82 Yz490 ??

[mkpack77]

I currently have an 82 yz490 that runs like a champ. I've read a lot of neg. about the bike, but it's a beast and I love it. I'm also about to get an 84 yz490 that I need to build. My questions are: what is the difference, if any, between the 82 and 84 and I've noticed in articles about different models, i.e. j,k etc...how do I tell what model yz490 I have??

 

[mkpack77]

Also, does anyone know where I can get a new or good condition throttle assy. for my 82 yz490???

 

[XRpredator]

if you've got a 490 running right, I'd do all I can to not change a thing on it!

 

[zoommx]

82: exhaust comes up on chain side; shock resevior is long and gold, on right side of front frame tube; 6 stud head
84: is the last year of front drum brake and the exhaust comes up on brake side; 7 stud head

The main performance differences are the rear suspension on the 82 had a little more weight and friction than the more modern looking 84. The 84 has a 2mm larger carburator and the cylinder has seven ports instead of five.

 

[mkpack77]

thanks, thats the info I was looking for. What about the model designator?

 

[Beuford]

The year code should be in the 10th digit of the vin on the steering stem. this link had the 490 model codes in it.
http://www.merrittmotorcyclesalvage.com/yamahamodelcodes.htm

 

[midlifemoto]

the 84 had a 4 speed which I hated, but it was scary fast

 

[zoommx]

The year code should be in the 10th digit of the vin on the steering stem. this link had the 490 model codes in it.
http://www.merrittmotorcyclesalvage.com/yamahamodelcodes.htm

I don't think the vinumbering system applied to dirtbikes until 84. The uniform 17 digit VINumbering did start in 80 though. Here's a good decoding that will apply to all those: http://www.amsoil.com/lit/g3000/2008/sections/VINNumberCodePage.pdf
I changed my 82 to a 5 speed from an IT transmission. For MX, I believe the 4 speed trans would be fine.

 

[OriginalRider]

The 82 yz490 weighed 19 pounds more then the 84 yz490.

 

[Bob1972]

I currently have an 82 yz490 that runs like a champ. I've read a lot of neg. about the bike, but it's a beast and I love it. I'm also about to get an 84 yz490 that I need to build. My questions are: what is the difference, if any, between the 82 and 84 and I've noticed in articles about different models, i.e. j,k etc...how do I tell what model yz490 I have??

Hi
The frame number contains the letter referring to the year eg. J=1982 I can't remember what position the letter is in the number it may be the last one.
Hope this helps