Yasuni Z Pipe Tuning For Eton Beamer

[bvulic1]

Recently started tuning my scooter to this pipe. Purchased and installed the Yasuni Z, 90main jet, stock air box, new cvt belt, 4g Dr. Pulley sliders, 2k clutch springs, 1500k torque spring, performance coil. From what I've read, the power band on the Z is 8500-9000 rpm. With the 4g sliders, it revs to 8500-8700rpm easily. Top speed on gps is at 42.6mph so far.

The belt leaves about 1/4 or 1/3 of an inch at the top. Any idea if anything sticks out as an issue with this setup? I should have a lot more top end but I do not  know what is limiting it. I have a feeling the mixture is still a bit lean, and the mid range seems to not pull as hard as WOT. Thinking of dropping the needle a couple notches. Any info is appreciated.

[2stroked]

Own the same.bike. The major limiting factor for these is the shit awful 13.?:1 gears. I get to 49-50 and it's topped out. Polini cylinder technigas pipe and revvs to 9400. I would recommend a set of gears if you want to go faster than 50..

[bvulic1]

Thanks for the reply, any ideas on how to get higher belt travel? Key issue is that i am not using all of the belt travel leaving 1/4-1/3" off the top.

I had a similar build aside from a Technigas exhaust instead of the Yasuni and i got it to 45.5 gps. I feel like something in my setup here is leaving something on the table.

[190mech]

They came with a shorter belt,you need a 788 to get the travel and the stock variator has a cast in restriction that limits travel also,,so a mo-betta vari and 788 belt will help,but the 13.55 gears as stated will keep the speeds down still...

[2stroked]

Just like John said the stock variator has a built in bottle neck. Get a decent aftermarket front half and a 788 belt. It'll get you to the top of those damned gears. Mine will get there quick, and the engine "feels" and sounds Luke it had more, but the gears are holding it back. Sucks too, cuz I love these little guys.

[repherence2]

I agree with 2stroked and 190mech about the variator and belt. Just a heads up, take a look at the roller ramps on the variators (upgrade) that you are intending to buy. I once bought a Motoforce variator thinking that it was a performance variator. However, the roller ramps were identical to the stock variator, no performance gain at all. I have since switched out to KELI high speed variator because they were readily available at local shops here. The roller ramps on the KELI are different, in length and curvature, than the stock unit. There are also the Malossi Multivar and the HOCA multivar clone as well.

As for belts, I run 792 because my 90 block came with it. All my previous set ups (stock and bbk) I used the 788 belt. I have come to like the 792 more than the 788.

[aeroxbud]

Sounds like these guys have pretty much nailed your problem. It probably does not help that the Yasuni Z does not like to rev once out off the power band. It's quite a good torque pipe. But you are hitting its peak power as the gearing tops out.
New variator, and a slight increase in gearing should see good results.

[bvulic1]

Thanks to all that chimed in so far. In the past, I have tried the 788 belt on my previous E-Ton and for some reason it seemed like the belt had some slack when riding. I didn't notice any top end gains from it. The 780 belt felt so much more direct and powerful which is why i kept it stock this time around.

As for the Yasuni Z pipe, am I spot on with the power band? I have it revving to 8500ish with the 4g sliders which is what i gathered is smack dab within the power band. Am i overrevving?

[aeroxbud]

You are pretty much on the money with the rev range. Here is a dyno graph www.pedparts.co.uk/c/asset/sports-pipe-blog/50cc.png

[bvulic1]

Great, I may go back to the 5g sliders because from my experience each gram up in sliders essentially drops rpm by about 250-300. That should bring me closer to 8250.

I'm still trying to chase the lack of full travel on the cvt belt. Trying to put my finger on it exactly aside from the belt and gears, because on my previous Eton, I had it up to nearly 46mph with the same exact setup aside from a Technigas pipe and 86 main instead of this Yasuni Z with 90 main.

[190mech]

I think 2 or 3 of us said the stock variator limits the travel,,how many more need to chime in???

[bvulic1]

I understand the variator is naturally limiting travel and I appreciate everyones input on this. However, aside from that fact, I am trying to fine tune and understand why I was able to get higher belt travel as well as higher top speed on essentially the exact same setup and same scooter in the past. Brainstorming out loud.

[2stroked]

Mar 21, 2019 13:40:38 GMT -5 bvulic1 said:

Great, I may go back to the 5g sliders because from my experience each gram up in sliders essentially drops rpm by about 250-300. That should bring me closer to 8250.

I'm still trying to chase the lack of full travel on the cvt belt. Trying to put my finger on it exactly aside from the belt and gears, because on my previous Eton, I had it up to nearly 46mph with the same exact setup aside from a Technigas pipe and 86 main instead of this Yasuni Z with 90 main.

That 46 is smacking the wall with the bike. 49 is the wall, but there are ways to climb over it.

Dig into the rear halves and clean the TD tracks. Make sure the driver can smoothly move. Also measure the width of the belt and make sure its in spec, if its too narrow it won't run out all the way.

You may get the rest of what you're looking for, but its unlikely. Two identical bikes will behave differently. There's not much more that can be done to get faster without getting a better vari. The vari on this bike may even be worn out more than the other one was, there by keeping you from reaching your goal....

[matlock]

i think you should try a heavier roller weight go up 1 gram or 2 and see if thst helps the top speed and maybe a little less on the clutch and contra i bet you be up in the 50 mark