Yuminashi variator and belt

[Mgalutia88]

You got it Wingz. Otherwise we would be increasin our weights instead of going lighter than stock. The main point I was making is that specifically with an exhaust change you would usually drop weight by 2g per roller. Each mod will be different an the target is for 8000rpm while in the variators range of operation.

[wingz]

All I have done is confuse myself. I'm still not convinced and I don't trust the calculations I posted.
I'll have to write it off as something I don't understand.

[waspmike]

That is, one should use 10% lighter rollers when increasing engine power by 10%.

Probably the opposite. If the torque slot is more active with increasing power, pulling the gearing lower constantly, you would need heavier weights to keep the same rpm that you had before.

That is what I said a few posts back. http://www.hondapcx.org/viewtopic.php?f ... 065#p29000
But I was wrong. Was I?
It is terribly confusing.

If you take a 150 vs a 125 the weights change to heavier slightly. Because the 150 can accept an "up-change" of gearing soon as it has more torque. Everything else being the same.

[Pcxdemon]

The more power engine makes will make current weights too light,like in my case ive nearly doubled its hp output and so i had to increase the weight of my weights a bit to maintain the 8k rpm limit. Also every vario is different at what weights will take for certain rpm,some will need heavier or lighter weights but not by huge difference. In may current state Takegawa vario needs 12g weights to maintain 8k rpm limit and Daytona is 13.5g for the same rpms....either way both perform at their optimum performance level but Daytona has slight edge due to its more steeper ramp profile....

[wingz]

Thanks PCXDemon. I was grasping at straws trying to make sense of something that didn't make sense to me.
I think my brain was already in holiday mode.

[Mgalutia88]

Wings, I took a look at the honda parts schematics and found that the stock teeth count on both esp models is 13/44. This means the yuminashi gear set of 15/45 is also a 3:1 just as the Kitaco is. The difference is the esp models have a different small gear than the pcx v1 does. Effectively the yuminashi kit does with two gears what the Kitaco kit can do with only one. I inquired with Kitaco on this and they do not produce a compatible high gear kit for the pcx esp models at this time...

[Mgalutia88]

Ok so Kitaco DID tell me that their high gear kit does not fit the pcx 150, however, according to the honda parts schematics it should!!! Kitaco and Yuminashi went about replacing different gears. Kitaco replaces gear number 07 in the diagram, while yuminashi goes about the change by replacing both gears 06 & 08.

Pcx v1
http://www.advantagepowersports.com/fic ... veh=190428

Pcx esp models
http://www.advantagepowersports.com/fic ... veh=135098

The gears 05&07 are identical tooth count for all pcx models however gear 05 is a different p/n. Gears 06&08 however are the same on pcx 125esp and 150esp models but different on the 2011 pcx. They are 13/47 on the v1 pcx while 13/44 on pcx esp models.

All this being said, with gear 07 being the same p/n and the gear Kitaco replaces it should be compatible and I wonder what would happen if you replaced both? What could you possibly do?

[sendler2112]

So either kit provides a gear up of 5.1 percent. That will take a 68 mph top speed to 71.5.

[Mgalutia88]

The main advantage is more for those of us in the above 75mph range

[sendler2112]

The main advantage is more for those of us in the above 75mph range

Down a big hill must be.

[you you]

The main advantage is more for those of us in the above 75mph range

Down a big hill must be.

Ferking mountain more like

[Mgalutia88]

75 on flat, 77 down short hill, 79 down long hill.

[wingz]

So either kit provides a gear up of 5.1 percent. That will take a 68 mph top speed to 71.5.

No... Kitako gives 3.9% while Yuminashi gives 12.8%.
http://www.hondapcx.org/viewtopic.php?f ... 81&start=0

I have looked at my stock setup but have not yet analysed and calculated what can be achieved in terms of variator mods.
So far, it would seem that (step 1) Dr Pulley sliders and (step 2) shortening the boss will be best bang for buck.

If after step 2, I still want a substantial increase in gearing, I'll look more closely at (step 3) Yuminashi gear set.

[Mel46]

I came in a bit late on this . what's the boss?

[Mgalutia88]

Ok I see what you are saying Wingz. It is a 12.8% increase. The main thin to understand is that the power curve is changed by variator ramps and roller weights. Just changing to dr pulley sliders will net a 1mph gain but loads of midrange. Shortening the drive boss changes the entire gear ratio because you change the minimum and maximum ratios.

I'm not trying to be a jerk but swapping the variator is the single best mod to these scooters. You not only increase speed and acceleration but also increase fuel efficiency. I get 85mpg running 70 mph. Before swapping my variator I got 75 running 68mph at wot leaning over. Don't try to reinvent the wheel, just use a proven product please. It saves everyone a headache.

[you you]

I came in a bit late on this . what's the boss?

Who's da boss?

[Mgalutia88]

An aftermarket variator durasticly expands the gearing range; as exhibited by a 13mph speed increase. A 12.8% gearing increase puts a pcx 150 at 76.7mph where as the yuminashi variator jumps the top speed to 81mph.

[sendler2112]

the power curve is changed by variator ramps and roller weights.

The power curve of the engine is unchanged and power at the wheel cannot change through any different gearing either. Mainly what is changed is rpm versus vehicle speed, so that the engine can rev right up to the power peak at medium vehicle speeds on hard accel. Instead of pulling at 7,000 rpm, you will want to tune the pulling rpm to above 8,000.
There will also be an increase in the maximum gear ratio from the front pulley being a larger diameter, which gives a higher vehicle speed for any given rpm. Red line top speed goes up with the longer gearing if you can still hit red line. And wind limited top speed goes up since the rpm will be lower and so, closer to the power peak below 8,500 instead of using the fading rpm range above 9,000.
And maybe a change in the range of rpms the trans uses between coasting and full power acceleration, to rev up to 8,000 when gassing it at 40 mph but settling back down to 6,000 when cruising.

[waspmike]

Shortening the boss may allow the belt to travel further up the pulley but it also has the potential to limit the travel downwards so in effect can raise "first' gear. Indicated by the fact that the fuzzy washer favoured by NP3 riders to lower the "first" gear for better off the line acceleration. If one is going to shorten the boss then one should also machine the bottom of the variator face to maintain the "original" distance at low rpm.

On the original 125 the boss length stock was 47.5mm with a stock pulley angle of 15 degrees. Some variators come with 50mm boss to give a better low gear for off the line and their pulley angles are in the order of 13-14 degrees to push the belt further out at maximum speed so getting a better overall ratio spread.

If all you want is top speed then for sure you can shorten the boss. Changing the ramp plate to one with a different angle would also be an option.

[wingz]

I came in a bit late on this . what's the boss?

The boss is the cylindrical piece that you tighten the outer front pulley onto.
Shortening the boss increases the min and max gearing. Adding a spacer decreases it.

In my case, cost as well as inconvenience of shipping is a factor. So I would rather machine 1mm off the boss than buy a new variator or ramp.
I'm not too worried about increasing minimum gearing; If it is a problem, I can simply add a spacer to the boss so that it is back to stock gearing.

Of course, fitting a kitaco or yuminashi gear set would have the same drawback.

I agree with Mgalutia88 regarding an aftermarket variator and would do it if I wasn't worried about cost and hassle.
The other option which PCXDemon and waspmike mentioned is to replace the outer pulley with one that is <15°.
Or just machine the stock outer pulley to <15° myself.