Trek 4500/ GP460/ 8 speed SHIFTER

Discussion in 'Frame Mounted Engines' started by DetonatorTuning, Jan 26, 2009.

  1. DetonatorTuning

    DetonatorTuning Active Member

    well all the parts are here and the final clearance fitting and alignments have been done.

    i'm going to be putting up a bunch of pics and explanations on this one so that anyone else who wants to do this knows from the begining what they need and where to get it BEFORE they start.

    to start with i'm going to give some much deserved props to the vendors that have been putting up with me the last couple months.

    i'm using the frame mount plate and 5:1 reduction trany from THESCOOTERGUY with an 11T output gear.

    i really liked Jerry's mount but didn't want to drill my frame and give up my pedals, so.........

    i'm using the SICK BIKE PARTS freewheel crank w/ 44T outer sprocket and inner jump guard.

    to get the most out of the RPM band of my engine i needed to build up a custom rear cassette ( i'll talk about the actual gear teeth and ratios later ) and to make it all work together i needed a custom inner front chainring to mount on the SBP freewheel.

    ANDREW at KINGS SALES AND SERVICE got the call and despite personal illness, a crush of orders and a part failing on his cutting machine, came thru with an AMAZING 22T SPB shifter kit sprocket cut to run 1/2" x 3/32" 8 speed bike chain.

    all this works out to a pretty cool package, a frame mounted HP 2 stroke with shift kit that retains pedals and pedal ability.

    i hope to get pics and further explanation in the next couple days.

    Last edited: Jan 26, 2009

  2. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    Looking forward to your pics and build info as always

    Sounds like a high performance does it run and
    compare to your other builds?

  3. DetonatorTuning

    DetonatorTuning Active Member

    same old 460 w/ .005" base gasket and custom expansion chamber, so nothing new there. i'll have a span of gears from 30.91 :1 - 15.45:1 this time though.

    everything has been pre- assembled for fit, alignment and clearance then taken back apart so i can take pics. it's more involved than the GEBE but the weight is above and ahead of the bottom bracket this time and it's MUCH lighter than the Staton and is solid mounted to the frame.

    i haven't run the engine on it yet so you 'll be there as the drama unfolds. hope it's minimal this time !! we'll see.......................................................................

  4. duivendyk

    duivendyk Guest

    Could be kind of rough on the 3/32 deraileur chain with all that power.
  5. DetonatorTuning

    DetonatorTuning Active Member

    we'll have to see about the chain, but i think it'll be OK due to the shock absorbing traits of the rear derailure. i don't intend any burn outs and since it's a centrif. clutch it'll be engaging progressively.

    i'm having some trouble with my camera and card so i'll try to offer some idea of the things i had to deal with to get this going.

    bought the mount plate and 5;1 tranny from THESCOOTERGUY.COM. this has the large clutch bell, proper dia. for my engine. BUT, my engine has a 3 shoe clutch with a slightly longer center bolt, so i had to reduce the height of the nut that holds the clutch bell to the input shaft. problem fixed, engine mounts up and ther is no contact or drag.

    bought the feewheel cranks and outer chainring from SICK BIKE PARTS these are nice high quality pieces. BUT, the cassette bottom bracket had too short of exposed spindle on the right. the freewheel bottomed against the BB before the pedal crank was tight. after some measuring i determined that a 122.5mm BB would give the fit and clearance needed behind the freewheel AND provide perfect chain line alignment with the tranny output gear.

    built my own rear cassette, now 34T- 15T. ratios will be 34T- 30.91; 30T- 27.27; 26T- 23.64; 23T- 20.91; 22T- 20.00; 21T- 19.09; 20T- 18.18; 15T- 13.64. i wanted a 17T last cog but there isn't one made that will take the keeper ring, it would have given me a 17T- 15.45 final.

    engine is as far forward and up as high as the frame allows, with the carb now forward and exhaust exiting rearward. BUT, i modified my Dominator expansion chamber to clear above my former Staton drive box. this worked out fine for this build because the pipe mounts the same direction BUT, this time the pipe goes up and over the top frame tube then down in front of the mount bracket, out of the way of both pedal strokes.

    hoping to get my son to help me with the camera and get some pics soon.

    Last edited: Jan 28, 2009
  6. DetonatorTuning

    DetonatorTuning Active Member

    OK we'll try to post some pics, hope they transfer. i lost a bunch of others some how. may have to start over to show more details.


    Attached Files:

  7. duivendyk

    duivendyk Guest

    It's nice to have a wide transmission ratio,these soupedup 2 strokes get their increased power to a quite an extent from improved top end performance.I don't think having a deraileur makes life any easier at all for the chain,keeping it clean and babying the thing helps, but is hard to do with the deraileur close to the ground.It's road dirt&grime that kills chains,I ruined a rear cassette in a few kmiles despite frequent attention to the chain.The best thing is just replacing it routinely to save your sprockets.The narrower the chain and the more speed and tension you subject it to, the quicker it wears.Chains don't "stretch",they wear at the pins.
  8. spad4me

    spad4me Member

    Sounds like a lot of fun.
  9. DetonatorTuning

    DetonatorTuning Active Member

    i readjusted my rear cassette this morning, droped one of the middle gears, it's now 34-30-26-22-21-20-17-15. 22-21-20 is where i'm going to be mostly, but the top three will be good for take-off and serious grade changes. 17-15 will be for long cruises down at 8600rpm for MPG's.

    even very good chains in this catagory are cheap and this being my work commuter i expect to maintain it like any other vehicle.

    spad4me, good to see you on the forum again, what kind of MAD WAGON

    devise of doom do you have rollin' now ?

  10. duivendyk

    duivendyk Guest

    The chain will be running pretty straight most of the time,that helps also,and as you say there not expensive.The trick is not to forget replacing it like I did.I learnt my lesson and bought one in advance now, to serve as a reminder.
  11. thescooterguy

    thescooterguy Member

    nice ! can you still adjust the sprocket alignment . even though motor mount is upside down . it looks pretty straight . here are some closeup pics of how the mount setup bolts on . you should be able to adjust chain tension or switch drive sprockets for different riding , and the pitch and toe angle on sprocket , because most bike tubes are angular not squared . you beat me to the punch on the freewheel . Ive got some threaded crank arms in the mail from sick bike parts , i have a freewheel setup all ready for them i used a scooter freewheel because it has the 4 bolt hole pattern and i will use the 8mm teeth from scooter for outer chain ring and bike 1/2 inch teeth for small inner ring , this way i can use the 8mm scooter drive sprocket on the motor. the availability on the sizes are great and cheap . and the chain is heavy
  12. Pezz

    Pezz New Member

    Gee, I like the artwork of your engine mount . . . . . :D
  13. DetonatorTuning

    DetonatorTuning Active Member

    Hi Jerry,

    you'd never believe how much time i spent looking at just those pics on your site before i ordered the parts !! :idea:

    the BB was the only thing i hadn't seen as a potential issue.

    my top tube is round, BUT the lower is OVAL and transitions from a horizontal axis at the BB to a verticle axis at the steering head. the transition is right behind the lower plate mount area.

    i have a "U" channel bracket that i haven't shown yet for the bottom. it mounts to the water bottle lugs and is dead on parallel with the top tube. it will allow me a solid position to make the toe adjustment, AND have a large enough sweep of front / back movement to pop the chain up and off.

    more to come, thanks
  14. spad4me

    spad4me Member

    Detonator tuning said "spad4me, good to see you on the forum again, what kind of MAD WAGON

    devise of doom do you have rollin' now ?"
    I don't want to hijack this thread your builds expand the paradigm of motorized bicycling.

    I will pm you
  15. thescooterguy

    thescooterguy Member

  16. Happy Valley

    Happy Valley Active Member

    Curious about the 5:1 gearbox. Any info about who and where it's made you can pass along and does it bolt up to a standard 4 hole mount with 78mm clutch drum?
  17. thescooterguy

    thescooterguy Member

    this is a basic scooter tranny Mitsubishi makes them but you will find them on lots of two stroke scooter motors , 33 43 49cc and also Robyn's 4 strokes , its is 5 to 1 and reverses the motor rotation for a right side drive . most scooter parts websites sell them for about 30 bucks or so .
  18. DetonatorTuning

    DetonatorTuning Active Member

    yes, it mounts up to the standard 4 hole mount on engines with 78mm drum.

    the problem being how the clutch pack is configured and/ or how long the engine shaft is.

    i could have made a spacer about 3/16" and made it fit on my engine unmodified. grinding down the keeper nut was easier for me, AND i maintained full internal clutch/ drum cantact. if i have a problem with it i'll just tighten it back up and spot weld it.

  19. thescooterguy

    thescooterguy Member

    is that a 47 or 49cc cag motor ? does the carb have floats ,or is it a diaphragm carb with the two fuel lines.
  20. duivendyk

    duivendyk Guest

    There will be quite a lot of vibration transmitted to the frame, thin wall aluminum with mounting holes in it, where stresses will be concentrated has questionable fatigue resistance.Has this been considered ?