Author Topic: YZ 490  (Read 2379 times)

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Offline SimonC

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YZ 490
« on: November 17, 2014, 02:58:12 pm »
Picked up a fairly original YZ490 at the weekend, seller says it is an 86, frame number 1LV00688.

Missing pipe, muffler, reed cage, inlet manifold, carby, front brake caliper and cylinder, is their much interchangeability with other similar year 490's and are front brakes the same as on the 250's.

Cheers

Simon

Offline tony27

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Re: YZ 490
« Reply #1 on: November 17, 2014, 04:02:33 pm »
Cylinder is listed as same part number as 84 & 85, piston is listed for 84-90 & 93 wr500 so I wouldn't be surprised if all centre port top ends fitted
It's worth looking on boats.net/partzilla for the part numbers as they list all fitments of each part which is what I did
http://www.partzilla.com/parts/search/Yamaha/Motorcycle/1986/YZ490S/parts.html
http://www.partzilla.com/parts/search/Yamaha/Motorcycle/1986/YZ490S/parts.html

Offline Iain Cameron

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Re: YZ 490
« Reply #2 on: November 17, 2014, 06:38:31 pm »
Be careful with the Partszilla listings they don't work all the time some of the so called matches are way out . EG they don't take the first 3 numbers into consideration so a DT 250 piston and a RT 360  piston share the same numbers except the first 3 , hence so many listing on Evilbay as DT\RT pistons . Yamaha uses the same numbers for groups of parts and only changes the first 3 for model but the last 2 numbers are the modification # . also in the us system they have another 2 numbers unlike Aust and Europe . Iain
Yamaha tragic ; dt1, rt1, dt2, rt2, dt2mx , rt2mx , mx250, mx360,sc500, 74dt125, yzx125, yzc250, yzc400, yzd250, yzd400, yzh250, yzh80 , dt100 , xr75 ko xr80 03 , it175 82 . Not a member of any club

Offline kim80y

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Re: YZ 490
« Reply #3 on: November 17, 2014, 09:31:50 pm »
As no carb you will want a WR 500 manifold, as it is 38mm not 40, and you can't buy a new 40mm carb anymore.
84,85 and 86 cylinders are all 4 transfer ports, 87 to 90 is 6, but interchange to same bottom end.
Not sure on calipers, but you should be able to get one cheap, the discs are about 27 bucks new.

Hope that helps,

Cheers
Kim

Offline SimonC

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Re: YZ 490
« Reply #4 on: November 17, 2014, 10:55:18 pm »
Thanks guys, some excellent bits of advise there.  Found a heap of stuff in the States for it, but postage seems to be getting pretty expensive from there now.

Cheers

Offline kim80y

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Re: YZ 490
« Reply #5 on: November 18, 2014, 08:28:09 pm »