89 145 HP, but 90 has only 102? What was changed?

[DreamV4]

89
https://www.motorcyclespecs.co.za/model/yamaha/yamaha_v max 89.htm90
https://www.motorcyclespecs.co.za/model/yamaha/yamaha_v max 90.htm

 

[Fire-medic]

The '89 was stock, the '90 had a Cobra 4-into-4 exhaust.

You did notice the difference in rpm's?

 

[MaxMidnight]

The clue is further down in the text - they are writing about a UK spec. bike which was restricted.

 

[DreamV4]

The clue is further down in the text - they are writing about a UK spec. bike which was restricted.

thanks.
Answer is here, unfortunately pictures are gone.
https://www.vmaxforum.net/threads/removing-95bhp-restriction.27333/

 

[Dansmaxresto]

Don’t forget those figures are measured at the crank not the wheel.

 

[ColoradoPhil]

Don’t forget those figures are measured at the crank not the wheel.

Exactly .... Crank is 145 rwhp on vmax is ~100 - 110....

 

[ColoradoPhil]

btw, with my stock vmax, i ran 12.20's .... when i went to chaindrive , i dropped to 11.90's .... gives you an idea what rwhp vs crank can do as that puts more HP at the rear wheel .... also there is some weight loss and they say 30 lbs is 1/10th of a second in ET

 

[Dansmaxresto]

I ran 11.63 @ 119 stone stock at Edgewater Raceway Park. The track sits at 800 feet above sea level. ColoradoPhil we’re you at 5,000+ asl? That makes a huge difference. What have others run?

 

[DreamV4]

Thanks, I feel better! It means my 92 has same 145 HP as 85 bikes have.

 

[Fire-medic]

Joe Alorio once PM'ed me a timeslip from a track session, it was in the 10.8 neighborhood at ~125 mph. Stock bike. I think the average schmo is good for a 11.5 to low-11 second run, speed in the mid-to-high 'teens.

 

[Dansmaxresto]

That’s a great time!!

 

[DreamV4]

My top speed was 70 mph, I just need bragging rights!

 

[ColoradoPhil]

Joe Alorio once PM'ed me a timeslip from a track session, it was in the 10.8 neighborhood at ~125 mph. Stock bike. I think the average schmo is good for a 11.5 to low-11 second run, speed in the mid-to-high 'teens.

Well thats a little far fetched IMHO .... First off a 10.8 on a stock vmax is almost impossible .... if you saw a 10.8 out of him , then it probably wasnt stock .... there are calculators , even if he was a small racer say 150 pounds , which PeeWee Gleason was a buck thirty thats roughly 830 lbs .... stock vmax makes 110 rwhp punching in 830 lbs at 10.8 shows 133 hp ..... So maybe he had more HP than stock ..

 

[ColoradoPhil]

I ran 11.63 @ 119 stone stock at Edgewater Raceway Park. The track sits at 800 feet above sea level. ColoradoPhil we’re you at 5,000+ asl? That makes a huge difference. What have others run?

Ya, i ran at 5800 feet .... so i worked my way down from there with my 1500 LR upgrade...my best time at Bandimere was a 10.27 @ 133 .....i went to sea level twice, one of the times , i ran a 10.1 twice around 135 MPH ..... Spent a decade trying to figure out why my trap speeds were so low ..... I figured it out on my last pass i ever ran ...... the fuel filter off the top of the tank was restricting fuel flow and it was leaning out on the back half of the track ..... Try running at 5800 feet with all that HP and Torque , then going to sea level and having 20 percent more and running almost the same number ..... Was an insane monster out of the hole and then i would stare at my timeslip and go wtf....... i called John Gainey at least a half a dozen times trying to figure out why my numbers were low .... You catch him in a "good" mood and he can be very helpful but most of the time , i find the man a couple beers shy of a six pack ... So i would like nothing better than to get my vmax running and take another season at the track trying to get in the 9's , its just so much effort heh...

 

[ColoradoPhil]

Incidently, they claimed the bike Peewee ran his 10.33 in was stock, i have spoken to many many people over time and it wasnt stock ..... a very ambiguous term ....

 

[Dansmaxresto]

I read the same about Peewee's bike. Even the magazine it was a "stock bike provided by the manufacturer", wink, wink. Not that they did anything radical but balanced, every tolerance perfect, etc., etc. I remember he ran a 10.50 for Motorcyclist Magazine also.
You're so close to the nine's!! I hope you get to try again.

 

[Fire-medic]

Well thats a little far fetched IMHO .... First off a 10.8 on a stock vmax is almost impossible .... if you saw a 10.8 out of him , then it probably wasnt stock .... there are calculators , even if he was a small racer say 150 pounds , which PeeWee Gleason was a buck thirty thats roughly 830 lbs .... stock vmax makes 110 rwhp punching in 830 lbs at 10.8 shows 133 hp ..... So maybe he had more HP than stock ..

As I said, Joe sent me a pic of the timeslip. I don't recall the exact time and trap speed, but it was in that range. He had written about it here before. Sadly, alorio1 is no-longer with us. As I recall it was about a half-second above the Jay Gleason time.

 

[1badmax]

I got to get me some of those Cobra 4-into-4's them for my 16. Hope they make them for Gen 2's.

 

[1badmax]

I had also heard the Max that Gleason posted the record 85 time was "stock" but Yamaha R&D was there 3 days and doing all kinds of tricks. So it wasn't like the one I bought in 85. To me Jay was about the best there was the best there was at knocking off tenths and hundreds. I heard him state in an interview that he looked at the quarter mile as ten feet. When you evaluate ET's the first ten feet is crucial in getting the ET's as low as possible. The launch is everything. Everybody's definition of stock is so different as we all know. To me stock means straight out of the crate and off the showroom floor. I ran consistent 11 teens with mine back then with the best time at 11.07. I had never touched anything on my bike other than dropping the air pressure for a better off the line shot. I had front end strap downs but I would not use them because to me that wasn't stock.

 

[Fire-medic]

You want 'stock,' ask Smokey Yunick, NASCAR and IndyCar constructor and mechanic, with GM backing, "what's stock?":

7 Hilariously Mad Racing 'Cheats' That Were All The Work Of Smokey Yunick (carthrottle.com)

Count those injectors, those cars had huge pistons and turbos, and they didn't burn gasoline. Offy power! Primed for battle in an IndyCar, the Offy could approach nearly 4 horsepower per cubic inch.