TREK 4500/ GEBE w/ GP460 build

[appye]

Steve, do you tighten the nut enough to compress the wave washer? I did the same thing with a regular washer, but had to try and find a "sweet spot" where the arm would still move freely. I really like your idea of putting something on the other side of the arm to keep it from cocking out, I should have thought of that Although it seems like yet another thing that can keep it from moving freely. This arm really should be riding on a bearing of some kind. I am also seriously considering putting the tensioner on there statically and avoiding the arm altogether. I would weld an old wrench right on to the nut if I can so I would still have some sort of quick release.

SO!!! Mileage? Even a rough figure? How many centimeters per seven tablespoons (cp7t) of properly mixed fuel? How many yards (ypl) can you go on one liter? Or you can just give it to me in kpl or mpg :b

edit: oops. scratch that for the mileage. I did not see your previous post.

 

[DetonatorTuning]

yes tighten to flaten the washer, and yes you still have to find the proper nut tension for it to move smooth.

you could use a bearing on the arm pivot, it might be a bit fiddlly to work out.

you can also do as you say and just lockdown the arm in a static position and be done. the problem as i see it is, which side to err on. bearing not far enough under drive cog = belt slip and damage, bearing too far under = extra belt stretch and need for even more tension.

a point to try with a new belt. using the stock tension spring and the arm in tension, mark the bracket lightly along the top of the arm. now install another extra spring about the same as the stock one. remark where the arm is now.


i have reports of 150+ mpg with the 460 and GEBE drive.

steve

 

[appye]

Steve, I noticed your posts over on motorbicycling.com ... the stock GEBE clutches engage at just above idle. They are fully engaged at about 10mph with a 14 tooth gear. At least they seem that way. I have done some low speed cruising at about 10-12 mph for long periods of time without having any clutch slip or excessive heat or smelling anything. This means that the clutch would be a low rpm clutch, no? The engine is engaged when I am slowing down pretty much all the way to a dead stop. I would not feel comfortable with high rpm clutches that would require me to get up to higher mph before they engage.

I just don't see compression braking and the reverse torque causing the belt to slip or even cause all that much damage. The engine is still connected to a flywheel that keeps the internals balanced nicely while decelerating, and I don't see abnormal bearing wear happening here. I would think your belt is slipping because of either the poor design of the tension arm or because of the power of your engine or likely a combination of the two. The reverse tension is definately what causes the arm to loosen up, and the thing just does not spring all the way back. Even with my 32cc Tanaka engine, I had to regularly reach back and pull the tensioner a good 1/8 - 1/4 inch because I would hear the belt start to slip.

I am pretty sure I am going to get me a similar engine and will likely do away with the quick release tensioner altogether. I hope I will be able to use the stock GEBE clutch just so I will get the behavior I am used to already. Do you know what rpm stock GEBE clutches engage at? I will just have to learn to finesse the throttle a bit when taking off. With the 32cc, I would pretty much pedal up to about 5mph and then floor it while still pedaling the whole time, doing this with the GP460 sounds like a If I ever run out of gas, I will get off, loosen the nut, and remove the belt. Generally, I don't let myself run out of gas.

I am planning on just using the stock exhaust, as 4.2hp is already waaaaay more than what i had before, but what is meant by the belt slipping when the "chamber goes into resonance?" Is there some kind of boost of power at this point? What exactly IS this resonance thing?

 

[appye]

150mpg huh? I am definitely getting this engine now! As far as the thing with the tension, I would just cut a slot in the plate, rather than just drilling a hole and having it in some static location. I would do away with the arm altogether.

.... waitaminnit! DUH!!! Why not just tighten the arm down and lock it that way? This way I don't even have to do any cutting or drilling. I will go look into am mirror and smack myself now.

 

[DetonatorTuning]

aug,
my tach just came in the mail. nice little unit, but no setup and use instructions at all. just the unit in a box.

i'll go see if i can make it work.

yes appye, just tighten it down. if you find the spot you like you can then drill thru both arm and bracket and put a bolt or pin in it.

steve

 

[DetonatorTuning]

yep, it works just ducky. wires should be long enough as is.

only comlaint would be that the wires could have been routed out the bottom of the case relative to the upright reading of the digits rather than out the top, but i can work with it.

my engine seems to have the idle set at about 3000 from DDM.

 

[appye]

Okay Steve! I just ordered the same engine! My heart is all a twitter and I should get it in by the end of the week! I am using the stock exhaust, but man, I hope this beast does not shred my bike apart. If it does, then I guess I will have to contact wheelmaster for a super heavy duty set of spokes. What gauge are yours?

Gotta go watch The Hulk now!

 

[augidog]

aug,
my tach just came in the mail. nice little unit, but no setup and use instructions at all. just the unit in a box.

i'll go see if i can make it work.
___________________________
yep, it works just ducky. wires should be long enough as is.

only comlaint would be that the wires could have been routed out the bottom of the case relative to the upright reading of the digits rather than out the top, but i can work with it.

my engine seems to have the idle set at about 3000 from DDM.

if you ordered a $30 one, it isn't programmable & i guess it doesn't need instructions, but see the .pdf i posted for some techie stuff. the completely programmable one, which would be a perfect shop item, is $50.

dang, i'm jealous...i want mine!

 

[kawasaki999]

460

Time 4 me to chime in, Appye the stock muffle wont work because it exhausts right at you,noise, and oil all over everything,and it wont mount vertically. First you need to locate some lighter clutch spring before u waste your money, I hated mine untill I found springs that work like the tanaka,only then you will see 150+ pmg, under 100 mpg with stock springs. I never open mine up until i am 30 mph even then its gradual. I have 2 460,s and 1 tanaka 47r and a 3rd 460 in the works. Craig...

 

[kawasaki999]

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some pic of bikes