Newbie questions... HP

[Stites]

Hey all.

Welp, I've made up my mind that I'm gonna work toward getting a Max to get groceries with and take the kids to school on... sure.:rofl_200::eusa_dance: Anywho, I've read the stories of 145-hp ratings since '85 - even remember reading in a mid-90s mag of a year when they were rated at 160 hp? Either way. I can't help but kinda think "WTF!" after reading on here about stock bikes turning 120ish hp at the wheel. Did I miss something as to how Yamahaw calculated 145 hp(and 160 in that one mag)? Could it be the shaft drive eating power?

Make no mistake, I WANT ONE. Just curious about the hp deal. The one I buy will likely get massaged anyway... a lot.


Also, I have an idea somewhere in the 90% of my brain I don't use. Kinda like this, but dual-port with a Holley 390-cfm 4bbl.
http://cgi.ebay.com/ebaymotors/V-Ma...rcycles_Parts_Accessories?hash=item4cec4d85a6
Would it be an improvement over stock? Has it been done? Thanks for y'all's help!

Oh, one tidbit that I think's cool. Some people(Cough-cough... Harley riders) may look at the Max as a Jap bike... well, it was designed by an Englishman, in America, along with Japanese support. Considering that America is the Heinz 57 of the world(British, German, Irish, Italian, French, African, Latino, Oriental, Native, you name it, we got it!) the very concept of the Vmax is American if you think about it... oh yeah, HD bikers don't think much.:ummm:

 

[mr.maxx]

we fight over this qwite often!! but i do belive the HP ratings were taken at the crankshaft. and all the stock gen 1 bikes ...even the famed 85 have equal hp. around 145.

 

[hubeerjw]

The 145 HP is measured at the crank. I think from 85 through 07 are about all the same as far as the power goes. With a good jet kit and headers you can usually reach in the 120's + or - some HP, a stock bike usually puts down about 110-115hp. The transmission and shaft drive eat up the rest. I think that carb on eBay may be too much for a stock bike and a few people here have tried it but I don't think many kept it on their bike. Good luck finding one and keep us posted.
Jeff

 

[one2dmax]

About any year will be fine and usually buy the newest your budget can afford (I have an 05 for sale lol). 96 and newer had the last of any big changes (99 and newer has a newer shift segment assy but that's easily fixed on the early models).

My 05 made 127rwhp with Kerker and one of our Muscle jet kits. It makes 115 rwhp stock (which is where it's back to - not counting it has one of my overdrive/undercut transmissions in it).

Sean

 

[Stites]

Thanks, guys. I've read up and found the rumor about '85s making more power to be false. Makes sense that the shaft and trans would eat some power. Still an awesome bike, no doubt.

My whole theory about the dual-port 4bbl is kinda factually based. Though the 350-cfm 2bbl setup on the ebay link is smaller than a 390 4-bbl overall, that 390 cfm is split over four smaller throttle plates than the two that the 350 is split between, offering the ability to run, in essence, TWO smaller induction systems which, when operating together, still feed the engine plenty of fuel. All in one carb/intake manifold. The benefits of this idea should be:

- higher intake velocity at part throttle, resulting in more low and mid torque, better mpg(?), and better driveability

- cheaper parts? I haven't priced Vmax carb jets and stuff, but I do know that our local Yamaha shop wants $6 for the same $1.97 spark plug at Advance Auto. Seems like Holley carb parts would be cheaper too, I think.

- easier to dial in. Tuning one Holley 4bbl, while more complicated than an Edelbrock or Carter 4bbl, is still easier than tuning and synchronizing four stock carbs and the V-boost.

I'll admit though... I am as new to the Vmax as new can be... feel free to set me straight on anything, and I do mean ANYTHING.

 

[Redbone]

I saw a VMOA member that has a 2bbl setup on his Vmax last summer, bike seemed to run good, but I didn't any specific details about the setup. His name is Brian Nash from Michigan and here are a couple pics of his setup.

 

[one2dmax]

The standard automotive carb wasn't designed to run the rpm range that our little engines operate in. You can make them run well down low or up high but usually not both. You only need about 200cfm for our engines so both are well above what the engine can use. Not only that but our engines don't make a really strong vacuum signal which is another issue with these carbs.

Sean

 

[Stites]

The standard automotive carb wasn't designed to run the rpm range that our little engines operate in. You can make them run well down low or up high but usually not both. You only need about 200cfm for our engines so both are well above what the engine can use. Not only that but our engines don't make a really strong vacuum signal which is another issue with these carbs.

Sean

Ahhh, I see. Thanks for filling me in, Sean. Out of curiosity, how much vacuum should a stock engine pull?

Good grief, you'd think I already had one, the way I've rambled about re-engineering it and stuff. Maybe I ought to get one first, eh?:hmmm:

 

[GREEN light BLITZ]

vacuum...So in retrospect youre asking how much should a V-Max suck???

The answer is easy! Its a simple equation!

Take the cost of a brand new Harley Davisdson divided by the number of payments the poor owner has left multiplied by the number of Harley owners it takes to screw in a light bulb...

Then add the percentage of tire it takes to do a stop light to stop light burn out and divide it by the quarter mile time of your V-Max!

Thats how much vacuum you should have! See its easy...

 

[06VMAXIMUS]

WOW...good formula.:rofl_200:

 

[gamorg02]

he forgot to add the carb chain multiplier

 

[Stites]

Oh, that's good stuff right there!

Using that formula, I keep coming up with zero as the answer. Looks like an accurate formula!

 

[GREEN light BLITZ]

SEE! Im a genious,I needed a bike that moved as fast as my BRAIN does and THATS why I got a V-Max...:whistlin:

Anyone else smell bull $h!t yet?:rofl_200:

 

[Stites]

Chemical soldier back in the day... if white phos and mustard agent didn't take me out, I'm sure a little bull$#!t won't hurt.