36 Hours of Fixes

[HeadSmess]

i find i can let the thing go for six months with no issues, and then all of a sudden, wham, just about everything goes wrong all of a sudden...

fix one thing, something else breaks, the best ones are when something breaks, youre making your way home by holding the part in place with your left pinky toe, and then something else falls off, and sooner or later, you get a flat or run out of fuel...

then its another six months til the gremlins catch up again...they come and go...moody lil things, gremlins...


pfffft, preventative maintenance...whatever

 

[AssembleThis]

When Things Fall Apart

Hi Timbone!

Sorry about all the problems your having. Yes thread lock the bolts and screws. But to save yourself a lot of aggravation, buy stainless steel hardware to replace all the hardware on the engine and motor mounts. Trust me it's no fun having to drill out and extract a broken one. Stock hardware is not good and they will fail. You can go to the local store and buy a couple at a time or do like I did and buy in bulk lots. Buying lots, is a lot cheaper in the long run. Here's a couple of links for you. Hope this helps.

6mm x 60mm
http://www.ebay.com/itm/321092808456?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

5mm x 20mm
http://www.ebay.com/itm/181330896105?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

Dave
AssembleThis

 

[Timbone]

Yes, all this info is crucial. I never really thought about the importance of good hardware until I took on these moto projects!

Let me tell you how this week on the moto went:

Got through the weekend just fine, running errands etc. Thing is running great; my little HT motor is a runner!

Tuesday morning, I gassed her up and took off to work very early in the morn. About a mile into the commute, I knew something was wrong. The exhaust was all loose and rolling all over the place. It was so dark, even with my headlight I couldn't tellexactly what the problemwas so I turned around, did a combo pedal/moto thing and took her to the garage. Drove the car into work.

Later that evening (after work and a 35 mile bicycle ride) I checked her out: the right side exhaust stud was gone. Not broken off as I feared, it was just gone. I had a perfectly sized 6mm 1.0 bolt and I fixed her up.

Next morning, same deal: riding to work armed with a 10mm wrench in the back pocket for quick exhaust battle if necessary. I was cruising at about 22 mph when I hit something HARD and the exhaust was instantly loose. I extracted the wrench, tightened the exhaust back up and wanted to roll but, sadly, PINCH FLAT! This has been the real Achilles Heel of my moto since the 700c x 25 tires are so vulnerable to raod hazards. Again, I turn around and pedal home for 7 minutes on a flat front tire. Bummer.

Friday morning and I am determined to ride the moto into work. And what a great, fast smooth ride it was. Very little traffic, and minimum resistance from red lights. On my final turn, the rear wheel squiggled under me at about 20 miles per hour. A very soft rear tire and another problem to solve. But I am here at work!

One of my coworkers drove me to the nearby Wally World and I bought a 27" tube and a $10 pump. Things were slow in the salt mine so my boss was distracted and was nice enough to allow me to fix the flat on company time. Hey, I was busy and, better yet, I looked busy!

On the ride home, once again I am on exhaust watch - fully armed with 10mm wrench in back pocket. Well, dammit, about a mile and a half into my ride, I am cruising in heavy traffic at about 28 mph and I glance down just in time to see the LEFT exhaust hub fall right out into the road and, yep, things are loud again. I pulled over at the first cross street and I saw that the right boltwas holding nicely and the balance was kinda holding the exhaust into place. I took off again and stoppedabout 2 miles down the road at a hardware store where I picked up a couple of 6mm bolts and some blue threadlocker.

The bolt was a tad too long, but with the threadlocker it held nicely and the exhaust was very steady. When I got home, I removed the new long bolt (it was kinda difficult because of the locktite) and I threaded a 6mm nut all the way to the head. I added a lock washer and a flatwasher and seated the exhaust bolt with threadlock.Then I tightened up the inside nut until it was tight and flush to the exhaust manifold.
That works!

Then...I went into my very hot garage and went to work on the new build. I trued both 26" wheels and they look quite good. But the hubs were very tight so I got out a couple of cone wrenches and adjusted the hubs. Very smooth now. Then I got out my allthread rod and fender washer assembly and very quickly seated the headset cups for the new front fork. I received my new headset via USPS today and the fork should arrive tomorrow so my plan is to slam this build together. I am very excited about having heavy duty mountain bike tires on the new ride! Goodbye flat tires!

=Timbone=

 

[Slogger]

I'm just in the planning stages, but I love me some allen head hardware. I believe I'll change out all the cheap china junk for hardened allen heads, use green (wicking) loc-tite on all of them and have a nice life with the little fart bike.

Has anyone had any success trying to cut the mechanical noise of these engines? I might try plastidip on the primary gear cover, after gluing a 1/4" thick piece of rubber on it, to deaden the gear noise.
I have some leftover fiberglass muffler packing out in the garage, maybe a wad in the muffler would help keep the noise down.
This is going to be fun. I want to make it a mellow powered bicycle, quiet and reliable. The finest machines in the world are very quiet.
I spent 40 years on motorcycles, big loud engines and all. I'd love the little engine more if it had the quiet purr of a little honda.

 

[Timbone]

Honestly, I think the stock muffler is decent. I did an experiment where I hooked some heater hose up to the end of the muffler and routed the exhaust out the back. It did make a noticeable suppression of noise but that was problematic, the biggest issue being that the hose clamp holding it was gonna fall off at some point.

I think that, short of welding up an expansion chamber there could be a way to significantly improve on the stock muffler - and at very low cost. I'll be working on something soon.

 

[Slogger]

Honestly, I think the stock muffler is decent. I did an experiment where I hooked some heater hose up to the end of the muffler and routed the exhaust out the back. It did make a noticeable suppression of noise but that was problematic, the biggest issue being that the hose clamp holding it was gonna fall off at some point.

I think that, short of welding up an expansion chamber there could be a way to significantly improve on the stock muffler - and at very low cost. I'll be working on something soon.

Anything you develop would be welcome info on here. I think the majority of the racket is mechanical, so I'm going to do some 'sperimenting with heavy grease on those gears and sound deadening material on the engine's side covers. If it doesn't cause heat problems, that is.

 

[Fabian]

About a mile into the commute, I knew something was wrong. The exhaust was all loose and rolling all over the place.

The issues with exhaust problems can largely be solved by filing the exhaust flange perfectly flat and using Permatex Ultra Copper on the exhaust flange itself as well as the gasket and the exhaust port face.
Replacing the standard exhaust port studs with equivalent length or slightly longer""allen head set screws"" is beneficial for reliability, as well as installing the set screws with Permatex Ultra Copper on the threads.

It is important to take a "bottoming tap" and run it down the threads to make sure the maximum available thread length is available for the "set screws" to grab onto.
It is also important not to tighten the "set screws" with excessive force. Just screw them in (with Permatex Ultra Copper) till they bottom out, then apply only light force to on the allen key. You don't won't to over stress the threads in the exhaust port area.

Attach the exhaust system with a small flat washer sitting on the outer face of the exhaust muffler flange, followed by a spring washer and another small flat washer on top of the spring washer and then the nut on top of that.
Apply Permatex once again to the exhaust port studs and screw everything together.

In nearly 60,000 kilometers (37,000 miles) i have never had an exhaust port fastener failure, and i don't use a muffler clamp on the bottom of the exhaust muffler. The thing is only held on by the exhaust port studs.

The biggest issue people face is that of the aluminium threads in the cylinder exhaust port fretting out when the exhaust port gasket compresses; reducing clamping pressure; giving the exhaust port studs the opportunity to hammer out the aluminium threads.
If you have to keep retightening the studs, you will eventually wonder why the exhaust port studs have pulled out of the threads in the cylinder; then blame the metallurgy for being rubbish quality.

 

[Fabian]

I am very excited about having heavy duty mountain bike tires on the new ride! Goodbye flat tires!

Make sure you install as a minimum, a good quality (thick) thorn proof tube/s. Those things take a beating against snake bit.
I run my front at 20 PSI and the rear at 24 PSI for the greatest possible comfort.

 

[Fabian]

I did an experiment where I hooked some heater hose up to the end of the muffler and routed the exhaust out the back. It did make a noticeable suppression of noise but that was problematic, the biggest issue being that the hose clamp holding it was gonna fall off at some point.

You need to use "1/2 inch internal diameter, chemical resistant, high temperature, silicone hose", with the left over internal metal tube (from the muffler modification) cut into two equal lengths (strategically placed inside the silicone hose to line up with the frame) so zip ties can attach it without crushing the silicone hose in the process.

Silicone hose absorbs noise surprisingly well. The hose shown on my bike is well over a year old; still being soft and supple even though it's turned a light brown colour.
The zip ties attaching hose to muffler tip last about 6 months before they crack and break-off. Replacing the zip ties every 3 months solves that problem.


http://news.thomasnet.com/fullstory/Silicone-Tubing-comes-in-nearly-50-sizes-586414


View attachment 54026

 

[Fabian]

Has anyone had any success trying to cut the mechanical noise of these engines?

A good part of the mechanical noise comes from the intake tract as well as the cooling fins resonating with engine vibration, causing them to emit a ringing sound, which gets mixed in with the gear noise; making it hard to isolate where all of the noise is coming from.

Placing rubber noise dampening spacers in between the cylinder fins is a trick used by motorcycle manufacturers.

I'd love the little engine more if it had the quiet purr of a little honda.

That's my goal: to keep exploring methods to incrementally quieten down the engine.

The gear noise will quieten down after they have done a good number of hours. To this day, i am surprised at how long those gears last, considering they are being run in an environment without lubrication.