Toro Suzuki gts 2 stroke mini bike.

[rwd4evr]

Hey everyone! Been awhile AGAIN but I've got this thing much closer to putting power down. There is a thread started 4 years ago I can't add to apparently that has some info on it.

" Toro Suzuki 2 stroke mini bike / pit bike"

I got a Bridgeport mill and a big lathe so I've been practicing my setup and stuff on some less critical parts. I'm just building this really to get around the pits at drift events so I'm going as light as possible to haul it on my dolly tongue. I used some 9" wheels off a x1 50cc pocket bike , the rear actually is exactly the right width with it's spacers and disc brake, total luck. The front just fits, I may need to machine a touch off to run the front brake but I kinda doubt it's necessary. Maybe fun for burnouts but .... I machined a baseplate from half inch aluminum to fit inside the frame rails perfectly. The I drew up the plate that stands up to mount the motor to in 2 d cad just to get some numbers to plot on the mill and a paper mock up. I'm using 6 rib serpentine belt pulleys and a jack shaft with a Chevy truck tensioner for a clutch. Not sure how that going to perform yet but worse case I can put a centrifugal on the jack shaft. It all looks feasible and the minibike brake cable is setup just right to hook to the tensioner with a couple holes drilled. This is the mock up motor, the better one I have has a different output and the pulley will sit way closer to the engine. As of now it's geared to do 44 at 6000 rpm. I'm not really sure what it's going to turn but I know it's got potential to make a lot of power with some port work and a pipe along with a real carb. I have a 24mm(I think off the top of my head) tillotson pumper carb for a big 2 stroke saw I bought years ago and a fakuni I can run if that's a dud. It's so small it's comical but I fit on it just barely. I'm thinking it might get sort of a cafe like straight back seat for a bit more room but I kinda like the look with the fake tank. I may have to whip up a real tank that resembles it from aluminum. I have a Vulcan 205 pro Tig I've done some projects, my bash bars on my drift car was the biggest, but I really haven't sat down and just gone to town laying beads all day to get consistent, and I have done ZERO aluminum. I'd like to weld up some sheelmetal in shape at some point and hydroform a proper expansion chamber but I think that's probably un necessary too. I have to chuckle seeing it come together finally.

 

[Snaker]

That looks fun.
Not every day you can use the dresser for a work bench.
I had a Toro snow blower with a Suzuki 2 stroke, wonder if this was one as well?

 

[rwd4evr]

That looks fun.
Not every day you can use the dresser for a work bench.
I had a Toro snow blower with a Suzuki 2 stroke, wonder if this was one as well?

Yeah there is one thats very similar. I think I remember someone saying the snow blower was reed valve though. This is piston port. I'd guess the snow blower was horizontal shaft too which may have been a lot easier to use. I have a toro snowblower with a much smaller 2 stroke too, I don't know the maker, looks very techumseh-ish, internal flywheel magneto. I have one somewhere, they don't have a nice beefy roller bearing bottom end like this one though. I think this motor is 121cc.
That dresser is funny, my buddy street grabbed it right after I got my first shop and it's been around for years. I just moved it to put my big lathe in and was kinda ready to trash it. After breaking my back for no reason screwing with this little thing on the ground 5ft away it got a new life again

 

[Denny]

I broke my neck sleeping.

 

[bob58o]

I broke my neck sleeping.

This aging thing is very exciting. Sometimes you wake up with a broken neck. Sometimes you wake up dead. As we age sleeping becomes risky business, like straying too far from the toilet after that first sip of morning coffee.

 

[Denny]

Farts are no longer your friends after 50!
Sometimes the do mean things.

 

[rwd4evr]

Farts are no longer your friends after 50!
Sometimes the do mean things.

You two need glasses. This is DIY GO KARTS, NOT
DUM OLD FARTS.
Wrong forum.
GOBLESS

 

[rwd4evr]

I got a whole bunch of machining done and got the basic drive train setup for proof of concept before setling on final height and exact positioning of the bearings for the jackshaft. The two stands at the rear will be bored for 3/4" flanged bearings. I have a 3/4" jack shaft with a 17mm end for the pulley. It looks like the tensioner will have just the right amount of swing to tighten the belt but still get completely out of the way to allow it to slip without grabbing. I hope it doesn't do some jerky intermittent grabbing with the clutch lever pulled. I have a plan for cable actuation, hoping I'll have enough cable movement. It looks like I will but not sure on how hard the pull will be. Maybe I'll need one of those hydraulic clutch conversion deals but I'd really rather not go there. I have a big bag of M8x1.25 socket heads on the way. To make it look nice. Time to get the non mockup motor ready. I have to cut and drill/tap the output to mount the pulley but that shouldn't be too hard on the mill. Once it's all finalized I'm going to go nuts milling out a ton of unneeded material to lighten it up and make it look nice. It's really not even that heavy though. Probably still lighter than a flathead Briggs.

 

[rwd4evr]

Doesn't look like much new progress but put the actual engine on the mount, machined an old aluminum timing belt idler flat(looks awesome) and pressed out one of the bearings to replace it with the 17mm Id tensioner bearing. Needed to bore it to 40mm from 37mm. Set the final jack shaft position for tire clearance with about 3/4" (Incase it grows at speed) and verified belt tension and complete release(I'm pretty sure at least) with the available cable pull distance. The engine pulley looks funky because there is a smaller puller that the belt is on and a slightly larger one is just being used as a spacer to keep it in place for the belt test. It's looking like it's going to work nicely. Made absolutely sure I can just pop a centrifugal on the other side of the jack shaft just in case it is unrideable with the belt/clutch deal. It could be real grabby to accelerate from a stop. I'm thinking it would be really easy to just give it a little push and pop start it though. We shall see. So cool when something that had lived in your head for years is final in reality.

 

[rwd4evr]

Jackpot! Basically got everything mounted(not final of course) and operational more or less. Machining the bores for the jack shaft bearings was super stressful. I've never had to do a pressfit into a bore. I got flanged .750 x 1.375 bearings to put on the inside of the uprights for the jack shaft. Fortunately my Bridgeport came with a ton of tooling and has a nice quick change tool holder. I have a few adjustable boring bars that seem to be super accurate. First try was too small at "1.373. I cranked on the hydraulic press, got it in but it was super tight and the bearing was locked. I cracked the flange too. DOH! It still rolls ok for testing but it's trash. I took .0005 at a time out of them and it took a few passes. I got them fitting real nice and orderd a new pair, one extra never hurt. All put back together with the jackshaft and pulleys for the first time. Super happy with it. Went through a couple different attempts at a cable actuating the tensioner. First was a big fail. Not enough leverage. It worked if I had the big ratchet and bar I've been using to slightly assist but couldn't pull the lever with my hand alone. Made a lever from .125" steel plate that attached to the tensioner and messed with lever length. It works great with the lever long where I drilled the first hole but it's not enough travel. It might be disenaged but it's going to want to pull and probably jerk. I moved the cable mount down and the cable pickup point down twice. The middle I just clamped/held it on the lever, it works better but still a little short on travel. I moved it down again and drilled a hole. now it's pretty close to where I'm happy with how loose the belt is with the clutch lever pulled, but it's pretty stiff. It is a ****ty little BMX brake lever though. I think with a proper motorcycle clutch lever, or maybe just machining a new finger lever that fits the base, that's longer and shaped to get more travel, it will possibly be a good solution, but it's really putting some tension on that cable. Beefier actual motorcycle cable would probably be a solution there too. I think it's going to work that way but I'm very curious about those cheapo hydraulic motorcycle clutch conversion setups on Amazon and temu and whatnot. I may start a thread asking about if anyone has any experience with them. I neeed to find out how much travel they have. If anyone has that info I'd love to hear about it. Going to try to do some searching on that.

Last things I need to do to get it close to operational are a intake adapter/manifold that's probably going to be a couple 1/2 in aluminum pieces port matched at both ends, the engine port is a funky rectangle with a 20mm circle in the middle (you can see the gasket I port matched on the intake with the tape blocker) that needs to magically become a 25mm hole for the carb. Bolt holes are 90° off so two pieces sandwiched will make porting the shape easier and let me mount bolts in it to use for the carb studs. Air cleaner mount will double as a throttle cable bracket. I need to make the aluminum clamps that will hold this whole drive train to the frame too. I'll start worrying about the exhaust and final tank after I have the main **** working.

 

[ezcome-ezgo]

Wacky

 

[Denny]

Foot clutch like Harley and Indian used to do back in the 20s and early 30s.

 

[rwd4evr]

Foot clutch like Harley and Indian used to do back in the 20s and early 30s.

Terrible setup. Especially with no neutral. If it starts leaning left(or whichever side the foot clutch is)at a stop your screwed. I've considered a suicide clutch with a handle but then it needs foot brakes or right side brake. It may get a front brake on the right handle bar I suppose but not high on the list right now. Pretty sure I'll get the cable clutch setup working ok. I found one eBay listing for a hydro setup with 22mm of travel. Definitely a bit short but it may have more leverage plus no cable friction.

 

[rwd4evr]

Halfway through the intake setup. I want to hear it run. That big tillotson looks so cool. I hope it's not too much.

 

[rwd4evr]

I was doing a little searching on weather a pipe mounted pulse vs a crankcase would be ok for the fuel pump and found some info saying the pumper carb may be a little bit lightswitchy on the throttle. Guess I'll find out cause I'm going for it anyway. I can always put a boring mikuni on it later. Plus an experimental motor with no adjustable jet is silly. Started setting up for machining the intake setup on the rotary table but it's stupid hot and humid. Had to go AC for awhile.

 

[Bansil]

Drill and tap the bolt head on tensioner, so you can hold a handle say 2ft long onto it...kinda like a suicide clutch handle it would move maybe 4 inches at top.
Just make a hex (12 sided would be best for adjustment)to fit bolt head and all the tapped hole will do is keep it from falling off.

Do you have a dividing head with the mill?

 

[rwd4evr]

Drill and tap the bolt head on tensioner, so you can hold a handle say 2ft long onto it...kinda like a suicide clutch handle it would move maybe 4 inches at top.
Just make a hex (12 sided would be best for adjustment)to fit bolt head and all the tapped hole will do is keep it from falling off.

Do you have a dividing head with the mill?

I've already mounted this lever(circled in red) to the tensioner for the cable to attach to. You can see the cable routing
. The back of the tensioner right behind the pulley is drilled and tapped. If I need to do a suicide clutch type lever I can go off of that. It's just a not great solution. This thing is going to be a handful already being so tiny. One hand on the bars with a possibly grabby belt clutch is far from ideal, especially in the crowded pits at a racetrack which is mainly where this thing will be used. I picked up a real clutch lever and throttle with cables. Unfortunately the nice long clutch lever has a shorter fulcrum point so it actually reduces travel which I can't afford. The positive is that the much higher quality and thicker cable has far less friction so the original minibike brake lever makes it work. The actual lever is short and bent for kids fingers so I lose a bunch of travel. Im going to try moving the cable attachment down the lever with the clutch lever and see how that works. It's just going to be a lot of stress on the cable I think. If not I'll make a lever for the other base that has the short curved lever.

I don't have a plate and hole type dividing head but I have a rotary table that mounts vertical or horizontal with .01 degree graduations so I can pretty much divide as needed. I'm going to make a mount for a lathe chuck in it as well. I have a spare 7x12 lathe to use the tail stock as well for some 4th axis machining possibilities.

 

[rwd4evr]

Finished up the intake manifold tonight. It came out nice. Still want to dress it up with some material removal and shaping but that's later. Everything is going to get cleaned up and made finished looking. The port match was an interesting exercise. Drilled the pulse port to come out of the side of the manifold , I'd love to take the bottom end apart, remove the governor shaft and use that for the pulse port but I'm not really liking the idea of breaking the seal and possibly damaging the crank seals in the process. There is a couple threaded bungs in the bottom end, I think I'm going to carefully drill in through one with pressure in the intake to blow any chips out, and then tap into the side of it for the pulse. The threaded portion is going to be supports to help stabilize the engine under torque so I can't just go in that way. I love the way that carb looks on there. Gotta brab a couple bolts tomorrow and tap the manifold for carb studs and it's ready to fire.

 

[rwd4evr]

It's alive!! Intake all done and the pulse port tapped in the block. I used some nickleI copper brake line pressed in to the hole. I wish I got a little vid of it with the muffler off. It's a whole different animal but holy crap is it loud and doesn't idle very well. I have a little fmf silencer that will go on a pipe that will have some strategic sizing but it's not going to be a proper expansion chamber because tuned length is way longer than the bike without making a crazy snake pipe. Maybe someday. The clutch does release. It's got some drag but some fine tuning should work. Probably going to take a break and get some other stuff done now I know that the majority is going to work.

https://youtube.com/shorts/pJiZmNa9aEY?feature=share

 

[rwd4evr]

Damn totally forgot pics. Did a little messing about a couple times when I had and hour or two. Got the drive/driven pulleys and jackshaft, drive sprocket almost handled( bought a 40 chain drive sprocket and it's basically bike chain width, had to machine it down). Started on the clamps to hold it in the frame last night.