Rejetting Muzzy Exhaust

a.kozak · May 25th, 2013, 01:48 PM

Hey guys I just picked up a used full muzzy exhaust system.
Got it installed at the dealership but they couldnt find a proper jet kit for my bike so they did something temporairly to work.
I want the full gains from it and that its done right so im going to try and find a kit.
Does anyone here have experience with rejetting the muzzy system and recommend any jet kits to use?
If so, where could I find a reliable place to order from?
Thanks!

choneofakind · May 25th, 2013, 01:54 PM

Air box or pods?

Your options for a jet kit are Factory Pro and Dyno Jet. Both have jet kits designed for use with the air box, and both have kits designed to work without the air box.

From my experience with the Muzzy system, carb tuning, and EFI tuning, I recommend keeping the air box. It really does work well for controlling the incoming air so it's smooth (not choppy) and at a consistent temperature (not affected by engine temp or cross winds).

However, the same results can be found by using individual main jets and adjusting the height of the OE needles with SAE #4 washers.

a.kozak · May 25th, 2013, 01:59 PM

Havent done anything to the airbox its all stock.
Just put on the fully muzzy system apart from that no other engine mods.
Between factory pro and dyno jet which one would you recommend?
What stage jet kit would I need based on my mods?
Can I just order of their websites or anywhere else offering for cheaper?

choneofakind · May 25th, 2013, 02:05 PM

FP and DJ will both offer the same results. No one is particularly better or worse than the other. Pick the one you like best. I think they're both a waste of money.

If you get a kit, you'll want to go with the option that is meant for use with the air box. That should be their 'Stage 1' kit. 'Stage 3' is the same needles with larger main jets. That's the only difference.

Again, spend $0.50 on some washers to raise the OE needles and skip buying the whole kit. With the stock air box, 105 mains (stock), 2-3 washers under the needles, and stock pilots works very well. Trust me.

I got very good results from my bike with a Muzzy, 108 mains, and opened intake lid, new OE air filter, 3 washers under the needles, and the mix screws backed out and extra 1/8 turn from stock. Only cost me $12 for the jets + shipping, and I already had the washers in one of the spare hardware drawers in my garage.

FvnnyL3tt3r1ng · May 25th, 2013, 02:10 PM

I agree with chone that simply buying some washers from the hardware store is very cost effective. I don't necessarily agree with using the stock main jets however. Maybe you can order 112s, 110s, and 108 sized main jets off of ebay and see which work best with your bike. You've got the most expensive part out of the way. Pods and a jet kit would be about $150 or so. Washers from the hardware store + snorkel eliminate mod would be like less than a few dollars. I'd really hate for you to not get it jetted right because from my experience if you're not real close with the jetting you're way off.

Pay close attention to how the bike runs when you first start it up cold and after it's warmed up. Both top speed, pull, and how well it can maintain a constant rpm (7k is where you'll notice the biggest jetting flaws in my opinion).That will tell you loads about your jetting (too rich or lean).

I wouldn't doubt the open intake lid giving the best performance, but I chose to go with pods for convenience sake. The tone isn't too bad either imo.

a.kozak · May 25th, 2013, 02:11 PM

Perfect thanks for the info and tips!
I'll put a hold on the order and find out exactly what the dealership did.
Rather save my money then waste it when it could only cost me $12.
Thanks for the help!

FvnnyL3tt3r1ng · May 25th, 2013, 02:13 PM

Also, downloading the instructions to jet the bike with either kits would be a good idea even if you don't plan on using them because it will walk you through the process step by step.

choneofakind · May 25th, 2013, 02:16 PM

Justin, respectfully, there's no need for any jets larger than 108 with the air box. 105's are big for the stock exhaust. Once you switch to a full exhaust, the 105's are near perfect. 108's are really good for an opened intake lid with a full exhaust system.

I'd order a pair of 108 main jets and some washers, and you're good to go!

FvnnyL3tt3r1ng · May 25th, 2013, 02:18 PM

108s weren't big enough for my pods + stock exhaust.... Don't ask me why but you can read my posts about it in the "How to pod" thread not too far down.

choneofakind · May 25th, 2013, 02:23 PM

Yes, but that's because you went with pod filters and the stock exhaust. Pod filters are a pain to jet because (as I found when I converted to fuel injection) they simply don't deliver consistent smooth airflow. Combine that with the stock exhaust system being your newfound bottleneck, and of course your jetting is going to be funky.

Respectfully, you're wrong. From firsthand experience, 105 or 108 mains work really well with a full exhaust and the stock or opened intake.

FvnnyL3tt3r1ng · May 25th, 2013, 02:48 PM

Quote:

Originally Posted by choneofakind

Yes, but that's because you went with pod filters and the stock exhaust. Pod filters are a pain to jet because (as I found when I converted to fuel injection) they simply don't deliver consistent smooth airflow. Combine that with the stock exhaust system being your newfound bottleneck, and of course your jetting is going to be funky.

Respectfully, you're wrong. From firsthand experience, 105 or 108 mains work really well with a full exhaust and the stock or opened intake.

I see. I still don't miss the airbox at all. I've never had any crosswind issues though.

choneofakind · May 25th, 2013, 02:51 PM

I had issues with mine. I also could watch the temp of the incoming air rise and fall according to the engine temp at lights on my logged data. With the air box, the incoming air temp stays within a few degrees of the outside temp all day long. Much better.

May 25th, 2013, 01:48 PM	#1
a.kozak ninjette.org member Name: a.kozak Location: Canada Join Date: Feb 2013 Motorcycle(s): 2006 Ninja 250 Posts: 27	Rejetting Muzzy Exhaust Hey guys I just picked up a used full muzzy exhaust system. Got it installed at the dealership but they couldnt find a proper jet kit for my bike so they did something temporairly to work. I want the full gains from it and that its done right so im going to try and find a kit. Does anyone here have experience with rejetting the muzzy system and recommend any jet kits to use? If so, where could I find a reliable place to order from? Thanks!

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May 25th, 2013, 01:54 PM	#2
choneofakind ninjette.org certified postwhore Name: . Location: . Join Date: Feb 2011 Motorcycle(s): . Posts: Too much. MOTM - Feb '13, Feb '14	Air box or pods? Your options for a jet kit are Factory Pro and Dyno Jet. Both have jet kits designed for use with the air box, and both have kits designed to work without the air box. From my experience with the Muzzy system, carb tuning, and EFI tuning, I recommend keeping the air box. It really does work well for controlling the incoming air so it's smooth (not choppy) and at a consistent temperature (not affected by engine temp or cross winds). However, the same results can be found by using individual main jets and adjusting the height of the OE needles with SAE #4 washers.

May 25th, 2013, 01:59 PM	#3
a.kozak ninjette.org member Name: a.kozak Location: Canada Join Date: Feb 2013 Motorcycle(s): 2006 Ninja 250 Posts: 27	Havent done anything to the airbox its all stock. Just put on the fully muzzy system apart from that no other engine mods. Between factory pro and dyno jet which one would you recommend? What stage jet kit would I need based on my mods? Can I just order of their websites or anywhere else offering for cheaper?

May 25th, 2013, 02:05 PM	#4
choneofakind ninjette.org certified postwhore Name: . Location: . Join Date: Feb 2011 Motorcycle(s): . Posts: Too much. MOTM - Feb '13, Feb '14	FP and DJ will both offer the same results. No one is particularly better or worse than the other. Pick the one you like best. I think they're both a waste of money. If you get a kit, you'll want to go with the option that is meant for use with the air box. That should be their 'Stage 1' kit. 'Stage 3' is the same needles with larger main jets. That's the only difference. Again, spend $0.50 on some washers to raise the OE needles and skip buying the whole kit. With the stock air box, 105 mains (stock), 2-3 washers under the needles, and stock pilots works very well. Trust me. I got very good results from my bike with a Muzzy, 108 mains, and opened intake lid, new OE air filter, 3 washers under the needles, and the mix screws backed out and extra 1/8 turn from stock. Only cost me $12 for the jets + shipping, and I already had the washers in one of the spare hardware drawers in my garage.

May 25th, 2013, 02:10 PM	#5
FvnnyL3tt3r1ng ninjette.org certified postwhore Name: Justin Location: Florida Join Date: Aug 2012 Motorcycle(s): Ninja 250 2001 Posts: A lot.	I agree with chone that simply buying some washers from the hardware store is very cost effective. I don't necessarily agree with using the stock main jets however. Maybe you can order 112s, 110s, and 108 sized main jets off of ebay and see which work best with your bike. You've got the most expensive part out of the way. Pods and a jet kit would be about $150 or so. Washers from the hardware store + snorkel eliminate mod would be like less than a few dollars. I'd really hate for you to not get it jetted right because from my experience if you're not real close with the jetting you're way off. Pay close attention to how the bike runs when you first start it up cold and after it's warmed up. Both top speed, pull, and how well it can maintain a constant rpm (7k is where you'll notice the biggest jetting flaws in my opinion).That will tell you loads about your jetting (too rich or lean). I wouldn't doubt the open intake lid giving the best performance, but I chose to go with pods for convenience sake. The tone isn't too bad either imo.

May 25th, 2013, 02:11 PM	#6
a.kozak ninjette.org member Name: a.kozak Location: Canada Join Date: Feb 2013 Motorcycle(s): 2006 Ninja 250 Posts: 27	Perfect thanks for the info and tips! I'll put a hold on the order and find out exactly what the dealership did. Rather save my money then waste it when it could only cost me $12. Thanks for the help!

May 25th, 2013, 02:13 PM	#7
FvnnyL3tt3r1ng ninjette.org certified postwhore Name: Justin Location: Florida Join Date: Aug 2012 Motorcycle(s): Ninja 250 2001 Posts: A lot.	Also, downloading the instructions to jet the bike with either kits would be a good idea even if you don't plan on using them because it will walk you through the process step by step.

May 25th, 2013, 02:16 PM	#8
choneofakind ninjette.org certified postwhore Name: . Location: . Join Date: Feb 2011 Motorcycle(s): . Posts: Too much. MOTM - Feb '13, Feb '14	Justin, respectfully, there's no need for any jets larger than 108 with the air box. 105's are big for the stock exhaust. Once you switch to a full exhaust, the 105's are near perfect. 108's are really good for an opened intake lid with a full exhaust system. I'd order a pair of 108 main jets and some washers, and you're good to go!

May 25th, 2013, 02:18 PM	#9
FvnnyL3tt3r1ng ninjette.org certified postwhore Name: Justin Location: Florida Join Date: Aug 2012 Motorcycle(s): Ninja 250 2001 Posts: A lot.	108s weren't big enough for my pods + stock exhaust.... Don't ask me why but you can read my posts about it in the "How to pod" thread not too far down.

May 25th, 2013, 02:23 PM	#10
choneofakind ninjette.org certified postwhore Name: . Location: . Join Date: Feb 2011 Motorcycle(s): . Posts: Too much. MOTM - Feb '13, Feb '14	Yes, but that's because you went with pod filters and the stock exhaust. Pod filters are a pain to jet because (as I found when I converted to fuel injection) they simply don't deliver consistent smooth airflow. Combine that with the stock exhaust system being your newfound bottleneck, and of course your jetting is going to be funky. Respectfully, you're wrong. From firsthand experience, 105 or 108 mains work really well with a full exhaust and the stock or opened intake.

May 25th, 2013, 02:51 PM	#12
choneofakind ninjette.org certified postwhore Name: . Location: . Join Date: Feb 2011 Motorcycle(s): . Posts: Too much. MOTM - Feb '13, Feb '14	I had issues with mine. I also could watch the temp of the incoming air rise and fall according to the engine temp at lights on my logged data. With the air box, the incoming air temp stays within a few degrees of the outside temp all day long. Much better.