NEWBE ? 1986 CR250

madmarticus
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madmarticus
Edited Date/Time 1/7/2014 9:48pm
I just picked up a 1986 CR250 for 250 bucks. I'm so excited to go ride it. I'm new to dirtbikes but I know how to fix stuff.

So I was told it's been sitting for ten years. I rebuilt the carb. Took off the gearbox/mag covers, reed valve, and head top. everything looks beautiful inside. I have a few questions for you more experienced than me members.
1. gearbox had pure white, thick gear oil. I've never seen white gear oil before, it did not look like water in oil like I've seen before.
2. Is there anything else you recommend before I fire this baby up and ride?
3. is it the normal 40:1 gas/oil ratio?


Thanks in advance for your help. I have a manual coming in the mail.

Matt
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Donny O'Slow O'Hara 1/2/2014 10:09pm
1/2/2014 10:09pm
Drain the Anti Freeze, pull the water pump cover, look for corrosion, then stick a flashlight in the radiators to see if they are plugged up, from the magnesium corrosion. Pure white, thick gear oil doesn't sound good, it sounds like water has gotten in to your gear box, and solidified . All the 82 through 89 CR have magnesium clutch & water pump covers that get corroded and rotted.
barkhard696
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barkhard696 1/5/2014 4:58pm
1/5/2014 4:58pm
Madmarticus, there's a detailed explanation of replacing the magnesium clutch cover with a cover that won't rot. Basically, Honda made these back in the day with sand-cast magnesium clutch covers, which while very trick, "rot" in the presence of water. Since even 100% antifreeze has some water in it (yep, look at the ingredients next time you buy any antifreeze -- the #2 igrendient is water) - the '82-'89 CR125/250/500s all have clutch cover rot in some form.

Honda recognized this problem, and made a run of '89 replacement covers with more aluminum and less magnesium. You can back-fit these updated '89 covers to your '86, in fact one is for sale here http://www.vitalmx.com/forums/The-Bazaar,26/CR250-Inner-clutch-cover-right-side-case-cover-85-89-NEW,1263512

There is a detailed explanation of how to mount this cover in the build of my 1987 CR250 (the mechanics of the clutch cover replacement are the same) here on Vital, just search "1987 CR250 Build"

I have a set of VMX sidecovers brand new in bag I'll sell you for $45 shipped to you door, if interested, PM me.
CamP
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CamP 1/6/2014 6:38am
1/6/2014 6:38am Edited Date/Time 1/6/2014 6:41am
I installed a new 89 cover on my 87. It's an easy installation, but it's not a direct bolt-on replacement. The bore that holds the powervalve spring has to be relieved and chamfered with a die grinder. Otherwise, the spring will hit the case as it moves through it's arc.

The 89 cover also requires the little plastic alternator cover and o-ring.

The Shop

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madmarticus
Profile picture for user madmarticus
Posts
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Joined
1/2/2014
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Vacaville, CA US
madmarticus 1/7/2014 9:48pm
1/7/2014 9:48pm Edited Date/Time 1/7/2014 9:49pm
barkhard696 wrote:
Madmarticus, there's a detailed explanation of replacing the magnesium clutch cover with a cover that won't rot. Basically, Honda made these back in the day with...
Madmarticus, there's a detailed explanation of replacing the magnesium clutch cover with a cover that won't rot. Basically, Honda made these back in the day with sand-cast magnesium clutch covers, which while very trick, "rot" in the presence of water. Since even 100% antifreeze has some water in it (yep, look at the ingredients next time you buy any antifreeze -- the #2 igrendient is water) - the '82-'89 CR125/250/500s all have clutch cover rot in some form.

Honda recognized this problem, and made a run of '89 replacement covers with more aluminum and less magnesium. You can back-fit these updated '89 covers to your '86, in fact one is for sale here http://www.vitalmx.com/forums/The-Bazaar,26/CR250-Inner-clutch-cover-right-side-case-cover-85-89-NEW,1263512

There is a detailed explanation of how to mount this cover in the build of my 1987 CR250 (the mechanics of the clutch cover replacement are the same) here on Vital, just search "1987 CR250 Build"

I have a set of VMX sidecovers brand new in bag I'll sell you for $45 shipped to you door, if interested, PM me.
Sidecovers, are you talking about the ones with the race numbers on them?. I'll look up your build and read the install.



Thanks for all your help guys.

CamP, are you talking about the spring for the kickstart? Can I put a bolt in the alt cover?

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