Is my Q-matic toast or easily fixed?

[GlueKill]

Note: I just emailed my dealer about this, but figured maybe some folks here had some pointers.

I've only been riding the bike about 2 weeks now, and it was mostly trips around the neighborhood. I did make two 6-mile round trips to work last week (since my plan all along was to commute on it during nice days) and didn't notice anything out of the ordinary. No loss of power. No weird smells that I could tell. No grinding noises or anything like that.

I made it back home from work last night with no problems. I figured I'd take the bike into town afterward since it's the weekend. Halfway into town, I heard what sounded like a loud howl that resonated through the bike. I immediately hit the kill switch. I did a quick inspection of the outside of the bike and didn't see anything wrong. Nothing externally was loose. I turned the bike back on and gave it a bit of throttle to check if the noise would come back, and by then it had stopped sending power to the rear wheel.

Since it was night time, I pedaled the bike back home and waited until daylight to try and find out what the matter was. I wound up taking my pedal bike into town, but by then the bars had closed. Weak.

Hmm....looks like something tried to escape from my transmission. The bike has never fallen over or been laid down on its side.

I removed the transmission case to find it was full of plastic and metal shavings. Hey, what's that little metal piece?

Turns out the key that sits in between the pulley and the drive shaft worked its way loose, grinding away the transmission cover before falling out completely, allowing the pulley and drive shaft to go out of sync.

It then allowed the pulley to slip and make contact with the transmission case, grinding away parts of both. I loosened the allen screw on the pulley to pull it forward to show the damage.

Before totally voiding my warranty, I figured I'd wait to hear back from my dealer before attempting to get the pulley and drive shaft lined back up, reinserting the key and tightening the allen screw back down to see if that holds. Or is that a horrible idea?

 

[Fossil]

You are correct. The set screws worked loose and allowed the key to work it's way out. Now the good news! The drive is not toast. It just needs to be put back together. Replace the key and set screws (if they are missing) and you should be good to go. Also don't forget the blue Loctite on the set screws! This is very important. They need to be very tight and they have to stay that way. Please keep us informed please. Good luck.

Jim

PS Even though I am also an EZM dealer, I'm not trying to undermine the service of your local dealer. If you wish to wait to confirm with him what I see from the pictures, by all means go ahead. We are all here to help each other.

 

[scotto-]

One thing I did with mine was bolt a large, light flat washer to the end of the crankshaft to keep this from possibly happening. I'm sure you've got an easy fix rather than toast.

 

[Fossil]

One thing I did with mine was bolt a large, light flat washer to the end of the crankshaft to keep this from possibly happening. I'm sure you've got an easy fix rather than toast.

Good idea! A bolt with a fender washer is the trick. Now that I think about it I have one on my HF Q-Matic build.

Jim

 

[Quenton Guenther]

Not to worry, you are under warranty!

If you need any replacement parts, let me know.

The crankshaft is threaded and as Scotto suggested a large washer [fender washer] can be placed on the end to avoid the pulley contacting the cover in the future.

Be sure to use loctite on the set screw and firmly tighten on the drive pulley.

The small hole in the cover can be used as a vent by glueing a small piece of screen on the inside, or if you prefer send the cover and we will replace it.

I have attached pictures of the latest edition Q-Matic. Version #6 has the hole behind the drive pulley enlarged to allow the removal of the drive without removing the front pulley.
Version #6 also uses plastic clips to attach the guard instead of the 1/4" X 20 screws.

I also installed a fender washer and took pictures to detail the information by Scotto & Jim. Be careful to check the threads in the crankshaft as some are 6 MM X 1, and some are 1/4" X 28. The installation of the large washer will hold the 3/16" key in place if the pulley were to ever work loose again.



Have fun,

 

[Fossil]

Now how is that for service!!!

Jim

 

[silverbear]

What size would that bolt be? It sounds like a good preventative thing to do, just as a kind of 'insurance policy' for peace of mind.
SB

 

[GlueKill]

Thanks for the fast responses, guys! I got the notches in the pulley and shaft to line back up by yanking the pull start a few times with the choke off so it wouldn't fire. The key slid back in, but seems a bit loose in there. I think I might need a new pulley, though, as it looks like a chunk of it was ground off up to the set screw.

Also, what size bolt do I use on the end of the drive shaft? Were they left off because of clearance issues?

 

[azbill]

my rear shaft is 1/4-20 thread
I also have the shaft at the rear (bearing carrier) 'trapped' on both ends with a 1/4-20 bolt and washer

I have a similar hole in my cover, but it's at the rear shaft

hope that helps

 

[Quenton Guenther]

Hi GlueKill,

Pulley looks to be OK, however you have a 100% warranty and if you want the pulley, cover, etc, replaced, just send the parts to the NC location and we will ship replacement parts right away!

I just checked several motors in stock, and most are 6 MM X 1, however I did find one with 1/4" x 28. The bolt can be approx. 1" long.

Have fun,

 

[GlueKill]

Thanks again. The bolt I needed turned out to be 1/4" x 28. I applied blue loctite to it and the hex screw after lining things up as best I could. I think the spring-loaded tensioner is wide enough to accommodate slight variations. I'll go for a ride after it cures for a bit. I may keep the cover as it is, but I kind of want to make the entire side clear lexan now.

EDIT: Just went for a ride around the neighborhood again. Everything stayed put. Not bad for about $5.

 

[Fossil]

Glad to hear it. I have a pulley here that came with the kit I used on my Harbor Freight engine. I used a larger pulley so I have this one if you want it. I may take me a little to find it out in the shed but say the word and it's yours. We stand by our product!

Jim