2010 kx250f compression....

[rexisme]

What should the compression be on a 2010 kx250f?

 

The reason for asking is I'm looking at a used one, the seller says as of recently;

 

"on 1/14/2014 the bike was taken in to get the following and was put on an replaced :
spark plug
msr fuel screw
needle jet
nozzle main
valve float

gasket
adjusted valve clearance
compression was good at 78PSI
replaced exhaust gasket"

 

Now, I tried searching the internet and I cannot find the definitive answer for what the compression should be. All I find are people arguing about the auto decomp. So I am looking for an ideal range. A little more info, has kibble white valve spring kit, pro x piston, and complete hot rods bottom end kit. He has receipts showing that the recent stuff was done and receipts for the engine work and engine parts.

 

I'm just trying to keep myself from purchasing a grenade. I'd rather buy new but I'll be able to get on a bike a lot faster if I purchase a used one.

[mxracermx]

What should the compression be on a 2010 kx250f?

The reason for asking is I'm looking at a used one, the seller says as of recently;

"on 1/14/2014 the bike was taken in to get the following and was put on an replaced :

spark plug

msr fuel screw

needle jet

nozzle main

valve float

gasket

adjusted valve clearance

compression was good at 78PSI

replaced exhaust gasket"

Now, I tried searching the internet and I cannot find the definitive answer for what the compression should be. All I find are people arguing about the auto decomp. So I am looking for an ideal range. A little more info, has kibble white valve spring kit, pro x piston, and complete hot rods bottom end kit. He has receipts showing that the recent stuff was done and receipts for the engine work and engine parts.

I'm just trying to keep myself from purchasing a grenade. I'd rather buy new but I'll be able to get on a bike a lot faster if I purchase a used one.

I believe the range is 60-100 psi with 5 kicks. Accurate way is a leak down test. It's possible to have new parts but still have valve seat issues or cylinder issues.

[Shawn250]

does it nor have an hour meter and the hours when the piston was done ?

[Taco13]

My 2011 kx250f registered 100 psi after 5 kicks. I did not warm it up but that can increase results. 

[rexisme]

does it nor have an hour meter and the hours when the piston was done ?

No it does not. He said it had 6-7 hours on it since it was all rebuilt. He does have the receipts for install and receipts for the parts though with dates on them. I'm not sure though, I've talked to him a little bit. Seems kind of wishy washy, kind of apprehensive to sell it, I think he thinks he could possibly "trade up" to something better other than coming off it for the money. I mean, if you have something for sale and someone inquires and wants to buy. You would think that you would sell it. He asked if I wanted to trade or buy and I told him buy, he stopped talking to me. So whatever.. .

 

I've got a 01 kx250 with under 3 hours on it since purchased on the back burner, looks like it rolled off the showroom floor for $1700, he works with me and its been in his family since it was bought. The guys 54 years old. It has absolutely no case/frame wear on it at all. Actually, looked cleaner then the 2014 kx250f sitting outside the dealer.

 

I'm also trying to get ahold of this guy to look at his 2011 yz250f but he seems kind of wishy washy to me too. His price is a little high but it has all quality parts on it. He has no receipts and no idea how many hours are on it though. He said he bought it off a buddy thats how he knows all about it.

 

Where do you guys look for your bikes?

Edited June 3, 2014 by rexisme

[mxracermx]

No it does not. He said it had 6-7 hours on it since it was all rebuilt. He does have the receipts for install and receipts for the parts though with dates on them. I'm not sure though, I've talked to him a little bit. Seems kind of wishy washy, kind of apprehensive to sell it, I think he thinks he could possibly "trade up" to something better other than coming off it for the money. I mean, if you have something for sale and someone inquires and wants to buy. You would think that you would sell it. He asked if I wanted to trade or buy and I told him buy, he stopped talking to me. So whatever.. .

I've got a 01 kx250 with under 3 hours on it since purchased on the back burner, looks like it rolled off the showroom floor for $1700, he works with me and its been in his family since it was bought. The guys 54 years old. It has absolutely no case/frame wear on it at all. Actually, looked cleaner then the 2014 kx250f sitting outside the dealer.

I'm also trying to get ahold of this guy to look at his 2011 yz250f but he seems kind of wishy washy to me too. His price is a little high but it has all quality parts on it. He has no receipts and no idea how many hours are on it though. He said he bought it off a buddy thats how he knows all about it.

Where do you guys look for your bikes?

good thing about Yamaha is they are cheap to maintain and are fairly bullet proof.

[Dragon67]

Warm up engine thoroughly

Attach compression gauge

With throttle fully open, kick the engine over several times until the gauge stops rising.  Compression is the highest reading.

 

Usable range per 2011 manual (should be similar) is 62-103 PSI at 5 kicks.  We got 93 or so yesterday.