HMF VS Stock exhaust

[srx2002]

Hi guys, I have to say I'm really happy with my new HMF for the sound and fit....But i have to say the vmax just don't seem as powerful in the low,mid,top with the new HMF's . It seems like to me that while I had the stock exhaust on on roads that I could never WOT, with the new HMF I can WOT on every road.

I mean she runs well, no hesitations, no stumbles, the Bike just dont seem as fast in general.

I'm thinking the stock exhaust with whatever way the yamaha engineers designed it.....they got it right the first time. Perhaps that's why it's so heavy..who knows.

My Bike specs: 06 vmax
Stock carbs ( 1 turn out on the mixture screws from stock settings )
K & N filter
sea-level
presently about 5 degress cel. ( just above freezing)

Plug color seems a whiteish on the Porcelain but the tip is brownish color

Any suggestions ????, cause I'm thinking about taking it off, because it certainly isnt helping me keep up with my sportbike friends.

 

[Rusty McNeil]

A pipe alone (or pipe and jetting) are not going to make enough difference to keep up with your sportbike friends. The Max is sorta heavy....

I don't know if it's the pipe itself or the wieght loss (about 22lbs) but when I went with the UFO pipe which is identical in design it shaved about .2 off my quarter mile time. Bottom end theoritically would suffer since the exhaust isn't scavenging all four cylinders and flow velocity drops with the larger primary pipe diameter.

The way they sound oughtta be enough to make you happy:biglaugh:

No way in hell I would go back to stock, Heck, I threw my old exhaust in the dumpster so it ain't an option anyhow.....

Later,

Rusty

 

[4gasem]

Not sure because my '06 runs like a strip ed ass'd ape!

I have the Holeshot system and turned the screws out 4 from all the way in...:thumbs up:

 

[srx2002]

4gasem, is that all you have done, no stage1 jet kit or anything?

 

[maleko89]

You may need to drop your main jets. I ran into the same symptoms with Mark's system. I went from 152.5 to Mikunit 147.5 main jets. You may want to check yoru float level, set a/f screws and then sync your carbs.

Mark
#1098

 

[4gasem]

4gasem, is that all you have done, no stage1 jet kit or anything?

I rejeted it and spaced the stock needles up with washers and am running a K&N filter too...

Like Mark said. Check your sync. I checked mine 3 times during breakin and it was off every time by quite a bit.:surprise:

Mine is stupid fast and pulls the front right up in 1st and I'm a fat ass... :whistlin:

 

[shawn kloker]

You have something wrong.

 

[srx2002]

Ok, I'm runing at sea-level...I thought you normally have to increase the main jet size from stock when running a free flowing exhaust like HMF? my stock is 152.5

I called tom at python motorsports, he said I may wanna try replacing my jetting with 155 or maybe even 157.5 and getting a very small shim for the needles and richen that mixture..Does anyone know where I can get the proper shim that Tom is taling about.

Mark, you suggest going to a 147.5? Does Vmax's normally run rich in stock form?

so...now I'm confused as F*ck.

somone here MUST be running an after market exhaust and near Sea -level ( less than 1000ft )

Thanks in advance

 

[srx2002]

4gasem, I forgot to tell you that my 06 could pull up the front tire anywhere and anytime with the simple twist of the throttle in 1st gear from the day I bought it.... HMF didnt " help " it any.

Maybee your forgetting what your stock vmax was like?

 

[srx2002]

Oh, i forgot again....I have a Morgan Carb tune, and I check my sync very regularily and I'm within 2 cmhg.

 

[4gasem]

4gasem, I forgot to tell you that my 06 could pull up the front tire anywhere and anytime with the simple twist of the throttle in 1st gear from the day I bought it.... HMF didnt " help " it any.

Maybee your forgetting what your stock vmax was like?

HaHa... My Vmax was only stock for 150 miles...

What you don't know is I weigh 285 pounds so it's no small feat to do what it does with me on it...:whistlin:Mine runs strong from down low to up high... Like Shawn said... There's something wrong.

Pic of me included...:whistlin:

Mark believes that freeing up the exhaust side richens the bike whereas freeing up the intake side leans it out. Not sure I completly agree but he has a lot of knowledge and time spent tuning these bikes so I am not one to disagree...

 

[vmaxinID]

Wow man,

a picture of you?

No way!

 

[4gasem]

Wow man,

a picture of you?

No way!

I know right? I am on a diet so that will be changing soon...:whistlin::thumbs up: Over a stone in two weeks... 1 stone = 14lbs

 

[vmaxinID]

I ear ya bro.

Winter work out time is here.

6'2" 245lb

 

[hubeerjw]

Ok, I'm runing at sea-level...I thought you normally have to increase the main jet size from stock when running a free flowing exhaust like HMF? my stock is 152.5

I called tom at python motorsports, he said I may wanna try replacing my jetting with 155 or maybe even 157.5 and getting a very small shim for the needles and richen that mixture..Does anyone know where I can get the proper shim that Tom is taling about.

Mark, you suggest going to a 147.5? Does Vmax's normally run rich in stock form?

so...now I'm confused as F*ck.

somone here MUST be running an after market exhaust and near Sea -level ( less than 1000ft )

Thanks in advance

I am running into the same problem with my 02, I put on a Kerker system and a K&N air filter and had it dynoed and it showed I was running very rich. I have absolutly no problems with it, but I would definately trust these guys on the forum. You may want to try dropping your mains even though a free flowing pipe "should" actually lean it out. I haven't messed with the stock carbs and the settings, the brass air-screw plugs are still in place, and probably won't touch them until I install a stage 7..... I have a brand new stage 1 if anyone is interested. Good luck, and keep us up to date with what you do.

Cheers,

Jeff

 

[4gasem]

I am running into the same problem with my 02, I put on a Kerker system and a K&N air filter and had it dynoed and it showed I was running very rich. I have absolutly no problems with it, but I would definately trust these guys on the forum. You may want to try dropping your mains even though a free flowing pipe "should" actually lean it out. I haven't messed with the stock carbs and the settings, the brass air-screw plugs are still in place, and probably won't touch them until I install a stage 7..... I have a brand new stage 1 if anyone is interested. Good luck, and keep us up to date with what you do.

Cheers,

Jeff

Don't do stage 7... Go with Sean Morley's system. Better yet. Go with us in July next year to Topeka and you and I can install it together...:thumbs up:

Your bike does take a while to warm up... :whistlin:

 

[hubeerjw]

I'm up for any good mods to get me into the 10's.... unless it requires me to loose weight and exercise!

 

[4gasem]

I'm up for any good mods to get me into the 10's.... unless it requires me to loose weight and exercise!

10's are a lot farther away than you think Jeff... It's amazing what it takes to take tenths off let alone seconds...:bang head:

 

[Dezeez]

You asked for someone at under 1000ft and and a aftermarket exhaust. I'm your boy. I'm at 400ft. Just bought the bike with a UFO 4-2, Stage 1, K&N filter and a Tboost. The bike really ran like crap with the boost at 6k. Ran O.K. at 3K. Seemed rich (blubbered) and while I'm mechanically inclined, I don't do carbs. Never. I live close to John Furber and I took it there for a front end job and he said it needs tweaked a little but to let it go until spring and then he'd do the carbs. I seached the net and read about removing the airbox "Y". What a difference! I can use the Tboost at either setting now and overall, the bike runs much better. Worth a try.

 

[hubeerjw]

10's are a lot farther away than you think Jeff... It's amazing what it takes to take tenths off let alone seconds...:bang head:

Thanks for the vote of confidence! You are starting to should like my wife... telling me what I can and can't do. :no no no: Damn, I'm this forum to try and get away from all that!

All I need is 1/2 a second. I figure with me loosing 50 lbs., getting my carbs worked on, a new tire, lowering the whole bike, learning to launch like a pro, and maybe a shot of NOS, I should be there..... nuthin to it!!!!

I know, I've got a long way to go..... just let me live in my own fantasy for a while:cheers: