is basically a "close-up" of the data in the small screen at the bottom... the portion shown in the black brackets [ ] is magnified in the big screen above. You can slide the brackets left or right to view different portions of your run in detail.

The data shown in the box on the upper left is the numerical data that corresponds to the black "cursor" line on the big screen. Where ever you click the mouse, the curser line will indicate where the numbers are being taken from to fill the data box.

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Obviously there's still some problem with the carbs or the Tempa-flow unit... the EGT's are 60 degrees apart during the run. (They are within a degree or two of each other at room temperature.)

Filed in '98 Polaris XCR700

Wash Me!

Posted by David - WI , 29 January 2006 - 03:41 AM

So it's 9:30 the night before our first big trip (skipped the radar runs, going trail riding) and the pig is going to the car wash to hose off all the spilled anti-freeze and oil from a couple monthes of taken stuff off and puttin' stuff on!

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Actually, it looks like that little piglet needs a wash worse than the War Pig does... but that'll have to wait until I get home on Tuesday.

Filed in '98 Polaris XCR700

Yost "power Tubes"

Posted by David - WI , 28 January 2006 - 08:42 PM

I've read good things about the Yost Power Tubes on some of the biker forums... and we all know how well Harleys idle and run; so I figure they gotta be good. LOL


The install is just like changing main jets... boring, no photos! tongue.gif

I'm really not expecting any horsepower increase, dispite their claims of 5hp - 13hp increases. I had the thing dialed in pretty well last year already, but I'm hoping for a little crisper throttle response and perhaps some increased fuel economy.

Last year this pig did better than the 600cc sleds I rode with... but I think that's mainly due to better clutch tuning and perhaps slightly leaner jetting that's possible with the Holtzman Tempa-flow control the temperature compensation automatically.


Filed in '98 Polaris XCR700

Pro 2000 Clutch Tool

Posted by David - WI , 28 January 2006 - 01:57 AM

This Pro 2000 alignment tool by TNT Tools is my favorite: Pro 2000

It lets you line up the engine and set the center distance via the cranshaft centerline... rather than indexing off the primary clutch like a lot of tools do.

You can get the crankshaft & jackshaft properly spaced and perfectly aligned using this tool... damn flash ruined my picture!
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I'll try to replace this photo when I have time... the main thing is that you can see the disk on the crankshaft is parallel to the bar. You'll just have to trust me that the tiny pointer is exactly on 12.0" for now.

With these high-durometer motor mounts from SLP and two torque stops on this engine... I set it up parallel right from the start. With softer mounts you might want to start out with a slight "pre-load" to under load everything will line up.

Filed in '98 Polaris XCR700

No Buzzy Grippy!

Posted by David - WI , 28 January 2006 - 01:44 AM

Last year I noticed that even though the engine seems very smoooove ... the handlebars really seem to "buzz" at certain rpm's.

I installed a new billet steering post support that uses a plastic nyliner type bushing but I decided to try making some "dampeners" too.

They're just 1/2" steel bars with o-ring grooves machined into them. I hate to add a pound of steel, but hopefully the o-rings will act as a dampener for the mass of the steel bars... and absorb the "buzz"?

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NOTE: This appears to have been a mistake at this point! rolleyes.gif

Filed in '98 Polaris XCR700

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Project Overview.

The build-up of my radar-run sled... a Polaris XCR 700.

Being a "blog" format, the first post is at the end... the last page is the oldest, the first page is the newest.

There are quite a few "details" that are left out... at least until I can do some testing.
I don't want to recommend a bunch of clutch and carb tuning info... and then find out later doing testing that some other combination works better than what I have in there now.

Eventually, the "secret" stuff will be posted in the "Comments" for each entry... so check them out, too.

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