used to be the Wife's 2002 BWS 70cc Build

[Zino]

Your set your weights so they jump to a rpm level that is in the center of the power band every time you hit the throttle wide open . We call this the shift point .

I set my weights for the athena and yasuni pipe to jump to between 9000 and 9500 rpms and then rise from there .
This gave me max speed and responsive throttle .

Try this put the aluminum foil in the heaviest weights you have 6.9 +.5 =7.4 ,
This will cause your transmission to shift too quick and feel boggy and then it will pick up speed at a certain rpm.
Note that rpm and set weights that shift at that rpm.
I found that for each half gram change in weights I could change the shift point by 300-500 rpms.

Right now you are hitting 8800 rpms with 5.7 grams
If you find your shift point needs to be at 9100-9400 rpms after the too heavy test ,buy weights in the 5 to 5.25 range.
here is a good reference
The Atheana you are running is the same as the stage 6 sport Pro MK1 in the charts Athena made that cylinder as a clone of its own
www.pedparts.co.uk/blog/sports-exhaust-testing-50cc-and-70cc-sports-mopeds-part-two

[davybondo]

Wow that info you gave is amazing
there's so much good reading on that Pedparts page to
I have a new Torque Driver, clutch, Contra spring "yellow Malossi" and clutch bell coming, I have a white spring right now
the stock clutch must have warped cause the shoes were twisted slightly that must have been the slipping
when I get the parts I'll try the weights again, it takes 2 weeks for the stuff to get here
I'm amazed this scoot is so fast, that Doppler pipe must have been ahead of it's time
I bought that in 2003 cause she said it was to slow, put the pipe on and jetted it and it sat ever since cause she said it's to fast
Thx for your help Zino

[Zino]

stiffer contra springs need Heavier weights to overcome the spring
I found if I go one notch stiffer on the contra
I need to raise the weights by a half gram to a gram to get similar shift points .
I was able to get buy with the malossi white spring

the way i look at tuning the trans is work back to front
for the contra
just stiff enough to stop belt slip this cuts down on heat and belt wear.
I want clutch springs that have me take off with power I want to jump of the line when I hit the throttle .
Variator weights that give me the best top speed and have the best on off throttle feel

When you have a tach it helps make tuning faster and easier
for example
you can use the way too heavy weights in the variator you will feel where the power band starts and note that rpm

As you change transmission components like contra springs you can use the tach to find the right weights that get you back to the rpm that has you in the powerband .

[davybondo]

Thx
when I bought the variator it came with the red spring
I put it in yesterday then took it back out because I couldn't compress the pulleys
to install the belt
I have a yellow spring coming but now after what you said I think I'm gonna stick with the white spring for now

[davybondo]

I picked up a Drive Belt sootertuning
it's a Mitsuboshi Hyosung 772x16.5mm
real size is 761x16.2 wide by 8mm deep
Model: VC30920
and was the last one they had in-stock
I installed the 107mm NYC rear pulley and 107mm Mallossi Fly clutch with a yellow spring




these pictures are the 1st ride 12.5 miles so I gotta break it in more yet
I'm getting full travel on the rear pulley with 3mm left outside edge



the variator has 2.8mm shims at the boss and belt is riding down 10mm from the the boss





I'm hoping as the belt wears a little I'll be able to take some shims out and give the lock nut more threads
I didn't use any shims against the starter clutch
it's slow on take off so I'm thinking of trying to split the shims and put half of them against the starter clutch
I don't now if it'll make any difference
I have 5.2g and 5.7g rollers, speed is good still 50ish mph at 9800rpm and it has more to go it's like there's no end
I don't wanna blow it up

I've gotta get the carb sorted out now
running at 40mph it's rpm is 9100 and the temp at a 287f
at that speed it sometimes almost feels like it's running out of gas till I open it up again
and it wont start when it's warmed up unless I give it gas
gas mileage is terrible I can almost see the gauge going down so I just made it back before bending the empty needle
1/2 tank for 12.5 miles so now I'm looking at the carb and float needle setup
the plug BR9HS doesn't look to bad maybe a bit rich (to me anyways) the 92 main is still in
and the mix is 50-1 gas is Mid grade 89 and 5% Ethernol
one side of the plug is darker than the other
if you guys can give some advice that would be Awesome Thx

[Zino]

You are on the rich side for jetting based on your temps and plug color and gas mileage .

I like to use a gps to find the jets that perform the best on wide open runs.
Start with your 92 Note top speed and responsiveness
Go down to the 90 If it is faster and feels more responsive go down to the 88
Keep going till speed levels off .

Then from your notes take the richest jet that gives you the best top speed and feels best .
Double check with your temp gauge to make sure that the temps level off on wide open runs .


After you have the carb dialed tighter you could try thinner shiming to see if that cleans up your bottom end .

.

[davybondo]

Thx Zino
I'm doing that right now
I have a Garmin that records top speed and mileage