98 CR250r Starting Issues, Have fuel,Spark, and Compression, PLEASE HELP!

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dc4lsteg

Member

Jul 24, 2013

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• Jul 24, 2013

• #1

Hi, so Im trying to get my cr250 running again after sitting for a couple months. I have good compression, spark, and fuel.

Bike was always hard to start since I got it, and would take forever to start unless it was already warm from running.

So the bike sat for awhile and I decided to go riding again and I couldnt get it started. First I started by changing the spark plug and check for spark which is good. Next I checked the compression with tester and got 160 on a dry test. Then I verified fuel was getting to the carb without any restrictions, after that I pulled the carb apart and cleaned everything out. Got it back on and still nothing , It would sound like it was going to start but wouldnt fire.

So after searching on what it could be I decided to not try and troubleshoot with this carb(PJ) and when and picked up a PWK "air striker" at a local shop(used)I used my stock throttle cable and installed the matching slide off the PWK. Threw it on today and it fires sometimes and will run for a couple seconds but bogs when i hit the throttle and it wont idle by itself, also on some kicks the bike will just back fire really bad.

Also its not very hard to kick the bike over I can almost do it with my hand, as said compression was checked(160), and from looking at the piston and ring theres no obvious signs of damage.

So from the info I can find Im narrowing it down to incorrect ignition timing, air leak, crank seal, or incorrect carb adjustment. Is there anything else I should check? Im just trying to be able to take my bike for a ride before I move in 2 weeks and can no longer ride at home.

ALL HELP/INPUT IS GREATLY APPRECIATED!

 

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dirt bike dave

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May 3, 2000

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• Jul 24, 2013

• #2

Replace the reeds. Any cracks or warps can make cold starting very difficult.

When my '99 CR got hard to cold start, replacing the reeds fixed it 100%.

Also, before you try to start it, turn the gas and choke on and lay the bike on its side for like 10 seconds. You want gas running out all the overflow tubes. Pick it up, prime the cylinder by kicking it over SLOWLY two or three times. Retunr the kick start to top, find Top Dead Center (just after the compression gets less as you move the starter), the KICK HARD. On my CR, it wanted like 1/16 throttle.

 

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dc4lsteg

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Jul 24, 2013

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• Jul 24, 2013

• Thread starter
• #3

The reeds look pretty much brand new with no visible damage

 

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dc4lsteg

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Jul 24, 2013

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• Jul 24, 2013

• Thread starter
• #4

ok I kicked it a couple of times and pulled the plug and it was somewhat wet not to bad. Also when I went to recheck spark right now, Im not getting spark on every kick, sometimes its a couple kicks before it sparks once. Its a new spark plug, and I changed the coil to a known good working one

 

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dc4lsteg

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Jul 24, 2013

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• Jul 24, 2013

• Thread starter
• #5

The spark plug wasnt extremely wet. Also the more I back the air screw out the easier it seems to want to fire, and it will only fire with both the gas and choke turned on. Does this sound like there could be a vacuum leak somewhere?

 

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dirt bike dave

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May 3, 2000

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• Jul 24, 2013

• #6

My '99 had carbon fiber v-force reeds, and they looked good, too. One or two very small chips, no noticeable warping. They were just old. The bike gradually got harder and harder to start, a little worse each ride until it was a real bear and did not want to even bump start. No problems once it got warm. Took me a long time before I buckled down and replaced the reeds.

Not saying your problem is not electrical, but if the reeds are old, you might consider replacing them. Just trying to save you some aggravation... I hope you get it sorted out.

 

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dc4lsteg

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Jul 24, 2013

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• Jul 24, 2013

• Thread starter
• #7

Thanks but even when it does start it doesnt run good at all then will shut off in a couple seconds. So it could still be the reeds even if they look new and are in perfect condition? Is there anyway to test if they are bad?

I still find it weird that my bike has good compression, but its very easy to kick over.

 

High Lord Gomer

Poked with Sticks

Sep 26, 1999

11,788

35

• Jul 24, 2013

• #8

Have you check to ensure that the woodruff key that aligns the flywheel on the crank is there and not missing or sheared off?

 

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dc4lsteg

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Jul 24, 2013

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• Jul 24, 2013

• Thread starter
• #9

I will be checking that tonight when I get home thanks

 

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dc4lsteg

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Jul 24, 2013

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• Jul 24, 2013

• Thread starter
• #10

If it is sheared off, am I most likely going to need a new flywheel and crank, Im not to familiar with bikes but I know that is the case for cars

 

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dirt bike dave

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May 3, 2000

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• Jul 24, 2013

• #11

No, if it is sheared you just need a new key. It's a slice of metal shaped like a half circle that fits in a groove in the flywheel and in the crank, so that they stay in proper alignment. The key itself is usually on a couple of $.

On your bike, the magnets that energize the ignition are inside of the flywheel. The flywheel has to be lined up properly for you to get your spark at the right time. If the woodruff key shears, the flywheel will slip/rotate on the crank to be out of proper alignment.

You will have to pull the flywheel to replace the key, and that which usually requires a flywheel puller.

The keys do occasionally fail (happened to me once), but it's not very common. If it fails, a bike can go from running and starting perfectly to not running at all.

I notice you said your bike was always hard to start since you got it. How long have you had the bike? Has the problem gradually gotten worse and worse?

 

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dc4lsteg

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Jul 24, 2013

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• Jul 24, 2013

• Thread starter
• #12

ok lets just same im an idiot and shouldve pulled the cover months ago. I pulled it to see if the flywheel key had been stripped out and the sensor that connects to the alternator wire wasnt even bolted in and was just hanging freely. I screwed it in and bike started right up on the first kick and ran fine. I didnt get to ride it though I need to fix my chain I will be riding it tomorrow

 

RM_guy

Moderator

Damn Yankees

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Nov 21, 2000

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North East USA

• Jul 25, 2013

• #13

Ha! You're not the first and won't be the last one to do something like that.

I was riding with a buch of friends last year and my buddy's bike just stopped running. He got out his tools and replaced the plug and tried to bump start it about 5 times but it wouldn't start. He fiddeled with it some more, kicked it over and it started right up! He gave us the thumbs up and we took off. Later I asked him what happened and he had forgotten to turn the gas back on after a brake we had earlier. I busted him pretty good about it until later in the day when I did the same thing!

Glad you got it running. At least you know all the other stuff to look for the next time it won't run.

 

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dirt bike dave

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May 3, 2000

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• Jul 25, 2013

• #14

Congrats on getting it solved!

 

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dc4lsteg

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Jul 24, 2013

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• Jul 25, 2013

• Thread starter
• #15

Thanks guys, and thanks for the help it is greatly appreciated! Ill be taking the bike out today for the first time in awhile. See how it runs now with the PWK and new sprocket set up.

I knew a bike couldnt be that hard to get running

 

High Lord Gomer

Poked with Sticks

Sep 26, 1999

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• Jul 25, 2013

• #16

That's great!

I've done much worse.

 

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kneedrag05

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Sep 16, 2013

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• Sep 23, 2013

• #17

most likely if the woodruff key is missing, out of place sheared off you will just need a new woodruff key.

Personally I think its time for a new top end. I have over 45 hours on my CR250 with 225+ pounds on a compression test. I'd say 180 is on the way out. I would not want to ride my bike at 160 for fear of damaging the plating on the cylinder wall.