Lost compression

reymund77 · Post by **reymund77** » 08:11 am Oct 12 2008

Hi, while riding back from trail ground at abt 80-90km/hr wif rev abt 6-7000rpm....suddenly the bike gave a pop sound...not very loud but then suddenly the engine jus dies off,stop the bike and realise bike lost its compression totally...removed the plug and end of the plug (NGK Iridium) shows its whitist.....having it tow to a bike shop tomorrow but like to know wat could be wrong?

Cos the day before, I jus replace my water pump seal and a oil seal and bearing...bike had been running well all along....but the mechanic locally told me my valve did not open and rode today realised tat true..jus dun wanna...bike had an engine rebuilt on April with new wiseco piston, new gearbox, bearing, seals etc and since clocked 70hrs+ and abt 2000km odo.

Post by **Indawoods** » 08:25 am Oct 12 2008

Valve? What valve?

reymund77 · Post by **reymund77** » 10:55 am Oct 12 2008

the KIPS power valve....normally the bike will comes to live abt 6000rpm and exos sound will also become louder...when the valve fail to open, the exos note is quieter...the rev still builts up but no power / surge nor change in exos sound after 6000rpm anymore

Post by **Indawoods** » 11:02 am Oct 12 2008

That would not cause the bike to die or lose compression. But yeah... sounds like the KIPS is failing....

Colorado Mike · Post by **Colorado Mike** » 09:01 pm Oct 12 2008

It would be interesting to know if the KIPS worked after the rebuild. Sounds likely whomever did the rebuild tweaked the KIPS shaft and broke the pawl in the case. You might want to check for that, and if broken make sure your tranny is ok. My kid had a shift stop lever disintegrate on his YZ. That's on the clutch side (outer) of the cases, but parts of that made it into the transmission .

<edit> Oh, and as for what is wrong to cause low compression, you probably burned a hole in your piston, or broke it. got any silver grains on that plug? pop the cylinder head off and see what you got. Post pics, we love seeing that stuff!

reymund77 · Post by **reymund77** » 09:40 am Oct 13 2008

Post by **Indawoods** » 09:44 am Oct 13 2008

No oil in the gas... big air leak... went way lean in any case!

reymund77 · Post by **reymund77** » 10:16 am Oct 13 2008

reymund77 · Post by **reymund77** » 10:26 am Oct 13 2008

another note...tried to manually turn the KIPS gearing/valve with my hands ( the gears attached to the cylinder)...I can't turn it....the "stick" coming out from the clutch cover/water pump can be rotated...forgot to check if it can be pulled up/down (freeplay if there's any)...the gears on that shaft looks ok and the gears on the KIPS valve/cylinder looks ok too.....is my valve dead???....

Wondering now if the mech had screwed up on the powervalve installation while replacing the water pump seal, bearing and the oil seal there (my initial issue as its leaking engine oil out from the water pump drain nut)..tats why I sent in for repair/replacement of the seals......and then mech put them back together, told me my valve are jam.....I rode on Sunday and realised tat...no more high pitch sound....bike wasn't like tat before

Post by **Indawoods** » 10:29 am Oct 13 2008

Find another mechanic... like you!

reymund77 · Post by **reymund77** » 10:42 am Oct 13 2008

sob...the mech is a ok mech locally that I can find...he rides and race a CR250 n does only repairs of dirt bike like KTM, RMZ, XR etc..but sad to say, as the KDX220 is very rare in sg...he might not have laid his hands on one before or probably a few years back only....

There's another mech that's more pro on KDX locally but he got a stinking attitude and I've had enuff of his nonsense recently so din go back to him on the waterpump seal rebuilt...but my last engine rebuilt, new wiseco piston, gearbox, stator, coil, CDI, wiring etc are done by him in May and things had been running fine since til the oil seal on the waterpump side gave up...

Very low morale now...gotta scout for parts since nobody stock them in Singapore or prob only tat attitude mech but relationship had soured and tried to ask him for stock on piston and he jus hang up on me....argghh

Any good place to hunt for parts tat will ship internationally???...else need to use a fren working in US to help me out or some international postage office....guess gonna be out of riding for a period of time

reymund77 · Post by **reymund77** » 10:46 am Oct 13 2008

Indawoods wrote:No oil in the gas... big air leak... went way lean in any case!

138,45, 1.5 out,top needle....using Maxima Castor 927 2T oil with mixture of 15ml to 1 liter of gasoline....its abt sealevel in sg...no big mountain or high terrain to climb here

reymund77 · Post by **reymund77** » 11:08 am Oct 13 2008

another question...which piston size should I go for?...69 or 69.5 or 70 for wiseco?.....sending the cylinder to "polish" and mech claims it wun wear out the nikasil

Colorado Mike · Post by **Colorado Mike** » 11:13 am Oct 13 2008

69 is the stock size for a 220. If you were trying to buy a stock piston for a 220, maybe that's why the mechanic hung up on you. Get a Wiseco or you may well be doing it again sooner than planned.

reymund77 · Post by **reymund77** » 11:24 am Oct 13 2008

canyncarvr · Post by **canyncarvr** » 04:55 pm Oct 13 2008

I didn't follow all of this real well...but I don't see any reason found for the failure. Any put-together without knowing what caused it will likely have it happening again.

I don't know what 'polish' means. You can hone an electro-fused cylinder and be fine. If it's done wrong, it will ruin the coating, yes.

You got aluminum in the crankcase. Can't NOT have done that. You should give it a good rinsing. Use kerosene or a light machine oil...like Marvel Mystery oil or somesuch.

You have reused base gaskets? That might be where the leak came from.

Don't put an OEM piston in..old, new, or any other age.

The correct size piston is the one that is the correct size. If your cylinder is original (not bored, not made 'bigger' at all) it will take a 69mm piston. It SURE won't take a 69.5 or 70. 1/10mm is about .004". .020" difference in piston size is a HUGE difference. NOT a difference you need unless the cylinder has been 'overbored'.

reymund77 · Post by **reymund77** » 08:47 pm Oct 13 2008

many thanks...still trying to resolve what cause it.....

Guess the word polish used by the mech could be honing refer over here and he claim it will not really ruin the coating, I hope his right and sent it to the machinist that knows what his doing.

first no coolant in radiator, tonite will flush out engine oil and see if coolant got in there...if tats the case, prob the mech screwed up on the water pump seal and oil seal installation.......but I did notice when I top up fuel at the gas station...water/coolant like dripping bit by bits from a hole below the water pump casing near the drain plug of coolant after I stop my engine.

Will relook into my air/fuel mixture...and look out for any air leak particularly the intake rubber boot btw the reed valve and carb...any other place to look for?

Any other things to look for?

Ok, thanks for all the points and advise raised...anyway, during my previous rebuilt, it was new pistons, gaskets, O-rings, oil seals and bearings......I was sitting thru watching the mech put them back together

Dispite that I'm desperate for another weekend ride...guess I have to give it a miss and continue hunting for all new parts and put them back together again since nobody advise to use back old gasket or pistons

Colorado Mike · Post by **Colorado Mike** » 09:01 pm Oct 13 2008

A few notes after finally being able to see the pictures you post.

1) I told you so.

2) Comfort Note- You don't have to wear MX boots to work on your bike unless there is some sort of caning penalty in Singapore for not doing so.

3) Did your knees catch fire from the extreme heat that bike had to be putting out as it was melting down? My 220 becomes unbearable when it runs hot. Of course, that's when it is actually pumping water which yours may not have been doing.

4) From the pictures, it's hard to say if that cylinder will clean up without bore/plating. Eric Gorr told me to use Muriatic acid to try to remove aluminum from a plated cylinder, but I never tried it. I just very carefully used 600 grit wet-dry paper with lube and made an afternoon of it. Your's is way worse than the one I was working on.

5) Like CC said, you have a big problem. Either your cooling system was broke, or you had a way wrong plug in, or both, you better get that fixed before trying to run that motor.

6) Also like CC said, your bottom end is in trouble. At the bare minimum it needs to be rinsed out, but if it was me, I would split the cases and put another crank, bearings and seals in. another $250-$300, but saves you from doing it again in a month if you miss something.

7) thoroughly clean your intake tract (especially reed valves) and pipe. parts get blown into them and then get sucked back into the motor after the rebuild.

8) Become your own mechanic. Nearly every one I have met was borderline retarded. The rest were either near-genius or barely able to breathe and pump blood at the same time (chance of you finding a genius is pretty itty-bitty).

ok, that's more than a few. Keep us posted.

reymund77 · Post by **reymund77** » 09:36 pm Oct 13 2008

Many thanks for your everyone prompt response and reply

Guess the caning penalty went really big in the US...its strict but not to tat extent for sure....its one of the nicer and safer place to live / work in SE Asia actually

I was on my riding boots and gears so can't feel the heat..prob the coolant had not been there for quite awhile?...and I was riding back on the high way cruising at 80km/hr ard 6-7pm

Guess will leave the cylinder to the mech to sort it out, flush the crank and inspect intract tract, repalce reed valve etc

I really wish to have time and space to be my own mechanic..but here 80% of us stay in high rise building / flats...and no personal garage or shelter area to work on the bike halfway and call it quit so if u have to carry ur tools etc from 11 floor down to the carpark, strip things up and get things put back again same day...its kinda troublesome or prob u can say I'm procrastinating...but if I had a garage or a landed home, I would certainly invest on tools and a service manual and work on things myself or with another riding mate.

Colorado Mike · Post by **Colorado Mike** » 09:59 pm Oct 13 2008

We could use a good bit of the caning thing over here. I was in Singapore once. Beautiful city, and the people are awesome.

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Lost compression

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