1983 Yamaha IT490 Project/rescue build

KDXohio · Post by **KDXohio** » 10:04 am Oct 06 2016

Wife is letting get it on the trails for this year!

KDXohio · Post by **KDXohio** » 10:06 am Oct 06 2016

Noticed a lot of dirt around the shaft of the shock and very bouncy I pulled it apart and there was only a couple teaspoons of Grey slime left inside of it. Anyone know where I can find replacement Grey slime when I put it back together?

Old Yamaha de carBon monoshock

KDXohio · Post by **KDXohio** » 10:10 am Oct 06 2016

The reservoir has no shader valve on these instead they use a self sealing/healing rubber valve that you are supposed to charge and de-charge through with a hollow needle like a syringe neelde. I decided to drill, tap, and install a 1/8"NPT shader valve for future service. Another option would be a 46mm racetech reservoir cap and kyb 46/103 bladder which is the route I will probably go in the future if the piston seal starts failing

Post by **KDXGarage** » 10:12 am Oct 06 2016

Wow. It sure looks different than a KDX shock.

KDXohio · Post by **KDXohio** » 10:12 am Oct 06 2016

Tank is cracked new tank is 240 bones from clarke

KDXohio · Post by **KDXohio** » 10:17 am Oct 06 2016

Huge piston bigger than a hockey puck! 84.50mm

KDXohio · Post by **KDXohio** » 10:35 am Oct 06 2016

Jason wrote:Wow. It sure looks different than a KDX shock.

Yes I was a little hesitant to take it apart the factory service manual does not cover shock rebuild only tells what the nitrogen pressure should be.

I think this winter I will put together a new shim stack for it too I feel like it could be seriously improved appon

david · Post by **david** » 11:24 am Oct 06 2016

Man I bet that thing is going to be a beast! I've been on a couple of old open class motocross bikes (CR480, YZ490) but never a woods bike.

KDXohio · Post by **KDXohio** » 11:28 am Oct 06 2016

david wrote:Man I bet that thing is going to be a beast! I've been on a couple of old open class motocross bikes (CR480, YZ490) but never a woods bike.

Should be very similar to the yz490 but with a 5 speed tranny instead of 4 speed im hopIng to have a very fast tractor when it's done

Jim B · Post by **Jim B** » 02:34 pm Oct 06 2016

Has the head been modified? Isn't there a problem with the cylinder head design on the 490?

KDXohio · Post by **KDXohio** » 02:56 pm Oct 06 2016

It did not appear to be modified. They have a tendency to ping when hot. I considered doing the head mod but I'm going to get her on the trails first and see how it runs.

I have a sneaking suspicion that I will not have the issue since I wont have the engine wound up all day long on the trails my thought is that the issue is more prevalent with the MXers, sand dune guys not so much the trail bikes but then again I have no evidence to back this up other than there being way more discussion about the head mod on the YZ490 than the IT490 this could also be due to a smaller following of the IT's.....

david · Post by **david** » 04:42 pm Oct 06 2016

I wouldn't want to ride it in the woods. The YZ would stand straight up in every gear with just a wick of the throttle.

KDXohio · Post by **KDXohio** » 04:51 pm Oct 06 2016

david wrote:I wouldn't want to ride it in the woods. The YZ would stand straight up in every gear with just a wick of the throttle.

I am planning on plating this at some point to be able to dual sport it as well

KDXohio · Post by **KDXohio** » 07:55 pm Oct 06 2016

KDXohio · Post by **KDXohio** » 07:48 pm Oct 07 2016

Bad picture but the headlight came today...black just didn't look right...

KDXohio · Post by **KDXohio** » 07:51 pm Oct 07 2016

Took a lot of strpiper to get that paint off

Wasn't in too good of shape underneath

KDXohio · Post by **KDXohio** » 07:53 pm Oct 07 2016

Scraped it all clean and cut a new background for it

KDXohio · Post by **KDXohio** » 07:54 pm Oct 07 2016

Went ahead and cleaned up the side cover and cut a background for it too

Dekon · Post by **Dekon** » 09:29 pm Oct 07 2016

Looking good. You might want to look into joining the yz490 group. I think it's a Yahoo group, not sure but some members of a New England group I belong to said they are a great reference for theses bikes.

KDXohio · Post by **KDXohio** » 09:34 pm Oct 07 2016

Dekon wrote:Looking good. You might want to look into joining the yz490 group. I think it's a Yahoo group, not sure but some members of a New England group I belong to said they are a great reference for theses bikes.

I have not come across that group yet. I am however a member of the yamaha IT forum they'very helped me some with dad''s IT200. I believe theyre based in Australia?
Links in case anyone else has any interest in the ITs
Forum:
http://www.yamahait.com.au/forum/index.php
History
http://www.yamahait.com.au

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