what did you do to your motorized bicycle today?

Today I pulled the top end off my Dax that is on the old 63 Western Flyer bike, this is/or was my fastest bike, I took it for an easy cruise a few days ago and noticed a serious power loss developing in the lower rpms, engine never raced as if it had an air leak or never idled funny or any sure signs of trouble, it still revved up good once the rpms came up but it became a complete DOG on the bottom end.

I figured the afternoon I needed to just pull the jug and see if I could figure out what was going on, I was hoping for a gasket issue or something simple but I was met with a very serious problem, I made a crude video of what I found, you'll have to forgive my yanking the crank around to much and the fact that I'm not much for talking about things on camera, so try to ignore the Red Neck camera work and my talking best you can.

This is my first major Dax engine failure, Not sure what caused it, but I know the lower wasn't exactly right from the get go since the crank rotation was tight and had areas that would ease up and then get tight again as it was rotated, If I had not used this lower for this high rpm build it may have lasted good for a very long time and then again maybe not, but it's for sure that this may become a parts donor now.

https://www.youtube.com/watch?v=-jTAvG55n6E&feature=youtu.be

Map
 
Rump Rocket said:
Ordered a new Mechanical Speedometer the last China made junk I bought lasted 14 miles before crapping out.
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So far I haven't found any mechanical speedometers that will last on my bikes, I've destroyed several and some were vintage and really nice speedometers and that just made me sick to know I ruind them....

They just aren't design d for the vibes and the higher speeds and fall apart in a very short amount of time.

Map
 
crassius said:
'http://file2hd.com/' brought the vid down OK - yes, that looks like a failure in the mains
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Im hoping the crank is still ok, but the case is probably junk, im thinking that one of the bearings probably spun in the case and ate it up allowing the crank to have the end play it has, when I get the engine off and tore down Ill know for sure.

Map
 
Today I'm going to grease my clutch. It's a maxtorque clutch (4 stroke), and it needs lubed every so often. Most people recommend putting motor oil on the bushing, I actually take it apart and put grease inside the bushing and on the shaft as well. This helps eliminate any chatter. It takes off smoothly without slipping since I've been doing this.
 
I found a good digital one on e-bay that has worked for me for two yrs now and the only thing I had to do is replace the batteries once the sellers name is all-in-one-town item number 151204524973
 
mapbike said:
Im hoping the crank is still ok, but the case is probably junk, im thinking that one of the bearings probably spun in the case and ate it up allowing the crank to have the end play it has, when I get the engine off and tore down Ill know for sure.

Map
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The crank should still be ok, I've had the same type of issue on my previous engine, that one was working just fine and I took it apart just to do a quick post break in inspection when I found out it had about 1/8" of side to side play. When I took it all the way apart, all the individual parts looked good, including the bearings, but it had that play so since I had the crank out I put it on the lathe and corrected the runout, then I put in the good bearings, the original bearings were good, but I wanted to put the good stuff in while it was apart.
My engine was running just fine when I took it apart and I just removed the jug to inspect the cylinder wall, but I'm sure it would have shortened the life of that engine considerably if I didn't fix it. I've since then replaced the bottom end with a Dax bottom end but still got the old bottom end and new top end parts for it so I can get it running again when I have the time to mess with it again... I'm mainly using that engine for mock ups, test fitting parts I'm making, and measurements, but it's in excellent shape and will run again.

Since everything looked good in there I just measured how much play there was and made up some spacers out of large washers that were .040" thick, I had to turn them way down on the lathe but could have drilled several thru the circumference of the washers so the oil could still reach them easily. this reduced my side to side movement down to .040" which is much more acceptable.

You should be able to make spacers for yours just as easy by using a 5/8" or 16mm washer on each side of the crank, a piece of 1/5" id pipe sliced really thin would work too.

Hopefully a set of new bearings, seals, and make up some spacers and it'll be running again.
 
Well Dave Im hoping when I get into it I dont find anything seriously junked, this engine had zero detectable side to side movement of the crank when I first built it up, the crankshaft did have a tight spot in it when rotating it, which worried me a little since things should move freely without a serious tight spot, the main concern I have is with the case, I have another engine that did this very same thing and the magneto magnet/flywheel ate into the case and destroyed the crank seal, that engine ran excellent up to that point and showed no signs of a problem until that seal got seriously damaged and then we all no what happened then, major air leak than made the engine run away with itself.

Something had to have seriously wore out in there to allow the crank to get that much side to side movement, this current engine has around 3/16" to maybe 1/4" movement..... that is a lot, I have some new seals and some new bearings, Im sure I can also make up some shims to get everything back where it needs to be.

I need to go into both of those engines now and see what has happened for sure, the older bgf engine has been sitting in the shop floor for about three years now so I guess its time to dig into that one when I get a chhance also, just trying to figure out in my head right now for sure what has happened that would allow the crank the develope that much end play.

Oh well when I get it tore down Im sure Ill see exactly what it is that's happens with both of them.

Map
 
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Didn't do much to it today. Bought a new build off of Craigslist and the engine chain broke after a few miles. Replaced the master link and re-positioned the tensioner, adding a mirror and speedometer later today. Minor stuff. Just getting back into the hobby, so I am going to start out small. Might replace what looks to be a pit bike expansion chamber with a SBP one I have on an old build from 2-3 years ago.
 
I had pretty much the saem issue with my old engine too because I really don't remember it having any side play when I had it apart before running it, but it did turn over nice and free when I checked it before putting it together for the first time, then after about 10 hours of run time on the engine I took the jug off to inspect it and that's when I noticed the play. Mine had about 1/8" play in it but I didn't see any other issues that could have caused it. I could only imagine what 3/16 to 1/4" of play could do to the case covers and cases tho... Hopefully the cases are ok and you can shim the crank with spacers.
Anyway, let me know what you find out when you get a chance to take it apart
 
Davezilla said:
I had pretty much the saem issue with my old engine too because I really don't remember it having any side play when I had it apart before running it, but it did turn over nice and free when I checked it before putting it together for the first time, then after about 10 hours of run time on the engine I took the jug off to inspect it and that's when I noticed the play. Mine had about 1/8" play in it but I didn't see any other issues that could have caused it. I could only imagine what 3/16 to 1/4" of play could do to the case covers and cases tho... Hopefully the cases are ok and you can shim the crank with spacers.
Anyway, let me know what you find out when you get a chance to take it apart
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Will do, im hoping that I'll have time to take that engine down Wednesday or Thursday.

Then aill tak some pix or a short video to show what ai find.
 
Today I shortened my throttle cable. A few days ago, I ordered a mini cable knarp (cable stop for those of you unfamiliar with the term knarp), and it arrived this morning. My throttle cable was so long that I had to wrap it around my seat post. So When I got it, I compared it to the end of the cable that sits in the slot on the throttle tube, and it was the same size, so I cut the end off the cable and slid it out of the sheath. I then cut the sheath to the length I wanted and attached the slide and adjuster to the carb, then slid the cable through the sheath. Then I put the cable stopper on the end and cut the cable to the length I wanted. Put the throttle housing back together and twisted the throttle a few times to make sure it works, and it does. Very happy with this product, and with treatland. They always ship super fast.
 
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