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OK, so finally I got my bike properly jetted, with the correct springs and the right roller weights. I am still stuck at 44mph top speed (GPS-verified). In summary this is what I've done so far from stock:

- CDI & Variator derestriction. This alone got me up to 42.5mph.

Then I did all of the following:
- 130/70-12 rear Michelin Bopper tire.
- Tecnigas Next R exhaust.
- K&N Pod Filter.
- Rejet from #90 to #110.
- New spark plug.
- 1000 RPM main spring.
- 1500 RPM clutch springs.
- 7.5g roller weights.
All of this just got me an extra 1.5mph and I think most of it came from the tire. F-ing ridiculous!

The only positive is that I learned some mechanics along the way.

I checked the wheel ratio which thebatman had asked me to do. The clutch turned a total of about 10.6 times for one full rear tire turn. I don't know how this helps in the diagnosis. You talked about some ZX's having different gear ratios.

So anyway, I don't want to keep my bike like this. I am either going to get rid of it and get a faster one OR put a BBK on it. I just got my Motorcycle endorsement so that's not an issue anymore. Money is no longer an issue either as I sold another bike that I had.

So here's what is going to sway me one way or the other and your insight is much appreciated:

1) Is this BBK thing as simple as buying a kit/new-carb/air-filter (I already have the pipe), then bolt it all on, do some plug chops and then I'm done? Or is there a whole lot more invloved? If someone can point me to some instructions that would be nice.

2) I am also worried that I get all the work done and still no gain. I've read that this has happened to some people and so far that's what I've encountered. Any comments?

3) It looks from what I have read elsewhere that after putting in a BBK reliability goes way down and that you should expect to be stranded, so if this is going to be a common occurance, I'd rather pass. I'm all for learning to work on my bike but I really mostly want to ride.

Thank you!

Ahh! OK, I understand now. Yeah mine is 28mm as well. I ordered this filter:
http://www.knfilters.com/search/product.aspx?Prod=RC-2540
Will report back once I have this and rejetted.

Hey bat, you wrote a few replys back:

"Stiffer springs in the cvt... 1000 main....1500 clutch springs if not 2000".

I am not sure I don't understand. Am I supposed to try the different strength spring to see which one is better (as I am doing with the roller weights)? Or should I just go with the stiffer ones (2000)? Or?

Wow, the rear wheel nut finally came off. I had to take it to a shop to get it done. Even with an impact wrench it took the guy half an hour to loosen it. Anyways, I was doing 42.5mph before, now with the new rear tire I am at 44mph. Not a big improvement but it still counts. I am going with the pod air filter next and play with roller weight sizes some more.

Question for bat, you said to use a #90 jet after putting in the pod filter, but I recently read (can't remember where) that the scoot has a #90 jet in it's stock form. Did you say that because when yours was stock there was a smaller jet in there?

If mine then has a #90 stock, what # do you recommend I start off with after installing the pod filter? Keep in mind that I also have the Next R installed.

And there is only a main jet that can/should be changed, right?

Yeah you guys are right, I think I'm gonna have to splurge on a Kit. Which one should I get? Same with the carb. It looks like the stock one is a pain to rejet, so which one should I get?

Sorry for taking so long to get back here. Life has been throwing a lot of curve balls that have distracted me from my bike, but anyways here I am again with another inquiry. I am completely puzzled. I finally installed my new Next R pipe. The pipe came with ~5.5g rollers but I didn't install them yet. The reason I didn't is because I was under the impression that if I kept the stock rollers that I would get a higher top speed being that these are ~8.5g.  My logic is based on: heavier rollers = higher top speed but lower acceleration while, lower weight rollers = lower top speed but higher acceleration. Well, turns out that I did a test run and gained 0mph. I basically saw no speed improvement whatsoever. I was doing a GPS-verified 42.5mph top speed with the stock pipe and with the new pipe I saw the exact same top speed. Based on the logic above, I would think that putting in the 5.5g rollers would lower my top speed. So my questions are: Is my logic correct? Or am I missing something? Would the 5.5g (or other) rollers actually give me more top speed?

Another thing I wanted to ask about is I bought the pipe from Provo Scooter and on their website it shows the following note for the Next R.

"NOTE: Due to increased emission regulations all Tecnigas exhaust now come with the washer restriction in the mounting flange, which should be removed to get maximum power gains."

I didn't see any washer on the mounting flange (which is the input to the exhaust pipe right?). Is the washer inside the pipe? Would kind of defeat the purpose of getting an aftermarket pipe though. Did I miss the washer somehow?

Thanks for your help!

Hey bat no prob. Thanks for yet another reply. Sorry for the long absence here also. Have had a lot of work. Just got my new Tecnigas Next R yesterday. Will install this weekend and send an update on how it went along with some pics of course. Right after that I am getting the rear tire. I want to do one at a time to see the effect each mod one has.

Thanks again for the reply thebatman.

So bigger tires sounds like a great idea. I assume the scoot then “catches up” with the actual speedo then? So say, since my speedo is currently reading 45mph (probably a REAL GPS 40mph) with the new tires (front and rear) I WILL be achieving a REAL 45mph? If this is true, it sounds like just the rear tire change will give me an extra 5mph and the front one is what will make the speedo reading accurate. Or am I missing something here? Also, do these tires slip right in without needing to take off (or mod) the fenders?

Regarding your original post suggesting to drill holes in the stock exhaust. I am just curious. Where would these holes go? Any pictures? I know this will of course make it louder, but with that and the Pod Filter is it a LOT louder? How is the noise compared to getting the Technigas? I really don’t want to piss off my neighbors.

I also saw on scooter-assassins an exhaust that looks like the stock but it says it is unrestricted. Anyone tried that one?

Here’s the link to it:
http://www.exportstrength.com/product_info.php?products_id=677

BTW, on that website when looking for parts for my 2005 Super Fever ZX50 it shows two options:

ZX 50 ( Fever II ) ZXII

and

ZX 50 (Fever) KCA Model

Which one do I have?

I’m in the US BTW.

Thanks!

Thank you much for the reply thebatman. I’ve read so many of your posts. Thanks for sharing everything you know.

1) So I took here apart with the intent to shave the boss drive but as soon as I removed it I realized that the boss drive didn’t have any “shoulder” on it. It looked just like this one:

http://www.exportstrength.com/product_info.php?products_id=403

I’m just not sure I see it clearly in the scooter therapy link that I posted originally, but I assume the “shoulder” is a small section of the drive boss where the diameter is slightly larger than the rest of the cylinder?

If yes, then I assume that the fact that mine looks like a perfect cylinder means that the derestriction had already been done, right?

If anyone has a picture of (or a link to) the stock one with the shoulder still on it I’d like to see it just to be sure.

Anyways I guess I need to go measure my actual speed with a GPS. I assumed I would be getting 45mph after the two mods, both of which it seems I already have. Thing is my speedo is reporting 45mph and I understand that it likes to exaggerate, so really I’m getting sub 40mph?

2) Now onto thebatman recommendations. I’m not sure I want to drill holes in my exhaust or do any head shaving (I don’t want to take my engine apart yet). I don’t want to make irreversible (or difficult to revert) changes. That’s great info though. So I guess that makes it so that I will have to fork out some dough if I want some more speed. So how about this?

What if I got this exhaust?
http://www.provoscooter.com/scooters/kymco/kymco-zx-50-2t-ac/tecnigas-next-r-expansion-pipe-chrome-honda-dio-kymco-dj.html

Along with a Pod Filter (recommendations?), 6g rollers (should I get Dr. Pulley’s?) and rejetting the stock carb, that shouldn’t take me too far off my $200-ish budget.

So, what would be my approximate speed increase?

Am I missing anything that must be part of this package in order to gain some speed without destroying my engine prematurely?

I wouldn’t HAVE to do the head shaving, or would I?

Thaks again!