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The IT465 and IT490 thread

Discussion in '2 smokers' started by dawid, Mar 10, 2008.

  1. FJ_Kevin

    FJ_Kevin Been here awhile

    Joined:
    Dec 28, 2010
    Oddometer:
    731
    Location:
    Maryland ==> originally from Long Island

    Welcome Chappy,

    You got yourself a nice couple of bikes there. I think that YZ490 looks far too good not to restore. If you have a look at my YZ465 thread you will see I am in the middle of restoring one of these myself. I also have an IT490, another great bike.

    Perhaps you can initially focus on whichever bike is mostly complete. The IT & YZ motors will fit in either chassis so you can mix and match as needed to get you going. You can interchange the top-ends as well. Once you have one bike up and running you can take your time getting the other one in shape. I would not be too discouraged about the suspension. You can buy all the replacement bearings in the aftermarket. Used parts show up regularly on ebay. You will save money if not in rush. The '83 YZ shock is specific to that model (and the 83 YZ250). You cannot use the IT shock in the YZ they differ in width at the top mount. YZ shocks turn up on ebay from time to time I paid about $100 for one that was in very nice shape. You probably already know that the IT is 5-speed while the YZ is 4-speed. Also, check out boats.net (search yz490k). They are a good source for OEM parts at a discount.

    There are a few threads on here coving the 465's and 490's that should help you out.

    Good luck with your bikes, keep up posted on your progress... they are fast as hell and, being air cooled, easy to work on. Post a pic of the IT490 so we can have a look at it!

    Kevin
    spokester likes this.
  2. FJ_Kevin

    FJ_Kevin Been here awhile

    Joined:
    Dec 28, 2010
    Oddometer:
    731
    Location:
    Maryland ==> originally from Long Island
    If you are at 2mm then it is likely a forge Wiseco piston. If your cylinder is not badly scorn then you should hone it and measure the piston to cyclinder clearance. Keep in mind that the Yamaha manual will call out a clearance based on the OEM cast piston (2 or 3 thou). The forged piston expands more than the cast. The clearance recommended by wiseco is more like 5 to 7 thou. They tighten up as they warm.

    I have never seen a 490 piston larger than 2mm. A used cylinder (should you need one) is likely cheaper than having one sleeved.
    spokester likes this.
  3. FJ_Kevin

    FJ_Kevin Been here awhile

    Joined:
    Dec 28, 2010
    Oddometer:
    731
    Location:
    Maryland ==> originally from Long Island
    If you are at 2mm then it is likely a forge Wiseco piston. If your cylinder is not badly scorn then you should hone it and measure the piston to cyclinder clearance. Keep in mind that the Yamaha manual will call out a clearance based on the OEM cast piston (2 or 3 thou). The forged piston expands more than the cast. The clearance recommended by wiseco is more like 5 to 7 thou. They tighten up as they warm.

    I have never seen a 490 piston larger than 2mm. A used cylinder (should you need one) is likely cheaper than having one sleeved.
  4. Chappy58

    Chappy58 Been here awhile

    Joined:
    Feb 17, 2015
    Oddometer:
    122
    Location:
    New England
    I did some checking into resleeving the YZ cylinder. To make a new one and have it installed, you are looking at about $325 from advanced sleeve. Then you need to get a piston kit & have the cylinder bored as well, so throw in another$200. I've got the cylinders off of both bikes- The YZ was left to rust in a shed, and the IT has seen it's share of use/abuse as well. That piston is toast. I might consider honing the IT and putting the YZ piston in it ( which looks new ). The YZ I really want to make new again. I know I will spend more than the bike is worth, but this is what I do for fun.

    The IT is in terrible shape as well. The IT cylinder is really worn around the exhaust flange, to the point of having a hole in it. The frame is broken in 2 places- an easy weld fix though. Both these bikes have seen some serious time on them. I will probably steal what I can for parts, because some of what I need for the YZ is good on the IT. Crank, Fork tubes. I will look into rebuilding the shock. CCycle suspension is a local suspension guy, so I will at least get his opinion.

    Anyone kknow if the timing is different on these bikes? I'm thinking a YZ with the ability to put lights on, and a 5 speed gearbox at this point.
  5. wfopete

    wfopete Suffer Fools; Gladly!

    Joined:
    Aug 19, 2004
    Oddometer:
    842
    Location:
    Somewhere North of Dover, AR
    Chappy58:

    Before you go after the top end fix, get ALL the way into these motors. Carefully check the cases for cracks and the condition of the transmissions. Yes these bikes are a blast to ride when they are "Right" but getting them "Right" can be a journey in time, money and mental stability.
  6. NortwestRider

    NortwestRider TRIPOD ADVENTURER !!

    Joined:
    May 25, 2008
    Oddometer:
    5,138
    Location:
    3.7 miles North of Hell...SEATTLE....
    ANYBODY have a usable IT490 tank for sale ??.
    If so PM me please ...


    Live life,be yourself !!!!.
  7. Chappy58

    Chappy58 Been here awhile

    Joined:
    Feb 17, 2015
    Oddometer:
    122
    Location:
    New England
    IMG_20151002_191734_293.jpg IMG_20151002_191749_351.jpg Here is a picture of the IT. I bought it basically because the forks were good, and the pipe/silencer were new. Turns out a lot of these other parts are not so great. The frame is broken in a couple places

    IMG_20151011_085031_005.jpg
  8. Chappy58

    Chappy58 Been here awhile

    Joined:
    Feb 17, 2015
    Oddometer:
    122
    Location:
    New England
    The YZ continues to disappoint. Talk about a machine that has been ridden and not maintained at all. Well it did have a new piston in it.....
    IMG_20150930_191143_133.jpg


    But the cylinder is shot, and on last oversize, 89mm.

    IMG_20151011_090203_413.jpg

    Look how thin the steel sleeve is...

    IMG_20150930_191240_083.jpg
  9. Chappy58

    Chappy58 Been here awhile

    Joined:
    Feb 17, 2015
    Oddometer:
    122
    Location:
    New England
    The frame is in about as good shape as the cylinder- footpeg mounts worn completely out, bad weld repairs, and threaded holes stripped out, rear of the frame is bent too. There's no telling if this thing is anywhere near straight....
    IMG_20151011_085342_439.jpg IMG_20151011_085159_466.jpg IMG_20151011_085141_023.jpg

    But I am determined to have a 490. I bought a clean low time frame yesterday... and so begins the loss of too many dollars....
  10. Chappy58

    Chappy58 Been here awhile

    Joined:
    Feb 17, 2015
    Oddometer:
    122
    Location:
    New England
    here is a shot of the pistons - YZ on the right, IT on the left. The IT cylinder might have got by with a hone, but the exhaust flange is just completely shot, nice hole in it. The IT head had an interesting design in it as well. My buddy said it was probably modified to help the detonation problem these bikes had.. IMG_20151011_090050_670.jpg
    IMG_20151011_090130_535.jpg

    IMG_20151011_090100_781.jpg
  11. Chappy58

    Chappy58 Been here awhile

    Joined:
    Feb 17, 2015
    Oddometer:
    122
    Location:
    New England
    Started dis-assembly of the engines to see what I have here. Homemade clutch tool made from YZ clutch plates. Machining the nut off the countershaft on the IT engine. At this point it looks like the YZ clutch cover is salvageable. The clutch on the YZ is horribly loose in the motor. Looks like they only did the top end.

    Anybody got a usable YZ cylinder lying around?

    IMG_20151011_091421_184.jpg
    The IT engine being torn down.

    IMG_20151011_095306_176.jpg

    Couldn't budge the countershaft nut, so I machined it off. Now I can't budge the primary gear off the crank, so I'' probably have to make a puller..time to take a break! maybe go split some wood, it'll feel good to hit something......
  12. wfopete

    wfopete Suffer Fools; Gladly!

    Joined:
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    Oddometer:
    842
    Location:
    Somewhere North of Dover, AR
    That is an interesting head mod. I'd like to know the story behind it.

    [​IMG]
  13. NortwestRider

    NortwestRider TRIPOD ADVENTURER !!

    Joined:
    May 25, 2008
    Oddometer:
    5,138
    Location:
    3.7 miles North of Hell...SEATTLE....
    I will be parting out my 83 IT490 soon ,if anybody needs anything hit me up before it all goes on EBay.


    Live life,be yourself !!!!.
  14. joexr

    joexr Banned

    Joined:
    Jan 4, 2011
    Oddometer:
    5,022
    What happened ? :dunno
  15. NortwestRider

    NortwestRider TRIPOD ADVENTURER !!

    Joined:
    May 25, 2008
    Oddometer:
    5,138
    Location:
    3.7 miles North of Hell...SEATTLE....
    To many projects..
    Filled up my new garage !!!!.


    Live life,be yourself !!!!.
  16. Earthmovin490s

    Earthmovin490s Adventurer

    Joined:
    Sep 24, 2013
    Oddometer:
    40
    Location:
    Great Appalachians in PA
    Are you still parting out your 83? If so, let me know. Several parts I would be interested in. Thanks
  17. Pete-NZ

    Pete-NZ Long timer

    Joined:
    May 8, 2011
    Oddometer:
    1,349
    From what I read.... It lets the flame front travel faster into the sqush band area....
    but i bet yer wont see this of a factoy team race motor...
  18. anotherguy

    anotherguy Long timer

    Joined:
    Jun 18, 2009
    Oddometer:
    15,491
    Location:
    the hills
    Snake oil. That head is now a doorstop.
  19. NortwestRider

    NortwestRider TRIPOD ADVENTURER !!

    Joined:
    May 25, 2008
    Oddometer:
    5,138
    Location:
    3.7 miles North of Hell...SEATTLE....
    Decided to get my son involved and build the IT for him and teach him along the way.Last weekend I showed him how to disassemble rebuild and reassemble the forks.Today we mounted the YZ pipe,had to mod the mounts.Ordered a Clarke tank ( in Natural ) also put on a new chain,front fender etc.Let my son try to start it but it was a no go !!.
    I rebuilt the carb about a year ago but we need to open it up and clean it again .
    [​IMG]
    [​IMG]


    Live life,be yourself !!!!.
  20. Earthmovin490s

    Earthmovin490s Adventurer

    Joined:
    Sep 24, 2013
    Oddometer:
    40
    Location:
    Great Appalachians in PA
    Kudos for getting your son involved with the IT! Thats a much better idea than parting her out. I'm at least 10-15 years away from being able to do that with my daughter or son, but I hope that my love passes on to them. Keep us updated on how the process goes. Also, if the carb and tank aren't completely drained and dries, ethanol will wreck havoc on the carbs. If you want to leave gas, add a couple of ounces of Star Tron to it and let her sit.