Mark's Exhaust

[markmax]

Just got the phone with Mark. I'll be getting one of his exhausts in about 3-4 weeks. I can't wait. I ordered 12" cans with a 2 1/4" openings. Gunna be loud OH so loud. Just got to get the Max Jetted up for them and then hit the mountains. Man I can't wait!!! :th_image003: :Exclamation:

 

[maleko89]

Mark, I recommend at least 147.5 mains. 145 would probably be better. I'd look for a set of adjustable needles too. DJ stage 7, stage 1 or even Factory Pro. The best would be stock adjustable Canadian needles especially with stock carbs.

Did you get an exhaust tips on yours?

Enjoy!

 

[markmax]

I was wondering about what jets to use. Just wish I knew more about the carbs to do the jetting myself. But I think I'm gunna have to take it down town to get it jetted.
I got them with out the tips. I thought I would like the look of that better and Mark said it didn't change the performence of the exhaust.

 

[maleko89]

Rejetting the carbs is easy once you do it for the first time. I can change my mains in 45 minutes now. This forum is to help so let us know. Do you have a Clymer? Everything you need to know is in there.

Correct, the tips don't affect performance. I got them because one...I like the look. And two, the turn-down tips direct some of the sound away from the passenger.

 

[Rusty McNeil]

Mark, I recommend at least 147.5 mains. 145 would probably be better. I'd look for a set of adjustable needles too. DJ stage 7, stage 1 or even Factory Pro. The best would be stock adjustable Canadian needles especially with stock carbs.

Did you get an exhaust tips on yours?

Enjoy!

Congrats on the exhaust. I have heard nothing but good things about Marks fit and ease of installation. I bought UFOs and they did not go on there too easily although once on I LOVE them.

I changed my mains in about an hour the other night. Mark Milne is right on; this place is for advice and help so don't be afraid to ask. Changing needles is pretty simple also.

Mark, when you say 147.5 mains are you referring to the Mikuni or dynojet jets? My stock mains were 152.5 Mikuni's and I went with Dynojet 165 which I believe are one step richer than the Mikuni 152.5"s

I found this over on Vmaxoutlaw, don't have any idea if it's correct or not...

http://www.vmaxoutlaw.com/main.html

Go to tech tips and info,
Carb and carb tuning,
Jet size comparison......

 

[maleko89]

Rusty, the DJ 165's are just a tad richer than the Mikuni 152.5's. When I said 145's or 157.5's I was talking Mikuni, thanks for allowing me to clear that up. I prefer to use Mikuni because some of my DJ jets have different sized orifaces even though they're labeled the same size.

 

[Rusty McNeil]

Rusty, the DJ 165's are just a tad richer than the Mikuni 152.5's. When I said 145's or 157.5's I was talking Mikuni, thanks for allowing me to clear that up. I prefer to use Mikuni because some of my DJ jets have different sized orifaces even though they're labeled the same size.

Thanks Mark,
I've heard that before also from Don Smith, I talked to him on the phone when I was trying to set this up and he seemed to think that Dynojets Q.C. was pretty poor. I have no idea myself.

He also said that the Dyno jets aren't chamfered and have a sharp edge which I think the link on Vmax outlaw also pointed out as well.

Damn the learning process never quits, I thought I knew how to tune a carb back in High school when I could set a float level and chage a main or an accelerator pump cam, I realize now I knew almost nothing and less and less as time goes on....

 

[maleko89]

lol, learning is a good thing! Otherwise we'd be bored!

 

[mikemax04]

Thanks Mark,
I've heard that before also from Don Smith, I talked to him on the phone when I was trying to set this up and he seemed to think that Dynojets Q.C. was pretty poor. I have no idea myself.

He also said that the Dyno jets aren't chamfered and have a sharp edge which I think the link on Vmax outlaw also pointed out as well.

Damn the learning process never quits, I thought I knew how to tune a carb back in High school when I could set a float level and chage a main or an accelerator pump cam, I realize now I knew almost nothing and less and less as time goes on....

Have you ever heard of "The more I learn, the more I realize how little I know"? Face it Rusty, you're getting smarter, but that's a GOOD thing.

 

[markmax]

Guess I'll have to head down town to buy or at least order a book for the Max. I think it's the adjustable needles that worrys me the most. Getting them adjusted right for the altitude here. Does the Clymer go over the adjustments and will I need any special tools I can start getting while I wait for the exhaust and book to get here?
Thanks for any and all help...I've always wanted to learn to work on the carbs, but never wanted to mess them up so I never have.

 

[shawn kloker]

Mark,we can talk you through most of it.you will need to be able to resync the carbs after having them off of the bike.Always resync! I do every couple weeks in riding season.Everytime That I work on the carbs.

My biggest problem with rejetting my bike is just being able to test it with out getting pulled over for speeding.To test them properly you have to run wide open.I do have a section of 4 lanes where I know the cops can hide along the sides for about 4-5 miles.Then you just have to hope none of them are going to get passed 140 plus in an unmarked car.

 

[vmaxman99]

:band:

 

[markmax]

you will need to be able to resync the carbs after having them off of the bike.

So how do you resync the carbs. isn't there a tool for this?

 

[maleko89]

Yep, you need a carb synchronizer. Google Morgan Carbtune II. Otherwise, go to www.denniskirk.com to pick up a mercury carb gauge from MotionPro.

 

[markmax]

OK, now I have a Morgan Carbtune II on order also. If I remember correctly, doesn't Mr. Morley sell Jets and needles and all that stuff.
How much does altitude effect the jets i'll need. I'm sitting about the altitude as denver here. Not near as much air up here. Or is that where the tunning with the Carbtune come in to get the correct air/fuel mixture?

 

[maleko89]

Yep, I get my jets from Sean.

The general rule is to decrease the size of your main jet 1% for every 1000 feet above sea level. The stock 152.5 main jet was set by Yamaha for sea level. I think you should assume 150's for sea level as I believe Yamaha flooded the high end with sea level 152.5's to compensate for the lean settings of the pilot mixture. Before my stage 7 setup, my stock carbs and Mark's exhaust setup ran best with stock needles and 147.5 mains.

You can tune your mixture screws by ear. Do 1 carb at a time. Turn the screw all the way in. BE CAREFUL, if you turn to quickly you could damage the screw if it seats to hard. You should ear the idle go down. Now, turn the screw out slowly until the idle recovers. I usually turn the screw an additional 1/4 to 1/2 turn. Do the other 3 carbs in the same way. Remember, with Marks' exhaust the left side carbs go to left muffler and vice versa for the right. The stock rear headers crossed so that the right rear when to the left muffler and vice versa.