pauljdehmer

The Tomos Targa: The most noob bike one could possibly own. Many claims exist that with only a biturbo exhaust these a35 engines can reach speeds of 50mph. These claims however are entirely false. I bought this bike from the MStar with a Parmakit, Tecno Estoril exhaust, and a 15-16 Dellorto SHA carb for $500. Not a bad deal.

Frame Modifications:
- New short circle headlight
- Removed oil injection
- 22 tooth rear sprocket
- Battery powered lighting system
- Lowered handlebars
- Removed stock fairings

Engine Modifications:
- 70cc Alukit cylinder kit
- Custom 20mm intake
- Mikuni VM20 carb
- K&N style air filter
- Technigas Next expansion exhaust
- HPI internal rotor CDI
- 31 tooth front sprocket
- Custom clutch linings (1st gear only)

I did some work on the tomos last night and figured out why it wasn’t running. The bottom of the reed was getting sandwiched between the reedblock and the reedcage on the cylinder. So the reeds would open enough around the sides for it to run at idle, but anything past that and the reeds wouldn’t open up enough to let in enough mixture for more powah!

Here’s some videos:

I dremeled out the reedcage on the cylinder and reinstalled the reeds. They move freely now and it actually revs out. So I took it out for a spin and its fast as fuckkkk. It needs some more tuning, and there are some other outstanding issues that need to be taken care of, but I think i’ll actually be able to make the first race. Time to go look for some leathers…

it works!

after thinking about how i was going to do the trailing arm caliper mount for my disc brakes, and doing some research, i came across some cr80 forks on ebay for 88 bucks shipped. pretty cheap. they have a caliper mount already on it, and they are wayyyyy beefier. awesome.

anyway i snapped a pic with the wheels mocked up and the old forks while i waited for the new ones to show up in the mail:

a few days later my forks showed up. THEY WERE MASSIVE. i would have to have the fork tubes stick up about 7 inches above the triple trees to get the wheel close to where it was stock. so after ripping the forks apart and doing some research on shortening forks i actually found out that you have to insert a piece into the forks to shorten them. sounds weird i know, but heres details on how it actually works.

basically i can put a spacer between 7 and 13 which will raise the bottom of the fork by however long the spacer is. i bought some metal tubing from ace and cut it to 6 inches for each tube. this will however put more initial pressure on 3 (the main spring) so i had to cut this down so i could get the cap assembly (14) on the top of the tube. i preloaded the spring a bit, because the forks are pretty damned springy, and preloading the main spring will keep tension up and help the fork from bottoming out and the wheel from hitting the bottom of the triple tree during hard braking and extreme bumps. travel will be limited with this setup, but i think i’ll be alright, i’m not doing jumps like the dirtbike these forks were made for.

installing these was a total bitch. i mocked up the steering tube and the triple trees and realized that the head tube on the frame was too long.

so i had to cut down the headtube to make everything fit. the problem with this is that the cups for the bearings sit on a “shelf” inside of the tube

so if i cut the tube down the end of the cups would still only be able to go in as far as that shelf, so i had to cut the cups down by the same amount as i took off the head tube so they would seat all the way.

now with the head tube shortened i mocked everything up. problem number 2: the top race for the bearing sits on top of the ball bearings, which sit in the cup. so when properly tightened down, the forces on the top race (from the ball bearings) even out so the race will not move back and forth. if the race is tight around the steering tube this is what keeps your steering tube stabilized. however the race for tomos bikes is slightly (probably about 1mm) LARGER than the steering tube, so the steering tube can move back and forth inside the race, making the forks wobble. to solve this problem i welded the top race to the threaded nut that goes on the bottom set of threads on the steering tube. this will anchor the top race to the steering tube so there is no play between the race and the steering tube, and therefore no wobble in the forks.

so that nut/race combo gets tightened down, then the top triple tree goes on top of that, and the top nut secures all of this together.

I cleaned up, respoked, and converted the 16″ garelli spoked rear wheel to sealed bearings. also disassembled and reassembled the cr80 wheels just to clean everything up and make it shine. bling bling. The sealed conversion was a breeze on the garelli wheel. knock out the cups, put it some 32×12x10 sealed bearings (fits perfectly, no boring required), cut up some spacers from 3/8″ electrical conduit, and done. super duper easy.

so i finally got it all put together and mocked up with the wheels and new forks on after some crazy work to get everything to fit and work properly.

my old handlebars will not fit with the fork tubes sticking up, so i bought some clip ons.

also i recieved by brake/tail lights in the mail and installed them. i got 2 of these off ebay for 8 bucks shipped.

installed

the top set are the running lights, bottom set is brake lights. sweet.

i also got some battery mounts to secure the battery to the top tube.

and i cut a hole in the frame behind he battery so the wires run directly into the frame hidden behind the battery. much cleaner looking that that picture.

also an update on the clutch. i decided to lighten my shoes so the clutch engages at higher rpms. this may prove to destroy the clutch extremely quickly, but i’ve gotta try. new clutches are fairly cheap anyway.

oh i installed boyesen dual stage reeds on the reedblock too. i dont know if i mentioned that in an earlier post or not.

so heres what i still need to do:
-true my spoked wheels
-buy and install tires and tubes
-figure out steering stop situation for the forks
-fab a caliper mount for the brakes
-install and bend my pipe up a hair (when i welded the exhaust bracket on my bike, it was at a bit higher of an angle. plus that pipe is a bit low anyway, so i’m going to bend it up to look better/have better clearance)

its getting really close.

These forks look so fuckin good.

it’s a shame i’m going to have to sell them. I bought some cr80 forks off ebay for 90 bucks shipped (cheap!). they should be here this week and if they fit, i’ll be selling these nicely painted forks

i also bought a master cylinder, caliper, and controls mount off ebay too. i’ll need to fab up a plate to space the mounts right, but that shouldn’t be too difficult.

i’d say i came out pretty good, spending only ~180 bucks on a complete disc setup when the complete setup from tomos costs 450 plus shipping.

did some mild porting to the cylinder. widened the exhast by 1-2mm on each side and raised it by 1-2. polished the exhaust port. done. we’ll see how it does.

Painting is completed. Mock assembly:

I’ve got some ideas (blatently stolen from here about disc brakes in the front. I bought a cr80 front wheel off ebay for 5 dollars (plus 19 for shipping). so i’ve got some work to do on getting that jigged up.

i need to convert an extra garelli spoked rear wheel to sealed bearings to use for the rear wheel.

I’ve been working diligently on this bike. The step-thru conversion is complete. It took me forever to get it finished. I must have spent about 5 hours welding and griding that damned tapped petcock thingy onto the frame. The shitty gasless mig we have down at the shop, combined with two different thickness metals, made it damned near impossible to get an airtight weld. so after getting it very close to not leaking, i lathered some jb weld over the area where i welded and sealed it up. I also put the gas cap area on the top and did my best at making it air tight. we’ll see how it holds up. i might have to throw some jb weld on that area also to make it not leak too badly, but we’ll see in time.

after the jb weld dried, i took the bike apart and started on painting the bike. black and yellow, who would’ve guessed. anyway, heres some pictures.

frame: black

swingarm: yellow

fork tubes: yellow

gas cap: yellow

disassembled engine

more peices to the puzzle

I’ll repair my clutch this week, and probably do some VERY mild porting on the cylinder (it’s my first time).

Last night i welded a cross brace top tub top bar whatever you want to call it onto the tomos. I also hacked off part of the body that held on the rear fender. And Fixed up some welds for the seat mount. Also I took out the fork lock.

I also started some prep work for turning the frame into a gas tank. More updates soon.

With the Mid American Moped League Moped Cup Races coming up in the spring, I need to get to work on my Tomos: Race Edition.

So here’s my list of things to do:

-fix my clutch pads
-new seat
-remove all excess weight
-install crossbar
-spoked wheels
-new reeds
-step through conversion
-new pedals
-powerwash the fuck out of it

here’s where i am so far:

I tore apart the tomos clutch last night to check on how the pads were holding up. I opened up the transmission to find this:

The material compressed a bit and flattened out from my original dremeling, which is good. Everything looks to be in very good condition except for the edges of 2 of the pads which seem to be peeling back from the clutch arm. This however is my own fault. When adhering the pads to the arms i didn’t apply the epoxy all the way to the edge of the arm. i only applied epoxy to where i wanted the pads to go. In hindsight i should have just applied it all the way to the edge to avoid the peeling of the pads. I’ll have to pick up some more material, enough to do both 1st and 2nd gear clutches and redo it. For now, i think the clutch will hold up fine for a while.

I installed the new clutch material on the tomos clutch yesterday. First off i removed the old clutch material from the arms and roughened up the area where the new material goes.

I bought some epoxy (Devcon 5-minute) to adhere the material to the arms and a hose clamp to keep pressure on it while the epoxy dried.

So i mixed the epoxy and spread a generous amount on the arms and attached the new clutch material. I hose clamped it in place and waited for an hour.

Once it dried i cut the pads to the correct length. They were still too thick and would barely fit in the clutch bell so i had to shave them down with the dremel and a grinding bit. Even with this i was still experiencing the clutch grabbing slightly at idle so i cut the clutch spring down a few coils. This helped, but didn’t cure the problem. I decided against taking even more coils off because of the weakened state of the spring because of this mod, and the extra pressure on the spring also because of this mod.

I took the bike out for a good hour ride last night and the new clutch performed beautifully. Smooth transition into first gear (maybe engaging a bit too early, but thats ok), and smooth transition into second (I’ll need to do this mod eventually to the second gear clutch). I’m going to open it up tonight and see if the material held up to the stress.

I stopped by the local brake & clutch shop today to see about getting some friction material for the tomos clutch. The guy went in the back and found something that i think will work.

it’s a tad bit wide for the clutch, and a little thick, but with some dremeling and sanding i think i’ll be able to make it work.

when i asked the guy how much i owed him for it he said, “dont worry about it. its not worth writing up an invoice”. rad dudes for sure. If you’re ever in cincinnati and need some friction material, hit up Industrial Brake and Supply on the W.P. Dooley bypass.

After installing the HPI cdi on this bike the increased rotational speed of the crankshaft tore apart the stock clutch. The weak cork lining on the arms disintegrated and let the arms rotate outward more than they were designed to. In turn, when I was riding at the Grand Rapids rally, it exploded.

Since no real aftermarket clutches exist, I did some research and tried to find a pocket bike clutch that would work with this setup. I found one that I though would work with minor adjustments and bought it. It was only 25 bucks so no big deal if it didn’t work. It would save me a lot of hassle in the future if it did. Today I went to the shop to make a real effort at installing this.

After tearing down the transmission I realized I made a big mistake. The clutch i bought was supposed to spin in the opposite direction of the way it would on the Tomos.

It’s the clutch with the blue springs. The stock clutch is the one to the left of it.

I can’t think of a way to make this work without A LOT of work to the clutch so I’ve come up with a new plan. I’m going to try and get the stock clutch relined with a better friction material at a local clutch shop and see how that goes. Hopefully the new material won’t fall apart and the clutch arms won’t spin out farther than they are supposed to. Hopefully this keeps the clutch intact.