Every time I ride it something breaks! Grrr...

heathyoung

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Hey all... I'm sure everyone has this issue but anyways... Maybe I have worse luck :(

Setup is an Australian sourced (from china?) Gebe knockoff, with a 31cc ~1hp (700W eep!) 4 stroke, 16 tooth drive pulley (to keep rpm low so it doesn't exceed 200W limit).

So far... Belts come off regularly - alignment is OK, tension is OK, problem comes from the lack of a dynamic tensioner (as per Gebe design). Made up my own dynamic tensioner with two bearings, some scrap metal, a spring and some bolts and nylock nuts - solved.

Stupid engine has to be tilted back too far, and the fuel filler leaks fuel out as a result. Made up a cradle from scrap aluminium and turned it around so the filler faces the front of the bike, not the rear. Tygol hose is expensive, but good stuff!

Sum-ting-wong brand sparkplug dies without warning, replaced with NGK, no problems. Revs better.

Backfire blows airfilter housing off in traffic, gets run over by a truck, unrecongisable now. Replaced entire housing with cheap pitbike K&N knockoff + 40mm plumbing end cap. Noiser, but revs better.

Fuel filter picks up air (very bulky design) when tank low. Replaced with smaller 'whipper snipper' type.

Bolts always fall off/bend. Replace with good quality high tensile bolts, with lock washers etc and nylock bolts.

Sheared off weld on clutch going downhill. Really poor penetration on weld. Stupid drive pulley kept unscrewing itself on the way home, had to keep on the throttle and brake to stop it. Got the local exhaust guy to weld it back on, much better job.

Positives: Gets me to work on time with some exercise, costs about $3.00 per week in fuel as opposed to $50 per week in the car. Clutch is holding up very well, expected a lot more wear the way I ride.

I'm not sure what else is left to break :p

Negatives: very little power due to poor gearing - I'm going to get an 11 tooth I think - to better suit the motor and the very steep hills I have to push the bike up (grrr...) Engine is cantakerous, always starts, but when it gets good and hot, tends to ping (even on 98 octane) and leans out + misfires.

'Shoulda bought a gebe with a tanaka, or built my own (which is what I am in the process of doing - slowly - probably using this engine and a CVT).

Anyone else have as much luck as me?

Cheers
Heath Young
 

AlphaGeek

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Sep 18, 2008
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Silicon Valley, CA
Sorry to hear about your experiences. Sounds like you bought a hobby and not a solution.

As a thoroughly biased GEBE/Tanaka owner, I think you were exactly correct with this statement in your post:

'Shoulda bought a gebe with a tanaka

That said, hopefully you're through the worst of your component failures so you can focus on getting things running properly. From what I've read here and on the other motorized-bikes forum, owners of the low-end Asian motors do eventually reach a point where they get things running to their satisfaction. And then the seasons change and you have to adjust the carb again. :)

-AG
 

Mountainman

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Jun 15, 2008
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up top mountain -- Sourthern Ca.
that's a LOT TO DEAL WITH !!!!!!!!!!!!!

So far... Belts come off regularly

lack of a dynamic tensioner

engine has to be tilted back

fuel filler leaks fuel

Sum-ting-wong brand sparkplug dies without warning

Backfire blows airfilter housing off in traffic

Fuel filter picks up air when tank low

Bolts always fall off/bend

Sheared off weld on clutch

Stupid drive pulley kept unscrewing

very little power due to poor gearing

Engine is cantakerous

when it gets good and hot, tends to ping

misfires

for the COMMON MB man or woman

THAT'S A LOT OF STUFF TO DEAL WITH

not sure that if most knew this before hand -- they would buy

because many only truly want to do one thing --

RIDE THAT THING
 
M

Member 5549

Guest
Well I don't know about the GEBE knockoff , but there Kill Switch looks cool !!!!!
 

heathyoung

Member
Local time
8:42 PM
Joined
Jul 30, 2008
Messages
185
Not according to any dyno graph for an engine.

Engines produce pretty much the same torque across the RPM range, but the power goes up along it - the power output of the engine (whilst obviously not linear) will increase with RPM. An theoretical engine that produces 700W at 7000 rpm will produce 200W at 2000 rpm.

Restrict the engine by loading it up (use up all the torque so it cannot rev any harder even at WOT) and you get yourself a power restricted engine. Fix up the gearing so it revs better, you remove the restriction. This is the reason for the very silly 16 tooth gearing - it restricts the engine power something awful (but it does go well down hills :)
 
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