Polini Corsa Kit Owners Read This

[itzmepete]

Well,
Finally got my Polini Corsa kit from Daywot on ebay. After I purchased it I asked him a few questions and he would not answer. He can communicate when he wants to and be difficult at times as well.
The Polini kit is a nice kit. The exhaust port is ported out. The piston skirt also has a cut out on the lower skirt for the boost port. Other than that thats it. I had a hard time lining up the 4 cylinder bolts. finally loosened the manifold bolts as it might have been hitting the hard reed gaskets causing it not to line up? Anyway, finally got it on. A cold pression check was at 155psi, gotta do it hot but will do it tomorrow.

One note. the spark plug position is off. Its not centered on the air shrould but sits to the top making installing the spark plug boot a pain in the *. Anyone else had this problem? I find it hard to believe that such a high quality kit would have this issue uness the position of the plug was vital for more power.

Also, the included carb jet , which did not fit my carb but was for a jap dio carb, was a 82 jet, my carb had a 78. I thought it would need a 100 jet? Anyhow, I drilled it with a #61 bit a 1 mm so now its a 100 jet. Started it up, starter struggled, idled it and will run it tomorrow.

Anyone had these issues with the polini Corsa kit?

Peter

[itzmepete]

Ran it today, kinda ran a hair rich but wasn't fully warmed up. I did a few easy runs, didn't hesitate though. With the kickstand up and rear wheel in the air, reving it you could tell it was slightly rich. Riding it however you couldn't, it ran very good. I gunned it yes I did. It reached 38mph, a few more MPH than what it did before but accelerated unreal. I have to agree with what most everyone says, a big bore kit won't give you more speed, period. It does have power up the ying yang and should speed up alot with my new 8:44 to 1 gear set comming in a few days. I am still running the stock muffler, once I replace that I am sure the engine will lean out a bit more. A 100 jet is for big bore kits with gears and muffler.

Gonna let it cool down and then make another run this time with the airbox cover off. If it dies on throttle opening up, I know I am close to what teh mixture should be.


Just removed the side airbox cover only, not the foam, ran perfect. No smoking, smooth all the way to 40mph! Pulls unreal and strong. I started to trim away some of the restrictive plastic in the air passage on the cover. Removed the center plastic divider that seperates the two air passages, then opened up a 3rd passage just above the two air passages, then trim some more here and there and finally removed the square plastic flap on the cover that leads to the air passage. Now it gets all the air it needs and runs perfect while looking like a stock airbox. The uni filter would have been ideal but then the rain issues, I wanted to keep my airbox. The new gears should slow the engine down unless it still has alot of power if not then the new speed variator should, then the preformance muffler should give it more pop again. I am hoping it all works out and stays that way!

I trimmed and ran, trimmed and ran while doing the airbox cover. Now I can't help but wonder, my scoot wouldn't run without the airbox cover, too lean. I wonder if I was to have drilled out my main jet, not as much as I did now but say to a #90 and opened up the airbox if it would have ran fine and stronger. Well, too late now but might be something for someone to try to get more power cheap without doing a big bore change.

Anyone have any input to this Polini kit especially the spark plug being off center, let me know. Thats the only thing that has me bumed out.

[itzmepete]

Well, got that Tiawani cheapo 8:44 to 1 final drive gear set, was no good. The spline on the middle shaft was not manufactured correctly. Now I gotta return this junk back to get my money back. Broke rule #1 don't pay high shipping as S/H is non refundable. Informed the seller of this defect and he said it was that it is manufactured for the Jap model Dio, I think he is full of it as he pulled all his gear sets off ebay. He says he will refund all my $$ including shipping to and from, lets see.

In the meantime, I called ebay seller Daywot and ordered a new Speed Variator, Polini drive belt, and Koso gear set 8:44 to 1. Gear set had some surface rust , cmae off with a Stainless Steel brush, Belt was nice and the Variator, well, read on.

I took apart my speed variator to clean it out. Had a few light rub marks from the belt. The rollers had more flat spots than I can count. Figured, heck, just buy a new Keli Preformance Speed Variator, now is the time. So I ordered one that promises better fuel economy and an increase of 4 to 6 mph.

Well I got it in. First, doesn't come with a new ramp, gotta reuse the old one. Doesn't come with a new bushing where the belt and the variator rides on, gotta use the old one. So what does it come with?

6 each new 9 gram rollers and the housing. yup. Well, its a preformance housing, gotta be bigger to get the belt up higher right? Well, nope, same diameter of the stock unit. Infact, even if it was a larger diameter, it wouldn't fit in the Elite SR! So, gotta have something different right? After all its a preformance pully? The angle as to be different right? Nope, angle is the same, fact is it can't be different or it won't mesh/seat with the belt correctly as the other drive face, the starter gear drive face plate angle has to be same with the pully. So, how do they get an extra 4 to 6 mph then? They don't, they get it only if your unit is worn, or rollers have flat spots and you lost the speed due to this. What you are getting is the original speed that was lost due to wear.
If your speed variators drive face is not scared or eaten up, here is some advice, clean it good, replace the rollers and maybe the 3 Ramp guide plastic bushings, thats it, your done. Don't think this $45 Preformance unit is any different than the stock one, its the same and anyone says differently is BS'in you. Now, on another scooter, it can be possible, on the Honda 1999 Elite, a larger diameter one just won't fit to to clearance issues with the transmission case.


I have digital pics of both Variators installed and you can see the diameter is the same, so no taller gear, no free speed increase.

If you doubt me, PM me ur email and I will send pictures. I am learning as I go about these Elites and some things are not worth the money, the cylinder was, the muffler is, the speed variator, if its not worn, save the money and get just a complete roller weight set for $14.99 on ebay.

Gonna finish installing the gears, once done, I would have done the following,
Polini Corsa Kit, New Speed Variator, New Wider Polini drive belt, 9 gram rollers, 8:44 to 1 Koso Final drive gearset, Carb jet drilled out with a 1 mm drill bit to equal a #100 jet and airbox modified by opening it up some to increase airflow.

Once done, I will report the preformance gain as well as difference from my 35 mph stock speed.
Last will be a new R1 muffler and I will note preformance gains.Hopefuly someone will read and learn from my experience as well as my mistakes !

Anyone has the Polini Corsa or Contesta kit and had the same issue I have with the spark plug not being centered on the air shroud hole???

[MySpree]

UHHHHHHHHHHHHHHHHHKAYYYYYYYYYYYY, # 1, The polini corsa kit is made like that, yes the plug is there for a reason, its placed for more power, you need to sometimes shave the kit by the intake, # 2 yes there is a diff from the normal elite and jap dio, # 3, the jet is for a aftermarket carb, like a oko, #4, daywot is a good guy, and knows his s***, #3, THE KELLY RAMP IS DIFF, LOOK AT IT, IT HAS THE SAME DIAMITER, BUT IT HAS LONGER RIDE GROOVES, WHAT DO YOU THINK I RAN ON MY ELITE!!! AND ITS STILL MY FAV VARI, I HAD TO USE THE SAME BACKPLATE AND s***. AND NO IM NOT B.Sin YOU, YOU HAVENT BUILT NEARLY AS MUCH DIOS AS I HAVE. NEXT THE R1 PIPE SUCKS, SORRY ABOUT CAPS!, I KINDA STARTED TO TYPE IN THIS, AND HAD TO TYPE TO MUCH TO CHANGE IT...

[itzmepete]

Well, I agree with you on most.
#1 I knew or figure the spark plug angle was changed because of more preformance OR maybe because the angle is different on the Jap Dio motor? In any event, I wanted to hear back from someone that has purchased it for their american honda and see if they had the same experience. I tend to think it is probably designed to match the japanese Dio motor but I could be wrong. In any event, I don't like it. I will try and find a new replacement head with the correct angle for my plug OR I will bead blast my old head, machine the lip around the top to match the bigger cylinder bore, and next time use my old head with a metal gasket. I just don't want to fight the plug shrould issue every time I mess with it. If the jap air shrould is different then I will try and get one of those, I just know the polini kit is not cheap and I did not expect that.

#2 I did not shave the kit on the intake side, but got it in when I loosened the manifold and or tapped the cylinder down with my hand. I saw it rubbing on the exposed reed excess gasket that was slightly sticking out. I would rather trim there than the head.

3# The jet I was told would not fit my stock carb, as per VT. I emailed Daywot about this. I wanted to see if he had a jet that would work, I never heard back and was forced to drill mine with excellent results. I was lucky to have such small drill bits, what if I was out in the boonies and did not have a drill bit of the right size. Would have sucked to buy an expensive kit only to fnd this out later. The included Polini jet is also a smaller diameter, its a #84 I think if i recall correctly, not a #100 like what VT recommends, my stock jet was a #78. If I had an after market carb and used this jet, I fear it would have been too lean. I know my drilled out #100 jet is giving me a perfect chop plug. I know Patrick is busy with other buyers on ebay, would have still been nice to hear back from him after all I just purchased a $245 cylinder kit. The Kelli Variator is the same angle, same length as my stock. My stock is just smooth and shiny from years of use. Yes it has little groves put on there from the machining process, weither on purpose or to assist in traction or belt travel, the belt will only go as high as the rear ramp plate allows the housing to travel and push the belt up.

The R1 may be crap, but when I buy it , I will get the black one, strictly because I want a stock look, not a preformance look. I know how a good 2 stroke motor "Pipe" works. I used them on my model airplane Rossi engine racers. A good 2 stoke preformance muffler uses a tune pipe design which looks like two cones. This design pulls exhaust out of the cylinder, as well as a little of the next air fuel charge thru the cylinder and into the very begining of the muffler. When the exhaust travels inside this tuned PIPE, it creates a sonic bounce back and then travels back into the cylinder pushing that extra bit of fuel air charge back inside the cylinder before the port closes to kinda turbo charge it. I used tuned pipes on my airplanes 2 strokes and cut them down at the header until the engine goes on "Pipe". Its not easy , if you make the pipe too short, it doesn't work right and too long the engine doesn't go "on pipe" The R1 is not the best, but for a 72cc, its * of a lot better than a stock muffler especially with a big bore kit.

Last , as for Daywot, he is a cool guy, I have recommended him to others. He got out a new set of gears to me super fast and saved the day when the cheapo generic one didn't work. He also gave me a break on the price and was the last set of 8:44 to 1 set as even VT was out so I am not picky by no means although it had some slight surface rust. Rust on a journal is not a good place to be, luckily was slight and again cleaned off with scotch brite. I under stand that these metal gears if handled with hands, will get sweat on them and can rust if a coat of oil is not on them. I did ask him about the polini head spark plug deal and he did not know, which I would have expected him to know as he sells alot of these. The speed variator, I still don't agree, look, I have pics of my old one with wear marks, the belt rode almost to the top if not the top. I am sure with heavy weights, the belt will ride as far as it will go. Belt can't run higher or it will rub on the trans case. My point is the speed variator on this specific model, the honda elite, is not a place to spend a ton of money, period. A good stock one, clean with new rollers will work just as good.

I will buy from Patrick again with no problem. He is more expensive but his stuff are quality parts all the way and faster getting them from him than VT Cycles. I never said the Kelli variator was a cheap part quality wise. I am sure its cheaper $$ than buying a stock one thru Honda. I was just not impressed with it. I don't believe it will outpreform a new stock variator BOTH using same weights, rear ramp, both new, period.

Not in a * match here, just don't want someone new to think on this elite model, that some things are better than a stock one. Spend the money elsewhere on the bike.

[chevyguyjay]

yea, thats way to much typing for me......lol

[itzmepete]

I type fast. My point is, most newbies here all ask the same questions, "What can I do to speed up my SR50 cheap?" I know I asked this. No one really answers that, just replace this and that which costs money, time. Now I am just redoing it all and learning from it. So others that are on a budget can choose what to upgrade, what to just clean and fix to get best bang for the buck. Don't need to spend $45 let alone $125 for a speed variator especially when it doesn't come with a new ramp. Some new assorted roller weights, a new belt and a can of carb cleaner is fine unless your variator drive face is chewed up or worn.

That is the purpose of a forum, to share experience and learn from one another by reading in detail is always helpful!

[burnt_toast]

After market vari is better if you can tune for it, rams and plate DO make a difference. Key is TUNING.

[Dac]

After market vari is better if you can tune for it, rams and plate DO make a difference. Key is TUNING.

QFT

[itzmepete]

Pics where I am today. Yes Toast, Key is rear ramp plate, weights and tuning which can be done with a stock variator housing as well. I will buy an extensive variator weight set, maybe a rear plate or two but no variator if its the same diameter. I was curious so I temp popped the rear gear housing, with my hand, I expanded the rear clutch and squeezed in the old stretched belt all the way down in the clutch. Then installed it and stretched with my hand the other end of the belt. It just made it to the outter end of the variator pulley, I tried it with the new Polini belt and no way, too new and tight. So technically, if you machine the case to take a larger variator, if you use a stock belt, it MAY, may not be long enough to take advantage of the larger front pulley to make it to the outter top edge as its already bottomed out at the clutch end. Thats what I was trying to say. My goal is to get max speed, drivability, reliability while keeping the "Stock" look. I ordered a new rear clutch BTW, mine was 75% worn.

I am not trying to argue here now, all friendly but I just want to get feedback from those that have been doing this for a while, as well as share my newbie experience so others that don't have the tons of money can spend it where it helps the most. Plus, always nice to stir the pot and get everyone thinking isn't it?

[burnt_toast]

Well I've been tuning scooters for about 5 years now, and to a certain extent you have a point. I have an MRP variator on my Zip90 that drastically helped my shift curve, and with a proper belt boosted my top speed by 10mph! This bike is fully built and at the time had needed this change badly.

But, I decided to try the same MRP variator on my Triton and Zip50, which where both close to stock at the time (Triton just had chamber pipe), and the SAME variator that added 10mph on my stroker, did very little when installed on these bikes!

So in conclusion, where you may see a bigger difference with these vari's is when you have more mods and power. Also keep in mind the previously mentioned are all jog based, Dio may be different in characteristics.

[itzmepete]

Well,
Finally got the old 12.2 to 1 final drive gear pressed out and replaced with a new 8:44 to 1 gearset. The local machine shop used a hydraulic press, took bout 10 min and they did it for free!

Cleaned out complete tranny case. Got my New 8:44 to 1 gear set back in, new variator, 9 gram weights, Polini Corsa kit, drilled carb jet with a 1 mm drill bit which leaves you with a # 100 jet. Still using stock muffler, modified airbox by opening it up, I have included pics of the airbox below. Still function as before just let more air into the housing. I basically started by removing the plastic divider in the two air passages, Then added a 3rd square opening on the plastic lip not seen cuz it was removed when I needed still more air to come in. End result is what you see now. It runs the same with the cover off as it did on. Before it ran fine but with the cover off gained 5 mph so thats why I started opening it up little by little.
I used new gear case gasket ALTHOUGH as others have said, if you are careful, you can reuse the old one. The gasket is very think and durable, a little permatex or Indian head gasket coating is ideal, I would not use a silicone forma gasket. I added 3 ounces of oil which is acutally just UNDER the oil fill port. I did not use 10w30 as I am in Florida, hot, plus figured with the new faster gear, 20w50 would hold up better. Popped everything back together. Started it up and went for a ride.


Was easy on it till it warmed up, rode at 25 mph for a few blocks. I noticed right away that with a cracked open throttle and I was doing 25 MPH! Once warmed up, I opened it up a bit and was going over the 35 reading with about a 1/4 travel on the throttle. Stopped and from a stand still I gunned it. First, from a stand still, takeoff is about same or a hair less than stock for the first 5 feet then accells slightly harder than stock gear and stock 50cc for about 2 or 3 seconds and then much harder! Problem is that it keeps accellerating past 35, fuel guage and then dissappears! All smooth and very fast. There is no need that this thing go this fast , its scary BUT it will not only keep up with 45 to 55 mph traffic, you still have power to spare if needed. I have not maxed it out for max speed but will do so after I run a few tanks of gas thru it.

PLEASE REMEMBER THIS, THE BRAKES ON THESE SCOOTERS ARE NOT DESIGNED FOR THESE SPEEDS! Make sure they are in top shape. I know the Jap Dio's have disk brakes. A conversion kit would be ideal and I will look into that when I deal with the new speedo.

Now my assesment. I big bore kit is a must, any brand will do, I prefer steel cylinder. I did reasearch all the different kits. I settled for the Polini Corsa as a steel cylinder is a steel cylinder but not every aluminum piston is the same so with the Polini I felt I had two things.
1 A factory ported Cylinder of the highest quality
2 A high quality piston. Even the piston skirt was machined to improve the boost port. I don't know if other big bore kits have this feature.

I never used the street preformance Reed that came with the polini. Figured I'd save it for a rainy day. Mine works fine, why mess with it now I figured.

A cleaned rebuilt Variator is a MUST. This mean clean it, use new rollers and a NEW belt. I think everyone here knows my OPINION on a so called racing Variator.

Don't make a mistake I made on a cheap taiwan gearset, check the spline carefully for proper fit. The seller told me the spline was correct but made for a Dio gearbox. I am skeptical of his answer but he did refund my money and told me to just keep it. I have no use for it. I guess it can be used but I would have a professional welder lay a few welds on the gear and shaft to make sure the spline doesn't give.

1mm drill bit works great on a carb's stock jet.

With just the polini or any big bore kit and stock gears I won't advise as
1 Engine revs higher with stock gears, Eats ALOT of gas, and you can overheat it easy. I was getting I guess over 85 to 90 mpg stock, swapped the head with the big bore and I could see it eating gas for the little time I test ran it.

2 Yes, with a big bore and stock gears takeoff is unreal but top end only improves by 5 mph, thats it. I dunno, if you were racing some sort of short track, top speed of 35 mph then fine cuz you want neck snapping accelleration. Otherwise, get gears, 8:44 to 1 is perfect. I cant really see using these gears with a stock 50cc. I can't imagine the poor accelleration, the load placed on the motor as the gears would be alot for a stock motor but it can be done and if I had to use a stock 50cc, I would use 9 to 1 instead, stiffer clutch springs and maybe a tad lighter vari weights.

New gears with Big bore slows the engine back down and takes advantage of the big bores extra torque and power. It also brings back the fuel economy. I can't imagine what the fuel economy will be now as it takes very little throttle to get it going to 35/40 mph.

I am very please over all, I could probably replace my clutch springs with a tad stiffer and improve take off but like I said, takes off just like a stocker for the first 5 feet then it zooms! I was doing 45 up a small hill, not so much as hesitated, slowed down or anything. Headwind, not a problem. 35 mph is attained with a mere 1/4 throttle travel!

Gonna go on a 95 mile trip to my friends house, easy 40 mph , open it up a little every now and then as well as shut it down when I stop and take a break. Figure back and forth would be just under 200 miles and a good break in. I am adding 1 ounce of Castro 2 stroke injection oil in the fuel tank till I get some Honda oil. Eventually, once broken in, I will top off the oil tank, mark the full level on the neck with a sharpie marker , run a gallon of gas and then top off the oil again to see how much oil it ate. This way I will know exactly the fuel oil mixture ratio. I do have my oil cable adjusted all the way but not wired open as I don't think all that oil is needed at slow speeds. Plus, I did a chop plug and plug looked great. I hope this helps anyone out there. All that is left for me is a new muffler!

[itzmepete]

An update, I did all my mods and noticed that take off speed from a stand still with the Polini and 8:44 to 1 gears was not as good as when it was stock or with the stock gears and big bore kit. I had ordered a new , well a used (345 miles) rear clutch as mine was about worn, I'd guess 80% worn. Thought about up'ing the clutch center spring and the 3 shoe springs. Well, clutch came in and I popped it in stock. Take off from stand still is now great. I credit it to several things.

1) While the clutch is stock, it is new and the springs are fresh.
2) Shoes are new and makes a perfect contact. My old shoes had maybe a 60% contact. See dark area on pads, the white area is a groove cut and did not make contact.

With the new lower gears, its obviously harder for the clutch to turn soooo, a clutch in good shape is a must. My old clutch had uneven wear as if something let loose inside and wore out a center section of all 3 shoes.

In any event, Take off now with the 8:44 to 1 and the Polini is as good maybe better initially , first few feet, and then much better than stock, hold on! Here is a few nice pics of bad clutch good clutch.

I am half way thru my 1 gal fuel run and then gonna check the oil tank to see how much oil it is injecting so stay tuned.



Good Clutch $49 ebay like new

[itzmepete]

Update, almost 2 years later the old factory crankshaft bearings went out. Trashed the Polini Corsa. Working at Delta Airlines I had alot of access to tooling so I tore it all down. Media blasted everything including side covers and both wheels. Did a run out check of the factory crankshaft and was true as well as the bearing was fine. Then I replaced the crankshaft bearing with new Honda bearings. Used aircraft PRC sealant to seal the crankcase halves. Repainted the Crankcase grey PGP polyurathane. Repainted the side covers gloss black same as well as the stock intake and oil pump and starter. Repainted the wheels and they are super clean and white looking better than new. Replaced all the seals, gaskets, thrust washers everything. Tranny already had new gears and bearings. I did not want to waste another $300 on a Polini so I got a $99 kit from Chopchop on ebay. It was an 80cc kit and was all first quality. Put it all back together using the old R1 aftermarket bigbore muffler. Bike started right up. Still breaking it in. Preformance wise is almost as fast as the Corsa at 1/3 the price. Runs with the airbox opened up when it wouldn't with the Corsa. Carb needs to be tweaked after I break it in and I think it would do better with a better exhaust but I am wanting that stock look. Video on YouTube under author itzmepete search Honda Sr 50 Alarm Big Bore. Added a super cool Thor keyless remote alarm and start.

[kingkamehameha]

Your not gonna get maax perfformance witth a uncut boost port and stock carb. No wonder you blew the corsa you didn't even break it in good. You shoulda bought a crap bore first then a corsa later after your tuning was all good. Noooob