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Post by 4950cycle on Sept 11, 2016 10:50:41 GMT -6
I was wondering I was wondering if anyone's ever done a compression test on their 257 cc Linhia engine ? I did mine today after only 7,000 miles and I only got about 135 psi on a cold compression test. I would have done it motor warm like I am supposed to. But I have had bad experiences messing with aluminum spark plug holes while they are hot. I do engines cold now and still get a pretty good base line compression reading IMO. Seems kinda low to me for a fairly fresh engine though. Any feedback anyone ? PS. I broke engine in by the book. And changed oil every 1,000 miles or so. Read more: scooterrebels.proboards.com/thread/2686/260-linhai-compression-psi#ixzz4Jy0CvwHYg if anyone's ever done a compression test on their 257 cc Linhia engine ? I did mine today after only 7,000 miles and I only got about 135 psi on a cold compression test. I would have done it motor warm like I am supposed to. But I have had bad experiences messing with aluminum spark plug holes while they are hot. I do engines cold now and still get a pretty good base line compression reading IMO. Seems kinda low to me for a fairly fresh engine though. Any feedback anyone ? PS Tes, I broke engine in by the book. And after that changed oil every 1,000 miles or so. Read more: scooterrebels.proboards.com/thread/2686/260-linhai-compression-psi#ixzz4Jy0CvwHY |
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Post by crwford on Sept 11, 2016 12:23:13 GMT -6
We 1 did you do a compression test when you got it for base line? mine is zodiac pretty close to your cc. Question how often do you change oil,what type of oil,are you using a screw in compression test, how many time do you rotate engine, Did you add a little in spark plug hole and check you test again. If it doesn't change check valves gaps my Zodiac's have 5,000 miles base line was 165 psi still holding 165, Never changed plug,gas hose,vacuum hose, same battery, after break in changed to AMSOIL metric. 1,000 mile 3 oz used. Except for oil still all stock.  |
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Post by crwford on Sept 11, 2016 12:29:03 GMT -6
By the way anti-seize is your best friend on heads, when I did mine for base line all plugs got it for that reason.
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Post by 4950cycle on Sept 11, 2016 15:37:40 GMT -6
Please read post as far as oil change, But use fossil Castrol. Did not compression test when new. Have antiseize in plug hole. Still scared to do hot test.  Could be valves. Didn't do a wet test. Or could be faulty comp. gauge. Would not be the first time it happened to me. But keep the feedback comeing. BTW , Doesn't blow any noticeable amount of oil. IOW I never need to add any between changes. |
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Post by cyborg on Sept 11, 2016 18:38:15 GMT -6
135 does seem a little low in my book,,,,,
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Post by crwford on Sept 11, 2016 20:23:13 GMT -6
When I said 3 oz after 1,000 miles we are talking hard mile in smoky mountains speed I averaged was 60 to 65 but some times 68 all my mile were also put on 5,000 were in one year my oil changes last 2,000 miles with amsoil and all stock even plugs.
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Post by 4950cycle on Sept 12, 2016 21:43:35 GMT -6
Well, I am going to rent a compression tester at Orieley's auto parts. I will check my engine with that one in case mine is giving a false reading. Hey, It happened to me before.
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Post by crwford on Sept 13, 2016 9:38:06 GMT -6
Most auto parts loan for free check it out
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Post by crwford on Sept 15, 2016 10:50:53 GMT -6
wondering if he get a compression test done? and if so did it change much?
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Post by 4950cycle on Sept 16, 2016 10:48:11 GMT -6
Just finally got the compression tester from Oreily's. Had to buy it so to speak with promise to return in 48 hrs. for refund. That's how they loan tools around here. Place is full of broke scrounge balls. Anyway, Going to do a cold then maybe hot test. If cold test bounces up to 165 lbs. I will know all is well and no need to do a hot compression test. And if it doesn't do well my money would be on leaky exhaust valve. These cheap arse heads have seats with no steel insert for God's sake ! The super hot exhaust valve closes/seats on raw aluminum ! It would be no wonder the motor has inherent valve recession . I researched pictures of a Linhai 250-300 head on Ebay and came to this conclusion. The exhaust seat in said head sure did look like shiny aluminum to me ?
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Post by jct842 on Sept 16, 2016 22:58:37 GMT -6
Most people who have thread stripping on alu heads are going way too tight on the plugs. When I was a kid I was told to go snug on the plug then about a flat on it and no more than two flats tight. I used to use a model T pliers on my james motorcycle. I have never stripped one....yet! The plugs today all come with a copper crush gasket and if you torque it down all the way it is way way to tight. I am using less torque than most recommend but since chinese alu is so soft I like to believe I am right.
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Post by 4950cycle on Sept 17, 2016 13:35:14 GMT -6
And you are right on how you do plugs IMO . Update, Just did a warm compression test with loaned comp gauge from Oreiley's . I got 132-135 psi again. My comp tester must be correct I guess. Then did wet test and it bounced up to 150 psi. So my take is rings have some wear and valves might be slightly leaking. And I believe crawford is right when he said I should have about 165 lbs psi engine in good shape.
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Post by 4950cycle on Sept 17, 2016 19:43:35 GMT -6
Update, Just did a warm compression test with loaned comp gauge from Oreiley's . I got 132-135 psi again. My comp tester must be correct I guess. Then did wet test and it bounced up to 150 psi. So my take is rings have some wear and valves might be slightly leaking. And I believe crawford is right when he said I should have about 165 lbs psi engine in good shape.
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Post by crwford on Sept 21, 2016 19:21:46 GMT -6
In all fairness just check valves one more time the ride it it still runs right. Also try changing you oil amsoil 10-40 metric I use. I'm not saying to use it but try a different company's may a 15-40 oil but all in all if it run well use it and not saying this to be a smartass but the way it's broke in is also be a clue.
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Post by januar on Sept 22, 2016 1:35:31 GMT -6
I was wondering I was wondering if anyone's ever done a compression test on their 257 cc Linhia engine ? I did mine today after only 7,000 miles and I only got about 135 psi on a cold compression test. I would have done it motor warm like I am supposed to. But I have had bad experiences messing with aluminum spark plug holes while they are hot. I do engines cold now and still get a pretty good base line compression reading IMO. Seems kinda low to me for a fairly fresh engine though. Any feedback anyone ? PS. I broke engine in by the book. And changed oil every 1,000 miles or so. Read more: scooterrebels.proboards.com/thread/2686/260-linhai-compression-psi#ixzz4Jy0CvwHYg if anyone's ever done a compression test on their 257 cc Linhia engine ? I did mine today after only 7,000 miles and I only got about 135 psi on a cold compression test. I would have done it motor warm like I am supposed to. But I have had bad experiences messing with aluminum spark plug holes while they are hot. I do engines cold now and still get a pretty good base line compression reading IMO. Seems kinda low to me for a fairly fresh engine though. Any feedback anyone ? PS Tes, I broke engine in by the book. And after that changed oil every 1,000 miles or so. Read more: scooterrebels.proboards.com/thread/2686/260-linhai-compression-psi#ixzz4Jy0CvwHY |
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Could be valves. Didn't do a wet test. Or could be faulty comp. gauge. Would not be the first time it happened to me. But keep the feedback comeing. BTW , Doesn't blow any noticeable amount of oil. IOW I never need to add any between changes.
