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The NCY 85cc starts easier than the 72cc did, the static compression ratio of cylinder and head appears to be lower for the 85cc..

Of course your crankshaft will wear quicker than with a 50cc, but it won't fail in a few miles, if all else is right...

I've been told by mechanics at different shops that a lot of the crankshaft failures they see in these Kymco engines occur with just the stock cylinder, and most failures can be traced back to oil pump failures or low oil levels in the past anyway...

And, if you really worry about durability, you shouldn't own a motorized vehicle I guess - they all tend to break expensive parts at the time your bank account is empty :-)

With my 2010 Agility, the rocker arm assembly was just fine as it was... Even if you need an alternative one, the cost is almost nothing, especially compared to what you will spend over the next few years, now you've started modding...

Just like with the 72cc, the only "mandatory" changes are a larger main jet and heavier roller weights in the variator.

The best way to go about this, in my experience, is to only read the information on the Revolution70 website, and the manual they ship with the cylinder kits. These guys really know their stuff....

The world wide interweb, on the other hand, is full of stories about completely different parts and engines - and also full of morons who don't know or understand anything :-)

Only changing the cylinder, camshaft and main jet is fine.
Main jet should be 2..4 sizes up from 50cc, mine was running fine with 86..88 (before I modded the filter box)...

Consumption will increase according to how much of the extra power you really use. Mine went from 1L/43km to 1L/35km..

Exactly the kind of shop that I was looking for !

Thanks   

The PE20 is not a CV carb, so I would expect them to be easier to tune indeed.
Also, slide carbs are _said_ to have a quicker throttle response than CV carbs...

In my experience, the tiny difference in throttle response time (if any) can only be relevant for manual shifty bikes, where you have to open/close the throttle lots of times to get somewhere, not for our "just twist and go" automatics...

And, I also think that the advantages of a CV carb are worth the extra bit of effort for learning how to tune and maintain them. To be honest, I think that people who can't get a CV carb setup right would also struggle with a regular slide carb, unless they're just lucky... The simpler construction of a slide carb increases chances of getting it right accidentally, I think that's one of the reasons they're so popular...

Another thing to consider is the way the throttle cable is installed... It comes out of the top of the carb, and since it can only bend so tight and you need to allow for some headroom because of the rear shock compressing, you'd probably better forget about using the underseat storage for anything else than the throttle cable with these carbs...

Personally, I would look for a 20mm CV carb instead...

Just my thoughts...

I've noticed no significant difference in handling when I went from a 90/90-10 to a 100/90-10 on the front wheel of my 10" Agility....

But then again, the 10" has always been a nervous unguided missile anyway, one of the reasons I bought a 12" as well... 

Speedo should be exactly the same since the height stays the same, only width changes

The indicated hight of a tyre is a percentage of its width - it's relative, not absolute...

Therefore a 130/70-12 will have a slightly larger diameter than a 120/70-12...

You'll probably need about 7mm of extra headroom for a 130/70-12.. But since tyre sizes aren't as exact as one would expect, and you're changing the shape of the tyre by putting it on a narrower rim, there's only one way to find out...