Zuma fifty top speed loss

[jaysan]

Ok so my zuma used to hit forty miles an hour then one day it maxed out at thirty four miles and hour one day .

I did a search and someone said it was a variator issue

So I bought new seven gram weights and belt . New weight housing sorry not sure the name .

Well after I installed everything my zuma maxes out at thirty miles an hour .

[Zino]

Take a sharpie and mark the variator from inside to outside edge make a high speed run
and measure how much mark is still left
The stock variator can get below 3 mm left
7 gram weights are heavier than stock weights They run 6 or 6.5 grams typically
That would cause your peak rpms to drop and Top speed .
Going too heavy holds back rpms Going too light on weights doesnt let you take advantage of the full gear ratio of the variator 

[Zino]

top speed is a factor of how many rpms with power times your gear ratio .

starting with variator gear ratio is easiest to diagnose .

[jaysan]

I will mark it with a marker . I bought this used and noticed the other side where the clutch springs go it said malossi . It also has upgraded exhaust. Low end rips .

[jaysan]

Apr 11, 2021 6:00:10 GMT -5 jaysan said:

I will mark it with a marker . I bought this used and noticed the other side where the clutch springs go it said malossi . It also has upgraded exhaust. Low end rips .

[jaysan]

[jaysan]

Rollers don't have flat spots . I don't see a weight rating on these

[geoffh]

You need a set of small scales to weigh your rollers,measure the belt you used to get to 40mph and compare with the replacement,not all belts are equal!!.

Geoff

[Zino]

Do you have 6 weights for the variator ?

Please take a picture of your back pulley set up .
So we can see what clutch you are running and to see how far out your belt gets on the back pulley at rest .

What belt were you running before and now ?
Stock yamaha works best till you start going overrange transmsision .

[mrchilled85]

do you have all the rollers ? i would be checking for wear on the ramps on the variator and check belt wear to as i had this last year i was only getting to 33 mph fitted a new belt and was back over 40mph

[ThaiGyro]

Just have to ask...did you change anything else in the fuel system? Ignition? Use premix or injected oil? All things being potential problems. I always check ignition timing first, because that is my experience with sudden failures/power losses.

Then look at combustion and drive systems. I also suggest getting a tach and cylinder head temperature gauge. Makes life a bit easier to diagnose For example: If you were turning 9,000 rpm at 40 mph and still at 9,000 at 30? That is dramatic and could be drive related, but could be a partially plugged pipe. Could be your ignition jumped somehow...but less likely. (It would run super bad or not at all)

If you are only reaching 8,000 rpm then a whole new set of possibilities open up.

How smooth does it accelerate? No stumbling? How much pipe smoke? Different than before? Just seems that there must be more to it...

[jaysan]

[jaysan]

The first image is the old stuff I pulled off and used to be able to run forty miles an hour

Then one day top speed was thirty four miles an hour

[jaysan]

Second image is the variation trophy set up and it now does thirty miles an hour. It appears new set up isn't allowing the new belt to go all the way out ?

Also the new belt seems shorter than the belt I pulled off

[aeroxbud]

If the belt is shorter, it won't get top speed.
You might need to shim the variator out for optimum performance.