Clutch Doesn't Work Grubee SkyHawk GT5

W_Hamilton · Jun 23, 2011

I just bought a Grubee SkyHawk GT5 on GasBike.net and I'm having problems with it. I'm not good with engines but I think that I have installed everything correctly (at least to my knowledge). The issue is that when the clutch is engaged, the bike won't move freely. The chain is being pulled through the engine sprocket. Am I missing a part? Is my engine bunk altogether? How do I fix this problem?
Thank You
Will

socialdistortionkid · Jun 23, 2011

I got the answer

i have a gt5 and had to adjust the clutch.

This is what you need to do. Same steps as described in your manual that came with the kit.

YouTube - ‪Motorized bicycle starfire 2 stroke kit, Clutch adjustment‬&rlm;

let us know if this did the trick!

2door · Jun 23, 2011

Clutch engaged = Rear wheel will not spin free.
Clutch disengaged (handlebar lever squeezed) = rear wheel spins free.

What problem are you having?
Tom

W_Hamilton · Jul 5, 2011

I watched the video on clutch adjustment and it seems like that might be causing my back tire not to spin. The issue now is (1) which way do I turn the adjustment nut (I assume CCW) and (2) what is a good tool to do that with because it is extremely hard to turn considering how flat it is.

rohmell · Jul 5, 2011

Pull in and lock the clutch handle, and see if you can adjust the nut easily. If not you can try using needle-node pliers with the ends of the pliers' jaws in the 'petals' of the flower nut.

earl.k · Jul 5, 2011

if you have the stock setup.(no shift kit) as long as your rear wheel is moving your chain will be moving. this is because you back sprocket is not on a freewheel.

when your clutch is disengaged your wheel will turn without turning yours drive gears. the drive sprocket will still always turn with the back wheel. so if you can ride your bike normal with it pulled in. and when you let it out it turns your motor over its all good.. if its not try re setting it up. here are some step i follow to start with.

when i set up my clutch i just make sure the lever is out. i push the clutch arm in lightly till it stops.(remove slack) and then i push it in about a half inch and set the cable stop. after that i pull in my clutch and push the bike to see if the wheel turns without turning the motor.(it still will turn the chain)

it all goes well and i dont need to re do step one. i make the final adjustments with the cable adjusters.. good luck and i hope some of this run on helps at least a bit.

Hiigel · Dec 9, 2011

I had an aswer but lost it.

I went out to ride yesterday, but the motor willnow turn over. Of course, it's been in the teens for a week now; just thought about that. Anyway, the rear wheel continues to turn, but the motor will not fire. I read about taking the little clutch cable holder, don't know the name, but the part the cable goea through on it's way to the clutch arm and sticking a nail set in and turning opposing nut to tighten an inside spring or nut. Can yo give me a better idea as to what to try?

There was grease on the outside clutch pads, and I hit it with brake cleaner, but same thing; engine will not turn over, just drags me down. I have COPD and simply cannot keep trying to get it to go.
All and any help would be greatly appreciated.

I will bring it indoors and let her warm up; before I try much else. Everything was just fine the last time I rode it, so I am a bit puzzled.

Anyway, thanks,

Gary

nightcruiser · Dec 9, 2011

Hiigel said:
I had an aswer but lost it.

I went out to ride yesterday, but the motor will now turn over. Of course, it's been in the teens for a week now; just thought about that. Anyway, the rear wheel continues to turn, but the motor will not fire. I read about taking the little clutch cable holder, don't know the name, but the part the cable goes through on it's way to the clutch arm and sticking a nail set in and turning opposing nut to tighten an inside spring or nut. Can yo give me a better idea as to what to try?

There was grease on the outside clutch pads, and I hit it with brake cleaner, but same thing; engine will not turn over, just drags me down. I have COPD and simply cannot keep trying to get it to go.
All and any help would be greatly appreciated.

I will bring it indoors and let her warm up; before I try much else. Everything was just fine the last time I rode it, so I am a bit puzzled.

Anyway, thanks,

Gary

Lets see, you say the clutch drags but wont turn over the motor....
When the clutch arm (on the motor) has no cable pulling on it the motor should be engaged. So lets assume (make sure) the clutch arm is being completely released....
Since you have checked and cleaned the clutch pads already that shouldn't be your issue. It seems like you need to adjust the flower nut on your clutch to make it bite a bit more. There is a youtube video showing how to do that somewhere if you don't know how.
That is all assuming you don't have something wrong inside your motor that is preventing it from turning over? Like a spark plug that is too long, or debris or broken parts in the head etc, or even a jammed chain. I assume you checked for all this already? If you pull the spark plug the motor should turn over pretty easily for you to verify there is nothing preventing it from doing so.

Big G · Jun 26, 2014

These motors are pretty simple. All you need is gas and spark. Check to see if the gas valve is open. Check to see if the kill switch is not on. Check to see if your CDI wires are connected. In cold weather, make sure you choke it to start and lastly check your spark plug connections. If you do all of that and it still won't start, take it to a small engine mech. and let him sort it out.

Big G · Jun 26, 2014

Sky Hawk GT5 ran really good at all speeds. Installed a ported cylinder, high compression head, expansion chamber and Delorta SHA clone that I rejetted to run well at top end. Now the motor bucks when I go under 10 mph. Does anyone know what's wrong?

2door · Jun 26, 2014

You'll get better response if you start your own thread in the 'Troubleshooting' section than tagging onto a very old thread on a different subject.

As for the engine bucking under 10mph, that's normal. When you get that slow you should disengage the clutch and pedal. Don't try slipping the clutch. It isn't a motorcycle.

Tom

crassius · Jun 27, 2014

yet another incredibly old thread revived by Big G ??!!??

GearNut · Jun 27, 2014

Tom is right. 10 MPH is way too slow to be riding with the engine engaged, unless you have a 150 tooth rear sprocket.

Big G · Jun 27, 2014

crassius said:
yet another incredibly old thread revived by Big G ??!!??

Ok you're right. My question was more about the way it ran as stock and the way it runs now with the modifications, ported cylinder, rechambered head, expansion chamber and SHA carb. The bike idles at about 25mph and runs very smooth with a lot less vibration. I just wanted to find out what, if anything I could do, to get it to not buck because of the modifications i did.

Big G · Jun 27, 2014

GearNut said:
Tom is right. 10 MPH is way too slow to be riding with the engine engaged, unless you have a 150 tooth rear sprocket.

Gearnut
Thanks for the comments. This is the 9th one that I have built and it's the first one that I can't get right. Made some modifications that did cost some money and I just wanted to know what else that I could do to get it to not buck under 15mph or so. That's all. If there is nothing, so be it. I'm sure that if I go back to the original Arrow rechambered head, it'll run the way it used to at 10 to 15mph.
Big G

maniac57 · Jun 27, 2014

Slow speed bucking is normal. Go faster.

Big G · Jun 30, 2014

Yes it is. You are correct but bucking at 15 to 20 mph is not normal. I build these bikes to sell them. I can't put a new rider on a bike that won't go slower than 20 mph or so. All of the others that I have built will run fairly smooth down to about 10 mph. I was really hoping that some one out there would have a solution that involved carb adjustment or gear ratio or addresss the high compression head and ported cylinder. In other words I was looking for an informed considerate answer that took the variables into consideration.

KCvale · Jun 30, 2014

Is this a new GT5 with 415 chain?
You have to cut a spot on the left side of the sprocket cover or the 415 binds.

Pull off the sprocket cover and look inside, chances are you have some chain scar marks on the front side of that cover.
Just grind it all out there.

Big G · Jun 30, 2014

You are absolutely correct about that. Even the 410 chain will tear up the gear cover if the tension isn't just right. I line up the chain just to the left side of center and that usually eliminates tearing up the inside of the cover. My big problem with this build is to get it to run witout bucking under 15 to 20 mph.

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Clutch Doesn't Work Grubee SkyHawk GT5

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