Here's one for yuse guys..

[Mr. Wibbens]

I put a Wiseco in my '92 back in '03

Who knows how many hunnerds of hours are on it

A typical ride with Carvr you don't see the staging area for 8 - 10 hrs , not saying you riding all that time...

I'm sure the kips could use a good douche and the piston is probably due for a replacement...

But why?

It still runs very strong, even with me on it, and I've got to be pushing 300 lbs in full riding gear

It starts fairly easy, 1 - 3 kicks. Just checked the plug and it's about fouled

Just for shits and giggles I tested the compression a few minutes ago and she's right at 150psi

Well thats it for now, I gotta go wrastle with my rear tyre. Got a flat few weeks back and I had to settle for a 21" tube. I rode 100 miles with it like that but still I'd rather have the right one on there

[Rick]

Not sure on your compression, but it sounds a bit low. Just rings and carbon...........keep ridin!

[skipro3]

Could metal fatigue be a concern? I'd at least want to look at it for possible signs like a crack or something.

[Mr. Wibbens]

Not sure on your compression, but it sounds a bit low. Just rings and carbon...........keep ridin!

Book says 119 - 185 psi

[Mr. Wibbens]

Could metal fatigue be a concern? I'd at least want to look at it for possible signs like a crack or something.

If'n I take it down that far I'd might as well do a topend, but so far I don't see the point other the possible BIG BANG theory

[Jeb]

You know by the time this thread dies your energy would have been better spent just doing the top end! Or at least the rings and the KIPS.

Maybe she will run even stronger anyways. Stronger being relative, of course, since we are talking about a 200.

Everything seem OK with the 21" tube in your rear tire?


**EDIT**
Removed word scrambling . . . it was pretty early when I made the post!

[Mr. Wibbens]

21" works just fine

[KarlP]

That is good to know.

I've always felt "rebuilds" were done more often than necessary. In my case, anyway, half the time I probably do more harm than good.

Real testament to keeping an air filter clean and hole free, ain't it.

I once ran a KE175 so far past its prime that we ended up having to pull start it with full choke until it warmed up enough to run on its own. You couldn't shut it off for more than a few minutes once it was warmed up.

[skipro3]

I had a little 2 stroke chainsaw once, an Echo, with a 18" bar on it; very small motor. I ran that thing every fall and cut at least 3 cords of wood, sometimes five. At least half the wood was oak with the rest either pine or cedar. I almost always ran that saw at full throttle. There was a trigger lock to hold it wide open so your hand wouldn't get tired from holding the trigger down all the time. Anyways, I never rebuilt that motor. I went though dozens of chains and several bars, but other than a new plug each fall and blow out the little air filter once in a while, that saw had no maintenance; certainly not a top end rebuild. It always started easily too. I had that saw for 23 years and had bought it used. The guy I bought it from had it 7 years, so count about 30 years of use on that chainsaw, used hard without a top end job. Just thought I'd share how reliable a 2 stroke motor can be.

However, It's your butt that's gonna rely on that bike to get you out of the woods as well as it got you into the woods. I usually base my maintenance on that; can I trust this bike and KNOW it's in good enough repair to take whatever might come up today to get me back to the truck if there were an emergency.....

[canyncarvr]

There was a trigger lock to hold it wide open..

Surely that's illegal nowadays, isn't it? Can you imagine a kickback on a locked throttle saw... THAT could get real ugly real fast.

Anyway...why a rebuild.

Your bike seems increasingly harder to start as time goes on. I'd expect that to change with a top-end. But...

.."rebuilds" were done more often than necessary.

Probably.

My first rebuild on my first R5 was @ 47,000 miles. That was on an engine that had run 'race plugs' for years (that I was told would burn a hole in a piston...never did) and, unbeknownst to me, had been rejetted..and WAY lean at that. The thing detonated a LOT on anything below 3000'el. The manual said to remove the heads to 'decarbon' them every 1000...KLICKS. I never did that, neither.

The bike didn't RUN for diddle by then..but it did run. No Big Bang.

As much as you've ridden, I'll bet it's not anywheres close to 47,000 miles!

TUNE UP IN A CAN!!! Squirt some YCCC in there!!!

DONE!!

[fuzzy]

I wouldn't touch it until you notice unacceptable low end output....The low end will go long before you feel it get tired in the peak. A wore out 2T will still scream decent top, but might not even idle, and of course risks piston shattering at that point....Maybe that isn't even a concern anymore on a plated cyl. I think that wiseco would probably go until the thing won't start anymore without causing any damage. Go for the record holding top-end longevity test!

[canyncarvr]

Record holding top-end longevity?

What? 47,000 miles is the proverbial chopped pate? Besides..that was on a TWIN 2T, so the number is really 94,000 miles...right?

'Stronger being relative, of course, since we are talking about a 200.'

Yes. Relative to a much larger machine fer sure...as opposed to any kind'a 'I tried to rev over 6K an I thought I wuz gonna DIE!' bike.

Lessee..let's take a look at that top-10 list agin.......

[Mr. Wibbens]

Anyway...why a rebuild.

Your bike seems increasingly harder to start as time goes on. I'd expect that to change with a top-end. !

Yeah it's pretty tough to start

May take UP to THREE WHOLE KICKS when warm lol

Bikes been sitting for almost a month

Kicked it once yesturday (No priming kicks either) fired right up

Shoulda seen how nasty the plug looked

[Mr. Wibbens]

Stronger being relative, of course, since we are talking about a 200.

Like a 220's anything to call home about

[Mr. Wibbens]

Record holding top-end longevity?

What? 47,000 miles is the proverbial chopped pate? Besides..that was on a TWIN 2T, so the number is really 94,000 miles...right?

'

Hmmmmm, two cylinders doing the work of ONE

I think it'd be more like 23,500 miles

[Colorado Mike]

I would change the piston. For $80, it's just not worth taking the chance on one flying apart like what happened in my kid's bike. Granted he puts tons more pressure on the motor than we typically do (unless you're a 300 lb. yeti ) but why try to break a record on how long you can run a piston till it decides to become something else. Here is what Eric Gorr told me about my questions aimed at determining the cause of a recent YZ meltdown:

"You just went too long on the stock piston, the gray goo is disintegrated aluminum. Put an hour meter on the bike and change the ring every 10hrs and piston every 20hrs. The cylinder plating may be in tact but it might be worn out at the 2 points where the ring intersects TDC and BDC. This is called "ring-ridge" a deep wear spot where the ring changes direction. ...."

Mr. Black echoed the same , albeit a couple weeks earlier, which makes it hardly an echo I suppose.

In my case we are talking a 125 MXer here, so elongating the hours between piston changes would no doubt be fine, but maybe not to the extreme of the phenomenal RD numbers.

Change the piston.

[Mr. Wibbens]

Sorry, every 20 hrs ???

That'd be like every 3 rides

[Colorado Mike]

yeah well, that's where that "elongating the hours" part would come in. I really don't want to change YZ power valves at $153 each when they get pounded by piston parts anymore, or the crank, bearings, and seals at a bit over $200. Thankfully the cases didn't break, that's only a bit over $700.

Point is, changing a piston is way cheaper than all that stuff above. and I can tell you a Yamie cylinder is loads tougher than a Kawy one. If this happened on my bike I would be boring and plating now.

[fuzzy]

An MXer is a bit of a different animal. Would be like CC's RD example, but having the RD turn every bit of it's miles at the strip. A 2T 'on the pipe' will certainely wear out a lot faster...It's being supercharged in a way. Like Ski's can muffled chain saw...They will go A LONG time without being 'boosted'

[kawagumby]

I had a little 2 stroke chainsaw once, an Echo, with a 18" bar on it; very small motor. I ran that thing every fall and cut at least 3 cords of wood, sometimes five. At least half the wood was oak with the rest either pine or cedar. I almost always ran that saw at full throttle. There was a trigger lock to hold it wide open so your hand wouldn't get tired from holding the trigger down all the time. Anyways, I never rebuilt that motor. I went though dozens of chains and several bars, but other than a new plug each fall and blow out the little air filter once in a while, that saw had no maintenance; certainly not a top end rebuild. It always started easily too. I had that saw for 23 years and had bought it used. The guy I bought it from had it 7 years, so count about 30 years of use on that chainsaw, used hard without a top end job. Just thought I'd share how reliable a 2 stroke motor can be.

.....

The only reason that saw went so long is because it was equipped with an auto clutch. And everyone knows auto clutches won't let an engine run to its full potential. What else was done to make it easier to use? Auto clutch, trigger locK, hand warmer?

I had a Peoples Republic KuskaFoulan that was a four-stroke with a two speed tranny/overdrive. I could cut forty-two cords of wood in 5 hours flat. It was eventually outlawed in California due to fears that it individually was a significant contributor to global warming (that was part of the assault weapon ban law nobody likes to talk about). Same thing happened to the Fokker DR7 in WWI. Some people just don't understand that machine perfection stands above petty politics.

But I see your point.