Pulling Flywheel?

[Treejumper]

My YZ just slowly died one day while trying to ride and i've been trying to track down the problem. Going thru Eric Gorr's book of possible problems i'm down to pulling the flywheel to check the magneto and startors. The bike is an 86' YZ250. I tried a gear puller which i had to grind down the ends to fit betweent the flywheel and Magneto, no go. Too wide to get a good pull, it just pops off. Next i went to use the flywheel/steering wheel puller out of my car tools. There's no holes in the flywheel to thread the bolts into. So i'm going nuts.

I searched the internet for the proper tools but cant seem to find what i need. My year YZ isnt listed under any of the magneto pullers. All the flywheel pullers i saw said universal and the ones that had a picture look just like the one i have for my car. So what do i actually need to get this off besides loading the bike up and taking it to the dealer. I really what to learn this stuff myself instead of paying an arm and a leg for the shop to do it.

Maybe i'm trying to find the wrong problem so here's what happened just incase. I fired up the bike and went down the hill to play on the trails. Bike ran fine while mid to wide open. Got to a tight section and bike felt like someone put a plug in the pipe. It just died instantly! Sat there for afew minutes trying to fire it up and eventually it did. Rode for about 2 mins and hit a slow section again. When i let off the gas to take a turn and it died again. 5 mins of kicking and nothing. Waited afew minutes to catch my breath and it fired right up. So i hit the straight stretch to clean it out in 5th, bike ran fine. Stop back at the house to put some more air in the front tire and it fired right back up. Down the hill again and hit the trails and it died in the same section as the first time. This time it wouldnt fire back up and hasnt since.

I replaced the plugs, tried new plugs, fresh air filter, checked the reeds, pulled the carb and nothings wrong. Checked all grounds and they had no corrosion. The motor has a fresh top and bottom end with maybe 20-30 hours on it. Looks like good compression as far as i can tell without a gauge (blow plug out of pipe if not placed in tight). So i figured it had to be electrical since it doesnt look to be any spark. All the electrical componets are original 1986 with bike sitting for 14 of the years indoors except last 3. I pulled the flywheel cover since Eric's book says that they tend to allow alot of dirt and water in there. Well there was alot of dust caked inside the flywheel housing. So this is where i'm stuck at. Thanks for reading this far but thought i should give all the info i know. ;)

Thanks for any help you can provide!

 

[jmics19067]

well unfortunately you could have a host of problems.

1st are you sure there is no spark? put the bike in the shade make sure you have a good plug snapped in the the boot tight and grounded well and kick the the kickstarter smoothly yet quickly. You should have a nice blue spark if the spark is yellow weak or not consistent try another plug check the spark plug boot to the coil wire connection and try again. if it is still yellow or weak a guess would be the coil. But buy an ohm meter and the manual for your bike and double check, also you can check the stator coils without having to remove them with your new ohm meter and manual.

about the flywheel puller itself if you look at your flywheel you should see that it has a large female left handed threaded area right around the the nut that holds it to the crankshaft. if you have a set of calipers or inside micrometers and a thread gauge you should be able to tell what size puller you need. if not go to your local dealer and ask them to get you the right tool and let them worry about figuring out which one is correct.

 

[Treejumper]

Thanks for the reply! I'll borrow an Ohm meter and see what i can come up with.

 

[Ol'89r]

Originally posted by Tree jumper
So what do i actually need to get this off besides loading the bike up and taking it to the dealer. I really what to learn this stuff myself instead of paying an arm and a leg for the shop to do it.

Tree jumper. Your local Dealer should be able to pop that flywheel off using the proper tool for a small charge. Using the wrong puller could damage the flywheel.

Then, like jmics said, get a good service manual and ohm meter and start checking the values of each component.

Just my $ .02

 

[Treejumper]

Thanks! Just ordered a repair manual and it should be here by friday. A friend has an Ohm meter so i should be set for testing.