Results 1–30 of 138
Excellent work! Very clean, neat, and nicely detailed.
The angle of the exhaust port is the biggest issue with this. I had my port cut parallel to the bore and new holes drilled and tapped for the exhaust. I wanted to be able to switch pipes easily.!http://www.smallborebikes.com/images/machinework.jpg!The other problem I had with this was that the transfer ports were not fully exposed with the piston at bottom. I made a spacer to raise the cylinder an
Mars,I have a similar intake and it measures 23.9mm O.D.. The PHBG AS carb has a clamp I.D. of 25mm without a shim and 24.0mm with the thin shim that comes with them.For a quick intake, make a busing that is 0.874" I.D. x 24mm O.D. x 1" long, slip it over a section of old handlebar, and braze it in place.
I installed this ignition on my 1994 motor that originally had points. I had to flip the coil over and move the pickup to the other side of the stator. Just a little bit of dremel work after that and it works great.
I cut the window into the piston. I made it as wide as the boost section of the intake and set the top of the window about where the transfer ports close. This small window added 97 degrees to the intake duration.I will know how well this runs in a week or two. I
Excellent input. I will follow up with my results.
Lets try that first link again. "Port charts":http://www.smallborebikes.com/images/port_timing_charts.pdf
Thanks for the quick response. Here is the link to some blank "port charts":http:/www.smallborebikes.com/images/port_timing_charts.pdfand "another one":http://www.smallborebikes.com/images/blank_chart.pdf
I just picked up an Athena 50cc reed valve kit for a Puch. The piston that this kit comes with is obviously made for a piston port cylinder due to the lack of a window in the intake side of the skirt.I am considering opening the piston skirt as shown. The top of the window as marked is located at the closing of the transfer ports. I could probably go taller with it, but I will start conservatively
Using a second rectifier and relay is an excellent idea. I have a similar system, but am using an on-off switch. I may try this instead.I also find that the when the lights are on, the battery will eventually discharge. I just plug the battery into a tender to top it off after riding.Here's a tip, a computer UPS makes a good battery tender for these small SLA batteries.!http://www.apc.com/re
Here is a link to a "360 degree tape and port timing charts":http://www.smallborebikes.com/images/port_timing_charts.pdfI stick the tape on my flywheel and record the events on the chart. The tape is sized for a Puch or Tomos with points. The chart also includes a depth to degrees conversion. Here is a sample of a completed chart.!http://www.smallborebikes.com/images/port_timing_sample.j
I have ground down the top of a swingarm for chain clearance. I then reinforced it by tacking on a piece of 16ga to the inside of the swingarm, bridging the concave portion.Or, if you attach a 32T chainring onto the front, the chain will clear the swingarm with the 16T freewheel without modifying the swingarm.
I use a 16T freewheel on the back. For the front I have use 2 method for installing a 32T mountain bike chainring.First method. I used a Salsa aluminum chainring, cut the mounting tabs off, drilled through the chainring and existing chainring, and bolted them together.Second method. Find a steel replacement chainring and weld it onto the original.
Here is a link to a prior post of the "filter":https://www.mopedarmy.com/forums/discuss/read.php?f=1&i=823671&t=823671
This is not quite what you asked for as I'm using the Polini reed block rather than the Malossi. However, this picture should give you an idea of the space available.!http://www.smallborebikes.com/images/filter1.jpg!
I uploaded a port map "here":http://www.mopedarmy.com/mediawiki/images/3/3a/Tomos_a35_port_and_timing.pdf
Verify the scale that you printed the sticker at. 25 degrees should measure about 1" on the flywheel.
You can check your preffered exhaust duration with "this nomograph":http://www.mopedarmy.com/mediawiki/images/3/3f/Exhaust_nomograph.pdfAdd your cylinders port length to the tuned length shown on page 2 for your pipe. Use the degrees-to-depth calculator in the wiki to set the height of the exhaust port.
The flow stream contracts as an obstruction is encountered. The more abrupt the transition, the more the flow stream is contracted. The contracted flow stream has an effective cross sectional area that is smaller than the actual area of of the passage.
Sturmey Archer makes an 8 speed hub that will accept a disk rotor and is cheaper than the Shimano hubs. Also, the Sturmey's ratios are better matched to moped size wheels.Check out sickbikeparts.com, motorbicycling.com, and staton-inc.com for ideas.
In addition to the problems mentioned above, I found that the bottom of the transfer ports were below the piston at BDC by about 1mm. My solutions to these problems were as follows: Make an aluminum shim for the base of the cylinder to correct the transfers; Have the top of the cylinder decked by an amount equal to the shim thickness; Have the exhaust port milled parallel to the cylinder bore and
Linda, thanks for creating the wiki links.Wayne, you are correct. The length shown on the pipes is measured to the flange. The port length needs to be added to that of the pipe to get the true exhaust tuned length. I will add a note to the sketches when I get the time to do so.
A degree tape is a nice alternative to a degree wheel that can be applied to your flywheel. Try "this":http://www.mopedarmy.com/mediawiki/images/d/d6/360degtape.pdf
The link to the above "file":http://www.mopedarmy.com/mediawiki/images/3/3f/Exhaust_nomograph.pdf
I just did this conversion to my 1993 motor that originally had points. This motor has a three screw mounted stator and this made the conversion very easy. I moved the CDI pickup to the other side of the new stator, flipped the coil over, and elongated the slots a couple of millimeters. This gave me a better range of timing adjustment for the position that I mounted the stator. This is a very wort
Excellent thread. I may try this since the project only requires two beers to complete.
To calculate crank rotation from piston depth use the followinga=rod lengthb=rod length+(stroke/2)-piston depthc=stroke/2s=(a+b+c)/2crank rotation=2*asin(((s-b)*(s-c)/(b*c))^.5)convert from radians to degrees if necessary.19 degrees should equal 1.45mm + deck clearance.
I am using a Boss pipe on the A35'ed E50. I had the exhaust port machined flat and new stud holes tapped straight in so that a pipe made for a Puch could be used without modifications.