1983 Yamaha IT490 Project/rescue build

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KDXohio
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1983 Yamaha IT490 Project/rescue build

Post by KDXohio »

Wife is letting get it on the trails for this year! :boogie:
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Last edited by KDXohio on 10:51 am Oct 06 2016, edited 1 time in total.
1990 KDX200 FMF Fatty, Answer VFC silencer, VForce 3 Cage, Wiseco Piston, KX125-J series KYB USD fork conversion, Race tech goldvalves, J series front brake assembly, air-box snorkel removed, Acerbis Headlight, KX450F Front fender, Pro Taper RM bend bars, ASV front Brake lever, MSR Clutch perch and lever, RB Head mod, 36mm PWK carb, Trail Tech Kickstand.
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KDXohio
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Re: 1983 Yamaha IT490 Project/rescue build

Post by KDXohio »

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? :lol:

Old Yamaha de carBon monoshock

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1990 KDX200 FMF Fatty, Answer VFC silencer, VForce 3 Cage, Wiseco Piston, KX125-J series KYB USD fork conversion, Race tech goldvalves, J series front brake assembly, air-box snorkel removed, Acerbis Headlight, KX450F Front fender, Pro Taper RM bend bars, ASV front Brake lever, MSR Clutch perch and lever, RB Head mod, 36mm PWK carb, Trail Tech Kickstand.
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Re: 1983 Yamaha IT490 Project/rescue

Post by KDXohio »

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

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1990 KDX200 FMF Fatty, Answer VFC silencer, VForce 3 Cage, Wiseco Piston, KX125-J series KYB USD fork conversion, Race tech goldvalves, J series front brake assembly, air-box snorkel removed, Acerbis Headlight, KX450F Front fender, Pro Taper RM bend bars, ASV front Brake lever, MSR Clutch perch and lever, RB Head mod, 36mm PWK carb, Trail Tech Kickstand.
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Re: 1983 Yamaha IT490 Project/rescue

Post by KDXGarage »

Wow. It sure looks different than a KDX shock.
Thank you for participating on kdxrider.net. :bravo:
To post pictures from a device: viewtopic.php?f=88&t=24128
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Re: 1983 Yamaha IT490 Project/rescue

Post by KDXohio »

Tank is cracked new tank is 240 bones from clarke :doh:
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Last edited by KDXohio on 01:35 pm Oct 06 2016, edited 1 time in total.
1990 KDX200 FMF Fatty, Answer VFC silencer, VForce 3 Cage, Wiseco Piston, KX125-J series KYB USD fork conversion, Race tech goldvalves, J series front brake assembly, air-box snorkel removed, Acerbis Headlight, KX450F Front fender, Pro Taper RM bend bars, ASV front Brake lever, MSR Clutch perch and lever, RB Head mod, 36mm PWK carb, Trail Tech Kickstand.
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Re: 1983 Yamaha IT490 Project/rescue

Post by KDXohio »

Huge piston bigger than a hockey puck! 84.50mm
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1990 KDX200 FMF Fatty, Answer VFC silencer, VForce 3 Cage, Wiseco Piston, KX125-J series KYB USD fork conversion, Race tech goldvalves, J series front brake assembly, air-box snorkel removed, Acerbis Headlight, KX450F Front fender, Pro Taper RM bend bars, ASV front Brake lever, MSR Clutch perch and lever, RB Head mod, 36mm PWK carb, Trail Tech Kickstand.
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Re: 1983 Yamaha IT490 Project/rescue

Post by KDXohio »

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
1990 KDX200 FMF Fatty, Answer VFC silencer, VForce 3 Cage, Wiseco Piston, KX125-J series KYB USD fork conversion, Race tech goldvalves, J series front brake assembly, air-box snorkel removed, Acerbis Headlight, KX450F Front fender, Pro Taper RM bend bars, ASV front Brake lever, MSR Clutch perch and lever, RB Head mod, 36mm PWK carb, Trail Tech Kickstand.
david
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Re: 1983 Yamaha IT490 Project/rescue build

Post by david »

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.
'81 KDX 175
'90 KDX 200
'07 Vulcan 2000 Classic LT (totaled 4/25/15)
'82 Honda GL500 (sold)
'96 ZXi 1100 JetSki
'98 STX 1100 JetSki
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Re: 1983 Yamaha IT490 Project/rescue build

Post by KDXohio »

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 :shock:
1990 KDX200 FMF Fatty, Answer VFC silencer, VForce 3 Cage, Wiseco Piston, KX125-J series KYB USD fork conversion, Race tech goldvalves, J series front brake assembly, air-box snorkel removed, Acerbis Headlight, KX450F Front fender, Pro Taper RM bend bars, ASV front Brake lever, MSR Clutch perch and lever, RB Head mod, 36mm PWK carb, Trail Tech Kickstand.
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Re: 1983 Yamaha IT490 Project/rescue build

Post by Jim B »

Has the head been modified? Isn't there a problem with the cylinder head design on the 490?
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Re: 1983 Yamaha IT490 Project/rescue build

Post by KDXohio »

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.....
1990 KDX200 FMF Fatty, Answer VFC silencer, VForce 3 Cage, Wiseco Piston, KX125-J series KYB USD fork conversion, Race tech goldvalves, J series front brake assembly, air-box snorkel removed, Acerbis Headlight, KX450F Front fender, Pro Taper RM bend bars, ASV front Brake lever, MSR Clutch perch and lever, RB Head mod, 36mm PWK carb, Trail Tech Kickstand.
david
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Re: 1983 Yamaha IT490 Project/rescue build

Post by david »

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.
'81 KDX 175
'90 KDX 200
'07 Vulcan 2000 Classic LT (totaled 4/25/15)
'82 Honda GL500 (sold)
'96 ZXi 1100 JetSki
'98 STX 1100 JetSki
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Re: 1983 Yamaha IT490 Project/rescue build

Post by KDXohio »

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
1990 KDX200 FMF Fatty, Answer VFC silencer, VForce 3 Cage, Wiseco Piston, KX125-J series KYB USD fork conversion, Race tech goldvalves, J series front brake assembly, air-box snorkel removed, Acerbis Headlight, KX450F Front fender, Pro Taper RM bend bars, ASV front Brake lever, MSR Clutch perch and lever, RB Head mod, 36mm PWK carb, Trail Tech Kickstand.
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Re: 1983 Yamaha IT490 Project/rescue build

Post by KDXohio »

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1990 KDX200 FMF Fatty, Answer VFC silencer, VForce 3 Cage, Wiseco Piston, KX125-J series KYB USD fork conversion, Race tech goldvalves, J series front brake assembly, air-box snorkel removed, Acerbis Headlight, KX450F Front fender, Pro Taper RM bend bars, ASV front Brake lever, MSR Clutch perch and lever, RB Head mod, 36mm PWK carb, Trail Tech Kickstand.
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Re: 1983 Yamaha IT490 Project/rescue build

Post by KDXohio »

Bad picture but the headlight came today...black just didn't look right...
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1990 KDX200 FMF Fatty, Answer VFC silencer, VForce 3 Cage, Wiseco Piston, KX125-J series KYB USD fork conversion, Race tech goldvalves, J series front brake assembly, air-box snorkel removed, Acerbis Headlight, KX450F Front fender, Pro Taper RM bend bars, ASV front Brake lever, MSR Clutch perch and lever, RB Head mod, 36mm PWK carb, Trail Tech Kickstand.
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Re: 1983 Yamaha IT490 Project/rescue build

Post by KDXohio »

Took a lot of strpiper to get that paint off
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Wasn't in too good of shape underneath
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1990 KDX200 FMF Fatty, Answer VFC silencer, VForce 3 Cage, Wiseco Piston, KX125-J series KYB USD fork conversion, Race tech goldvalves, J series front brake assembly, air-box snorkel removed, Acerbis Headlight, KX450F Front fender, Pro Taper RM bend bars, ASV front Brake lever, MSR Clutch perch and lever, RB Head mod, 36mm PWK carb, Trail Tech Kickstand.
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Re: 1983 Yamaha IT490 Project/rescue build

Post by KDXohio »

Scraped it all clean and cut a new background for it
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1990 KDX200 FMF Fatty, Answer VFC silencer, VForce 3 Cage, Wiseco Piston, KX125-J series KYB USD fork conversion, Race tech goldvalves, J series front brake assembly, air-box snorkel removed, Acerbis Headlight, KX450F Front fender, Pro Taper RM bend bars, ASV front Brake lever, MSR Clutch perch and lever, RB Head mod, 36mm PWK carb, Trail Tech Kickstand.
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Re: 1983 Yamaha IT490 Project/rescue build

Post by KDXohio »

Went ahead and cleaned up the side cover and cut a background for it too
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1990 KDX200 FMF Fatty, Answer VFC silencer, VForce 3 Cage, Wiseco Piston, KX125-J series KYB USD fork conversion, Race tech goldvalves, J series front brake assembly, air-box snorkel removed, Acerbis Headlight, KX450F Front fender, Pro Taper RM bend bars, ASV front Brake lever, MSR Clutch perch and lever, RB Head mod, 36mm PWK carb, Trail Tech Kickstand.
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1983 Yamaha IT490 Project/rescue build

Post by Dekon »

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.
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1983 Yamaha IT490 Project/rescue build

Post by KDXohio »

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
1990 KDX200 FMF Fatty, Answer VFC silencer, VForce 3 Cage, Wiseco Piston, KX125-J series KYB USD fork conversion, Race tech goldvalves, J series front brake assembly, air-box snorkel removed, Acerbis Headlight, KX450F Front fender, Pro Taper RM bend bars, ASV front Brake lever, MSR Clutch perch and lever, RB Head mod, 36mm PWK carb, Trail Tech Kickstand.
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