Rejetting required with UFO exhaust?

[NorwegianMAX]

Hello! As the title says I am wondering if I have to install a stage 7 kit when replacing my exhaust with a full UFO exhaust with the megaphone cans.
It is a 1985 full power Canadian version. I pulls like crazy.. I think the carbs are all stock (how can I find out btw? measure the jets?).

Just got my hands on a cheap used full UFO exhaust set, 150 $. I just need some more sound, but I really dont need any more power.. haha. The pull scares the **** out of me...
Will I loose any power when installing the UFO exhaust without rejetting with stage 7 and will it harm the engine? I will install stage 7 and have it dynoed and tuned for the UFO exhaust next year.

Thank you guys! unk:

 

[Traumahawk]

Hello! As the title says I am wondering if I have to install a stage 7 kit when replacing my exhaust with a full UFO exhaust with the megaphone cans.
It is a 1985 full power Canadian version. I pulls like crazy.. I think the carbs are all stock (how can I find out btw? measure the jets?).

Just got my hands on a cheap used full UFO exhaust set, 150 $. I just need some more sound, but I really dont need any more power.. haha. The pull scares the **** out of me...
Will I loose any power when installing the UFO exhaust without rejetting with stage 7 and will it harm the engine? I will install stage 7 and have it dynoed and tuned for the UFO exhaust next year.

Thank you guys! unk:

You do not have to rejet when switching exhaust. Now....if you do, it will run better, etc. If your still running the stock airbox, your probably still running stock jetting on the carbs, etc, but the only way to be 100% certain is to check them out. (Which isnt hard at all, and if you need to, there are numerous people on here that can walk you thru it.)

You will lose a little bit of power because installing the exhaust without rejetting will make the bike run RICHER, usually 1 maybe 2 steps, but that will not hurt the bike. If you do want to rejet, still keep everything basically stock (stock airbox...etc) you can go to 150 main jets (from the stock 152's) and shim the needle just a bit. Again this forum can explain what is meant by shimming the needle, if you want to go that route.

Please be aware....UFO exhaust have a reputation of being LOUD.

Hope this helps.

 

[eggohead]

Like Tramahawlk said they are loud. I would recommend changing the mains. Your elevation will also make a big difference. I would even recommend dropping down to the 147.5s.. I love my UFO's, as long as I have my ear plugs in... Most other people hate riding near me..

 

[blaxmax]

If it has canadian carbs a sure fire way is to pull a carb cap and look to see if it has 5 notches in the needle. The taper will be a little different than a dynajet stage 1 needle. # 5EZ50 on the jet needle and should be on the 3 clip from the blunt end (top).There are a few jet differences but not much. Do you have a maple leaf on the steering head by the vin number?

 

[jwood]

Like Tramahawlk said they are loud

Huh...

 

[Geordie]

" Waken the dead" loud

 

[marsmax85]

Sweet music up to 3500 rpms then deaf metal ..lol

 

[NorwegianMAX]

Thank you for your replies!
so basically no power increse with UFO exhaust with stock carbs, and possibly loose some power midrange?
Does anyone have any pictures of what is the main jet? I looked today, screwed out what I thought was the main to check for the "152" but just some strange letters.
I have an extra set of carbs which have som tapered needles that are "doubletappered". The carbs on the bike have needles which look like normal... needles... the same tappering all the way. The needles also have different slots.

So anyone have a picture of how to shim the needle the correct way? slots, shims, and placing of the parts? Any anyone with picture of the main jet and maybe where to buy new ones?
Thank you for your help! much appreciated!

 

[Traumahawk]

Here is the thread about how to change jets. It should help alot.

http://www.vmaxforum.net/showthread.php?t=3570

Here is a pic of what the different needles look like. So in the pic, you will see stock, stage 1, stage 7 and FP needles (which is factory pro). Canadian needles, look like stock, but have the various notches. So when you move the clip further from the blunt end, you are raising the needle, and allowing more fuel to enter the cylinder at part throttle. The amount of distance between clips, is .040. A lot of times people will "shim" so put a washer inbetween, so it will take up space, so instead of a .040 distance, it will be say .020 (or what ever is the size of the shim.)

Here are the shims that I use....but usually unless you have a jet kit, you wont need to get that precise, but you never know.

http://www.exhaustgas.com/ProductDe...epartmentID=10&CategoryID=61&RepID=&BasketID=

You would need to order 2 kits.

So, underneath the plastic screw, you will find the spring, a flat washer, the e-clip, and a white donut. The shim will go between the e-clip, and the donut. Also, as you put the needle back into the slide, slightly rotate the needle, and you will feel it fall back into place. There is a little plastic tit, on the bottom of the donut, and it will fall into place, as you rotate the needle.

A lot of people on here will buy jets from Sean Morley [email protected]

A set of 4 jets is not expensive at all, but shipping might make them higher.

Hope that makes sense.

 

[blaxmax]

You don't need shims when your needles have slots. There should be a 1/2 step washer stored on top of your stock needle-being canadian you have 5 slots.Each slot is a full step and that washer on top is for 1/2 step underneath the clip. Your main jet is #28 on the schematic.
http://www.boats.net/parts/search/Yamaha/Motorcycle/1996/V-MAX 1200 - VMX12H/CARBURETOR/parts.html

 

[eggohead]

Just curious. Do you have 4-2 or 4-1 UFO's? And with the correct jetting you shouldn't loose power..my 90 screams with the muscle jet kit and my UFO 4-1's
....

 

[NorwegianMAX]

Thank for all the good links and pictures! Really helped! Loved the main jet turorial.
The new UFO exhaust is 4-2 with megaphone mufflers.

I am intereseted in the picture of the needles. As you said I have Canadian needles with the slots, but I think mine looked more like the factory pro needles. AND my spare carbs DEFFINENTLY have the stage 7 needles! What would you recommend? For the UFO, keep the Canadian/factory stock needles, move clip to third or fourth slot and swich the main to 150/147.5.
Or change to the stage 7 needles? And which other jets should I move over from the spare carbs to the new carbs?
(I can not use the spare carbs as a full unit, it needs a full rebuild)

I sorry for my lack of knowledge in this.. you make my life so much easier now, thank you!:worthy:

 

[blaxmax]

Thank for all the good links and pictures! Really helped! Loved the main jet turorial.
The new UFO exhaust is 4-2 with megaphone mufflers.

I am intereseted in the picture of the needles. As you said I have Canadian needles with the slots, but I think mine looked more like the factory pro needles. AND my spare carbs DEFFINENTLY have the stage 7 needles! What would you recommend? For the UFO, keep the Canadian/factory stock needles, move clip to third or fourth slot and swich the main to 150/147.5.
Or change to the stage 7 needles? And which other jets should I move over from the spare carbs to the new carbs?
(I can not use the spare carbs as a full unit, it needs a full rebuild)

I sorry for my lack of knowledge in this.. you make my life so much easier now, thank you!:worthy:

Depending on your altitude first-Keep the stock needles and personally I would not go 2 steps in a main jet to start with-1 at a time. Since you have needle adjustment use that first-go up 1 step towards the blunt end and see if there is improvement. Next would be the main jet and I would go 150 with no other changes yet.

 

[Traumahawk]

Thank for all the good links and pictures! Really helped! Loved the main jet turorial.
The new UFO exhaust is 4-2 with megaphone mufflers.

I am intereseted in the picture of the needles. As you said I have Canadian needles with the slots, but I think mine looked more like the factory pro needles. AND my spare carbs DEFFINENTLY have the stage 7 needles! What would you recommend? For the UFO, keep the Canadian/factory stock needles, move clip to third or fourth slot and swich the main to 150/147.5.
Or change to the stage 7 needles? And which other jets should I move over from the spare carbs to the new carbs?
(I can not use the spare carbs as a full unit, it needs a full rebuild)

I sorry for my lack of knowledge in this.. you make my life so much easier now, thank you!:worthy:

Glad that we could help....so lets start off with some specific questions.....are you running the stock airbox?

 

[NorwegianMAX]

Stock airbox, stock type filter. Altitude is at sea level. I do not have the K&N filters or the cranckase breather hose/vakuum hose and hope I dont need it. I also hope I dont have do drill the hole in the slides, get the stage 7 springs and the main air jet connector pipe. (I read the Dynojet stage 7 installation guide).

So now I think I will do this.
1. Install UFO 4-2. (ears will bleed... but loud pipes saves lives right? unk:

2. Use installed factory pro/ or Canadian needles: Adjust theese one clip towards the blunt end. (or one clip againt the tapered end?) (and dont bother about the stage 7 needles?)

3. Check main jet, the one underneath, inside float bowl. If this is 152 change this to 150.

4. Turn mixture screws 2.5 turns out from seated.

5. Sync carbs

Sounds right?

 

[blaxmax]

Perfect. Yes 2nd notch from the top. It will be 152.5 main and a K&N filter single filter will not hurt you and will not require jetting either but will trap impurities better as it holds oil. I also use my carb sync to set my a/f mixture screws and a thermal gun on my exhaust and heads.

 

[Traumahawk]

Stock airbox, stock type filter. Altitude is at sea level. I do not have the K&N filters or the cranckase breather hose/vakuum hose and hope I dont need it. I also hope I dont have do drill the hole in the slides, get the stage 7 springs and the main air jet connector pipe. (I read the Dynojet stage 7 installation guide).

So now I think I will do this.
1. Install UFO 4-2. (ears will bleed... but loud pipes saves lives right? unk:

2. Use installed factory pro/ or Canadian needles: Adjust theese one clip towards the blunt end. (or one clip againt the tapered end?) (and dont bother about the stage 7 needles?)

3. Check main jet, the one underneath, inside float bowl. If this is 152 change this to 150.

4. Turn mixture screws 2.5 turns out from seated.

5. Sync carbs

Sounds right?

Mostly sounds good.....so right now, stock air box, so dont drill the slides, or worry about the crankcase breather, thats stage 7 stuff.

150 main jets.

Use the FP needles (maybe Canadian needles.) If they are FP needles, you will probably need the 1st clip from the blunt end.

Look at the springs (under the diaphragm covers) Stage 7 springs are 5 inches long, stock springs are 7 inches long. Stock springs will make the needles start kicking in around 4000 rpm, and stage 7 springs will start kicking around 3200 or so (so if your running stage 7 springs....watch for richness in the area, stock might be best, you will just have to try and see).

Dont worry about the crossovers between carbs.....thats for a full stage 7 kit, and only if you are getting rid of V-boost. Lots of people on here still have Vboost with stage 7.

Yep, start with A/F screws 2.5 turns out. You might have to turn them more....but 2.5 will get you in the ballpark. One thing to keep in mind as your running around town, your just running on the A/F screw (1/8-1/4 of the throttle) The A/F screws are what control this area.

Yep, sync everything to make it work well together.

Hope this helps, and when you are ready we can help you get the stage 7 kit set up as well. let us know how everything works, and we can still help you tune.

EDIT** The stage 7 needles, you will have to run with pod filters...air correctors....etc. If you run them with a stock air you will be WAY too rich.

 

[NorwegianMAX]

Thank for your advises! I will try all this out and give you a feedback. I have been completely renovating the bike this winter, hopefulle be done and ready for first testride with the new exhaust early next week.
Talk to you soon guys. You are the best.

 

[blaxmax]

Thank for your advises! I will try all this out and give you a feedback. I have been completely renovating the bike this winter, hopefulle be done and ready for first testride with the new exhaust early next week.
Talk to you soon guys. You are the best.

Don't put your canadian needles on the first clip.

 

[NorwegianMAX]

Don't put your canadian needles on the first clip.

I think I will only change the main jets for now. Leave the needles as it has been. Bought the bike last year, beeing an 85 I bet someone have had an aftermarked exhaust on it before. So just change mains to 150 and test how the bike reacts to the UFO. Drive aroud for a day or so and then start testing different clips on the needles.