YZ490, welcom home old friend

# two

# two

Well-Known Member
Visit site
I finally went and dug this thing out of my folks garage a couple weeks ago. It hasn't run for 20 years and about 10 years ago I started taking it apart and ordering parts then wasss ... to busy? I don't know, anyway shes home now. Here are some pics. She's back together with fresh .040 over cylinder, new piston, rings, bearings, gaskets and full DG exhaust. It starts, runs and rides but I still need a few pieces. 2 of the 3 exhaust springs disappeared, 1 of the 2 plates of the upper motor mount as well, kick start return spring is broken and I only faintly remember repairing the rubber upper exhaust mount with a nut and bolt, but I must have because it has a bolt through it so I need one of those to.
 
I'll work on getting some video as soon as I get a new exhaust mount, right now it just beats my shiny new expansion chamber against the cylinder.
 
I was 15 when it burned up, so probably to much throttle for to long. I figured it would be melted pretty good but was suprised that it was broken.
 
Nice work getting her back running. Looks like more TLC needed but the hard part is over. I'm hoping to get a couple projects like this in a couple more years. :D
 
Yea, the old girl needs a little tlc for sure. I was just a kid and spent every free minute riding the sh!t out if it with very little time spent on maintenance. Any good tips on cleaning 20 years of garage residue off of plastic?
 
# two said:
Yea, the old girl needs a little tlc for sure. I was just a kid and spent every free minute riding the sh!t out if it with very little time spent on maintenance. Any good tips on cleaning 20 years of garage residue off of plastic?
Click to expand...

Probably the best stuff for old plastics... :D [ame="http://www.amazon.com/Novus-Plastic-Polish-Scratch-Remover/dp/B001J7EVCQ"]Amazon.com: Novus 1, 2, 3 Kit Plastic Polish and Scratch Remover: Electronics[/ame]

I had a Yamaha DT175 smoker when I was a kid. Rode the crap out of that but I kept it will maintained and shined. I had converted it from dual-purpose to strictly dirt. Bored, ported, polished, tuned pipe and full off-road plastics. :yes:
 
I rode a '76 YZ400 (1st Monoshock) for a long time and produced a couple of pistons that look like that one you posted. The giveaway is the melted alum spot on the face of the piston - suspect it's running lean or whatever you're using for premix oil is letting your down. Only premix that never let me down was Bel-Ray MC-1, even at 50:1 it was better than anything I had used before.

I got tired of getting beat by the red tide and sold mine to buy a red '83 CR480 - DeCoster's model with that crazy left handed kickstarter. I still have that one and hope to ride it again, but parts are getting hard to find.
 
Before the 490 I had an '80 CR250 w/ the left side kicker and duel springs out back but a tall stance like a mono shock. Before that I had a '68 kawasaki bushwacker 175 a 2 stroke duel purpose also converted to off road only.
 
My new kick start return spring came in today and as soon as I could I was wrenching. Of course the gasket did not survive when I opened the crank case. Does anybody love or hate rtv or any other gasket making products? I just don't want to order and have to wait for a gasket.
 
# two said:
My new kick start return spring came in today and as soon as I could I was wrenching. Of course the gasket did not survive when I opened the crank case. Does anybody love or hate rtv or any other gasket making products? I just don't want to order and have to wait for a gasket.
Click to expand...

Just clean the surfaces well and RTV should do the job. Most modern engines use that instead of gaskets for most of their sealing.
 
I used this with good results on an old Yammy XT that I flipped:

[ame=http://www.amazon.com/MSR-Plastic-Renew-8oz-PCR/dp/B00135KMLI/ref=sr_1_1?ie=UTF8&qid=1325268879&sr=8-1]Amazon.com: MSR Plastic Renew - 8oz. PCR: Automotive[/ame]
 
Ebay for the plastic? I had YZ465G the most evil bike ever I ever had! Handled like S??t but by god did it go!!!!! 160kph (100mph) power slide wheel stands when you least expected it! The new 450s just are'nt exiting enough but FZ1 is close. PS the 465 i think was 60+ Hp and 95kg (illegally light for Mx now).
 
You must log in or register to reply here.
Back
Top