Toro Suzuki gts 2 stroke mini bike.

[rwd4evr]

Oh yes. Damn near ready to move under its own power. Man, figuring all this out has been really time consuming and kinda addictive. I can't stop. Almost everything is made now. I have a throttle arm I want to make and an air cleaner base.

My goal in making this was to get familiar with the milling machine and make parts with high precision. It is CNC capable even though I'm running it fully manual. I need to know what it's capable of as far as how heavy of a cut it's happy about and feeds , for when I can actually write a g code program and let it go to town. The two sets of clamps are interchangeable as far as the two halves. Very satisfying. It all fits together so well. Almost every single bolt went in finger only with like no drag, and all the holes are snug. No oversized ovaled out stuff. The frame clamps on the sides were one of my biggest worries since they go around the frame and clamp on the motor plate with a thru bolt and had to be dead on. It fit perfect. The jack shaft upright on the belt side has a cutout for the clamp that fits perfect. The one screw up I have is that I cut the cutout out of the wrong one first. You can see only one was cutout in the first pics. Then I stared assembly and went "FUUUUUDGGGGE". The chain side is offset different so the frame clamp doesn't need to pass through it. Oh well. It's not going to hurt it.

 

[rwd4evr]

The four big threaded holes near the corners were already there in the plate I used. Annoying but it's stock I've had in a crate forever. Last few things are,
1. Carb finishing, I want a cool aluminum arm for the throttle cable and I need a bit of offset so 3/8 stock I have will be perfect. A air cleaner mount plate that will double as the choke pull stopper.
2. I have to final machine the drive pulley after cutting the crank off and drilling and tapping it. I'm going to face and bore the piece of crank I cut off and use it as a drill bushing stuck into the drive pulley to align it. Then I can cut down the excess from the pulley. It's actually the original blade holder that has been trimmed and turned down to be pressed into the drive pulley. That worked very nicely. It has a taper inside it that grabs the shaft when tight. So I will cut the crank as much as I can for foot clearance but leave enough to help stabilize the pulley outside of the taper. Then drill and tap the crank and match the final pulley fit so there is just a bit of space between the end of the crank and the edge of the pulley. I'll either get a bolt with a big flanged head or just weld a round piece of .125" to a Allen head. If it does try to slip it will be tightening itself.
3. Gas tank. I have a few maybes. Have to get the air cleaner on first and see what will look best. It's going to be a bottle or little tank up above the back tire for now. I have an aluminum deck from a scooter that fits really well as a rear fender and I may try some Tig practice to make it a tank/fender combo that mounts right on the jackshaft uprights.
4. Clutch lever. This is kinda waiting until I take a short spin and see how it behaves. Could be anything from it's fine to making a lever to trying to relieve some spring tension and maybe re.ove the stock spring and just adding a coil that will just do what I need it to do and allow me to get more travel with a different fulcrum. We shall see.

I've got an engine swap to do in my drift car, in less than 3 weeks it a 3 day fri-sun event with a competition sat. I'm 6th in points in the series and I want a podium. Putting a 5.6 in place of the 4.5 V8 and gaining over 30% power. So hopefully tonight will see this thing moving under its own so I can put it in the back burner and just tinker a little when I have an hour or whatever.

 

[rwd4evr]

Not quite moving. Got the throttle arm and cable mount done. Drilled and tapped the center motor mount holes. Mounted the throttle and rear brake handle. I need a little tab for the caliper to hook to prevent rotation on the axle. It does just run into the frame and works but not ideal. Fixed the idler pulley , it had some runout. My lathe chuck is off like .010" I discovered so I redid it on a live center in the tailstock. Biggest issue I have is the chain. I don't have any room to slide forward so I didn't give myself any adjustments possible, since the front clamps are on the cross bar/footpegs the side clamps can't really move. The motor plate is close to the rear tire but now that everything is final mounted I think I can remove a little material back there,slot the front mount holes and slide it back a bit which will hopefully get me enough to get the chain on. I was concerned about jack shaft clearance during design stage. Other wise I need a half link and a tensioner. Things I considered but didn't have the info on to make a final decision before this point. The exciting part was having it basically fully assembled for the first time tonight. This thing has to weigh less than 50 lbs. So psyched for that.

 

[rwd4evr]

Didn't have much time today, been finishing stripping a 1991 500sl to be scrapped. I have like 30 vintage Mercedes, many of them parts cars. I have a pretty large place and I'm out of parking. A bunch need to go really. I just hate to let **** go.

I got the front clamp bolts out and loosend the rear clamps so I could slide the whole thing back a bit. I got the chain on by moving it back like maybe 1 mm. Far enough that the M8 bolts won't go in but a M6 will still go through the hole. Of course I don't have 4 60mm M6 bolts to clamp it down for a trial run. So full disassembly so I can mill out the clamp holes in the plate. I guess I'll give it like 12mm slots so I can slide it up basically touching the frame and rearward a ways too. I'll buzz a little out of the motor plate by the front edge of the rear tire and a shave of the chain side upright, just near the inside tire proximity. It's not too close but things move around hitting bumps and stuff. I should have done it that way from the start but I just didn't see that option. The minor adjustments I've made to the clutch tensioner pulley and mount have changed the geometry a little so that needs some figuring. I hate the clutch cable looping around and entering from the rear so I may do a rocker arm so it just pulls forward and pulls the tensioner back. I can get more travel out of it too. I'm going to get it moving under power before I do it so I can see how much actual tensioner movement I need with a simple hand lever just for testing. I really want to feel the power and see how fast it is too. I think it looks pretty cool as is but it's tiny. Like balls on the back edge of the seat tiny. I'm like 5'11 so....I have a plan for a seat extension probably with the tank under it. Something like that Photoshop in .125" aluminum. I weighed it tonight with a hanging luggage scale. 62 pounds. I can totally live with that. The great thing is the handle bar uprights come off with a bolt on each side and being 2 stroke I have no dumping motor oil issue if I lay it however I need to. Maybe I'll stuff it in the trunk of the drift car while towing. Just need a shutoff for the fuel outlet and vent. It will get a bunch of material milled out for a nice machined look on all the big surfaces and a paint job. I may do some discs to cover the 3 spoke wheels or maybe paint the spokes and repolish the rim part. Need to get that toro logo freshened up and put on the starter cover too
What do you all think about the nearly finished machine?

 

[pearl111]

Looks good.

 

[rwd4evr]

It works! Kinda. I rode it for the first time besides like 100ft Friday before work. I decided sandals and no helmet was a bad idea plus it had no exhaust and it's deafening. The jockey clutch is sketchy but it does operate. It's squeals like a stuck pig....shocker. the biggest issue is the gearing. I guess mostly because a centrifugal slips until a fairly high speed, like maybe 10+ mph. This thing is at a pretty fast jog, being direct drive, going ,pop pop pop... Like barely running. Slip the clutch and it will take off. It was kinda early and I didn't want to go down the street. Just circled in my shop lot a couple times. I will guess it's got a very high top speed. I think I figured gearing to be 45mph at 6000 rpm. I've got a 48 tooth I can try instead of the 40 that's on it. It's 10/40 currently ,but there's reduction In the jackshaft too. The rear tire is kinda tall. Cant remember right now but maybe 14"? Could be 12".
Anyway I was up all night building exhaust and brake mounts and a couple other little thing. Had to machine a flange for the pipe to spring mount into like real dirt bike, becase the studs are top and bottom. No way to get bolts or nuts on there very easily. Here it is before paint. I may cut the silencer down to make it a bit shorter. The smaller one I had was too small internally with a straight pipe. I was looking at doing an expansion with a bunch of different stuff I had around but there's just no room without it being insanely twisty, and making it the right diameters but short just raises the rpm range which is the last thing I need. So it's essentially 35mm from the head pipe outlet to the muffler pipe that's like 32. Sounds pretty good. Haven't really reved it out yet...

 

[rwd4evr]

Well I took it for an actual ride today in a pretty big parking lot. The gearing is ridiculously long. It will basically idle around at like 10-15 maybe. In the first lot I hit 38mph according to my phone gps. It's a little slow to react too. That was seriously just starting to get into the power where it felt like it was pulling hard too. So I went to pick up some mail at my dad's and hit another parking lot that I used to rip my kart at and occasionally will run around in my drift car for a minute. Of course there's 3 cops on doghnut patrol sitting there. I figured what the hell I'm already here and there is zero people other than them, so I asked if they cared if I made a couple test laps. They said I had two minutes of noise. Unfortunately it's it kind of an uphill/downhill lot with a few big office buildings and the police were at the bottom of the hill. I went and rode a little and got a run down the hill but let off as it was really starting to get moving,plus I didn't have a few laps to see where any big holes were to be safe, and I didn't want to come down to the police doing 60 into a sand pit possibly. It hit 41(forgot the screenshot) on the GPS with tons more in it. The belt clutch is kinda a fail. It will accelerate and slip fairly smoothly but slowing down when it's released it's very unhappy and jerky and even tossed the belt once, it seems to climb the outer edge of the pulley and go wonky. Oh well. I'll change the gear and throw a centrifugal on it. At least I can use the clutch lever for some sweet 2 stroke rev action . All things considered it rides pretty well. A front brake would be nice, I skidded the rear a bit slowing down in the first lot. If I had some leather on on a smooth surface it would be a ton of fun to push hard, it lays over on the pocket rocket tires really nice.

 

[rwd4evr]

I kinda messed up with the gearing I forgot that the 3 gears I had were 32, 40 and 48. The 32 was the same as the sprocket on the x1 pocket bike I got the wheels off of. I was planning on getting an 8 tooth to go 4-1 with the 32, unfortunately I had to use the 5/8 jackshaft for an 8 tooth and it just complicated a few things so stayed with the 3/4" shaft I have. I completely was thinking that the sprocket on the bike was a 40. So I was running a 32/10 with a 1.33-1 ratio on the jackshaft giving a 4.25-1 ratio with a 14.25" tire. I drilled the bike sprocket pack pattern on the original sprocket so I can swap them easily. I went ahead and put the 48 tooth on it to try it out. That way if it's too short I can go to the smaller 40 tooth and just shorten the chain. Hopefully I'll get a little rip tomorrow after work. I want to figure out the gearing before I order a clutch so I am sure.

 

[rwd4evr]

Took her for a little rip today. Topped out at 38 and that seems just fine for now. Checked my gearing out, don't you love getting older and thinking you remember **** when you don't. Pulley ratio is 1.48 so final drive is 7.104, tire is 14.05 diameter. Math says 6398rpm. It accelerates pretty hard but definitely feels like it's falling off up top. I imagine it has a fixed rpm ignition since it was never intended to do anything but buzz along at 3450rpm. Is there a decent budget cdi box that people are using these days? Or maybe someone has the wiring diagram to one of the gy6 units to adapt one on it? 2 strokes are weird that they want a decrease in timing after a certain point to make power up top. I don't fully understand why but it's facts. It honestly is just fine for its purpose and will be great with the centrifugal clutch on it but I'm always tinkering to improve. I'm sure it's capable of way more rpm. I should probably look at the flywheel for a burst warning rpm too. I have pretty high faith in it being produced by Suzuki and not in Ghina though. It does need a real pipe for the proper sound though.......

 

[rwd4evr]

I put a centrifugal clutch on it tonight. Only took it for a short spin around the lot but it accelerates hard. It's a 2000rpm engagement clutch but the jackshaft is spinning 2/3 speed so it engages fully at 3000 rpm at the crank. It works lovely. Will still putt around with out really revving it too. It fit in there just right. This little thing really is 10 pounds of crap in a 5 pound frame.

 

[BaconBitRacing]

I love this build. Totally in the DIYGK spirit, making something cool and fast outta junk. Just janky enough to be exciting. Good Work!

 

[rwd4evr]

The only thing actually janky is the temporary gas tank. Everything is really solid. Starts on one or two pulls and will sit there and idle all day. Like 10hp on a tiny 65 pound bike is plenty exciting.

 

[rwd4evr]

It fits in the drift car trunk nicely. Off to go kill some tires this weekend! Woo hoo!

 

[rwd4evr]

Fully successful first weekend for the bit bike. Really came in handy with the new pit and camping situation at our track. I went out first round in the competition on what I feel was a pretty weak call. Very educational weekend though. I really learned that my cars nose is far shorter than I thought. Drove super aggressively with a lot of other killer drivers. So much fun. Then I got rear ended in the last session with mixed groups. Oh well. Not too badly damaged besides the body work. Thoroughly used that one