OZ ATV :: The Australian ATV Forum

[richie_supercharged]

Any progress
Or pics
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If in Doubt.. Flat out

84 ATC 250r (290kit)
82 ATC 250r
77 ATC 90

[ozquad44]

Long time no post from my end. Long story short, I had no shed space for ages. but thats about to change so next weekend looks like some progress may be just around the corner.

The 87 motor is back together finally. I had a hell of a time trying to find a base gasket. I was using the 86 kx250 gaskets and the base gasket is not the same as the KXT. Learn something every day. I had to throw a few extra base gaskets at the motor, the reason is detailed below.

Whilst the motor was apart we discovered that the piston had been making contact with the head. BS you say, well the witness marks on the piston top say otherwise. A fine ring around the whole crown of the piston. I can't believe the motor didn't fail. But it does go some way explain the crazy noise's at high RPM, poxy power delivery at certain throttle positions, the pinging, and constant fouled plugs. I'm praying I've seen the last of these symptoms

I also found out why the motor stopped last time I took it for a ride, and it wasn't the piston. The woodruff key had sheared off. So the timing was out. This would explain why I had spark, fuel, air, and compression but no bang. Given the other issues I had been having with the motor I though it had some major internal failure but it was only a woodruff key. Thank god.

I'll take some pictures next week of the piston, and a few other bits and bobs if your interested.
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State governments give us REC rego + area to ride ATVs legaly! State Status: VIC-No (Nazi's) QLD-Yes(no place to ride tho) NT-? NSW-Yes, Stockton. TAS-Yes, Areas for ATVs + ATV rego, Go Tazzie . WA-Yes, 2 top places within 1hr of Perth. ACT-? SA-No

[ylwgtr]

hmmm interesting....the 86 kx250 and 87 kxt250 have the same base gasket part number according to kawasaki micro fiche but the head gaskets are different

[ozquad44]

Mate I swear on a stack of bibles the 1986 kawasaki KX250 gasket supped by kawasaki did not fit. I've got two in the shed if you want them....
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State governments give us REC rego + area to ride ATVs legaly! State Status: VIC-No (Nazi's) QLD-Yes(no place to ride tho) NT-? NSW-Yes, Stockton. TAS-Yes, Areas for ATVs + ATV rego, Go Tazzie . WA-Yes, 2 top places within 1hr of Perth. ACT-? SA-No

[ylwgtr]

what was the part number they gave you?Was it a different shape or thick ness?

[ylwgtr]

also i normally put some solder or use smear of oil on the outer squish band on the head and also on the piston(with the piston dropped 10mm down the bore) then a ball of blutack on the piston again on the outside at 9 or 3 oclock.Put the head on with gasket tighten it up,then turn the crank until it rolls over TDC,take apart and measure the blutack or solder what ever your using....i wouldnt be running any closer than 1.3 for safety on that,altho you could run it as tight as 1.0 on a fresh bottom end but i wouldnt advise that close as its not likely to be sending man to the moon

[ozquad44]

Thanks for the info, many years ago I use to be on the tools, we used a product called plasti-guage. I asked around a few bike shops and no-one knew what I was on about, or what measurements I should be aiming for.

I recall we used to measure how much the plasti-guage spread to determine our clearances. Which was simple as the gauge had predetermined spread distances depending on how much it was squashed. I didn't even consider to just measure the height of something like bluetac. I've got verniers in the shed so determining the difference between 1 and 1.3mm won't be too hard.
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State governments give us REC rego + area to ride ATVs legaly! State Status: VIC-No (Nazi's) QLD-Yes(no place to ride tho) NT-? NSW-Yes, Stockton. TAS-Yes, Areas for ATVs + ATV rego, Go Tazzie . WA-Yes, 2 top places within 1hr of Perth. ACT-? SA-No

[ozquad44]

ylwgtr wrote:

what was the part number they gave you?Was it a different shape or thick ness?

It was the correct shape, but slightly smaller than it had to be. Its like gasket had shrunk a little. We just made our own.
_________________
State governments give us REC rego + area to ride ATVs legaly! State Status: VIC-No (Nazi's) QLD-Yes(no place to ride tho) NT-? NSW-Yes, Stockton. TAS-Yes, Areas for ATVs + ATV rego, Go Tazzie . WA-Yes, 2 top places within 1hr of Perth. ACT-? SA-No

[ylwgtr]

No worries,I use plastigauge aswell!but for bottom end clearance on slipper bearings....you can still buy it from repco/bursons ect....what was the part number of the base gasket?

[tbr926]

when are we riding again jas, joe Z pinged me

[ozquad44]

As soon as it cools down, Got my 87 motor finished.
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State governments give us REC rego + area to ride ATVs legaly! State Status: VIC-No (Nazi's) QLD-Yes(no place to ride tho) NT-? NSW-Yes, Stockton. TAS-Yes, Areas for ATVs + ATV rego, Go Tazzie . WA-Yes, 2 top places within 1hr of Perth. ACT-? SA-No

[Joe 250 Z]

Jas / Dale - yep all good for the ride when it cools down.

[ylwgtr]

Hey just thought I'd post just for future readers reference (in case any tecate owners are trawling and read about the gasket saga) I just rebuilt my engine last night using genuine rod kit,piston/rings,little end and gaskets...all genuine kawasaki parts and no issue at all....ozquad did you use a non gen piston (higher crown?) or non genuine head gasket (not fibre maybe thin black steel type?)