engine wont fire over

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kevin444 · #1 Post by **kevin444** » Mon Jul 06, 2009 5:27 pm

Hello all,

Well we went to Sand Hollow, Utah for the 4th. This place was awsome, the best of both worlds....you got a really nice lake and endless amount of dunes that run through the mountains.

Well the dale was running real strong and out of nowhere in 4th gear she died, not even a sputter. At this point I know this machine really well and went right to work. I'm in the dark on this one though. I've got spark, fuel, and air? Seems to have compression, but will check later once I know how much to look for? Please advise on how much compression "stock piston". back at the campsite I also pulled the plug and dropped a capfull of oil to see if it would fire. It's so damm hot here in for the first time not in a rush, but will have here running asap.

My guess is I either lost compression or possibly lost timing? I forget how to check that though.....so please advise before I tear this sucker down. Hopeing at worst it's a piston / sleeve issue. Is it possible that it's some electrical issue? I did not think so since it does have a good spark?

Also, I've been having issues with my gas tank / pump boiling over due to the heat out here and I feel that a lean issue might have beat the piston up, however I fixed that problem and up to the last second it was making 100% power....just shut off and has not fired since????

Thanks everyone and hope everyone had a great 4th!

Happyboy · #2 Post by **Happyboy** » Mon Jul 06, 2009 7:17 pm

Yank off the side cover and look at the flywheel. My guess would be you spun it. If you take the nut off the key groove should line up with the C in cannondale.

kdeal · #3 Post by **kdeal** » Mon Jul 06, 2009 7:22 pm

You say it has spark, fuel, etc. How are you validating the fuel part? Have you looked into the fuel tank while cranking the motor over to see if there is a steady stream of fuel reentering the tank? Have you tried a shot of gas or starting fluid (ether) into the spark plug hole? This would identify any fuel issues except for bad injectors. Check the keyway on the flywheel and see if it's lined up with the "C" in Cannondale imprinted on the flywheel itself. Compression is in the 75-100 lbs area on a Cannondale. This is due to the bleed off of compression by the decomp. My guess is fuel or electrical related.

kevin444 · #4 Post by **kevin444** » Mon Jul 06, 2009 8:59 pm

thanks you guys.....

just got unloading after a long and hot weekend. i took a nasty fall and got wrapped up in axle and exhaust with my legs, got burnt real bad right under my knee where the crease is, cant wait for the scab to begin!

ill go pull the cover off in a few, when i checked for fuel there was gas a nice stream from each injector, but more like a mist.....if there is fluid in the shop ill spray some in there as well. what would cause a weak stream of fuel? i got plenty going back into the return line of the tank.

keivn

kevin444 · #5 Post by **kevin444** » Mon Jul 06, 2009 9:12 pm

flywheel is fine, did not think that was the problem. this is a full rebuild from the bottom end up that has been very strong and impressive! the only thing that has been changed was i moved the fuel pump to where the ECM is, but seemed to not cause an impact since I've got probably 8hrs on it since the move. i did roller her earlier in the day, but went on 2 more rides through the dunes with no issues until this?

ill check compression and pick some fluid up later? is there anything i can check for at the fuel regulator? and how much of a stream should i see from the jets? she's gonna be a little more rich than stock since i did have boomer play with the ECM.....

kdeal · #6 Post by **kdeal** » Mon Jul 06, 2009 11:10 pm

The mist at the injectors is fine, the steady stream on the return line is good as well. I would only use the starting fluid to rule out anything fuel related, but all sounds good with the fuel system. Try changing the spark plug just for grins. Also, do you have a spare ECU to test?

peterock · #7 Post by **peterock** » Tue Jul 07, 2009 12:32 am

Did you actually pull the flywheel off to check to make sure it was aligned with the "C" still? And also make sure the key didn't shear off? Really sounds like a flywheel issue. Or maybe like one guy just recently had, end of the crank broke and the flywheel isn't even spinning anymore.

kevin444 · #8 Post by **kevin444** » Tue Jul 07, 2009 12:42 am

yeah,

i checked the flywheel visually, but i'll check for movement?!? its got a z400 crank in there and hope to keep it in there for a much longer time. i'll have some fluid in a little while and do a compression test as well.....

kevin444 · #9 Post by **kevin444** » Sat Jul 11, 2009 10:37 pm

well....tried starter fluid and had know luck

drained the oil and had a small amount of shavings, but not really much as all. I really would like to check the compression but dont have one that fits an ATV. im sure she probably sucked a ring. just odd because she was making what felt like 100% power right up to when she stalled. i got an estimated 80-100hrs on the motor with 4-5 dune weekends......and rode her like i stole it! i really think the desert out here did her in...riding in 110+ degree weather. either way its too hot to ride and ill tear her down in a few days, still beat up from last weekendm walking like a crippled. but for 125 bucks or so to rebuild is not to bad.

also,

what will i gain out of a higher compression piston? got full exh, ported head work, and re flash from dave "boomer".......dont want to spend the extra money for somthing i wont feel.

kevin

kevin444 · #10 Post by **kevin444** » Sun Jul 12, 2009 5:20 am

haha.....not even 30psi! well, at leat i get to have a fresh motor for when it cools down. Please just let me know if its worth getting the higher compression piston. Also, bet shes getting evans too!

Kevin