summit 700 only 65 psi in both and still runs great but wont start

[PHAZER500]

hey guys i have a 2000 summit 700 and it really has lots of get up and go when it runs but i have troubles getting it started. i did a compression test and it only has 65 pounds in each side. when i pull the rope to start it it will backfire and sputter but wont start till it is put in a heated shop and the plugs are warmed up. i just can figure it out how the sled has sooo much power and runs excellent when running but when its cold wont start. once out riding the sled will start all day. any help?!!!!

 

[sledderdoc]

hey guys i have a 2000 summit 700 and it really has lots of get up and go when it runs but i have troubles getting it started. i did a compression test and it only has 65 pounds in each side. when i pull the rope to start it it will backfire and sputter but wont start till it is put in a heated shop and the plugs are warmed up. i just can figure it out how the sled has sooo much power and runs excellent when running but when its cold wont start. once out riding the sled will start all day. any help?!!!!

Thats amazingly poor compression!! Things shrink when cold making it even worse. I would say that is the problem right there. I would pull the head and inspect how much wear you have.

 

[poorboy]

do you have the throttle wide open when doing your test needs full air to test and should be at operating temp also

 

[PHAZER500]

wel i will get the sled into the shop and getter nice and warm, fire it up, take it for a rip then do the compression test again. i didnt think that that sled would even run on that low of compression. thanks.

 

[Summitric]

wel i will get the sled into the shop and getter nice and warm, fire it up, take it for a rip then do the compression test again. I didnt think that that sled would even run on that low of compression. Thanks.

like poorboy said, did you doo the compression test with the throttle "wide open" and both spark plugs out and guage in one cylinder at a time???

 

[magnet]

how many times did you pull the cord? usually takes about three times to get accurate reading. is your gauge accurate? could be low comp. but its weird that both are at the same level. usually one is a bit better than the other.

 

[PHAZER500]

thanks for all the advice. i did a compression test again after a little ride and it read about 95 on both. i had the throttle wide open. i think i am goin to pull the head and see what the pistons look like and if they are good will just throw new rings on and see what the compression is like. hopefully its just rings, :d

 

[yippy82]

I had the same sled a couple years ago. This may sound stupid but is is getting fuel from the pump. My fuel pump somehow would build mosture and freeze when it got cold, don t ask me why but all i did was poor a pot of hot water on top of pump and it would start in the cold. In the garage i never had trouble starting it ever. I changed out the fuel pump and its been good ever since.

 

[gforce]

funny thing is right now i am selling 2 of these and i had a guy come out and look at them he did a compression test right there and both machines had 120 psi per side so im thinkin yer rings are done..bore it out in put new pistons and yer good to go..im sure the peeps on here can tell ya where to get that done,,i have always used cycleworks only cuz i dont know where else to get er dunnn

 

[sledidiot]

if your changing the rings do the pistons to, a skirt breaks off and screws the crank you will be pizzed.

 

[Modman]

if your changing the rings do the pistons to, a skirt breaks off and screws the crank you will be pizzed.

What he said ^^^ don't cheap out and just do the rings, that's a piss poor fix at best. Do pistons and rings and re-hone or don't do it at all. You'll save money doing it right the first time, because you won't have to do it a second time (or a third time....).

Just think - you think it really has power now, wait until you get it all back together with the right compression!!!!

This is classic 2 stroke. People think that because it runs really well that it can't be the rings. The hard starting part is a dead giveaway. 95 lbs is just barely enough compression.

 

[gforce]

and dont use el-cheapo oil;i only use castrol or brp and have never ever had a melt down...well on my toys anyway

 

[ridehard]

Get the piston to cyl clearances measured by a pro, and look/feel hard for anything unusual at the crank. How many miles on this sled? They ran great in their day.

 

[khaos_]

That just happened to me recently. Almost identical. Rings were gone, and the cylinders were scored. Top of pistons were pitted also. Just change everything out. Bore it, replace it...whatever, just make sure you replace everything or like the guys are saying, you will be sorry later.

 

[mxz sledhead]

overhaul on top end are cheap to do before thing break measurement
are very important 3hrs in the garage and $500 in parts will solve the problem