You guys.... if the pistontop to pin height is the same on both pistons, guess what...... the clearance is the same!!!!!! HELLO.

From that guys video run of EFI/351, I think it is obvious that there needs to be some serious head work done to add HP up top. I run the 351 for the torque out of the hole and hardly ever run over 8K, so I'm good. But I like to wring her out once in while too! .. so all's good, U 2 should just loosen up a little.

 

Valve reliefs measured to piston pin, not just the top. I went through that when I found a Vulcan 1500 piston would work in the KLX650.

 

I got the link from an ADVrider thread, The Amazing KLX351. No use to me, not buying an EFI KLX, but throw it out there.

Your insinuations toward me and some others like me have been far from cordial or respectful and mainly because we won't spend a bunch of money on our carburetion. No one can be blamed for being satisfied with the jetting that they can afford to do and the performance with which they are also satisfied. So why do you ridicule me and others like me when we never claim to be sole authority - all things to all riders? Do you have problems with being a gracious nice guy or do you just like acting superior to everyone?

You do realize you are the new "old school". You tell your version, the new the plug and play, granted it has better "pedigree" than the old stuff. The only way anyone knows they have it spot on is to do the exact same thing - gauging and dyno runs - otherwise they are doing what I did long before you did all your work, putting in what has been proven to be good based on the best information they can get. If happy, stay with it. Same old, same old - get the best information then plug and play. Unless the rider has problems and contacts you, you have no idea if they actually have the best possible fueling. You just know they are satisfied. Am I wrong, unless it gets on a dyno with gauging they have no idea if it is correct? If they like what they have for results what is wrong with that? Fueling is better than stock.

When it comes to incorrect fueling being "longevity destroying" (talk about proof, where is yours on this?) we have to look to rickypanecatyl, who has The Amazing KLX351 thread on the ADVriders forum. He did a BB 351 with the BB carb and all. He showed dyno runs, but not from his Amazing KLX351, yet somehow he got over 70,000 miles traveling around Malaysia and other Asian countries. At one point he thought he was burning oil. It was an oil leak, but he did a top end just because.. So I'm thinking your longevity claim is not very sound. The bike had done another 55,000 miles at the start of the thread. I think he did significantly more miles after that. How in the world did he did that? I hope my jetting "destroys" my bike like that! I'm betting there are thousands of riders out there "destroying" their pure stock KLX250s for a lot of miles.

 

Trying to read your novelette's sucks the life out of me..

As usual, the below pertains to engine tuning (fueling and ignition) only:
Does it make any difference, or matter, how many did such and such with whatever bike - even someone named "Ricky" (LOL)... No !
And that is another example of the "Herd mentality" flawed thinking rearing it's head again in here. The ole "hey this (or that) guy(s) ran with this or that jet(s) / setup, so you could too..

Do I recommend un-data-verified tuning ? No... But when verified tuning is used in a novel application, I urge dyno testing for verification..

While I love these little talks, wouldn't your time be better spent on a new hobby - Water Ballet, Painting with Bob Ross,
Alchemy (good results are needed..?), raising pigeons, Collecting paper clips, Farming Earth Worms, _____________________, _____________________________, __________________________ (enter favorites off your bucket list)..