SR50 Gear Ratio Teeth per Gear Question,New Honda Parts ebay

[itzmepete]

Hey guys, there is a new ebay Honda parts supplier selling parts on ebay. He seems to have serious preformance parts and kits. He has stroker kits for the Dio to go to 125cc, crank, bearings pistion for $175 and complete kits with exhaust for another $100 or so. Anyway, I have emailed several people that have purchased his parts and they all come back saying the parts are of very good uality.

So, I am gonna order a final drive gear set. I know I want 8:44 to 1 but don't know how many teeth on a gear that is? Does anyone know?

I know 9 to 1 is 42 teeth X 16

The seller also has 17 x 41 and 15 x 42 But I don't know what those are in gear ratio's?

If Anyone know for SURE, has a 8:44 to 1 , please count the teeth and let me know!

Thanks

[Dac]

this is a gear kit i got. its 8.44:1

[itzmepete]

DAC, whats the tooth count on both gears or did you already install it?

[Dac]

i already installed it.
but i took a few pictures and turned it into a 'how to install' type deal that can be seen in the Advanced Tech Docs. Check out the topic. You might be able to count the teath in the picture.
Sorry i cant help more.

[Dac]

17 on the little gear.
41 on the big gear.
{i looked at all the picture i had and was able to count. }

[itzmepete]

Thanks Dillian,
Yeah I downloaded the pic, and counted the teeth and I got 41. The ebay add Title says 17 and 41 but in the description it says 42 which would be too big and not work. I emailed the seller to confirm that its 41 and that he doesn't have the gear for the 9 to 1 which is 42 mixed in as he sells a 9 to 1 which is 16 x 42.

Anyway, I broke down and just ordered the Polini Corsa kit at $240 shipped. Debated long and hard over the cheaper CMR. I am gonna use mine as a dailer rider to and from work 15 miles each way so I opted for the best cylinder as I don't want to do this twice!

Gonna order this 8:44 to 1 gear and run it as is with the new #100 Carb jet ofcourse. I'll Run it with the Cylinder and take speed notes before and after. Then run it with the 8:44 to 1 gears and take notes again.

Next month I will order a new muffler and speed variator and do runs after each install just to see the speed gains!

[Dac]

you know all about the break in process right?

[itzmepete]

Yeah, I am a mechanic, A&P Aircraft, plus done 2 strokes model airplane engines for many years. Although I really don't agree with many about the easy break in yadda yadda yadda, I will still go easy on it for a few hundred miles.

The reason I don't believe in too easy a break in is this. Back in the 60's 70's and early 80's , not much was done with CNC machining. So tolerances were not close and prescise. A easy and long break in was required till the parts wore in a bit. Thats why the old muslce cars needed a easy break in and oil change after 1k miles. Todays new cars, no break in and oil change at 5k. Thats the reason, but it never hurts to just go easy for a but.
But in todays deal with CNC and CAD machining, tolerances are kept really close and precise. So little wear will occure and break in is relatively short. Now of course this also depends on the manufacturer. If its a cheapo or overseas deal that doesn't have the machining or quality control, then yes, more break in will be required. I will pull my micrometer out and check the piston against the bore and see how close they are. Being Polini and their top end kit, I expect it to be really close. I will shoot a bit of oil in the fuel the first tank or two and adjust the oiler cable to full as well. 200 miles later, I am running it hard!

[stillspeeding]

There is an old school way to figure out a gear ratio, all it takes is one finger the 8:44:1 ratio is useless, there is alot you can learn from me but i will kick back and watch the mistakes you make, a 125cc air cooled engine? dream on

[Dac]

There is an old school way to figure out a gear ratio, all it takes is one finger the 8:44:1 ratio is useless, there is alot you can learn from me but i will kick back and watch the mistakes you make, a 125cc air cooled engine? dream on

What are you trying to say now?
you never make any since.

[itzmepete]

Dac,
I have seen some of stillspeedings posts, don't worry. As for a 125cc kit, nope , I am not getting that kit, its a stroker kit and I am not up for machining my case. All you have to do is a search in ebay for hinda dio and you will find autotech355 stuff for sale.
I want a reliable every day rider. I ordered a Polini Corsa but this seller has a 125cc kit and its of good cuality, I just ordered the final gear drive from him.

I will post my results when I start the mods one at a time.

[happyman]

you know all about the break in process right?

could you elaborate on the break in process.. i don't have the polini but i do have a molossi which is decent quality.
Thanks Happy

[Dac]

you know all about the break in process right?

could you elaborate on the break in process.. i don't have the polini but i do have a molossi which is decent quality.
Thanks Happy

you have to break in a new cylinder. you just cant slap it on and gun it or you will have heat seizes and ruin the cylinder. ( trust me. i have done this a few times now.)
By breaking it in i mean to go easy on it for the first 300miles or so. As hard as it is, it will help the motor last longer.

[itzmepete]

Yeah that can happen. The problem is the aluminum piston is made of aluminum in order to keep the weight down, less counter weight on the crank is then needed and a smoother running engine. Aluminum expands quicker and more so than steel. So, if the tolerance are not right , say the piston is a tight fit, then you gun it, pistons heats up faster than cylinder which is air colled, piston rubs , usually the piston skirt, on the sides of cylinder, as well as the top piston causing the rings to press harder on the cylinder walls, piston overheats and starts to expand alot and thus seize. Sometimes it can ruin the piston. If its a steel cylinder, nothing will happen to the cylinder, worst case get a brake cylinder or small engine honing tool, Sears Cheap!, and run it very lightly with a drill and some light oil. The piston, could even be smoothed out with 600 or 800 sandpaper under water.

As an example. Found a briggs pressure washer 5.5 hp seized. Looked brand new. Owner ran it with no oil. Steel cylinder, aluminum piston. I cracked the case open, squirted WD-40 oil all over the inside. It was tight on the crank connecting rod. It losened up and after a few flips spun free. Cylinder still had factory honing marks, a good sign, piston had just a few almost unnoticable lines, quality aluminin alloy piston. I could have pulled the piston, wet sanded it and ran a light hone and new rings but didn't. I did pop the connecting rod end cap off, no metal, just a little scorn but it did stop running and seize now, remember. I just wanted to make sure no aluminum was on the crank and the oil hole was clear and unabstructed. Put it back together, oiled it up and ran it. Started fine, ran fine, I checked the oil and so long as the oil is fine, never had a problem with it. After ever tank full, oil went from full to half, with ever tank full of gas, the oil needed to refill usage decreased to now where every 6 full tanks of gas it needs oil. It rings reseated and no problem.

Also had a rider 12hp briggs. The crank oil seal gave way, owner didn't know and the engine seized. They gave it to me free The crankshaft had melted aluminum and brass from the crankcase base bearing. I sand blasted the crankshaft journals, yes, to get the aluminum off. Then using very fine emory cloth and a drill, I polished the crank in minutes. Got a used good Crankcase base. Honed the steel cylinder and sand blasted the piston, then wet sanded it with 800 paper under water carefully to remove the up and down scorn lines not from the lack of oil but from the 13 plus years of use. Honed the cylinder, new rings and oil seal of course and that engine ran perfect with no oil burn what so ever. Compression was unreal, power was awesome.

The point here is the tolerance and/or quality or make of of the aluminum used in the piston and rings. If its cheap aluminum or aluminum alloy, it will have different expansion qualities and it won't withstand the heat and pressure as that of a good quality alluminum alloy will. Back in the early 80's american auto makers had problems with aluminum cylinder heads and their attempts to compete with jap car makers. They didn't have the manufactureing process or correct aluminum ally part right, thus warped heads and cracks as well. Now no one would blink twice at a car with aluminum heads regardless who makes it. Infact high output and hi preformace cars have aluminum heads and some crank cases. Briggs used aluminum cylinders in their engines at one time, short only a few years runs, and that lasted but a few years, they wore out quick and were just not durable enough although today scooter aluminum cylinders have that Nicasil plating, I would go still go with steel cylinder.

Model Airplane engines, large one at that, were 2 stroke ABC engines which meant Aluminum piston running in a Brass Cylinder that has been Chrome plated. The tolerances were so perfect that No piston ring was used. As the engine ran and warmed up the aluminum piston expanded more than the cylinder and created a seal with very good results and high compression. Later some makers tried to cut costs with AAC and it didn't work well.

So, yes break it in easy is always safe, but not always true. The ebay seller that sells Tiawan honda racing parts says the maker of his cheapo steel big bore kit is his exact words
"KH,this maker are Piaggio,Stage 6 and MRP supplier.
CMR and FM also from this maker."

Basically he said this manufacture KH makes cylinders for these companies which I would believe. I am not so concerned with the quality of the steel cylinder, steel is steel, you can grab a dremel, port it urself, rehone it and what not. But if the piston is a cheap aluminum cast alloy, the piston will fail with abuse much quicker than a quality one. There is a website that sells cylinders no pistoon and pistons. They have $18 pistons and $65 pistons, obviously there is a difference.
Sorry for the rant on 2 strokes but info is knowledge. I started thinking about my cheapo ABC model engines and my expensive italian Rossi's and I had to go with the Polini Corsa. Mean I will have to wait another month or two ($$$) before I can order the muffler and Variator but I will at least rest assured I have a ported high quality cylinder and I ordered a generic final gear set. I will go 3/4 throttle , add some oil in gas and yeah not be too hard but I will also run it open up for short bursts as its improtant for the new cylinder to reach maximum operating normal temp for a good break in. Example, you wouldn't run a cold engine full throttle, you would damage it, casing accerated wear. But once broken in, and at operating temp, you could throttle up and leave it there, technically, with no added wear.

I am just not familiar with these 2 stroke hondas and the quality of the kits, I will compare the OEM against the polini when I get it.

[happyman]

good write upp.. i do a little break in and always have. the riving of a cold motor is a bad deal/ on my aluminum cylinder nakisi coated i did 4 good heat cycles on it and did a little putting around on it and did a few plug chops to make sure the low speed, midrange, and highwpeed looked good and performed with good throttle responmce.. after that was done i drained the dino oil out completely, and filled it with a real good synt. oil.took it out and got it warmed up did a compression check recorded it. took it out again and got it warmed up nice and spooled it to 10700 rpm and then backed and rode for 20 miles at 9500 rpm .today bout 2000 milers later the ccp is exactly the same, and it runs great all the way to 10700 rpm, which it sees often. maybe io am lucky. but then i also have a water cooled motor, hace a FEELING on my two new builds i am goinjg to have to be a lot nicer to them as they are aircooled. give um what they want and break them in halfway decent and and i hope we have good long lasting motors. quality oil i feel is a key in this too for the rpm we spool these things with the tolerances of today, from the companies that have the really great quality and what not.. anyway your a very interesting person to be sure with your experiances and ability.
Happy

Yeah that can happen. The problem is the aluminum piston is made of aluminum in order to keep the weight down, less counter weight on the crank is then needed and a smoother running engine. Aluminum expands quicker and more so than steel. So, if the tolerance are not right , say the piston is a tight fit, then you gun it, pistons heats up faster than cylinder which is air colled, piston rubs , usually the piston skirt, on the sides of cylinder, as well as the top piston causing the rings to press harder on the cylinder walls, piston overheats and starts to expand alot and thus seize. Sometimes it can ruin the piston. If its a steel cylinder, nothing will happen to the cylinder, worst case get a brake cylinder or small engine honing tool, Sears Cheap!, and run it very lightly with a drill and some light oil. The piston, could even be smoothed out with 600 or 800 sandpaper under water.

As an example. Found a briggs pressure washer 5.5 hp seized. Looked brand new. Owner ran it with no oil. Steel cylinder, aluminum piston. I cracked the case open, squirted WD-40 oil all over the inside. It was tight on the crank connecting rod. It losened up and after a few flips spun free. Cylinder still had factory honing marks, a good sign, piston had just a few almost unnoticable lines, quality aluminin alloy piston. I could have pulled the piston, wet sanded it and ran a light hone and new rings but didn't. I did pop the connecting rod end cap off, no metal, just a little scorn but it did stop running and seize now, remember. I just wanted to make sure no aluminum was on the crank and the oil hole was clear and unabstructed. Put it back together, oiled it up and ran it. Started fine, ran fine, I checked the oil and so long as the oil is fine, never had a problem with it. After ever tank full, oil went from full to half, with ever tank full of gas, the oil needed to refill usage decreased to now where every 6 full tanks of gas it needs oil. It rings reseated and no problem.

Also had a rider 12hp briggs. The crank oil seal gave way, owner didn't know and the engine seized. They gave it to me free The crankshaft had melted aluminum and brass from the crankcase base bearing. I sand blasted the crankshaft journals, yes, to get the aluminum off. Then using very fine emory cloth and a drill, I polished the crank in minutes. Got a used good Crankcase base. Honed the steel cylinder and sand blasted the piston, then wet sanded it with 800 paper under water carefully to remove the up and down scorn lines not from the lack of oil but from the 13 plus years of use. Honed the cylinder, new rings and oil seal of course and that engine ran perfect with no oil burn what so ever. Compression was unreal, power was awesome.

The point here is the tolerance and/or quality or make of of the aluminum used in the piston and rings. If its cheap aluminum or aluminum alloy, it will have different expansion qualities and it won't withstand the heat and pressure as that of a good quality alluminum alloy will. Back in the early 80's american auto makers had problems with aluminum cylinder heads and their attempts to compete with jap car makers. They didn't have the manufactureing process or correct aluminum ally part right, thus warped heads and cracks as well. Now no one would blink twice at a car with aluminum heads regardless who makes it. Infact high output and hi preformace cars have aluminum heads and some crank cases. Briggs used aluminum cylinders in their engines at one time, short only a few years runs, and that lasted but a few years, they wore out quick and were just not durable enough although today scooter aluminum cylinders have that Nicasil plating, I would go still go with steel cylinder.

Model Airplane engines, large one at that, were 2 stroke ABC engines which meant Aluminum piston running in a Brass Cylinder that has been Chrome plated. The tolerances were so perfect that No piston ring was used. As the engine ran and warmed up the aluminum piston expanded more than the cylinder and created a seal with very good results and high compression. Later some makers tried to cut costs with AAC and it didn't work well.

So, yes break it in easy is always safe, but not always true. The ebay seller that sells Tiawan honda racing parts says the maker of his cheapo steel big bore kit is his exact words
"KH,this maker are Piaggio,Stage 6 and MRP supplier.
CMR and FM also from this maker."

Basically he said this manufacture KH makes cylinders for these companies which I would believe. I am not so concerned with the quality of the steel cylinder, steel is steel, you can grab a dremel, port it urself, rehone it and what not. But if the piston is a cheap aluminum cast alloy, the piston will fail with abuse much quicker than a quality one. There is a website that sells cylinders no pistoon and pistons. They have $18 pistons and $65 pistons, obviously there is a difference.
Sorry for the rant on 2 strokes but info is knowledge. I started thinking about my cheapo ABC model engines and my expensive italian Rossi's and I had to go with the Polini Corsa. Mean I will have to wait another month or two ($$$) before I can order the muffler and Variator but I will at least rest assured I have a ported high quality cylinder and I ordered a generic final gear set. I will go 3/4 throttle , add some oil in gas and yeah not be too hard but I will also run it open up for short bursts as its improtant for the new cylinder to reach maximum operating normal temp for a good break in. Example, you wouldn't run a cold engine full throttle, you would damage it, casing accerated wear. But once broken in, and at operating temp, you could throttle up and leave it there, technically, with no added wear.

I am just not familiar with these 2 stroke hondas and the quality of the kits, I will compare the OEM against the polini when I get it.