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My opinion on the MAX HP thing, and the chain/shaft thing goes like this:
1st, the HP figures; 135-145 HP(measured at the countershaft-back of the motor), depending on who you talk to, are for a Yamaha 'ringer' bike, like the one Gleason rode in '85 to a 10.38 or whatever, prompting those poor suckers w/85s(& sometimes 86s) to think their bikes are THE HOT MAXs to own, when in reality, they 'normally'(in stock-read NO MODS!-configuration) run in the 107-110 range, with the vast majority in the 107-108 numbers. Newer models w/the digital ignition(90up) have run up into the 112-114 range. There are exceptions of course(I believe most of these are guys just following Yamaha's lead with their own 'ringer', or someone who is unaware that the previous owner may have 'breathed' on their MAX), but you have to realize that these are mass-produced machines, with large leeway in tolerances, and each is not supertuned just for you, no matter what your 'friendly and knowledgeable' salesperson has told you; he probably just read it off the Yamaha brochure, and you all know you can't always believe what you read. I am willing to bet that most MAXs stock would read 125-130 at the countershaft, with a few late models breaking into the low 130s.
2nd, the shaft/chain thing; shaftdrive is the thing for the street, with occasional strip use. The money involved for regaining most of the 10-15% lost in the 2 ring & pinions it takes to transfer power in a shaftdrive(a well oiled &properly tightened chain is approx. 99% efficient) can be more wisely spent in(bigbore pistons, cams-generally money is MUCH better spent degreeing stock cams than buying aftermarket, head work-THIS IS THE REAL PLACE to find BIG HP inside a MAX!), or on(blowers, turbos, nitrous) the motor; most chaindrives have the countershaft sprocket affixed inside the motor, requiring a case split to change a front sprocket, which normally is an easy job. Unless your bike will see more track time than street miles, my recommendation is to leave the maintenance-free, much cleaner shaftdrive setup on your street MAX, put all the HP you want in that motor, and if the shaft breaks, it's just an excuse to pull the shaft & housing, brace and notch the housing(extend it if you like while you're at it), and have a tougher driveshaft made(the stock one is TINY, and there's room for a meatier shaft in there). While I have a chaindrive, and have owned others in the past, I have bought them done, somebody else poured the $3-4000.+ into the conversion; I think that the chaindrive should be at the end of the wish list, with motor mods and chassis strengthening taking priority.
3rd and lastly, to the folks who still buy the bunk that the reason MAX jumps up in the rear under sudden acceleration is because of the shaftdrive, I can only say this: I have a chaindrive that tries to send the rear slick, rear seat, grabrail, and anything else back there, straight up my spine; it would wack me in the back of the head if it could! I am going to take video at the track this year, with and without Torque Rods, on the 'Lunatic' , and will be glad to share the results with anyone interested. This is misinformation fed to folks by the m/c mags, and Yamaha, who knew what the problem was( look at the Venture, which is where the frame was derived from, and you will find frame braces down the side of the motor) and have stood idly by, and said and done nothing for all these years. Hey, these are the folks who can't fix the steering headshake for 13 years; it takes some good old boys to figure that out, too!
Vmax/ Venture Rear end swap - Ken Boerman
I have swapped the the rear ends (Secondary reduction.) So far I am pleased with the results. I think the Venture benefits most from the swap. It is much easier to get the big boy moving now from stop lights. Although 5th is a little busy, 65mph is comfortable and it is turning 4500rpm at 75mph. Unofficial 1/4 mile speed 100mph
| Vmax 85 | Venture 89 | |
| Primary Reduction | 1.775 | Same |
| Secondary Reduction | 2.851 | 2.566 |
| 1st gear | 2.529 | 2.600 |
| 2nd gear | 1.772 | same |
| 3rd gear | 1.347 | same |
| 4th gear | 1.076 | 1.068 |
| 5th gear | 0.928 | 0.906 |
Mr Max has plenty of power to pull the higher gears and is more cofortable at cruising speeds now. After riding it awhile I don't notice the difference anymore. Top speed at 5000 foot elevation was 135 in 4th gear. I didn't try 5th so am not sure if I could have brought it up any more.
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