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  #7421  
Old 09-13-2014, 08:54 PM
Rudz Rudz is offline
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Location: Tyler TX
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Default Re: what did you do to your motorized bicycle today?

Killed my first magneto today, it confused me at first because the bike ran great, I stopped because the tank had shifted, then I couldn't get it running again.

Make sure choke was off, line had gas, I was so sad. Pushed her up the steep hill home, tired after working, drenched in sweat.

After I got some sleep I dragged her outfit, checked the carburetor, line, made sure everything was tight. Then I replaced the spark plug and the magneto.

I said a prayer, and praise jesus she started right up.

I put the ngk plug back on and it still fired up, so my plug is good.

Used my spare magneto, so I ordered another.

Also, anyone looking for tank mounts for wide top tubes, I found some conduit straps that look exactly like the $6.99 plus shipping, brackets I bought from bikeberry (this is before I heard they were the devil)

I cracked the original bracket when I bent it to fit, been holding until last night.
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  #7422  
Old 09-14-2014, 10:12 AM
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mapbike mapbike is offline
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Location: Central Texas
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Default Re: what did you do to your motorized bicycle today?

went for a nice ride late yesterday evening just before dark, first time I've even started one of my bikes in a while now, was a cool and relaxing cruise for a few miles down the ole dirt road.

We've had nice cool weather here in central Texas this weekend, such a welcome break from the upper 90's - 100+ degrees we have been dealing with, some around here are cold when the temps go from 100 down to the upper 50's to mid and upper 60's but this ole country boy like it, makes me feel like a buck and I kinda go into rut just a little andfeel like gettit outside and doing things.

hoping to ride more as time allows, I'm needing to rebuild the top end of the dax engine on my old 1963 Western Flyer bike, needs new jug and piston, engine still runs but has lost compression due to rings not being seated well and I'm tinking they have lost their tension due to overheating, this is the upper that I run my person best top speed of 50.3 mph with, to many high speed runs on those rings and they have given up the ghost...lol

The engine has low bottom end power because of the timing changes I made to get the high rpms, I dont care about going that fast anymore so Im going back to a more stock configuration that will give me better torque.

Happy safe riding y'all.

Map
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I dont always ride WOT, but when I do..I do my best to keep the rubber side down..Ride safely my friends!
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  #7423  
Old 09-14-2014, 11:05 AM
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electron electron is offline
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Default Re: what did you do to your motorized bicycle today?

MIXTURE PAIN, never need to use choke?
Note, if this is too long, sorry, but how else would u get the whole pic

First 50cc was stolen a few years ago. Was fast and reliable. All factory (some carb and exhaust manifold matching) inc old style black filter carb with replaced throttle and kill sw. as was the case years ago.

Now ive seen my mate with his 50cc (27" stock, flies!) and when he gave me a bike (700) i couldnt help myself (80 (66?)cc).
Sometimes under load it starts to pull hard and "purr". Played with plug gap. Plug lead "head" fell appart: replace with nice automotive lead (unscrews from coil (coil/cdi). Less speedo interference, few dollars, may need to be reduced in thickness at coil.
As allways i started messin with it too early, slowly increasing speed for short moments, playin with the needle. Soon to come down to 20 to 1 (200km). I think 16 to 1 is extemely oily. Ill soon compare 30 and 20 to 1 to c how it compares in performance (stick with 20 if neglagable difference). Plug has been black and oily during all conditions (flash tests, or whatever theyre called) for all needle settings, which is strange and i never need to use the choke?. China plug, but ive never had a prob with em, the coil/cdi or magneto. May consider ngk for after run in fuel mix. Ngk 6, 7 8? for south australia (med hot, dry), bpr7hix (with washer if u hav high comp head) or bosch wr7ac. Im guessin 6 is too hot. Need a spare is my excuse.

Prob should have stopped messin with it untill i was on my final running mix, but even though its obviously too rich and chocking on all that oil, i read about .8mm jets and blindly decided i will drill out the jet (nothin to loose). This made it worse, of coure. I need more air!

Dont really want high compession issues (although cooling may b eventually beneficial) or to spend on exhaust, carbs, gears, balancing, major engine work. Chaint tensioner and Solid rear hub mounting would b nice, but kit style can b satisfactory. Run the best fuel, why not, it s peace of mind.
Did 43kms p hr (44t) briefly a few times and the vibes are reducing to very smmoth now.

Most of the time it sounds like a 2 stroke, but sometime, often under load such as uphill just starts to pull hard and "purr" (thats not 4 stokin is it?). So opened up the 2 manifold gaskets, bit better. Take off exhaust cap, just more noise, too much, no back pressure.
The kit i got had the old black filter carb, bummer i thought. Open it up 2mm dia. and insert o ring as manifold seal, more low end power. I had opened up carby so much that an oring would have been the limiting factor, remove o ring. Still good torque.
What about this exhaust, drill holes? Weld in curtain rod? Bugger it, cut the removable pipe (an aside, im still waitin on the replacemrnt exhaust i was promised, as my end cap and a weld leaked) and drilled out the remainder inside retaining the outer and weld, of course. Bit louder, dirt bike sound than i wanted (agressive and attracts a bit more attention, even when slow cruisin (which helped a bit today with pedestrians) and heaps of torque!

Today After a few more 43kph (27mph) spurts i got home and52.5 (33mph) was on the speedo (accurately calibrated). Sure their were a few declines and i did pedal hard.

Must leave it for now, but my can is empty of running in mix and the scr for my "roll your own cdi" is on its way, (got free quad coil from friend) . Will try to match base timing. 1 microF cap seems more aporopriate, but thats just the start of experimentation. Again "need a spare" is a good enough reason.

I do like to go fast sometimes, but im not after revs (or should i say these engines arnt). Eventually ill at least rebuild with proper mounting hardware, some intake porting/matching, exhaust matching, exhaust porting?, bearings?, piston skirt trim, piston lightening? Then its a matter of selecting the appropriate drive ratio. I want 20 to 50kpm (14 to 31 mph) @ 2 to 5 thousand rpm not 45kph at 5500 rpm, screamin (cheaper to stick with this rpm and it seems to love it. Sounds gr8 too. Maybe a little more compression. Is compression only good for higher rpm???

But for now i cant wait to try some lean mix fuel and some other jet sizes, but will have to wait due to studies being neglected because of this legal (not) chinese drug. Thanx for any sugestions. Sorry about the punctuation, it's soooooo hard on my tab. Sorry no pic, they are too high res for this site. Cheers'

Last edited by electron; 09-14-2014 at 11:16 AM.
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  #7424  
Old 09-14-2014, 11:45 PM
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electron electron is offline
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Default Re: what did you do to your motorized bicycle today?

Pics in my album up!
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  #7425  
Old 09-19-2014, 04:28 PM
woogie_man woogie_man is offline
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Default Re: what did you do to your motorized bicycle today?

My intake tube fell apart, and drug my can through my chain. No damage to me or the bike, but a few small holes in the carb body and the intake. So guess I am out for the season, due to the cost weather and snow coming soon. That and I am.com liking at a new frame and doing some work on the engine so what better time than now.
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  #7426  
Old 09-19-2014, 06:05 PM
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Cyclin Cyclin is offline
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Default Re: what did you do to your motorized bicycle today?

So I've been wrenching here and there the last couple weeks. New rear wheel + matching sprocket adapter so I have a spare. I hit 35 the other day which was cool. Recently I have been 4-stroking a lot at 25+ mph at full throttle. So I cleaned the carb, tightened the choke lever (which had gotten loosened due to 4-stroking vibes), and put on a new air filter, and drilled a vent hole in my gas cap. I also replaced the fuel line with a polyurethane one and added a new fuel filter. Still 4-stroking above 25mph so today I am going to check the toque on my head bolts, if that doesn't fix it I will try gapping my spark plug. If not that then I will replace the jet. I think I may have a pre-made spare hidden in my toolbox, but if I can't find it or it's the wrong size I'll just break out the solder and drill. Then for giggles I may as well re-seal where the carb meets the intake with some Permatex Ultra Black.

I did some other stuff but I can't remember. Fixed a brake, bt there was something else... d*mn this awful memory. What I'd really love to do is install a jackshaft, like the SBP HD kit, but man, $200 feels like a lot for that kit.

Last edited by Cyclin; 09-19-2014 at 06:09 PM.
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  #7427  
Old 09-19-2014, 08:43 PM
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electron electron is offline
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Default Re: what did you do to your motorized bicycle today?

http://motorbicycling.com/showthread.php?t=49842
Probably too rich like mine, prob try the jet, smaller and keep an eye on the spark plug
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  #7428  
Old 09-20-2014, 04:59 AM
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electron electron is offline
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Default Re: what did you do to your motorized bicycle today?

After drilling the jet out to 0.8mm (no good) I had to fix this.
I soldered up the jet and drilled two 0.5mm holes, which works out to about 0.7mm.
Goes awesome now. Nearly no 4-stroking (prob need 0.65mm or so). Plug is dark grey instead of wet black. This is so critical, 50 times improvement!
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  #7429  
Old 09-20-2014, 11:45 AM
Rudz Rudz is offline
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Default Re: what did you do to your motorized bicycle today?

I want a re jet mine but it's not totally broken in yet.
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  #7430  
Old 09-20-2014, 01:13 PM
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electron electron is offline
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Default Re: what did you do to your motorized bicycle today?

As long as you are using running in mix and you check for lean conditions, i don't see the problem with a more appropriate mixture. It runs nicer, even if you're still running in and less vibrations, smoother.
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