TREK 4500/ GEBE w/ GP460 build

Discussion in 'Rack Mounted Engines' started by DetonatorTuning, Jun 7, 2008.

  1. DetonatorTuning

    DetonatorTuning Active Member

    well i started assembly today , and being at my day job, trying to hurry, and havin gmy head you know where, the first things i did where wrong bu ti later saved it and made it all work

    1st pic, scribe mark to remove material from DDM Dominator pipe. you'll proba bly see 2 things wrong right away, kind of wish i had.

    2nd stinger silencer installed in pipe end.

    3rd pipe in mockup position, this i swhere i realized what a dope i'd been.

    4th pipe bracket bolts in place and new hope for making it work.

    5th rear bracket spacers

    Attached Files:

  2. DetonatorTuning

    DetonatorTuning Active Member

    6th front bracket spacers

    7th tensioner plate/ mount plate w/ handle mod handle full up

    8th handle clearance full up

    Attached Files:

  3. DetonatorTuning

    DetonatorTuning Active Member

    9th handle full down

    10th handle full down again

    11th business end

    12th curb side

    beyon dthis i testfitted the opright bracket and set the engine on it to be sure the lower portion of the header waqs well away from the tire. it all looks good.


    Attached Files:

  4. DetonatorTuning

    DetonatorTuning Active Member

    HA, you got in while i was having a senior moment and having to result to quoting my own post to contiue the thread and attachments.

    i'll have pics of the bike, wheels/ tires, mounting rack and fuel system in the next couple of days.

  5. spad4me

    spad4me Member

    Better now HUH.

    I like your bike build.
  6. lennyharp

    lennyharp Member

    Is this a higher performance motor with custom specs or what? it looks great. What are its specs and performance expectations?
  7. A GP460 (Chung Yang) will knock you on your butt.
    4 port, RC style engine, very fast, and revs very high.

    Just be sure to use really good oil, and watch the plating.
    CY plating can be ok at best.
    When they are running right, they kick so much butt.
    Did you get the clutch saver springs for it?
    It's a worthwhile investment of $15 for a lower clutch engagement,
    and less chance of breakage, like stock 460 springs are known to do.
  8. augidog

    augidog New Member

    Last edited: Jun 8, 2008
  9. sawman

    sawman Guest

    Better buy alot of belts. you will go through them with that beast. GEBE needs to step up to the plate with a tougher belt for us performance hungry people. i had to go to a chain setup... i could tear a belt up in one ride.
  10. DetonatorTuning

    DetonatorTuning Active Member

    i think all the current questions have been covered so i'll take the comments.

    after break in i'll be using Amsoil i think............

    i have a set of clutch savers but i installed a set graciously provided by another member that could prove to be the long sought 3000-3500rpm engagers. clutch savers come in at about 6400 which is much better than the 8100 stockers but not really good enough either.

    BELTS, this is the real point of opinion and widely varying experiences with the GEBE setup in general. people with much smaller motors have reported low life and the few i've spoken to personally, with this motor, say that if you pedal away from stops, ease in the throttle progressively and NEVER pop it wide open in the midrange that the belt is fine.

    if it turns out that i need a chain setup, it will be one of my own design. it's aready in my AutoCad program. like most of my stuff it's not truely orignal, just a novel use of presently available pieces from various sources.

    and because you asked directly lenny, i expect to topout around 55+.

    yes, i have my nomex suit on guys, flame away !!

  11. lennyharp

    lennyharp Member

    Cool. I had a feeling you were talking about HI Performance!!! That will be fun. I have mentioned other places that a steep head angle and good weight distribution makes for a good handling bike even at those speeds. There is more to it than that but to simplify you look at races like the tour de France where the mountains are 10% grades at times and they ride at 60mph with bikes that have 73-76% head angles and little more than 1" fork rake. That would be down the mountain, not up.

    A friend built a bike that he used to motor at about 55mph behind a truck with a wind screen to break wind and drag him along at Phoenix Raceway. I do remember he built it with very steep head angles and little fork rake.
  12. DetonatorTuning

    DetonatorTuning Active Member

    man i love this place !!

    Lenny, as commuter this bike is going to have an adjustable steering stem from the LBS and a set of bars and windshield from my motorcycle parts bin.

    i presntly think i'm ok on geometry and weight distribution, i'll soon see if i think the hardtail was the right choice, i have my eye on another full suspension bike if not and everything i've done can just be transfered.

  13. DetonatorTuning

    DetonatorTuning Active Member

    it's alive !!

    staright forward GEBE install no issues suprizes or problems.

    had thought i'd have to put a couple of washers behind the drive cog to get past the Bontrager Hank 2.2's but didn't yet. we'll see what belt stretch etc makes nec.

    i might drop down to 2.1 or 2.0 tires, but only if forced to. these tires ride very nice and have an outragious circumference (read speed )

    i di 2 slow pulls to half throttle and the bike was moving surprizingly fast. this thing is going to ROCK when it breaks in.

    the springs i was given to try are 300rpm engagers afterall and work very well. i'm going to see if i can source them. in the mean time, i fyou have a motor with the 76-78 3 shoe clutch and want low rpm engagement get ahold of Staton. you can fin dthem by putting "Honda GXH50 clutch " in their search bar.

    bike is not anywhere near complete, had the gas tank duct taped on for the shakedown runs. will clean it up and get some pics soon.

  14. DetonatorTuning

    DetonatorTuning Active Member


    i'm not sure i'm as enthusiatstic tonight as i was yesterday.

    i was out putting somemore break in miles on the bike for awhile and experienced a symtom i'm sure isn't good.

    running down the road, just stabilized at half throttle, hit a bump, bounceddown on the throttle about an 1/8 more and felt and heard a short...


    got off it and was thinking about it while i eased it back up to half. then i did it on purpose. same thing and i know i didn't imagine it this time.

    Ssoooooooo, i'm certain that's the drive cog spining under the belt as this piped engine comes into full resonance. i'm thinking right no wthat i'll put a second spring on it and see i fi get by that easy. if that won't hold it, i guess i'll try the stock exhaust because i want chain drive to be the last resort.

    on a high note, everywhere i go in town people come out o ftheir houses and want me t stop and tell them what it is, where to find out about them and how to buy or have one assembled.

    here in the heartland people like and want this option in fuel use.

    more latter.

  15. augidog

    augidog New Member

    are you certain it's the drivegear spinnin'? does the belt show any sign? not doubting you, but geometrically (do you have a profile-pic of the drivetrain?) i'm having a hard time seeing it...i guess that powerhouse is mighty jumpy, eh? anyways, i'm thinking you might try shimming the engine/mount up a bit, but only because i think i'd prolly at least try it.
  16. DetonatorTuning

    DetonatorTuning Active Member

    i don't know for certain it's the cog. yes, the belt now has a couple edge frays, grrrrrr

    mechanically i guess it would be the tensioner pulling out and the belt coming around the drivering as the belt will still have good wrap and contact with the cog.

    the belt tracks dead center and i have both legs all the way seated on the axle. i feel the geometry of the kit components is very accurate. i'm pretty certain this is a tensioner issue related solely to the power of this motor and pipe combo. although it seems i've gotten quite a bit of belt stretch already. i could jack up the legs of the bracket to take up more slack but i'd rather put more spring tension on as it be easier. if i can varify results there, i can look at other permanent measures.

    i recieved my iridium plugs yesterday and had put one in along with the nitroblast amp before i went out. those that feel they are getting everything out of these engines without that combo needs to try them. the diff. is remarkable.

    kawasaki999 assures me he had one belt problem on his 3 Tanaka and GP460 bikes and it was resolved by dialing in the tensioner too.

    i'll get some pics up.

  17. augidog

    augidog New Member

    sidewear on the belt...ok, i'm just mumblin' to myself here..."i wonder if the system is flexing slightly under load?"

    btw: if any side-threads are dangling, cut each end off short. i had a temporary misalignment that "scored" the side of the belt, about 2" of one thread was exposed, i merely clipped it off and realigned the drive. that was over 300 miles ago.

    another btw: IF one were to wanna try shimming, i think it would be easiest to add a 2-hole plate under the mount instead of trying to lift the whole strap assembly.
    Last edited: Jun 11, 2008
  18. DetonatorTuning

    DetonatorTuning Active Member

    can't say about the flex issue with any certainty, i guess i can have my son drive along side and watch.

    these threads are 1 each side ( not in line with each other ) and it's just one thread ( not deap into edge ) about 1/8-1/4" long.
    i clipped them in hopes that not having additional contact may stop them.

    yeah, somewhere down the line i MIGHT have thought of using the plate shim idea. NOT !!

  19. augidog

    augidog New Member

    steve: FYI per your request

    original tanaka 32 setup & configuration, 14 tooth drivegear.

    Attached Files:

  20. DetonatorTuning

    DetonatorTuning Active Member

    thanks aug,
    looks just like mine. if you place a straightedge against the O.D. of the tensioner bearing it's right in line with the thread bore on the drive cog.i did some tweeking of my tension arm today too. put a thin wave washer between the arm and bracket, made the arm move very smooth.

    it's waiting for the belt from GEBE now. the original is a wad of ripped and twisted carnage.

    i'm going to take the pipe off and remount the stock exhaust while i wait. i think the stock torque and HP o fthis engine is right on the edge of the belts abilities.

    when i was out today and gave it easy throttle increase from a steady 1/2 throttle cruise it was hitting a point where it was picking up much faster than the throttle increase relative to the span before that.

    this is a crazy little engine, it'll be a shame to detune it very far or go to chain just to run it. i was using the pipe and stock plug to start with, the trouble started AFTER i put the iridium and hot ignition on it. kawasaki999 has one with the hot plug and ignition but no pipe without problems ,Ssoooo......