257cc (260) Linhia comperssion test PSI By 4950cycle (Read 968 times)

[4950cycle]

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: scooterdoc.proboards.com/thread/13087/257-260-linhia-compression-test#ixzz4Jy3Kih1n

[4950cycle]

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 crwford is right when he said I should have about 165 lbs psi if engines in good shape.

[zack]

Sounds like you're due for a cylinder overhaul.
Doing a leak down test will tell you if it's rings or valves leaking (probably both).
If you reuse your valves or replace them you'll want to lap them into the seats.
Also, don't forget to order valve stem seals if they don't come with your gasket set.

[zack]

It's a good idea to run synthetic oil to avoid premature ring failure in the future.
After you get the motor back together put regular oil in it and run two or three tanks of gas (normal riding) through it to seat the new rings in the cylinder.
Avoid WOT for a few hundred miles to avoid accidently micro welding between the rings and freshly honed cylinder.
You'll know the rings are seated when you see normal blow-by from the crank case breather tube.
Heat and contaminants in the oil are what wears out the piston rings and cylinder. We can't do much about the contamination, the piss poor oil filters in our machines only catch the chunks of crap in the oil system. That's why changing the oil at the correct intervals is so important. Synthetic oil lubricates better than conventional oil, especially when it's hot.
I've installed a small fan that runs all the time on my cf 250 in an effort to keep the engine as cool as the thermostat will allow (running an engine too cold makes a whole different bunch of problems).
I've seen $15 oil coolers that wouldn't be hard to plumb into the external oil line that runs to the head on my machine. The ultimate fix would be to incorporate a oil filter and cooler into that oil line.
You know...... you have a good excuse to get a big bore kit for your machine now....just sayen....

[crwford]

I run Amsoil so I believe that's why my engine are healthy all mine have compression from day 1, 165 psi 2 of which have over 5,000 miles the outher 1 has only 1,200 mile. I just fell into a Dong fron with 26 miles 2012 year been in a garage. It's a reverse trike took it out for a spin runs really well. The old timer who brought fell off never road it again when he pass away his wife starting selling his toys. Some how when he fell off he broke the swinger lock cable this is a device which locks wheel and frame straight up. right not you can lean into craves like bikes do. So Monday will be calling the company se how to order it. It looks like a choke cable.

[4950cycle]

Not to be a weenie but I ain't overhaulin nothin ! #1 these things are way to labor intensive to own to be sinking a bunch of time , $ ,and effort in. #2 I didn't do anything lazy to let this thing wear out premature already @ 7000 miles . I broke it in by the book just like crawford. And AFTER that I changed it every 1000-1200 miles. Never overheated it, Used Castrol oil that I have put more than a million miles on in my vehicles including motorcycles without ever, ever having to tear one down except to make high performance . And I run 15 to 20 year old cars I might add. If this thing is indeed wore out its time for a Honda Forza or something along those lines. I've heard tell about guys with 40,000-50,000 miles on these china 250 scoots. Truth is I have NEVER seen one with my own eyes with more than 9,000- 12,000 on the OD. And almost all I have seen havn't had more than 5,500 on them. I live in scooter country and have never seen one of these China 250 scooters for sale on Craigs List with more than 8,000 miles. I bet because that is their max life span. I think I can do better than a bike that is worn out at 10,000 miles. And I'm starting to think thats what I have here fellas.

[ellpee]

Sez the guy who's made a virtual career out of trying to eke out a few more MPH at top end.

[crwford]

I just finished compression test on the reverse trike with 36 miles 155 psi but then it still has the same oil it came with so I will be changing it and start a brake in proceeding the oil change. This bike really impresses me upper and lower A arms have grease fittings something are car companys seem to left off our cars. For what it is seems well built safety switches if locked in vertical won't let you go over 30 miles per hour 1 switch tell you your are locket up the other tell carbs to kept fuel down so not to do over 30 mph. Easy to service has oil pressure Gage,oil Gage,gas,temp,tack,Gage My Ice bear only has gas,temp that's all.

[4950cycle]

Is this the reverse trike with the motor you had discribed as a Linhai ( the cylinder points forward and low) /

[cyborg]

Sept 25, 2016 18:52:38 GMT -6 crwford said:

I just finished compression test on the reverse trike with 36 miles 155 psi but then it still has the same oil it came with so I will be changing it and start a brake in proceeding the oil change. This bike really impresses me upper and lower A arms have grease fittings something are car companys seem to left off our cars. For what it is seems well built safety switches if locked in vertical won't let you go over 30 miles per hour 1 switch tell you your are locket up the other tell carbs to kept fuel down so not to do over 30 mph. Easy to service has oil pressure Gage,oil Gage,gas,temp,tack,Gage My Ice bear only has gas,temp that's all.

Pics please

[crwford]

After I finish my mods to my new to me c A motor home I will take picture of my whole family getting bigger by the day my wife says it's gotta stop I believe she put her foot down but she is right.

[cyborg]

Very nice!!! How much was the little gem?? Hhhmmmmmm?

[crwford]

E Bay way sold 950.00 plus shipping 160.00.

[crwford]

I must say upper and lower a frame grease fittings was a surprise on dash amp gauge, miles reset,tack,my Ice Bear came only with a gas gauge, To me the Sunny is a well built unit I HEARD many bad thing like death things like death wobbly I had it up to 55 mph and no problem. It has a cam lock so if you are in a slow mode like bumper to bumper traffic it will hold bike straight up for speed of 30 mph. It even shows it's locked in on dash.

[cyborg]

Oct 2, 2016 18:43:18 GMT -6 crwford said:

E Bay way sold 950.00 plus shipping 160.00.

What did you pick it up for mr jones