Burning oil and 90psi compression

Burning oil and 90psi compression 17 May 2019 07:04 #804018

Scottbob76 Topic Author Offline User Posts: 10 Thank you received: 0	Hello recently bought a kz440 ltd After bike warms up it starts smoking lots I did a compression test and got 90 psi on both cylinders after it had been running a minute (Probably not fully up to temp but deffo warm) What would be your next step Cheers Scott
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Burning oil and 90psi compression 17 May 2019 07:11 #804019

Warren3200gt Offline User Posts: 1446 Thank you received: 655	I don't know what compression your bike should have but 90 sounds awful low. However having said that what colour is the smoke and has it been standing for a long time? It could be the rings are gummed up and a bit of use will free them or it could be they are knackered and need replacing and or a rebore. Z1000J2 somewhat modified!
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Burning oil and 90psi compression 17 May 2019 08:01 #804024

Grcko Offline User Posts: 158 Thank you received: 30	Usable compression range is 109 psi-156 psi or less than 14 psi difference between cylinders (from the manual) As Always, 1983 KZ440
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Burning oil and 90psi compression 17 May 2019 09:54 #804033

Scottbob76 Topic Author Offline User Posts: 10 Thank you received: 0	The smoke is white And yes it has been standing years I have just got it and put oil spark plugs and fresh petrol in it
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Burning oil and 90psi compression 17 May 2019 11:23 #804039

Warren3200gt Offline User Posts: 1446 Thank you received: 655	White smoke is condensation not oil. Change the oil which may have moisture in it and then let it warm up to full temp. Fingers crossed once its warm right through and dried the exhaust system it'll stop smoking. Z1000J2 somewhat modified!
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Burning oil and 90psi compression 17 May 2019 15:26 #804052

M_a_t_t Offline Sustaining Member Posts: 254 Thank you received: 41	Make sure your tester has a valve in the tip. For smaller engines that can really throw off readings. kzrider.com/forum/2-engine/606826-low-compression-s-on-kz1100 83 KZ1100A (shaft) 17 Versys X 300 abs 81 kz650h1 81 kz750e2 90 Honda CBR600F (brother's) The following user(s) said Thank You: Scottbob76
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Burning oil and 90psi compression 18 May 2019 00:39 #804068

Scottbob76 Topic Author Offline User Posts: 10 Thank you received: 0	Cheers gonna try today a bit later (early for revving motorcycle) Deffo oil I think as when the exhaust was not tight a black substance was dripping out it was like a very thin oil with a slight fuel smell I’m gonna leave it running to warm through and burn everything off then strip the head I think
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Burning oil and 90psi compression 18 May 2019 07:18 #804076

Patton Offline KZr Legend Posts: 18640 Thank you received: 2098	Before stripping the head, would suggest changing the oil and filter, assure the valve clearances are within specs, lube and adjust the chain, assure correct psi in the tires, perform any further obviously needed maintenance, then ride it for at least 100 miles, and re-assess the situation. Good Fortune! 1973 Z1 KZ900 LTD The following user(s) said Thank You: Scottbob76
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Burning oil and 90psi compression 18 May 2019 10:31 #804088

Warren3200gt
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Thank you received: 655

Scottbob76 wrote: Cheers gonna try today a bit later (early for revving motorcycle)
Deffo oil I think as when the exhaust was not tight a black substance was dripping out it was like a very thin oil with a slight fuel smell

I’m gonna leave it running to warm through and burn everything off then strip the head I think

Oil smoke is blue / black not white. The "oil" you had dripping "could" have been condensation with exhaust port soot in it. It would smell fuelish due to the exhaust gases.
As Patton says change oil and filter and ride it.

Z1000J2 somewhat modified!

The following user(s) said Thank You: Scottbob76

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Last edit: by Warren3200gt.

Burning oil and 90psi compression 18 May 2019 11:14 #804091

Scottbob76 Topic Author Offline User Posts: 10 Thank you received: 0	Ok thanks guys Gonna take your advice and ride it for while with fresh oil I’ll update in a few weeks
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Burning oil and 90psi compression 18 May 2019 14:33 #804101

Nerdy Offline Sustaining Member Posts: 1006 Thank you received: 378	Warren3200gt wrote: Oil smoke is blue / black not white. I always associate blue smoke with oil and black with an overly rich fuel mixture. ~~1979 KZ400~~ Gifted to a couple of nephews 1967 Yamaha YCS1 Bonanza 1980 KZ440B 1981 Yamaha XT250H 1981 KZ440 LTD project bike 1981 GPz550 2013 Yamaha FZ6R
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