Yamaha XT500

Discussion in 'Thumpers' started by TimberlineAdventure, Mar 29, 2008.

  1. motocrossross

    motocrossross Been here awhile Supporter

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    It seems pretty good, not ungodly loud, not as much on top as an open silencer, but better bottom and mid. One thing, the supertrapp discs are stamped differently now. There's supposed to be .023" between the discs installed, ive got an .023 wire feed welder, and the wire will not fit between the newer discs. I had a stack of 3" discs from eons ago, .023" will fir between those, so im running the old discs. It wouldnt run right with the newer ones, too much back pressure, even with 16 discs.
    I'm working on another muffler, its a street bike can, it will be longer, with 4" supertrapp discs. Its round though, and i can't figure out how to keep it from invading on the tires space. Im a hammer mechanic, not an engineer.
    Old Smokey likes this.
  2. ReidCycles

    ReidCycles Adventurer

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    Hey Old Smokey, the FMF can on that yellow TT MX’er is for a Honda CRF150R. We’ve done a few like this. Use a TT head and mid pipe, then grafting on the 150 slip on takes minimal fab work and the can’s mounting bolt lines up about perfectly to the TT’s mounting tab. Not period correct, but they sound great, not obnoxiously loud and come in USFS versions. Cheers, Reid Cycles
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  3. motocrossross

    motocrossross Been here awhile Supporter

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    New 390mm Hagon trail shocks. Much better than the originals. IMG_20200424_175642336~2.jpg
  4. Old Smokey

    Old Smokey Been here awhile

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    IMG_8252.jpg

    First trail ride on the rebuilt xt in the books. Got a few paint scratches and battle scars. Makes the bike look a bit nicer to be honest. In its element.
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  5. motocrossross

    motocrossross Been here awhile Supporter

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    Your bike looks brand new, Old Smokey. Nice job!
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  6. motocrossross

    motocrossross Been here awhile Supporter

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    Old Smokey, how is the TM carb working? Mine has VM34ss from a '76 TT500 at present. I've been thinking of replacing it with something....
  7. Old Smokey

    Old Smokey Been here awhile

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    It’s so good. I love it. Easy starting, and great throttle response. Very crisp. I can share my jetting if you go this route. Very much recommended.
  8. morini

    morini Newbie

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    AFDD4FA5-2291-4DF8-A041-74DC93ACE9D5.jpeg Last year I bought a ´79 TT500 which I think is one of the coolest bikes ever made. This example is original, has some battle scars from being used as intended, but has been kept technically in shape. Since I always end up trying to optimise my bikes I have been thinking about replacing the shocks with YSS 390mm and possibly installing a YZ fork (since I have a good one offered to me for a good price). The 390 swap is mainly for the esthetics (and for the higher quality shocks) since I think these bikes are a little low in the rear. To be honest I am a rookie off tarmac so the extra height is mainly vanity and hoping for a bike that looks a bit like HL500:-)

    1. How much taller are the YZ forks? Will the relative height front/rear be the same as original with 390 + YZ? Any pictures of 390+original fork vs 390+YZ fork for comparison?
    2. The YZ fork I am offered come with steering stem and clamps. Will they fit directly in my bike or do I need to use the originals and bore them up? I understand I need a brake plate from the YZ for this to work.
    3. My bike has the aluminium swingarm. Does this have the same geometry as original so that 390 is the highest I can go on shocks?
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  9. plugeye

    plugeye MC rescue

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    20200610_153313.jpg

    airbox flange cracked, on with a pod filter
  10. plugeye

    plugeye MC rescue

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    not too obnoxious...yet
  11. Old fart

    Old fart Keen AG100 rider

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    Trouble with those breathers is they blow oil when you do a long wheelie after about 1 K. With your setup it would just fill the filter with oil, with the standard airbox and a long wheelie the oil travels up into the bottom of the box and sprays into the foam. It sprays that much oil onto the filter that the engine gets oil straight into the carb. You loose power, the front wheel drops and you leave a trail of smoke screen :D called doen a smokey in the olden days
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  12. plugeye

    plugeye MC rescue

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    dont worry, i aint doin any long wheelies
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  13. plugeye

    plugeye MC rescue

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    revision A, mate up with DR350 case vent
  14. plugeye

    plugeye MC rescue

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    top end time
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  15. plugeye

    plugeye MC rescue

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    77 XT500 been ridin since last year, running well. my buddy dave mic'n the works. low mileage barn find with standard bore & rings still in spec.
  16. plugeye

    plugeye MC rescue

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    back on the road
  17. Old Smokey

    Old Smokey Been here awhile

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    Had my xt out for a couple hundred KM this week. Switched to a 4” supertrapp muffler from a wide open cone engineering big mouth. Volume is better (10 discs) though still suitably loud. Jetting had to go way leaner to run well though. Think I got it now.

    Adjustments.jpg
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    Adjustments.jpg
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    Adjustments.jpg
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  18. g®eg

    g®eg Canadian living in exile

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    2 quick noob question for the XT500 aficionados..
    I am going to look at a pretty clean '78 on Wednesday (and by look I mean bringing cash & riding it home).

    1) I used to have a Honda XR 650L, and one of the issues was making sure the oil temp didn't get out of control. For that I added the XR's Only Oil Temperature Dip Stick. Is oil temperature something i should be aware of with the XT?

    2) Curious about fuel mileage since I don't want to be a complete boob on the side of the road. Fuel capacity US 2.3 / 8.8 l, so I am guessing 80-90 miles between fill ups?

    thanks!

    if successful I'll post some pics after the deal.
  19. Old Smokey

    Old Smokey Been here awhile

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    I also have an XR650L so I can comment on that.

    I haven't had any of the same overheating issues on the XT, and I'm running a 10:1 piston and hotter cam. I've read that oil coolers are often not a great idea on the XT as the cooling system is more than adequate. Adding a cooler can make it difficult to reach temp on shorter rides and burn off condensation, etc.

    I have seen them on the Dakar bikes, but riding full-out in the desert isn't something the average rider is likely to do.. Also have seen them on SR race bikes occasionally. I'd not bother with it.

    Fuel milage - it really depends on the engine setup, and if it's in good tune. For reference, I have a 36mm TM36-68 pumper carb, 4" supertrapp, 89mm 10:1 and megacycle 251040 cam, Rex ignition. I get about 41mpg when riding on the pavement at about 50mph, with a 14/44 gearing. That puts me at 92 miles till I'm bone dry.

    With stock gearing, stock engine and carb, I think you could do closer to 45-50mpg.
  20. g®eg

    g®eg Canadian living in exile

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    wicked!
    thanks for the quick & detailed reply!

    teaser pic... how could anyone say no to this beauty?
    PDRM2005.JPG
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