Newbie from SoCal

[Mx360guy]

Hi KDXers,

I have been a Yamaha guy for awhile. Having a mid-life I guess so I got a 1980 KDX 250 that needs a second chance at life.

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Only 1,347 miles on the cool Odometer. Mechanical trip and total mileage.

The flywheel is my only real concern. It is really crusty. I been hitting it with penetrating oil. I have not attempted to try turn the bolt yet..don't want it to twist off...that would be very bad..Any thoughts on this would be taken to heart.

The engine is the best part. Bearings feel very good and so does the trans.
Happy Labor Day Weekend!

[billie_morini]

Hello MX360guy & welcome to this green forum.

You are smart to apply penetrating oil. I like PB Blaster for mechanical / metal parts and DeOxit for delicate & electrical parts.

When I have stuff like this that's corroded, I'll tap the part(s) with mallet at each liberal penetrating oil. The vibrations made by tapping help the oil get farther in.

Parts that are really stuck get heated before wrenches are cranked. Depending what, when, & where, heat is applied by electric heat gun or torch. Heat loosens parts by expansion. Heat application works so well that it's almost like cheating.

According to parts microfiche, the flywheel is anchored by a 10×40 mm flanged bolt (Part# 92002-1296). So, you can also use an impact wrench (but not without a couple of day's of penetrating oil and heat just before force application).

[Mx360guy]

Thanks for the reply! I am using PB Blaster. Good idea with the heat and tapping. A new bolt is on order. I plan on installing a Vape ignition. I noticed the light bulb was 6volts? I found a rusted through hole in the pipe..dang. That could be tough to find a good one. Getting a shop manual too. I read some good back in the day reviews and they liked the KDX250 over the Yamaha IT. I like the simplicity of the air cooled, twin shock, drum brakes. Good enough for me. Would you know if this model had the coated cylinder or did it have a sleeve?
Rambling.. thanks

[Chuck78]

Tapping with a rubber mallet on rusted parts that you're trying to get penetrating oil into is definitely a very very excellent idea....
I've been using Free All lately as I got a good deal on a gallon jug at $50, and have a WD-40 refillable spray bottle that I have been using for it. That is some really good penetrating oil.
Kroil was my other go to, but I thought I would try another very very highly recommended alternative to the big names.

Liquid Wrench penetrating oil beats out PB Blaster, so I would always recommend that over PB even though I really like the PB Blaster logo and can graphics, the retro vibe always gets me...

Welcome to the forum, you've come to the right place! The majority of the bikes supported on here are water cooled 200/220 models, but the older models still have a wealth of information if you dig deep with the search function or happen to catch the right people viewing your posts!

[Mx360guy]

Thanks Chuck,
This seems like an excellent forum. I will dive into the search for sure.

[SS109]

Welcome!