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Discussion Starter #1
Now that I am completely retired, I have been devoting a lot of hours to my bike building hobby, and since I have ratted out a bunch of old bikes for this very purpose, I can get right to it and I have several going at the same time now.(Note, I don't have a wife or kids any more so I can do whatever!) I built a YDS3 Ascot replica several years ago and I like these bikes and have a few to play with. This one is a bunch of mixed left over parts and bits from E-bay that I'm throwing together? I have a good YM1 motor and a DS6 frame to start with. The motor is bored .25 OS and mostly stock, I did find aluminum cylinders for it. The frame is de-tabbed and lightened as much as possible. The gas tank was a real turd, it was smashed in bad on one side and I beat it out as best I could and there is a bit of Bondo on it but it's good from 50 feet? The tires they allow on the track, 140/80-19 rear, don't fit the swing arm so I hacked and welded an aluminum one to fit the tire and the frame ( I think its a YZ250?) I shortened it as much as I could, it's still about 2" longer than the stock one, oh well. Also, I will change the front forks because the front tire, 130/80-19 rubs on the fork sliders, a lot! I'm currently searching for bigger ( Dia.) tubes and wider triple clamps to fit to it. I built high pipe expansion chambers for the Ascot replica I built, I will probably make low pipes for this one? I hope to build this one "on the cheep" so I will use as much old stuff as I can, also to clean out some of my parts horde? Here's a few photos from today; Sorry, my computer won't show my photos right now?
 

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Discussion Starter #2
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Discussion Starter #3
I finally found my photos, my computer seems to date them and hide them where ever it likes? It dated these photos 2018 but they were taken today!
 

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Discussion Starter #4
Well I found some 1981 Yamaha SX1100 front forks and trees on e-bay for cheep, they are 37mm and wide enough that the wheel clears the sliders. They were cheep cause they were ugly? they have a huge casting on the sliders to mount the brake calipers. I'm running a spool so I hacked the castings off and sanded them down to polish up cleanly and I like them. I still need to shorten them up a few inches. I had a hard time finding wheel bearings to fit the front axle (17mm), I finally switched to 20mm axle and bearings and it works good. I've worked on big trucks and machinery all my life and when we needed to cut an aluminum frame or bumper we always used a carbide blade on a skill saw, it's not OSHA approved but that's how we did it, so that's how I did this. you have to go slow and secure the work or the saw will kick and you'll be hating life! The flapper wheel sanding disk works best to smooth it out, leave it a little high and sand it to match the tube with roll sand paper. I also tried the import shocks, cause they were cheep. I've got most of the motor done now and will put it in the frame soon.
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here's some photos
 

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Interesting method to cut the tubes. 8Ball posted this thread on rebuilding new RFY shocks. You might want take a look.
 

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Holy **** buy a band saw, it gave me chills when I seen that circular saw :|

... seen a pair of shocks that looked very much like those and the nitrogen gas reservoir was broken off :sneaky: there were no holes in the casting between the shock absorber body and the reservoir, they were fake tits.
 

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RFY's can be made to work well. in general, they are way over sprung (too stiff) but they do have different rates i bought three sets when they were on sale for around $60 a set. I posted what i did to mine. i run a set on a rd350 road racer. another set is ready for a flat tracker but i need lighter springs.
 

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Discussion Starter #8
Thanks, I've heard most of the stories about these but I didn't want to run 50 yr old shocks or spend several hundred for racing shocks so I gave these a try. They do feel stiff but this is kind of a "bucket list" project for me, I might only run it a few times and then put it on display in my man cave or else sell it anyways? I will put a gage on them and make sure the pressures are at least equal. Now, I'm trying to make the exhaust pipes so I can fit everything up on the bike and mount pegs, pipes ,brake pedal, seat, and then finish painting the frame. Then assemble it all? I've made chambers before and it's not to bad, I found a diagram in a 1965 bike magazine that has all the dimensions so I made paper templates and will transfer them onto 20 gage steel sheet metal, cut them with tin snips and weld them up. The track requires mufflers so I will try to copy some two stroke mufflers I've got and make some to fit it. I chose this pipe pattern because it had the fewest parts and lets me use the stock head pipes. It may not make the most power but it's just for fun and I'm hoping it will look and sound ok. To make paper patters, I cut out a 3-1/8" cardboard disk, a 1-1/8" disk and 4 10" strips, taped them together to make a form, I made a tube by rolling some craft paper and put the form inside it, rolled it tight and taped it. Then I marked the tube on the inside next to each disk, pushed the form out, cut the tube lengthwise(through where it overlaps) and unrolled it, then I cut the ends where I marked the before and now I have these patterns THe (blue) center piece it 3-1/8" by 2" I will try to weld them up tomorrow.






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Discussion Starter #9
I did also put the bike together enough to mock it up some, the SX1100 forks still need to be shortened 2 or 3 inches? I'll try that next? These are 37mm, they fit the tire ok and don't hit the tank when turned lock to lock. I don't think the weigh much more than the stock ones either, I will try to weigh them to verify that when they are finished?
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Discussion Starter #10
I had to go to the metal supply and get a sheet of 20gage steel then I traced over the templates (see where the side of the template is not square but the metal is? 1st photo) I didn't cut the template perfectly so I straight edged over the line on the sides so I will have a straight, tight seam to weld. After I cut the metal, with tin snips, I hammered out all the edges to get them flat and straight, this also makes welding easier and faster, then I rough formed the cones, bending by hand, wearing gloves, till I had the shape real close. I have a collection of old bearings in different I.D.s and I tap them down over the cone to get the seam to fit tight then spot weld it. I repeat this all along the seam till it's tight and straight, then finish weld the seam. I grind the welds some so the bearings wont get stuck then I hammer the bearings down on the cone untill the metal touches the bearing all around, 2nd photo, this makes the cone as close to round as I can. If the bearing leaves a dent in the cone I put it over a piece of pipe and tap around it to work the dent out, 3rd photo, I like to get the cone formed as straight and round as I can, 4th photo, before I weld the sections together, you can't fix it after it's all assembled. The magazine article said to cut the original head pipe off 10" from the flange so that's how I did it. The muffler in the last photo is what I'm going to copy, in steel, it will have the inside pipe made in the I.D. and length that the diagram calls for and full of holes and packing to fit around it, then an outer shell and cap to look like the photo?
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Discussion Starter #11
I did more work on the muffler today. I had bought a 2' by 4' sheet of 20 gage steel so I have plenty to work with. I made all the muffler parts from this 20 gage, drilled a bunch of holes in the center pipe, bent the holes inward like the muffler I'm coping, wrapped it with 2 stroke muffler packing and painted it up. I decided to make the outer tubes run all the way to the cone so it would be stronger? the whole thing is pretty light. I will see if I can run both pipes out the same side? or it might be easier to do it on both sides? Also, about the rear shocks, they are to long and the chain will rub so I ordered shorter ones.

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Hats off to you for giving it a good go yourself.
The exhaust looks pretty good.
Let us know how the sound levels are
 

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lol as soon as you said that I could hear it doing that sorta,
hammer hitting the cooling fins trying to run ahead of itself thing ying ying ying :D
 

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Discussion Starter #15
These are the new shocks I got, they are 1&3/4" shorter and now the drive chain is off the swing arm. these also have a little softer spring an should be closer to stock? I made a torque arm for the caliper bracket and did more work on the L/H pipe but ran out of gas for the welder so that's it for today. here's more photos;
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Discussion Starter #16
I finished up the R/H pipe today. also got my aluminum shift lever, from Asia, I'm getting the intake boots from off shore too, I'm cheep! and ca wait 30+ days. I hope to have it running this month? I will work on the forks and electrical next? here's another photo;
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Discussion Starter #17
I'm still waiting for a set of intake rubber boots to mount the carbs. I started on air filters today, I'm cheep and this is a simple trick that I used before. I search the discount stores all the time for stuff ( especially stainless steel things) I can mod. to use on my projects. I found these nice stainless wine cooler vacuum bottles for $9.95 each, on sale for half off, $10. for the pair! I cut them off with my 5" grinder and cut off wheel, sanded the edges smooth with some 220 grit wet/dry paper and cleaned the insides with brake cleaner and a scotch bright pad to be sure there was no weld "goobs" or dirt that might end up in the carbs. I will try to find some foam filters I can fit to it and make some mesh steel spacers to fit them. Here's a few photos;
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Discussion Starter #18
Also, these are double wall vacuum bottles, so if you are carefull and cut both layers at the same time, you end up with inner and outer covers?
 
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