Project 1976 Yamaha YZ400

I may still mess with the stock shock on mine but for now I built this for my restore. It should work. The spring rate calculates close to what I think it will need. I have it set up for right at 8 inches of travel.

BTW, not to hijack your thread, but here is what I am starting with. Carry on.

Ray, I don't think you will find the inner fender on Ebay. I have looked. I checked out the parts diagrams and came up with this for mine. Luckily mine still had the hardware to attach it, and a shread of what was left. I used innertube and looked at alot of pictures to see what they were stock.

Please join in, let's all have some fun with these old bikes. Your bike looks GOOD.

edit: I propose we make this an all YZ thread. Everyone welcome.

NICE job on the inner fender!
I have a few ideas for a rear inner fender. I'll take an old front fender (or rear) and cut it to fit, or - take some flat aluminum sheet and cut/bend to fit. I can see it now... maybe next week.

Scootern29, that tank does not look good on your bike. Please send it to me for proper disposal.

Pretty cool idea for a replacement shock. I think I'll send my shock to Racetech, going to do the forks myself.

I can't seem to make a picture, but here's the pipe. Going to clean it up:


That clutch lever is NASTY:


Would you take a bike like this home to your mama?


It's a dirty job, but somebody's gotta screw with it:


There's that big ol' hairy motor! Shifter kart? Anybody?

You can dispose of the tank for me by giving me your KLX 300 in trade. Seems like a deal to me.

Hey Ray, for cleaning up gunky, icky stuff, go to a dollar store and get some LA's Awesome cleaner it works great. I actually said icky.

Thanks for the tip. I am always looking for some magic formula. A HUGE amount of time is spent on cleaning up icky - there, I said it, too - parts. I will try that LA's Awesome stuff. So timely, I have been cleaning dirty parts all evening. The good thang is that all is in fairly good condition - just dirty!
p.s. I like my KLX, it is a really good all-around bike. I could use a bit more power sometimes. Maybe that's why I've been wanting for a monster 2-stroke. I was looking at CR500's - they are asking high $$$ for those bikes. Found this OLD YZ400 on CL and bought it. I knew it was going to be some work. Turns out, it's going to be a big chore, but that's the way I roll:

Occasionally I will see an old monster 2-stroke on CL - KTM, Suzook, Yamaha, CR500, etc., - makes me drool. I think Supershaft has a thread in 2-smokers about old Maico's; those bikes had SCARY power. Too much fun...

Jack!

Years (decades) of dirt:


Hours and hours of hard labor:


Shock shipped off to Race Tech:


Parts all over the house:

Piece by piece, clean and paint:


I make lots of photos, mostly so I know what parts are what and how to put it all back together:


Need that shop manual. Found some parts diagrams online that help:


Baked on grease is the hardest to remove:


Several hours later and a few coats of paint:

Silencer:


Expansion chamber:


Frame:


and:

When I first brought the bike home I found the clutch very stiff. After a few can of Berryman's and penetrating oil I cleaned out years of rust and dirt inside the clutch cable. Seems to slide smoothly now::


Front brake. Oh, joy:


More work to be done:


In a few more months I might get it all put back together. Stay tuned.

Any tips on how to polish up the old plastic?

Use some fine steel wool to take of the oxidation. Then use a heat gun to melt the plastic. You have to be real careful as you do this. You will see the color come back out of the plastic. The downside is I did a Yamaha tank and I think with the new fuels and the heat gun it made it brittle and it cracked big time.

I will work on it... tomorrow. Thanks!

Just messin' around cleaning stuff:


Brand new old parts:


Seems like the old YZ is complete, not missing any original parts, just encrusted with decades of grease, dirt, and corrosion. Broken throttle:


If you can't fix it with JB Weld:


it can't be fixed: