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  #8681  
Old 05-28-2016, 02:26 PM
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Tony01 Tony01 is offline
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Default Re: what did you do to your motorized bicycle today?

Quote:
Originally Posted by MEASURE TWICE View Post
Is that a tube at the top of the head bolts maybe? It melds with the exhaust tube for support?
Yep. It's slightly larger tube than the primary pipe, I cut it in half lengthwise and flattened the end with some grinding to fit, and then cut a d-shaped flat at an angle into the back end of it to give a gripping surface for the hose clamp. It feels very solid and nothing has loosened up in 2 heat cycles (driving 15min and letting cool).

I'm determined to get the most out of this motor before I upgrade. Next mods:

1. Grind the plastic camshaft (have extra). Remove ~.030" radius from base circles and weld/.030" onto the lifters... Get some more lift - CURRENT LIFT is .157" from measuring the cam
2. Upgrade to a larger carburetor with a straight shot intake.. I'll get rid of that s-manifold I think I'm losing power cause of it
3. Advance timing 4deg- going to fabricate a plate that moves the magneto approx .220"
4. Increase compression further to where I have .020" valve clearance, maybe open up the transfer into the cylinder in the head

Bike mods- new design 2-speed (delete one js, delete two chains)
Full suspension


The current 2-speed while works, is difficult to adjust and keep it aligned. It's out of alignment frequently and I get fast wear in my chains and the power loss is noticeable on the top end. It isn't strong enough but I've proven the concept on this bike. Currently tops out around 45 on level ground. I wanna bump that to 50. It's still a legal displacement and hp for CA Mbs.
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Last edited by Tony01; 05-28-2016 at 02:35 PM.
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  #8682  
Old 06-07-2016, 12:28 AM
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mogollonmonster mogollonmonster is offline
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Default Re: what did you do to your motorized bicycle today?

Ordered parts today. Wrist pin bearing(needed), rings(just to have around), and an RT head(because I can)

I'm hoping with the expansion chamber pipe and "alleged" high compression head, I'll get enough power to run a slightly smaller gear, maybe a 40, doubtful a 36, too many hills for that

Since I'm not making the long commute, have a much increased income, and will have a second motor soon, I've decided to aim for 35. My top speed so far is 32.5mph, so it's not too much to ask,
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  #8683  
Old 06-07-2016, 11:15 AM
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Default Re: what did you do to your motorized bicycle today?

got my header in yesterday for my yz80 pipe, i need to do some clean up work on it and hope to have it installed in the next few days, i also put in a new piston and did some cleaning on the fins of the jug, it's starting to look so pretty. pics once i get this motor back in my bike and the yz pipe put on.
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  #8684  
Old 06-08-2016, 07:15 AM
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Default Re: what did you do to your motorized bicycle today?







I treated myself to a new engine, but I ordered the wrong front mount size... so I had to swap cases. Doh. New one seems way better than last one started.
Then my headlight died so I made a new one. I still run it all off white wire. This light is better than the last in performance.
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  #8685  
Old 06-08-2016, 01:09 PM
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racie35 racie35 is offline
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Default Re: what did you do to your motorized bicycle today?

Made some muffler inserts for whizzers..these things work good.
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  #8686  
Old 06-08-2016, 01:54 PM
curtisfox curtisfox is online now
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Default Re: what did you do to your motorized bicycle today?

KOOL , What do they look like?.............Curt
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  #8687  
Old 06-08-2016, 09:56 PM
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racie35 racie35 is offline
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Default Re: what did you do to your motorized bicycle today?

Here's one pic I sized right I guess
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  #8688  
Old 06-08-2016, 10:29 PM
curtisfox curtisfox is online now
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Default Re: what did you do to your motorized bicycle today?

KOOOOOOL ! Thanks
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  #8689  
Old 06-11-2016, 11:35 AM
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tgaydos tgaydos is offline
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Default Re: what did you do to your motorized bicycle today?

I swapped seats and added the sisssy bar, as well as the front disc brake it now stops so nicely. the seat is a tad uncomfortable as far as padding but the placement of it is superb. in the coming week i hope to have my yz pipe attached and should be ripping around even better than before.

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  #8690  
Old 06-14-2016, 09:39 PM
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mogollonmonster mogollonmonster is offline
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Default Re: what did you do to your motorized bicycle today?

Today I called Duane... Yes that Duane and that call. Tanglebones down. Motor dead.

My RT head came in from Dax a few days ago, which is very nicely made, far higher quality than expected. I tore down my top end to install said head, and discovered horror and carnage. Left side wrist pin retaining clip lost it's ears. The cylinder and piston found them.

From the looks of things, the fragments made their way into the exchange ports, took a stroll through the case to the right side transfer port and left the scene of the tragedy via the exhaust.

A few weeks ago, I heard a nasty metallic noise from the engine, coupled with a noticeable loss of power. I discovered a broken exhaust header weld. After changing pipes, I was back to riding, although a bit gutless, for about a hundred miles. Looking at the grooves in my top end, I can't believe it ran at all.
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