Hmmm, that's kind'a tough because the various changes had varying affects - some affected one thing while others affected another so it's kinda like comparing apples and oranges to try and compare them against one another. First off, I would take the first 4 mods and combine them into one - add jetting the CVK carb to the list and call it:

1) Carb rejet, drill slide, airbox, crankcase breather, drill stock pipe - I think this is what most folks refer to as the "grapevine" mods. These should all be done at once, IMO. I did the smog stuff at this time also.

2) Exhaust upgrade

3) Gearing - while I did a gearing mod to 14:49 for a short time, and it felt similar to going to 250cc -> 300cc bore, but different, i.e., with the big bore there was no high RPM buzzing at cruising speed (that's a plus), no low end gear for bushwhacking and pulling stumps (that's a minus). So I'm not going to list gearing as on my performance list so I don't have it, but it's similar to a big bore upgrade in what it feels like, but different - if that makes sense.

4) 250cc -> 300cc - similar to a gearing change, more horsepower and torque

5) 300cc -> 331cc - more of the same, excellent mid-range performance, good down low

6) FCR pumper - instant throttle response, makes the bike really fast off the start when you whack the throttle. But I don't think mine is jetted quite right - seems a little weaker in the mid-range than my CVK did, so I think I need to dial in the jetting / mixture screws a little bit.

Please note that all these are seat of the pants feel - there's absolutely nothing scientific about this and I may be completely full of BS. With that disclaimer, the following "meter" is how I would roughly characterize the upgrades I've done as they felt to me keeping in mind the order that I did them. The order I did them is the progression of the graph. The order you did the mods is important. I think some will argue the pipe had more of an effect than than the grapevine mods - generally I've noticed that the one you did first is attributed to the highest of the two.

Also note, and this is important, that I spend most of my riding time in the low to mid-range. I've not a WOT person - I mostly liike the slower technical trails, I love hills and climbs, rocks and logs, streams, that sort of thing. I do like to wind it out every now and then, but that's the exception rather than the rule. So when you look at "my" interpretation of these mods, that's important because that's how I'm gaging the mods - what they do for the low to mid-range performance of the bike.

So here you go - The "nobrakes upgrade meter", no express or implied warranties, in no event shall "nobrakes" be liable for direct, indirect, incidental, special, exemplary, or consequential damages however caused arising from the use of this graph.

 

From my admittedly limited experience from it, the best thing about it is the instant throttle, very strong off start or any time you snap the throttle open.

Right now, I think it is not quite dialed in because in the high mid-range RPMs, it doesn't feel as strong as my CVK was with the 331cc bore. I must have just gotten lucky on the CVK and adjusted it just right before putting it in for the 331cc upgrade, because it felt really strong in the mid-range. I seem to have lost a little with the FCR in that region. My FCR in that region feels a bit reminiscent of what my CVK felt like on my 300cc before I rejetted it for the 331cc - little bit of stuttering or hesitation, at least until you whack the throttle in which case it takes off like a rocket. So I'm pretty sure the FCR is not quite dialed in and I'm going to have to work on tuning it a bit.

But the low-end snap just off the throttle is a bit intimidating. That's really what I was looking for though, so for me it is just about right and I could be very happy with it as-is. But I will most certainly dial it in more, even if I need to get some expert help. It would be a shame to put on a carb like this and not fine tune it.

I don't think the CVK was starving the 331cc except in the condition where you whack the throttle. The FCR has the accelerator pump for that condition which is what I think I'm feeling in that low-end snap. The other good thing about the FCR is the slide is connected directly to the throttle cable - that gives you direct control over the throttle response unlike the CVK.

But the CVK was not bad at all - just not quite up to the level of the FCR, especially in the area of just off the start.