If you were to say compose a chart to try and help people find the sweet spot on carb size for their setup it would have to be such a insanely large chart with an insane amount of R&D and mostly done by the same trusted group of people.
You would need to test every size engine with various styles of intake manifolds, reed cages/reeds, exhaust systems, etc etc etc to make an actual accurate chart on what size specifically works the “best” with each setup.
And then you’d need to plot out curves to show horsepower and torque for each setup so that people could look at it and decide what they consider the “best” setup is for them.
You can only crunch numbers and run programs on this stuff so much and the real world is almost always in some way, minute or not, different than what can be predicted.
^ this is why it hasn’t been done me thinks. And people who have dedicated themselves to this amount of R&D spent a lot of time and money on the information and you won’t catch most of them giving it out for free.
So what you’re left with is subjective speculation from a group of guys on the forum that each have their own unique experiences with totally different conditions and setups that are all trying to guide someone in the right direction. Sure you can look at CFM other things and make an educated guess but that’s only a starting point.
A 2 stroke engine is an air pump and bore and stroke aren’t the only thing that play into how much air it can take in at any given rpm. You have to account for the supercharging nature of a properly setup 2 stroke engine with its given parts as well.
Very few people can look at an exact setups specs that they’ve never setup themselves and definitively say exactly what needs to be tweaked to get what the rider is after to the T.
I am a believer that you’d have to be stoutly over sized on carbs before you’d see the negative on most setups but that’s based on my personal experience and preference. I like that “light switch” feeling and less of a smooth pull which may be easier to obtain with a smaller oem setup.
What to me may seem like a rocket ship may to kevbo seem like grandmas Prius or vice versa.
Because we have no way of knowing what feels like it pulls harder without riding each others skis first hand it’s all speculation and even then it’s based on feeling unless you’re talking top speed under uniform conditions.
Thank you for listening to my Ted talk.
I agree with all the above.
I am novice at tuning skis and have been spoiled on running big motors with big carbs and sticking to full specs and dasa carbs that I KNOW how to tune as I have run them for years.
I like the mass responses in threads like this when i am doing something new. Right or not, i can weed through the statements of others even though their setup is different, their theories are interesting and I get to try different things based on what I think makes sense or seems like something worth trying.
I am not looking for someone to give me a step by step instruction of carb size, jets size and popoff and DONE. I like trying the different ideas and concepts.
Once this 701 is dialed on 44's I will bolt the 48's back up and see how good i can them them hitting.
I will also keep messing with pump pressure and pipes and just see what works best.
For instance, My theory on the BUN vrs PFP, seems to be WRONG. I thought the BUN would help the bottom end hit but maybe lose the mid hit some. I was wrong, the only difference i notice between the 2 is the BUN is SIGNIFICANTLY lighter, which is a plus but not a plus enough to change knowing what I know now as I had to reduce fuel volume to use it. A give and take not really worth it in my mind. A little more time and we will see if the give and take on the 44's vrs 48's is worth it as well.
Wrenching and testing and results are half the fun and I have missed that part of this sport over the last few years so i have enjoyed EVERYONES responses and ideas and cant wait to try different things. MY GF is prolly aggravated that I keep tearing her boat down, but she will benefit in the end.
