TREK 4500/ GEBE w/ GP460 build

this is a crazy little engine
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and i want one! i'd happily "detune" it to meet the gebe limitations, i'd just take it easy and give her a mile to peak out...have i mentioned i have a racing-made 16tooth on the way? ;)

the spring-washer is a good idea...i also heartlily recommend to gebe readers to at least drop a bit of 3-in-1 or similar behind the tensioner arm once in a while.
 
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i haven't run the engine on the stock exhaust so i don't know how "detuned" it will feel. but i do know that at about 9000rpm ( 1/2 throttle ) i'm right at the TRQ peak of this engine and transitioning on past that is where the problem arises.

being an O.C. gearhead of the more is better and all of more is best stripe may have got me in over my head this time.

i'm wondering if the 3000 rpm clutch springs i'm using may be putting much more decelleration stress on the belt ? and what is the effect of engine braking these 2 strokes that don't have manual clutches to get them "offline" ?

Hmmmm................ i'll have to think about that at work today.

steve
 
hmmm, good point about the springs. i had to completely change riding style when i first experienced centrifugal clutching. no such creature as engine-braking, at least with stock springs. i get off the trottle, i'm instantly in "coast" mode. engine-braking surely will apply back-stress on the drive, and that was not intended...the tensioner isn't built that way.
 
well i'm compression braking all the way back down to 3000rpm and walking speed, and now that i've been thinking it over i'm almost positive that's where the damage to the belt has been accuring.

how hard does your clutch engage ? at 3000 my clutch is silky smooth coming in because it actually has to catch up with the speed the wheel is already moving.

i'll have to do some more thinking on this. i'm now sure i want to avoid compression braking, but i don't want the clutch letting go and sliping anywhere below 35-40mph and 8100rpm.

i'll have to cross check my tach and speedo and see just what MPH the 6400rpm springs will disengage at.

i can see this is going to take some technique, if running high speed ,in all but emergency situations, i'm going to need to start backing the gas down real gradual till i get near 6400rpm.

this is cool, maybe i'll be able to keep the belt alive after all.

thanks,
steve
 
my stock clutch (at ? rpm's) likes to be pedal-assisted up to about 12mph...i like to go as far as 21mph because it's all-engaged and starting to hit it's range...i can also take-off from a dead stop with a 13 tooth, but i don't do it or recommend it.

when i first start it up, the first engagement is kinda chattery, then it starts to glide in very nicely, quite smooth...pedal and throttle are a lot of fun, imo.

the engine drops to idle fairly quickly...i can grind my way up a hill and let off just as i go over the peak, wait to see what kind of a "coast" i get, then i nail the throttle at just the right point, it responds, engages...anywhere up or down i can go to idle and be on pedal-power or coast instantly.

now, i've got myself a new sturmey-archer drum on some great wheels, & i've developed a style on hills or corners where i use finger on brake-lever, thumb on throttle...i get great response and control that way...i'm not sure a low-locking clutch would be near as much fun.
 
aug,
do you have any idea what rpm your clutch actually grabs and lets go at ? near instant idle, from where ?

i have the clutch saver (6400rpm) springs in now, they went in OK, i figured out a sequence for getting the last spring end to hook in.

not sure how much harder the 8100rpm stock springs are to install, but i won't be looking forward to it.

need to get my final fuel arrangement in order and setup my lights. the bars and windshield will be last since it's HOT here now.

thanks,
steve
 
apparently, you can extend the wire...i'm going to call today and confirm that.

$30 w/free shipping. 24K rpm range. i'll make it work.
 
please let me know if they have the extention cable or what it will take to do it.

tiny tach has cables for $10.00 don't know if they are compatible.

thanks,
steve
 

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