CR250 broken

[Pierce]

So... took the bike out to Fells Farm winter series today, ran it for the 2 lap practice which seemed to run fine but was pinging a fair bit. I changed the gas out and put some fresh stuff in. Seemed fine for the first lap then into the 2nd it started to feel like it was pinging again bogging (almost like I was trying to ride round corners in 5th gear or something). I slowed down then it started to die.

Bike seems like it has almost no compression when you try to kick it. Anyone had something similar happen to them?

2005 CR250R 2T.

[barty5]

So... took the bike out to Fells Farm winter series today, ran it for the 2 lap practice which seemed to run fine but was pinging a fair bit. I changed the gas out and put some fresh stuff in. Seemed fine for the first lap then into the 2nd it started to feel like it was pinging again bogging (almost like I was trying to ride round corners in 5th gear or something). I slowed down then it started to die.

Bike seems like it has almost no compression when you try to kick it. Anyone had something similar happen to them?

2005 CR250R 2T.

yup years back my cr250 i had did same thing i had mixed gas wrong any way had no compression ripped head off turned out it had seized up ripped the bottom skirt off the sleeve and totally trashed the piston was a large pulpy pastey mess in the bottom of the crank.

[Ride it till the red]

Might be a silly question but is your air filter in there? Watched a guy's bike die a while back as he ran it without one on accident... Symptoms would be similar too, pinging due to running lean and no compression now due to burning a hole in the piston. Otherwise with lack of compression I can only suggest taking the top off for a looksee.

[B0000M]

oh... doesnt sound good. pull it apart..

[cheese]

Yeah, did you run it with 2 stroke oil??

[little.whittle]

is the cylinder head cracked maybe ?? Happend to me before

[Pierce]

Def put the right gas in as I mixed it up just before the race, filter was in there as I put in a fresh one before I left Auckland. So it sounds like it's gonna cost a bit :-s

[B0000M]

sounds like its leaned out for one reason or another, best case scenareo, replace piston, rings, little end bearing- worst case scenareo, all the above plus a cylinder or sleeveing of.

intake manifold leak perhaps? split intake boot? loose or not sealing reed block? unsealed casings... fuel mixture? partially blocked main jets? shit fuel...

what plug and jets are u using?

[Pierce]

sounds like its leaned out for one reason or another, best case scenareo, replace piston, rings, little end bearing- worst case scenareo, all the above plus a cylinder or sleeveing of.

intake manifold leak perhaps? split intake boot? loose or not sealing reed block? unsealed casings... fuel mixture? partially blocked main jets? shit fuel...

what plug and jets are u using?

Bike is basically stock. plug is an BREG8 I believe.

[B0000M]

Bike is basically stock. plug is an BREG8 I believe.

as a comparison, i use BR9 plugs, and run a 430 main jet. i understand 420 is stock, both these mods equate to less detonation

[Reckless]

Bike seems like it has almost no compression when you try to kick it. Anyone had something similar happen to them?

That doesn't sound good when was the last time you did a piston or rings mate?
I concur with B000M either air leak somewhere to cause it to lean out, simply past its use by date and its lost compression or something has gone in/come loose and knackered the engine. Sounds like it needs a strip down. Clean the carb well and inspect the things B000m suggested carefully.

BTW: I ran a Br10 in my Cr some off the time so the move to a Br9 it wouldn't hurt at all.

[Sammikins]

yup years back my cr250 i had did same thing i had mixed gas wrong any way had no compression ripped head off turned out it had seized up ripped the bottom skirt off the sleeve and totally trashed the piston was a large pulpy pastey mess in the bottom of the crank.

Sounds like another rebuilds candidate for Friday night...?

[B0000M]

Sounds like another rebuilds candidate for Friday night...?

how late do these friday nites go?

[Sammikins]

how late do these friday nites go?

Till weneva really?

[barty5]

how late do these friday nites go?

depends on whats being built and who much piss there is, Worst was an all nighter bike finished round 11 drinking continued till we ran out and sort passed out lol