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Need a little motor help....

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The bike is an '04 CR 85. I was over at my friends house tonight trying to get his sons CR running. The bike is in great shape and has a new top end in it.

I checked for spark, held the plug up against a head bolt and you could see a white spark. Is white good enough? I thought blue was better.... Well there's a spark, so I think the ignition is working properly.

While the plug was off I put my finger over the hole and kicked it, blew my finger off the hole so I think the compression is fine. Like I said it has a new top end in it.

So we kicked and kicked with the choke on gas on etc....so when we pulled the plug it was very dry. Despite kicking it a lot we never smelled gas like it was flooded and like I said the plug was very dry.

I told him I thought the carb may need to be cleaned (jets) because I didn't think it was getting any fuel. The bike doesn't even try and start.

Just curious to what you guys think it might be that's causing the motor to not run. They got the bike back from the shop (2 hours away) ran the bike for about 10 min to break in the new motor..shut it off and that's the last time it ran. Ideas?

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the problem

the shop, its not running after they messed with it

this may sound stupid but gas in tank, petcock on

take the petcock hose thingy off the carb and turn the petcock on, fuel should come out, if not that hose is blocked,

otherwise try cleaning the carb

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Try a new plug as well. Buy a few NGK BR9ES plugs for $2 each at any auto parts store. Make sure gas runs out the fuel line when the petcock is on. With a cold, dry engine, try choke with NO throttle first. We have the exact same bike, and it can foul plugs with stock jetting. The plugs look fine, but they won't ignite the fuel. Once you get the bike running, take a look at the jetting if necessary. At 1000 feet elevation, we run "9" plugs, stock pilot jet and clip position, and one size down on the main jet.

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We did pull the fuel hose off of the carb, turned the gas on and fuel leaked out like it should. When you lay the bike over on it's side fuel will drain from the vent hoses. This means the fuel is making it to the float bowl, I think the jets may be clogged up and not allowing fuel into the motor.

The plug is brand new, the shop gave him a 10 instead of a 9, we are at sea level here. Is a white spark good enough? In addition to the top end the shop replaced the coil too.

I keep thinking all you need it fuel, air, spark and some compression.... I'm heading over next week to tear into the carb. I just wanted to run this by you guys to make sure I'm not overlooking anything.

I'm still scratching my head on this one....

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Gas tank vent hoses sometimes clog and or refuse to allow fuel to flow. pull it off and try to start to rule that out. also....why did the shop replace the coil? hmmmm now that sounds like the culpret.

Joe

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My first move would be aimed at the jets. Clean the carb, jets and especially the pilot.

The dry plug leans me in this direction.

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the problem

the shop, its not running after they messed with it

this may sound stupid but gas in tank, petcock on

take the petcock hose thingy off the carb and turn the petcock on, fuel should come out, if not that hose is blocked,

otherwise try cleaning the carb

I would try this first.

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you can also give it a shot of starter fluid. If it fires for a few cycles, you've got spark (although it may be a weak one)... and sometimes that'll overcome weak effort kickstarting and draw enough air through the carb to get going. If it runs a bit then dies again, your floatbowl isn't filling fast enough. If your air filter is badly clogged, it won't stay running either.

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Just clean the carb, jets, hoses, etc. and get them squeaky clean, then get some fresh fresh gas. And I would not use starting fluid as it is hard on seals.

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