N00B Question: Muzzy Exhaust on Ninja 500

[skilletrx]

Hello there KM Forums!

I am fairly new, and am looking at buying a Ninja 500. Its an 06 with 2600 miles. The owner put on a Muzzy Exhaust and did not tune/re-jet the carbs. I was wondering if this is harmful? He has been running 93 octane in case he runs lean. I am really new to bikes and don't want to re-jet/fiddle with carbs. Should I buy it them reinstall the stock exhaust, or will it be okay without a re-jet?

I was thinking about pulling out his spark plugs to see what color they are. Do you guys have any thoughts on this? Can I get away without a re-jet?

Thanks much in advance.

[ggman]

have him put the stock exhausts.

[Ironriot]

From what I've read on this forum so far the debate is like 50/50. Some say that re-jet is necessary while others say no. It all depends on who you ask but I'm pretty sure this subject has been beat to death so you can try searching it up. If it really concerns you that much and if you're getting a good deal on the bike then put the stock exhaust back on

[skilletrx]

is it hard to put back on the stock exhaust? (im totally n00b with this stuff). I asked him to put it on but he didnt want to put time into it.

[Ironriot]

Depends if you're mechanically inclined or not. Plus a good set of tools always helps . If the guy is being a dousche have it done by another person. There has to be someonce certified with motorcycles in you're area

[jtalbert]

Originally Posted by skilletrx

Hello there KM Forums!

I am fairly new, and am looking at buying a Ninja 500. Its an 06 with 2600 miles. The owner put on a Muzzy Exhaust and did not tune/re-jet the carbs. I was wondering if this is harmful? He has been running 93 octane in case he runs lean. I am really new to bikes and don't want to re-jet/fiddle with carbs. Should I buy it them reinstall the stock exhaust, or will it be okay without a re-jet?

I was thinking about pulling out his spark plugs to see what color they are. Do you guys have any thoughts on this? Can I get away without a re-jet?

Thanks much in advance.

no need to rejet if its just a slip on, but if its a full exhaust you need to rejet

[skilletrx]

it is a full exhaust

[skilletrx]

bump for other folks reading at work

[eidian]

Originally Posted by ggman

have him put the stock exhausts.

+1 to that!

And if he doesn't put the stock exhaust back on, have him take another $100 bucks off of the price and do it yourself. I haven't done it but it can't be that hard to do...what? A few bolts holding the pipes to the header and then a couple of bolts to hold the pipes onto the bottom of the bike and then the muffler? I'm lazy but I'd do an exhaust swap back to stock and then sell the Muzzy exhaust to make some money. The Muzzy is a two-to-one system, right? Ask him for the center stand too if he took it off (unless he used a bunch of washers to create spacers to accomdate the Muzzy exhaust, he had to take the center stand off); the center stand is one of the best features that comes on the 500R.

Re-jetting and/or putting on a new exhaust on the 500R is a waste...but doing one and not the other is doing something that's a waste but doing it half-@ssed. As the bike is now, it's not "harmful" to the bike but you're not going to get the full performance the bike is capable of, you're going to have a flat spot(s) in the power curve. Sure, you can "get away" with not re-jetting but you'll never be happy with the bike because you'll have the bike hesitate on that one part of the tach that will always drive you crazy. And if your'e thinking of re-jetting to keep the Muzzy, the bike will never be the same. I have yet to read anyone saying that they got the bike to perform as well as a stock one after installing an exhaust and/or re-jetting.

If he has all of the stock parts get them and the bike should be good. Just make sure that anything else that has to do with the engine wasn't modified.

Question to other members: I'm no expert at all but what does octane rating have to do with compensating for the bike running lean? A higher octane rating means that the fuel burns at a higher temp...what the hell does that have to do with the fuel mixture being lean?

[Ironriot]

A higher octane means more resistance to detonation or pre-detonation whichever you like to call it. In a lean condition there isn't enough fuel in the cylinders and that tends to cause detonation. Adding a higher octance fuel might save you from some of that detonation but it shouldn't be used to compensate. Its pretty much like what you said its just the half-@ssed way to do it

[mhess19]

You dont need to rejet with the muzzy, in fact I got rid of the jet job and put the carbs back to stock when I brought mine home. Nasty flat spot in the 6K range that I could not completly tune out and the exhaust stunk of gas. All you will need to do is adjust the pilot screws. Start at 2.5 turns out from seated and adjust from there.

Again, some have had some luck with the jetting, I found it to be a pita and stock worked out very well.

[eidian]

Originally Posted by Ironriot

A higher octane means more resistance to detonation or pre-detonation whichever you like to call it. In a lean condition there isn't enough fuel in the cylinders and that tends to cause detonation. Adding a higher octance fuel might save you from some of that detonation but it shouldn't be used to compensate. Its pretty much like what you said its just the half-@ssed way to do it

Wow...using octane to compensate for a lean mixture. Thanks for the explanation Riot.

Originally Posted by mhess19

You dont need to rejet with the muzzy, in fact I got rid of the jet job and put the carbs back to stock when I brought mine home. Nasty flat spot in the 6K range that I could not completly tune out and the exhaust stunk of gas. All you will need to do is adjust the pilot screws. Start at 2.5 turns out from seated and adjust from there.

mhess: Some technical questions for you since you have the Muzzy: 1) is the airflow the same with the Muzzy as it is with the stock system? If so, is the benefit of the full Muzzy system that it reduces weight and/or it has a better sound? 2) You mentioned a flat spot @ 6k with the re-jetting, do you notice any flat spots with the stock jets and a fuel mixture adjustment? 3) Finally, did you keep your center stand? If so, how difficult was it fabricating the spacers for the exhaust? I'd be interested in seeing a "How To".

I'm trying to build a knowledge base for myself--not trying to challenge you. Thanks in advance for the info.

[Ironriot]

So far I think the only performance gain you get out of putting on a full system is the weight savings. And the sound is a plus but I've been reading into it and it seems like its a hassle just to get the bike to perform as good as stock

[mhess19]

Eidian
Bought the bike with the muzzy, no center stand. I am kicking around getting one and trying to retain it with the muzzy. I dont know about airflow but it is lighter for whatever thats worth on these bikes.

Flatspots, not since I rejetted back to stock, reset the float height and did the airbox mod (1" hole on the left cover) and adjusted the pilot screws until I was happy with the thottle responce. It runs so much smoother now throughout the range, no flat spots at all and good acceleration. It use to have a bit of a kick after 7K which I lost but not worth the trade off to me.

[eidian]

riot & hess: Thanks for the answers. Good to know that if people do FOG's airbox mod and adjust the floats and mixture screws, they can get a smooth power curve. hess: you have the smooth curve but did you lose any HP?

[Ironriot]

He probably did after the 7k where he says he lost that "kick"

[mhess19]

Really dont know how much loss, to be honest, I think the kick may have been from coming off of that flat spot and it just kicking in.

bottom line, I can hit legal just as fast and with the smoother acceleration with the slightly modified stock setup.

If you really want a bit more kick around town, hit the sprockets.