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1978 YZ 400, just bought. Need info!

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I'm a newbie. What's the odds of me getting info on this bike here? Is it too old?

I got the bike, but no manuals. It runs, but PO never worked on it, he has no info at all.

Sure would like to take good care of it. Fluids, carb, suspension, etc.

Thanks!

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You can still get a Clymer manual for that bike.

Sure it is old, and parts may be nearly impossible to find. But those old air cooled open class bikes are a blast to ride.

My favorites were the '80-81 YZ465s and the last couple years of YZ490.

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I just ran it up and down the street once, then I figured I would go all over it. The front brake is sure not the same as the dual disc Brembos on my Ducati! It reminds me of the old Campagnolo philosophy on their bicycle brakes: They're not for stopping, they're for modulating speed...

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I just ran it up and down the street once, then I figured I would go all over it. The front brake is sure not the same as the dual disc Brembos on my Ducati! It reminds me of the old Campagnolo philosophy on their bicycle brakes: They're not for stopping, they're for modulating speed...

The 79 was before the double leading shoe brakes, wasn't it? I thought those came around on the 465. Too bad as those were decent and woudl help stop the bike. Prior to that, I know what you mean.

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These a very simple machines, and unless you're doing a full rebuild, you don't use the manual much any way. Check/change the air-filter, pop the exhaust off and have a look at the piston through the port and examine for wear, change the tranny fluid, check the headstem bearings (they go on these bikes if they sit too long). If it hasn't been done, sometimes the crank seals are worn out and will need to be replaced...the manual would help with that job. Otherwise, ride and enjoy...the 400 was a real torque monster!

On the brakes, a 465 wheel should bolt up, but not entirely sure. The IT 465 wheel may go on but there's a speedo/odo mechanism on the hub that would need to come with it. The IT 465 used about the same forks as the old YZ's.

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You can still get a Clymer manual for that bike.

Sure it is old, and parts may be nearly impossible to find. But those old air cooled open class bikes are a blast to ride.

My favorites were the '80-81 YZ465s and the last couple years of YZ490.

Actually, parts are easy to find for the 78 and earlier YZ400 due to it having the same engine design rooted in 1975. The 1979 “F” model is essentially a one year design and entirely different engine platform. The 1979 is rather hard to find parts for.

Most of everything can still be purchased through any Yamaha dealer. If there is something you cannot find, call Speed and Sport in Bloomsberg, PA, or go to their website and www.yamatopdog.com.

You can also go to www.vintagemx.us to the swapmeet, check www.AHRMA.org for guys that ride the Yamahas. You can find Genuine Yamaha owners and shop manuals on eBay. I may even have an owner's manual for the your "E" model.

There are a lot of websites that specifically focus on the evolution YZ’s.

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