Cold compression was 120, 120, 118 on PTO. Yamaha tecnician told me I need to see 140 or it is time for a rebuild. This seems high to me.
I have 7,500 miles on it.
I have 7,500 miles on it.
bADa$$ SRX
New member
i have 120 all the way across on my 99 srx600 and it runs perfect
YAMMIEGOD3:16
Active member
BOUGHT MY 2000 BRAND NEW IT WAS NEVER 140 psi. 125-130 MORE LIKE IT. 3:16 (yammie tony)
You would think Yamaha Certified technicians were trained from Yamaha. These guys amaze me all the time.
So I am safe for now at 120, 118? What numbers do I look for when it's time to do a top end?
So I am safe for now at 120, 118? What numbers do I look for when it's time to do a top end?
YAMMIEGOD3:16
Active member
NO I SAY THEY WERE TRAINED IN DISNEY WORLD. AC COUPLE OF THINGS TO DO. TRY A DIFFERENT GAUGE. KEEP A EYE ON THE PERFORMANCE OF THIS SLED. AND THIRD IF YA WANT, PULL YOUR PIPES AND SEE IF YOU CAN SEE ANY BLOW BY ON YOUR PISTONS. ANOTHER WORDS CARBON BUILD UP BELOW RINGS. I THINK YOUR OK. 3:16 (yammie tony)
Devilin AblueDress!
New member
Keep in mind elevation plays into that number. Engine @ sea level may have 140 take it up 7-8 thousand ft above sea level and same engine may only have 100. I never was over critical about comp numbers, just as long as all 3 are similar to each other. I had a sxr 700 burn down center cylinder, still had 125 comp, would hold 0 on leak down test.
X2 on that my old artic scrap had 90 psi on the mag side with a broken piston skirt and partially cracked case 
lol
lol
It was tested at 1,200 feet above sea level so it should be closer to 140 then.
Devilin AblueDress!
New member
Emphasis on "MAY HAVE 140" with 120,120,118 If it runs fine I would ride it! A leak down test will tell you 10 times what a comp test will. If you dont have one pick up a lil flash light with a bendy head on it ($10@HDepot) slip the head threw the plug hole and you can get a pretty good look at the top of the piston. Some people get all hung up on comp numbers, Compression is only part of the eqaution. For example, If you tear motor down, clean and inspect everything. All your bearings,crank,rods,pistons,cylinders look good. Put new rings in it and reassemble with lets say winderossa base gaskets (thicker than OEM) its entirely possible when your done you will have lower comp. That thicker base gasket slightly raises jug, slightly increasing combustion chamber.
Interesting. I do not have access to a leak down tester but I will get a flashlight to look at the conditions of the pistons.
madzx2
Member
my 00 srx 700 has 120 across all three, and it runs real good. id say you are fine.
blueblood68
New member
My 98 has 123 ,123,122 I originally thought it should be higher as I thought these sleds were to be closer to 150 but I was told that as long as the 3 are pretty even that everything was fine. It's when they are considerably different user have a problem.
SRX_700 said:
I've never seen a specific number in any shop manual (car/truck/snowmobile/whatever) so the only way your Yamaha tech could spout an actual number is through experience. I don't think you'll find folks with more experience than long time members here.
My '01 pumps around 120 +/- 5.
As Tony mentioned you can take a peek at the piston skirts for blow-by but I'm guessing you're fine.
supervr4230
New member
A leak down test will give you the best results on the health of an engine! JMO
supervr4230 said:
Totally agree. Do not have the equipment here to perform one. I assume if I am getting 13 - 14 MPG, hitting close to full RPMS (8,100 and I found a pull thru PV), plug color looks normal, compression close in all three jugs and piston wash checks out, the health of the engine must be okay.