Building a 1981 Yamaha YZ465 Factory Replica...

Discussion in '2 smokers' started by FJ_Kevin, Mar 11, 2012.

  1. ericm

    ericm Long timer

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    Oddometer:
    1,901
    Location:
    Santa Cruz Mountains, California
    YZ 465 G/H: 2.14, 1.75, 1.32, 1.05, 0.83 primary: 2.63 final: 14/46
    YZ 490 J: 1.75, 1.32, 1.05,0.83 primary: 2.63 final: 14/44
    IT 465 H/J: 2.67, 1.75, 1.32, 1.00, 0.79 primary: 2.63 final: 14/44

    all numbers from Colin MacKellars Yamaha Dirt Bike book (which I recommend if you can get a copy)
  2. Michael N.

    Michael N. Adventurer

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    Booah, thank you ericm !!!!!
    This helps a lot to figure out how the bike will behave with the different transmitions!
    So it´s funny that the 4 Speed tranny of the 490 has the same ratios as the 465, just missing 5th gear.
    so with 14/44 the 1st gear will be useable and the 4th will provide enough speed for wide open sections :)

    Basically i don´t like Amazon but found the Book there.
    I will look further, maybe i find it somewhere else.

    Thank you for your advice!

    Best wishes, Michael
  3. wfopete

    wfopete Suffer Fools; Gladly!

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    When is Kevin going to post the rest of race report?????????
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  4. ericm

    ericm Long timer

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    The gear ratios are listed with 1st gear first. The 490 has the 465's 2-5 and skips 1st. You'd have to look at the parts fiche to be sure but knowing how Yamaha likes to use as many existing parts as possible, I bet it literally was the 465's 2-5th. They'd only need to change the shift drum to put neutral between the old 2nd and 3rd so it'd be in the normal place between 1st and 2nd on the 490.
  5. Michael N.

    Michael N. Adventurer

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    I like the "your brilliant reply" in the message field here.... :)
    Yes, i performed a perfect nobrainer with the ratios!
    I never used the first gear with the current 14/48 (cane along with the bike)

    So thank you again!

    Greetings from Austria, Michael
  6. Michael N.

    Michael N. Adventurer

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    Hi, it´s me again.

    Have been busy with other things.

    What i did is to straighten the frame, more speciffically the subframe.
    It was bent and twisted we brought it back in shape with a pulley, and a
    hydraulic ramp where i leaned the bike during the bending.
    Was a little scary but worked well.

    Meanwhile the XZ490 transmission arrived, got one from ebay usa.
    all in all a good piece, exept one shift fork and the 1st gear wheel with 28 teeth.
    So no problem with the shift fork, got one cheap but i can´t find a 1st gear wheel
    in good conditions.
    On the one that i have the pockets are pretty worn out, i don´t want to use it in a rebuilt engine.

    So if anybody has one or knows where to get one left please help me out!


    The original part number is:
    5X6-17211-00-00
    Attached some pictures of the gear wheel.

    20151125_175805.jpg 20151125_175617.jpg 20151125_175634.jpg



    Thank you, Michael
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  7. Michael N.

    Michael N. Adventurer

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    Yeah, wonders still happen!
    Found a NOS 1st Gerr for the 490!!!

    Today the blasting media for my sandblaster arrived, then i will proceed with the hubs, brake plates, fork clamps, lower legs and swingarm.

    Cheers, Michael
    FJ_Kevin likes this.
  8. FJ_Kevin

    FJ_Kevin Been here awhile

    Joined:
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    OK... sorry for the delay in my updates.

    I've been involved in another race, that is a race in finishing up some work at the old farmhouse I've been working on, especially before the super cold weather sets in. I'm talking some real Abe Lincoln log house action. Don't believe me? Ha, have a look at this!

    [​IMG]

    Those are 200 year old hand hewn logs there. In fact, I'll be heading over there later today where there is no internet connection (yikes!) so lets see how far I can get before I have to sign off and get back to work.

    Recall the previous johnny B post included lots of photos of the neat old dirt bikes seen during the pre-race walkabout. This time we'll continue with the lead up to the racing action.

    And we did get more action photos of the various classes this year. One reason for this is that they changed things up a bit this year. Instead of running all the classes together (with staggered start), they split off the vintage class and ran their 1 hour race completely separate from the other classes. This allowed for the additional spectating and photo opportunities. This also meant that if you were man enough, you could run 2 classes for a total of 2 hours of racing! I did not do this, but wow, what a great day of racing for those that did.

    Anyway, an hour or so after the 1st vintage race would be the second race with combined post vintage and modern classes. These classes would be out on the course together but would be started in waves with 20 second intervals. The modern classes were waived off first, followed by the expert class and then the age graded classes. My class, 50+, would be the forth class waved off. There was also the sight lap open to all racers just like in previous years.

    Another noticeable change was the increase in the number of younger competitors on the modern bikes. However, as guests at this primary vintage event, they were reminded at the riders meeting not to be too aggressive should they find a need to pass a more seasoned competitor.

    On the other hand, I didn't hear any restrictions on how seasoned competitors could chose to overtake modern racers... no, it seemed vintage racers were free to kick ass and take names, just like the old days!

    Ok, so with that bit of tough talk out of the way, lets have a look at some more photos. First up are a few snaps from the riders meeting... some of these dudes do look rough don't you think?

    [​IMG]

    I had to really give a tip of the Motostar3 to the guy in the blue cap. He was wearing his Hi-points like me. Bet there was no electric start on his bike either.
    Watch out for him for sure!

    [​IMG]

    [​IMG]

    With the riders meeting wrapped up it was time to get big blue started up for the sight lap. The kick starter is pretty high on all these 465/490's and I find it helps to have something to perch myself up on. I used to use a wooden milk crate for this but broke it. The bike stand suffices this day. Again the big 490 fired up quickly... she was running strong!

    [​IMG] [​IMG]


    The sight lap is a follow the leader affair with one of the PVR event organizers as the leader. The idea is to just take it easy and have a good look at the course. Even so I tried to position myself to be in the front group so as not to get held up should someone get stuck in one of the more challenging sections, making it difficult to get around. Here I am lurking behind some of the modern bikes.

    [​IMG] [​IMG]

    [​IMG]

    We took off and made the lap without any issues. Even took the opportunity to have a little fun.

    [​IMG]


    More to come...
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  9. FJ_Kevin

    FJ_Kevin Been here awhile

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    Good job Michael... keep up the good work!
  10. wfopete

    wfopete Suffer Fools; Gladly!

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    Whew! Glad to see you back Kevin, I was beginning to wonder where you went.
  11. FJ_Kevin

    FJ_Kevin Been here awhile

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    So next up is the vintage class at the line. A nice selection of machines don't you think?

    [​IMG] [​IMG]

    Husky with mud slinger rims & short travel suspension.
    [​IMG]

    I like this TM... I had a 74 TM125 as a kid, great bikes. Looks like they adapted an up pipe to this one.

    [​IMG]

    [​IMG] [​IMG]

    [​IMG] [​IMG]

    And they're off!

    [​IMG] [​IMG]
    [​IMG] [​IMG]
    [​IMG] [​IMG]
    [​IMG] [​IMG]


    More to come...
    Michael N. and Scootern29 like this.
  12. FJ_Kevin

    FJ_Kevin Been here awhile

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    Hi Pete... yeah, trying to keep it all going. A week of cold weather had me focused on the farmhouse. I had some insulation work that had to get done before the temp dips too low.

    So what's going on with that engine case? You have a plan to fix that? Hope to see you back on your project too.
  13. Michael N.

    Michael N. Adventurer

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    34
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    Graz, Austria, Europe
    Thank you for the pictures Kevin! Looks like lots of fun!

    Today a parcel arrived, call me stupid to rejoice about an old, cracked, dirty peace of plastib but i do.
    It took me a while to find a matching rear inner fender for the YZ, finally found one in lets say repairable conditions...

    Will weld the plastic at the cracked areas and support it with a thin sheet of alloy.

    Meanwhile the frame is in the making, i chose to support the bottom (under the engine facing the ground) with an aditional layer of sheet metal to support it and prevent damage from stones and other nasty things.

    I also think about making a skidplate, has anyone done this yet?

    Greetings from Austria, Michael

    Attached Files:

  14. Bananapete

    Bananapete Been here awhile

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    Germany
    I tried to support a lot of plastic parts of different bikes with aluminum and 2k epoxy. Bit it always failed again.

    The best solution I found to support cracked plastic is to just put two layers of glass fiber or carbon fiber behind the plastic and "glue" it on with the resin. Works like a charm. For these kind of works carbon fiber is always "overkill" and wont add strength.
    Also take a look at my thread here http://advrider.com/index.php?threads/81-fantic-caballero-125-rebuild.990860/#post-25532728
    I only took carbon fiber here because I had it laying around and the color fits my part better.
  15. wfopete

    wfopete Suffer Fools; Gladly!

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    Should see an update soon!
  16. Michael N.

    Michael N. Adventurer

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    Thank you Bananapete.
    I will weld it and then i will try to sew it with a CF Roving.
    I think this should last very good and the visual issue is good too.

    Cheers, Michael
  17. Michael N.

    Michael N. Adventurer

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    Meanwhile in Austria..

    The frame got its reinforcement and the primer is on....

    The shift forks arrived today, had luck to get a pair in nearly perfect conditions for a bargain.

    The hubs will get a special treatment, i sand off the fins from the casting process for the "extra look"





    IMG-20151203-WA0000.jpg IMG-20151203-WA0001.jpg

    20151204_135547.jpg 20151204_135555.jpg

    Cheers, Michael
  18. Michael N.

    Michael N. Adventurer

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    And the result is: 900_884792835.jpg 900_-968893952.jpg 900_-996355993.jpg 900_-2144998688.jpg

    Just kidding... :)

    The US version is not ready yet, the frame is painted, the crank got new bearings and connecting rod, the cylinder is bored to 86.5mm and modt of the parts are sandblasted right now.
    will need some time to finish the bike, i hope it will be ready in a couple of weeks.

    The YZ above is my own Xmas present to me, ran into it and fell in love.
    The bike is already reatauradrs exept the engine which runs great without any noise.

    Wish you all a happy new year!

    Michael
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  19. FJ_Kevin

    FJ_Kevin Been here awhile

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    Well I hope everyone has made it into the new year OK.

    We got a lot of snow here in Maryland these last couple of days and so I have some time off from the normal weekend farm house restoration duties.

    So my goal in this post is to wrap up the Johnny B race, particularly the results of my own efforts.

    As usual, we will let the photos tell most of the story as this will give some more views of the event as well as other competitors.
    And there are plenty of photos too. I don't know how, but :sweeti got quite a few shots from different parts of a pretty long course and did pretty well in capturing some of the racing action.

    First up is this photo of the start as the various classes are waived off. As mentioned earlier, this was a dead engine start with each class waived off with 20 or 30 seconds of separation.
    Shown is part of the 1st or second group. Our group, 50+ was waved off fourth.

    [​IMG]

    And now here we go. The 490 started well but not as quick as some others so I was caught behind a bit. This was not a concern though as this is an hour long race and my plan was to take it easy this time. The reality is I have to pace myself if I am to make it to the finish.

    [​IMG]

    I believe this next one is of the class before us coming out of the back section. This years course seemed a bit tighter than in previous years but I like this back section because it is more open. This was one of the sections were you could crack the throttle on that big IT with good effect.

    [​IMG]

    I went into the back section in about 5th or 6th intending to take it easy and follow the leader. But next think you know, I am getting passed by one of the other old buzzards!
    Well that flipped the switch in me and next thing I knew conservatism was out the window and I was in high burn motocross mode passing two at a time.

    By the time our group came out of the back section I had moved up to first place. Somehow :sweeti was there to catch this bit of unbridled enthusiasm.

    [​IMG]

    [​IMG]

    [​IMG]

    All looks well so far but keep your eye on racer 222 (red Honda) as we'll be seeing more of him!
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  20. FJ_Kevin

    FJ_Kevin Been here awhile

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    Still on the march a few corners later. But look to the right... a read Honda fender peaking through!

    [​IMG]

    And now up near the parking field. Clever picture by :sweeti as she frames the shot with my YZ465 in the background :kat

    [​IMG]

    This next one is sometime later deep in the woods. The photo does not show it but racer 222 is just in front. He had followed me into the tight woods where I felt he was a bit faster than me. We had pulled away from the rest of our class so I thought I would wave him through, easier to follow than lead after all.

    My plan was to tail him and save my energy until the end. I figured either he would make a mistake or I would throw it in motocross mode on the final lap for the win. :rilla

    What could possibly go wrong? :deal

    [​IMG]

    There were quite a few challenging sections with stream crossings and pretty rocky down hills and up hills. Unfortunately she was not able to get photos in these areas.

    Eventually you do come out of the woods again. This next photo is along a corn field leading up to the scoring table. Having lit it up out of the woods, I am now on the brakes readying for my mandatory full stop at the table. Not shown is racer 222, just ahead.

    [​IMG]

    Although I was close behind into the scoring table, 222 would get a nice jump leaving as I wait for my number and time to be recorded.

    This would be something to be mindful of in the closing laps. Finally, I have the OK to go!

    [​IMG]

    More to come...
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