This could've been bad... very bad.

[yoothgeye]

Hmmm, that sure is a clean break... Your not on any new life insurance policies are you? :shock:
Just say'n.

No new policies... I think, I'll check in the wife's filing cabinet.

Yikes! Was there any sort of rubber buffer between the engine and the frame tubing? I didn't know those engines could fit properly on smaller tubing without some sort of buffers as it seems as though the engine mounts are designed for larger, new-style beach cruiser-type tubing.

Unless they are making the kits different, this is the same size as the rest, guys mounting them on larger tubing actually drill a hole through the downtube and put a weak looking mount on them.

If you put too much of a rubber insulator between the clamp and the frame the motor WILL slip, I had it happen with my first mount, it was not as bad as this, but close.

If you're not already a member you could sign up at motorbicycling.com or if a member already post the photos in a new thread there and ask for clues as to why it broke that way. Lot of experience with putting motors on bikes over there.

I am signed up over there, but was less than impressed with the way they treated new members and general air of superiority amongst guys who have been there a while, so I'm not posting anymore, though I did use a nice write-up over there the other day about carb tuning.

I know why it broke there, vibrations, and I think Deorman hit the nail on the head with the motor being clamped into the triangle it eliminated the natural flex of the frame and caused it to break. I don't want to hear a bunch of guys telling me I did it wrong just to make themselves feel good over there. Frame broke, the end. :lol:

 

[Harold_B]

"I am signed up over there, but was less than impressed with the way they treated new members and general air of superiority amongst guys who have been there a while, so I'm not posting anymore, though I did use a nice write-up over there the other day about carb tuning.

I know why it broke there, vibrations, and I think Deorman hit the nail on the head with the motor being clamped into the triangle it eliminated the natural flex of the frame and caused it to break. I don't want to hear a bunch of guys telling me I did it wrong just to make themselves feel good over there. Frame broke, the end. "

Too bad that has been your experience but I understand. That's how it can be on any forum depending on who decides to respond and how they communicate in writing. Forums and email are notorious for creating miscommunication due to the lack of tone. I have had a more positive than negative experience but as with any group where most users are anonymous the comments can get off topic. I've come over to RatRodBikes from the motorized side and really appreciate what both types of builders bring to a discussion.

As for your frame and mount, the bracket shouldn't be putting a localized stress point on the tube. I'd look into a better quality clamp that distributes the stress, i.e., a clamping force and not a pinching force. My opinion, for what it's worth. Good luck on your re-build!

 

[yoothgeye]

As for your frame and mount, the bracket shouldn't be putting a localized stress point on the tube. I'd look into a better quality clamp that distributes the stress, i.e., a clamping force and not a pinching force. My opinion, for what it's worth. Good luck on your re-build!

I believe a motor that mounts to a bicycle frame at 2 points MUST put localized stress on the tubes.

I probably won't spend much time on this thing, but in my mind the best option is a "cradle" built to hold the engine and then that cradle is attached to the frame with car style "boxed in" engine mounts with a rubber damper, so that if the rubber breaks, the boxed mounts still keep the motor from falling out of the frame sideways.

 

[Harold_B]

You are wrong and you did it wrong. Hey, that did feel pretty good! Kidding. I suspect this is one of those things where we'd be better off sitting at a table with two beers, a pad of paper and a pen. Then we could help each other understand our perspectives. I think we are talking about two different things regarding the pinch point and localized stress points. But, if it's not something you intend to mess with after this bike is gone then I can understand not wanting to dig into it. In particular if you feel you have a handle on it.

 

[yoothgeye]

I'm trying to get this motor out of my life (and make a little money without killing someone) so that I can put the money into my Yamaha Noped... something made for the engine it has on it.

 

[Harold_B]

Good call. I followed your link to your Moped and the things you mention like the tensioner are excellent reasons to jump out of the DIY camp. There are a lot of better quality parts available than those that come with the kits but they are not inexpensive. When I switched from two cycle to four stroke on my bike I took quite a hit on most of the parts I sold with the exception of the parts I bought used. They were cheap in the first place. Good luck on the sale and I'll be very interested to see what becomes of the Moped build.

 

[yoothgeye]

Today marks a year to the day that I crashed a pocket bike at around 35mph on the street with no protective gear. In an attempt to protect my head my shoulder was dislocated tearing my labrum tendon front and rear, my rotator cuff, and my bicep, not to mention road rash, cuts, and bruises. I had surgery over a month later and had full recovery 5 months later with extensive physical therapy.

That accident was a scary eye opening that made me make better decisions about mechanized transportation hobbies. The motorized bike was fun and cool, but the risk too high, and I just didn't want to put in the time and money to make it safer/more reliable if it was going to end up dorky.

If I make it a bike again to sell it, it will have a suspension front fork to keep the frame from taking the brunt of the bumps and road vibes. It will have additional brakes besides just the coaster I have on mine now, and then I'm losing the simplistic style I loved about the way I built the bike to begin with.

 

[frameteam2003]

I see another motored bike with a rigid fork.

 

[yoothgeye]

I see another motored bike with a rigid fork.

This was discussed in the comments above. When home for lunch I found a suspension fork for rebuilding this bike. I'm thinking this should relieve a lot of stress on the frame, and I get to keep my triple tree for a different (non motorized) bicycle.

 

[frameteam2003]

Rif was left holding the handle bars in the 2003 Wyman Ride across America!
He too was lucky--was stopping for directions when the bike fell out from under him.