what is stock compression reading for 1985 250r?

[bushwacker51]

Was wondering waht the compression reading should be on a stock 1985 honda 250r. thanks in advance Glenn Oister

[whyzee]

from 170 to 199psi on a warm engine with the throttle wide open while kicking, and the switch off:eek:

[ckb7890]

So if mine is at 160 psi would this indicate in need of a top end over haul?

[falloutboy]

It would be a good idea soon

[Keith Salyer]

That about sums it up. If you live at higher elevation your readings will be lower also.

[ckb7890]

Thanks for the input i will plan on doing this very soon. The bike is still performing really good I have noticed a slight lose of speed at WOT in six gear and on making a short turn at low RPMS the bike wants to load up a bit other than that performs well. I was reading on the technical sheet and it says compression to be at 142-170. In the thread it says compression to be at 177-199. Can someone please explain why the difference in compression readings. Thanks

[ckb7890]

I live in China Texas which is really close to the Gulf so elevation is more on the low side here.

[SWIGIN]

I keep seeing people on here saying they want to know the compression of there 2 stroke when they really want to know the cylinder pressure. Cylinder pressure is what is measured in PSI and has nothing to do with the compression ratio of the piston.

just a pet peve....

[ckb7890]

Yes you are correct. I'm looking for the cylinder pressure, is it because the wiseco piston generates more compression Making 177-199 psi then the stock piston back in 1985 which indicates 142-170?

[82 250r]

Kicking the bike WOT with the ignition off is called a "compression test" not cylinder pressure test. The test is measured in psi and has nothing to do with compression ratio.

Cylinder pressure is normally used during a leak down test.

The manual should give the correct level for stock bikes but you may have to adjust for high compression pistons.

Marc

[ckb7890]

I was told it was stock from the guy I bought it from. I haven't done a leak down test yet. All I have is a compression gauge and was wanting to know the difference in compression stated in the technical Manuel versus what I read here. I read 160 psi on my trike and wanted to know if that is getting low and would need to do a rebuild before causing damage. maybe I need to do some more research. Thanks for the information though.

[82 250r]

My manual states 170.7-199.1

At 160 you are on the boarder unless your at 7000ft or higher...you will show lower readings at higher elevations but 160 would still be low. I'm at 5000ft and like to see 185+ on a healthy motor.

I prefer to do a leakdown test before compression so I know the compression test will be accurate.

Marc

[gus]

What you could do is replace your rings and that might help instead of doing a hole rebuild?

[ckb7890]

Thanks guys, this helps I really appreciate the feed back.