Well one of my riding friends said I should do a new top end before the piston skirt cracks or breaks and does majors damage, The 200 95 H-model. Has been race in many Hair Scrambles over the years and when trail ridden rode just as hard, She has been rode hard but not hung out to dry, very well maintain and still pushing around 140 on the compression gauge, depending on weather she starts up on 1-4 kicks and still runs like a scaled dog with all the mods done the first year I purchase, ? is, Is he right or is he blowing me a bunch of smoke, I told him the manual says 150 psi new to 95 psi low, and I was weighting for when she got down to around 110 to do a new top end, Now I am a little worry about taking the old girl out for a spin this weekend, Just in CASE he is Right and I Told You So, I Have all so a XR-600 96 model still on same top end and rode just as hard with mods made as well, and he said is just find they run forever, So if she does need a top end I will do, but If you all say ride I'll be fine, That will ease the stress I am having this week, Just need to Know for peace of mine. Dixie4 out, Thanks for reading.
16 years one same Original Top end 140 psi
- Thread starter Dixie4
- Start date
Don't lose any sleep, the skirt issue has been primarily on the 220s not the 200s. Your results are pretty impressive, do you care to share what air filter you are using and how frequent the changes are, what types of conditions you are riding in (i.e.is it dusty)what type of oil you are using and the ratio. elevation, and jetting? Are you getting spooge?
Definitely change. $130 is easier to swallow now than the 600+ it's going to cost if the piston lets go and destroys the cylinder and crank bearings.
Yes, shattered skirts are common on the 220 with LOW hours, but also common on any cast piston which is run beyond it's service life, which you probably exceeded about 10 or 12 years ago.
Yes, shattered skirts are common on the 220 with LOW hours, but also common on any cast piston which is run beyond it's service life, which you probably exceeded about 10 or 12 years ago.
What causes skirt failure? the answer to this begs to question if the compression would remain so high if this was happening in the OP's situation. I always hedge toward the forged so I am with you on the cheap insurance. plus 16 years of kips fouling begs a top end but I doubt a piston grenade is eminent. I cant imagine the hours being too high on that bike.
No doubt but when the piston is in the position to allow the skirt to contact the bore, there is a leading and trailing edge on the rings which results in uneven wear, this will cause a eventual loss in compression. If the OP's bike has high hours and still has good compression, the likelyhood of skirt damage is suspect. I am not saying he shouldn't change it but I certainly wouldn't leave the bike parked over the weekend in fears of a skirt failure
dirt bike dave
Sponsoring Member
- May 3, 2000
- 5,349
- 3
Go ahead and ride it this weekend. Even if it grenades, you got your money's worth out of that KDX, lol.
As for compression readings, IMO different guages and testing techniques can result in wildly different measurements on the same bike. It's a great tool if you measured the bike new, and then can compare the same bike later with the same gauge to see how much compression it has lost. After 16 years including many races, you know the top end is worn, even if the gauge says compression is within spec.
Bottom line is order some parts and give the old girl her rebuild when they come in.
As for compression readings, IMO different guages and testing techniques can result in wildly different measurements on the same bike. It's a great tool if you measured the bike new, and then can compare the same bike later with the same gauge to see how much compression it has lost. After 16 years including many races, you know the top end is worn, even if the gauge says compression is within spec.
Bottom line is order some parts and give the old girl her rebuild when they come in.
The piston stays centered on the top, way better than the bottom! Go figure, NOT!
- Thread starter
- #11
Well bike ride and race got cancel By the Wife , My Daughter is in Iraq and had to take the grand baby to the nat-guard for a day of trick or treat that I forgot about and the Wife reminded me about, But any way, To answer your ? Ride junky, I use a Twin Air filter , Chain saw or 220 lathe oil on filter, wife's panty hose or white fiber filter for a pre-filter oiled, after every race, on trail rides I am the lead dog so every 2-3 rides, Condition, Muddy to dry and dusty, more dust in the last 3 years here in NC, Oil type OPTI-2 for the 16 years since new at 100-1 ratio, Jetting is 42 pilot main is 150 boyesen 2-stage reeds, Elevation around 70 ft in the Sand Hills to 3000 ft Foot Hills , and at home 752 ft. And to Dirt Bike Dave , same compression gauge EQUUS brand, Fountain Valley CA, Don't if this is a good gauge or not, But yes the 200 has been through a lot, My other riding Buddy has a WR-400 Husky 1986 with only one ring on the piston and he has not do a top end on that bike as well , I know a 130$ won't break the bank, I may ride a few more times and do one this winter, still would like for more feed back, Maybe mine is unbreakable !!!
I am curious what the book says the top end pressure is supposed to be?
- Thread starter
- #17
You can purchase but you can only buy it 55 gal drum and is very expensive, It's by Schaffer Oil Works and One of my other buds runs it in his Drag Car, It will keep your Race Fuel Fresh for 2 years, this stuff will blow any off the shelf fuel additive AWAY, Wal-Mart can't touch this or Advance, AutoZone, Oh no I just let out the company secret.
ok so i searched a read a bit but are you saying instead of a 2stroke mix you are running something in place of it?
I did not see a 2t mix in there line up of products
also it appears everything is available in quarts or gallons though I did see offers of the 55gal drum as well.
I did not see a 2t mix in there line up of products
also it appears everything is available in quarts or gallons though I did see offers of the 55gal drum as well.
dirt bike dave
Sponsoring Member
- May 3, 2000
- 5,349
- 3
sr5bidder said:
The secret ingredient is in addition to his oil. He mentioned he is using Opti-2 oil at 100:1.
reepicheep
Member
- Apr 3, 2009
- 670
- 2
My 95 "KDX in a bucket" that I bought beat to heck and with virtually every part broken had a cracked piston skirt. The thing had been abused to no end, and I had to rebuild it from the ground up. No idea if the piston was original, but it was factory.
So yea, I'd replace it.
So yea, I'd replace it.
- Thread starter
- #22
Went to UWHARRIE Nat-Forest today and did 10 hard miles the first 45 minutes , Hard to do for the deer hunters, side by sides, jeeps and 4x4s, Only 3 bikes there Me on the KDX , one KTM , the other Honda CR , did a short rest break and did another 16 miles and called it a day, She ran like a top, so tomorrow going to either Brown MT or Twin Oaks or the Sand Hills to ring its little neck out. I think that I don't Ride Hard enough to wear it out, My Dodge truck 86 Ram 150 318 4 on the floor bought new 256000 miles and still runs strong, does use a qt of oil every 1000 miles.
- Thread starter
- #23
Well went to Twin Oaks, MX track was nice and dry, The Old Hairscramble coarse 5 miles or so was mud ruts, rocks, and roots and lots of leaves, the first loop took me 30 minutes to do, to much air in tires for the mud. Took a few pounds out cut lap time down to 22 minutes took 15 min break hit the track and woods and turn it up and down to about 20 min and 45 sec , a lot better 25.4 miles in all, she's full of mud no time to clean going to Brown Mt before the rain moves in Sunday I will do a compression test after I get her clean up and report back with the readings .
I know several people that had bikes that ran great until a skirt dropped (not KDX's though).
My YZ put up over 240 psi on my compression gauge. This was the last test as I started tearing it down minutes later. The skirt was so barreled and cracked that the bottom 1/4" of the intake side broke off when set on the work bench.
As stated, compression only tells ring seal.
My YZ put up over 240 psi on my compression gauge. This was the last test as I started tearing it down minutes later. The skirt was so barreled and cracked that the bottom 1/4" of the intake side broke off when set on the work bench.
As stated, compression only tells ring seal.
