Yamaha XT500 Vintage Race Prep

Discussion in 'Some Assembly Required' started by TheGr8Pumpkin, Jan 31, 2019.

  1. TheGr8Pumpkin

    TheGr8Pumpkin Been here awhile

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    So, I will be participating in a 1000 mile mostly off-road race this coming August. All the bikes in the race must be made before 1981 and no mono shock bikes are allowed.

    After doing some research, I decided that an XT500 would be perfect and jumped on the first one that I could find.

    I got this bike in Michigan and have been going over it and replacing some stuff in preparation for the race.

    There is surprisingly little on the forum about XT500s. So, I figured I would put up as much as I can about what I do to this one, In case it can help someone else and also as a way to get pointers from all of you on what else I should be doing.

    Couldn't decide if this belongs here or in the XT500 thread, so if it needs to be moved go ahead and move it.

    So far I have:
    • Replaced the stock carb with a Mikuni VM36 flat slide pumper
    The pumper for the old carb had been clearly messed with and not in a good way, the pumper diaphragm had been replaced with a very thick rubber that was poking out of the sides.

    New Carb was a bit of a hassle to put on because part of the pumper actuator will rub the frame if the carb is placed straight up and down. So, the new carb is slightly turned to the left to fit. I could also shave down a bit of the plastic on the actuator to make it fit straight up and down, but this didn't seem necessary.
    • Put on a larger diameter high pipe to replace the stock low pipe
    • Replaced the Husqvarna exhaust with a supertrapp IDS2 quiet core
    • Swapped the bars for pro taper ATV high bend
    I tried some other bends but they all just werent anywhere as high as the original OEM bends
    • Swapped stock filter to a K&N
    • Checked compression - perfect reading at 150, but boy was kicking the bike over that many times annoying
    • Cleaned and timed points
    On the list to do
    • New points and ignition coil (on the way)
    still getting a little bit of popping at full throttle and the coil is out of spec so it can't hurt to replace it.
    • Suspension (taking suggestions)
    • replace one side cover that chipped and flew away while riding
    • Skid plate and handlebar guards
    • luggage rack - torn between just buying one or welding one up myself from old spare racks I have laying around
    • New Footpegs - something much more aggressive
    • 12v conversion?
    • brakes and cable replacements
    • bearings replacement
    • upgraded tank for more fuel storage
    • Anything else that will help this thing rip through 1000 miles!

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    #1
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  2. TheGr8Pumpkin

    TheGr8Pumpkin Been here awhile

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    #2
  3. TheGr8Pumpkin

    TheGr8Pumpkin Been here awhile

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    3 IMG_3603.JPG IMG_3632.JPG IMG_3608.JPG
    #3
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  4. That1Dude

    That1Dude Adventurer

    Joined:
    May 15, 2015
    Oddometer:
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    NY
    Nice bike! I had a 81 for a while.

    For suspension I swapped on an 85 tt600 from end for the larger forks and disc brake. It was fairly straightforward. I needed to add a spacer internally to shorten them 2”. On the rear I used a swing arm from 81 Suzuki sp500. It’s about 2” longer than the stock arm. Also had to get longer rear shocks to raise the back. I used progressive shocks, they worked ok, but I wasn’t racing or anything too hardcore. I ended up with 2 inches more suspension travel front and rear, and about 3” more ground clearance.

    I also but on a 12v conversion kit from Rex’s speed shop. It’s pretty much plug and play. Lighting is sooooo much better than stock
    EE0A9802-28B4-4F1F-8CB0-9A0F1347DDE4.jpeg
    #4
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  5. TheGr8Pumpkin

    TheGr8Pumpkin Been here awhile

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    Sweet bike!

    I'm leaning towards progressive suspension as well because of ease of availability and price.
    #5
  6. Scoozi

    Scoozi Been here awhile

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    Nice project, I'm another one that had one of these back in the 80's. Lot's of fun at the time, but I was never a fan of the flywheel magneto ignition as it would kick back viciously if it didn't start. Perhaps I should point out that original ones are getting valuable these days...
    #6
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  7. TheGr8Pumpkin

    TheGr8Pumpkin Been here awhile

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    So, update. I spent all day at the shop working on getting the carb tuned right and when I thought I had it worked out pretty well, the pressure from the engine when any throttle was applied made the supertrapp pop off. Much hammering and clamping later, the same thing happened and I still had a loss of power high in the rev range with a popping.

    Because the muffler wouldn't stay on I decided to say screw it and give it a ride without the muffler AND THE BIKE RAN PERFECTLY.

    So that leaves me with the assumption that I need to do two things
    • run the supertrapp with the largest amount of discs possible or run it with no discs
    • weld the super trap onto the header or add multiple retaining springs
    suggestions welcome on that second point
    #7
  8. Junglejeff1

    Junglejeff1 Long timer

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    TT/XT,pretty much same bike.All the mods for tt will work.Suspension I would put emulator in front(race tech)and order some falcon shocks.They set the shock up for your weight and custum valve.The steel bodies are decent price if you know we're to get them and way higher quality,cheaper, and rebuildable than progressive trash.If you want falcons pm me and I wIll give you info were to get a set for under 240 shipped.
    #8
  9. Junglejeff1

    Junglejeff1 Long timer

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    Considering your doing a 1000 mile event really go through that old beast.clean all those old terminals and grease them up with some terminal grease. Replace the ignition coil wire and put a ngp plug end on the end of it.Always a good idea on older bikes to replace brake pads as those old ones have a habit of shedding the lineing.My old tt500 dropped the linings off the backers 2 years ago even through there was plenty of lining left.Silicone is your friend (and lok tite)and water proof everything you can.Old bike =running a decent fuel filter as who knows what crap is going to bust free in that old gas tank.
    #9
  10. TheGr8Pumpkin

    TheGr8Pumpkin Been here awhile

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    Some very solid advice thanks! I already did the spark plug cap / ignition coil / coil wire, but checking all the terminals will definitely help.
    #10
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  11. plugeye

    plugeye MC responder

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    is the ride all daylight hours?
    if running in dim light or dark, convert to 12v with a halogen headlight cheap & easy:
    [​IMG]
    #11
  12. TheGr8Pumpkin

    TheGr8Pumpkin Been here awhile

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    Ideally, the ride will be daylight hours, but doing 200+ miles off-road on vintage bikes, there will definitely be a few days when some groups don't get in until pretty late. Pretty sure that I will be doing the 12 volt conversion, especially so that I can use the bike to charge other items if need be.
    #12
  13. plugeye

    plugeye MC responder

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    also an LED taillight works for this even though it's AC voltage. the shake at the taillight kills filaments pretty easily
    #13
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  14. TheGr8Pumpkin

    TheGr8Pumpkin Been here awhile

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    What type of rack are you using there?
    #14
  15. That1Dude

    That1Dude Adventurer

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    It was adapted off something else by the previous owner. I’ll see if I can find a better picture.
    #15
  16. That1Dude

    That1Dude Adventurer

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    #16
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  17. That1Dude

    That1Dude Adventurer

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    #17
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  18. DiggerD

    DiggerD DougFir from SuperDuke Days

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    Had a TT500 that I set up for dual sport riding with a plate...and a SR500...fun motor.
    Glad you went to a disk on the front.
    The foam in the seat might need replaced...nice big seat tho..
    My TT500 had a larger carb, bigger O.D. high header pipe, with Supper Crap mufffler, K&N filter.
    Loved to hear the K&N honk while on the stick.
    Keep you luggage rack small. That way you will be less likely to pack the kitchen sink.
    Photo below to shiny for your use, but maybe another life [​IMG]for it down the road.
    #18
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  19. Otis the Sasquatch

    Otis the Sasquatch Long timer

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    Aftermarket UJR. Universal Japanese Rack. It's "period correct". :lol3 Several different configurations + adjustability = dozens of possible fitments. None of them were bike-specific.

    I have a couple.

    This pic from 1986. You can NEVER have too many bungees! :rofl
    [​IMG]

    Have the bike. Rack's hanging on the garage wall.

    Here's an interesting variation. No passenger? Move the backrest up.
    [​IMG]

    They ALL need new rubber-strip inserts.


    Anyway...
    Used to have an XT500. Getting one again someday. Carry on!

    .
    #19
  20. DiggerD

    DiggerD DougFir from SuperDuke Days

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    Haha....had a flash back from my TT500 days..
    Trail riding ..got the bike from a bud who replaced the rear shocks..forget the brand..might come to me..blue and white...(White Brothers ? )..anyway they did not have much travel, more for fire roads....so I hit a water bar..the back end of the bike bucks me off the seat into a classic " Flying W"...He also installed these huge handle bar hand protectors...huge, that locked my hands to the bars that kept me from bailing off.
    My face was on the front fender and the rest of my body was vertical ,feet end up.
    I thought this was a heavy bike that I did not want landing on top of me..so I just chilled to see where this would take me...with my hands locked to the bars..I really had no choice.
    The bike did not skip a beat and I came back down on the seat as nothing happened.
    First thing I did when I got home was to remove those damn hand guards.
    #20
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