Peak RPM vs Vmax

[Lord Faversham]

So, the scooter is laid up presently awaiting new parts (Mivv Exhaust with Cat plus the PAIR pipe which disintegrated and a few other odds and sods - I plan on keeping the breathing pretty stock and will just muck about with the CVT tuning), however the downtime is giving me an opportunity to look into some other things. Chief amongst which is the current top speed/vmax vs. peak revs which I think is a bit off. 

When I brought the scoot home, I gave it the beans for a while and it was maxing out at an indicated 145kmh @ 8500 rpm. I know the speedos flatter the real speed so true vmax is likely to be at or just below 140kmh which is a little paltry it seems.  Performance off the line was strong (at least it seeemed to be) but of course at the time I had no idea of peak power rpms and whether or not the scoot would accelerate whilst in that band. I can't test it at present either due to it being without exhaust etc.

Given that 160kmh is apparently commonly achievable with the X500i, 145kmh at 8500rpm seems to suggest that either the bike has been tinkered with/set up improperly or, (as I suspect), the belt and contra spring are both worn.  I understand that peak power is achieved at around 7000rpm so presumably for longer legged cruising at a higher speed, the current situation would suggest that I should be aiming to reduce the max rpm and maybe go for heavier rollers/sliders and a new belt?  (It has 26k miles on the clock so highly possible that the belt/variator might need replacing)

I'm going to pull the CVT along with changing a load of other bits in due course so before I shell out for the wrong bits and as CVTs are a new thing for me, I throw myself on the mercy of those with far greater experience.

Please could those familiar with the bike give me an indication as to whether this vmax/max rpm is the norm or if it's a bit off as I suspect and what I ought to look at first in order to try to get closer to the optimum?

TIA

Faversham

[Lord Faversham]

Bit of an update on this issue it would seem. 

So I finally managed to get the CVT belt cover off after much argy bargy, and today I pulled the variator and driven clutch assembly for an inspection.  The variator came off ok and on inspection the rollers were found to be very flattened on one side which is what I had expected given that the scoot showed signs of not having been serviced in a long, long time. The variator faces are also stepped and worn so its a new one of those required.

On turning to the driven clutch assembly, this all came off ok too, in one piece.  I then set about having a look at it and found that the spring-driven face seemed to be seized solid. The contra spring was rusty too which didn't bode well. I tried the old "feet on the top of the clutch" trick in a bid to try to shift it and nothing. I know that the contra springs can be quite strong but somehow I don't think they are up to 220Lbs (my weight). I then tried shoving the whole assembly in a vice to try to compress the spring and get some movement but again nothing.  The conclusion is therefore twofold:

1. The clutch assembly is nerfed and needs replacing - no point trying to flog a dead horse when its all worn and buggered anyway.
2. The lack of movement on the driven faces would explain the lack of performance at the top end and the stepping in the belt faces.

New clutch assembly and variator on order.

 

[Lord Faversham]

Update on this to close the loop:

Clutch was seized sonic replaced with a new sub assembly.

New variator and sliders from Dr Pulley and it now goes like it should. (If not better!!)

Peak RPM in the equivalent of top is just on the red line and this equates to an indicated 102mph. (Prolly about 95 in reality) I’ve not GPSd it yet.

I put the iffy performance and red lining down to a knackered CVT.


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[CROSSBOLT]

Following this project with great interest!