Trek 4500/ GP460/ 8 speed SHIFTER

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.

thanks,
steve

Looking forward to your pics and build info as always

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

Thanks

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.......................................................................

steve

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

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.

thanks,
steve

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.

steve

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.

Sounds like a lot of fun.

duivendyk said:

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.

Click to expand...

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 ?

steve

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.