stubby exhaust with double baffle...

[lncoln]

Hello everyone, I'm new here. I have a 94 kat 750, and have a question about an exhaust.

http://m.ebay.com/itm/190829177245

I like the look and sound of the gp style shorties...however, they attract tickets...as well as suck your mpg. I found one with double baffles. It says it's for single exhaust, mine is dual. My question is...

Could I use em, would the double baffles help with the sound and back pressure, and would it cause any issues?

I plan on jetting the carbs, and upgrading the air filter at the same time of install. That way I can have it running right. Thank you.

[GSXFJim]

Welcome...


Those are generic auto tips from the auto parts store. nothing special, yes they will be loud as hell.
If you search motogp images, rarely will you find one that short.

If you look down a thread, I'm working on producing an exhaust system for 600 and 750's with a dual tip option. I like the dual cans as well..

Edit.. you will need to do trial jetting if you do use the tips.. and stick with the stock air filter... trust me on this one...

[lncoln]

Welcome...


Those are generic auto tips from the auto parts store. nothing special, yes they will be loud as hell.
If you search motogp images, rarely will you find one that short.

If you look down a thread, I'm working on producing an exhaust system for 600 and 750's with a dual tip option. I like the dual cans as well..

Edit.. you will need to do trial jetting if you do use the tips.. and stick with the stock air filter... trust me on this one...

Thanks for the response. Might I ask why I should stay with the stock filter? Unless you're talking about keeping the air box?

I was planning on keeping the box, just getting a higher flow filter....but if you could elaberate, I would greatly appreciate the knowledge.

[Kreylyn]

Air flow needs to be of a specific pressure and flow. The airbox with the proper filter provide that. A high flow filter does not.


Krey

[shpielers]

Air flow needs to be of a specific pressure and flow. The airbox with the proper filter provide that. A high flow filter does not.


Krey

+10000
I take it you're thinking K&N or something similar. They make the bike run too lean and dont provide the back pressure that CV carbs need to correctly operate. On some vehicles, they're great. Not on Kats.

[92xjunker]

+10001, K&N do not work well with CV type carbs, I don't care who tells you that you can rejet for them, it's bull shit, the slides will not function properly with them installed, I know. I was a dumb ass that tried it too.

[ygolohcysp]

+10001, K&N do not work well with CV type carbs, I don't care who tells you that you can rejet for them, it's bull shit, the slides will not function properly with them installed, I know. I was a dumb ass that tried it too.

Just to throw fuel (or a high flow filter) on the flames, I'd like to point out, there are more adjustments on the CV carbs than just jets, needles, and pilot screws. It takes an insane amount of tuning time, and trial and error, but it can be done. You're right about the slides, that ended up being my biggest problem until I started experimenting with different spring rates for the slides. They are vacuum operated, and the vacuum is created by the amount of air flowing through the carb, not by back pressure. Another thing that needs to change is the float level. By any normal standards, my bike shouldn't be running with my float level, but the carbs run good with it because of the increased vacuum. That said, even I gave up after a while, and there is still a range that has a vibration, likely due to mixture. If I took the time to tinker with the slide springs a bit more, I could probably get it right. To be fair, I also did cams and a full exhaust, so my situation is different.

All that said, just because it can be done doesn't mean it does anything helpful. I got a TINY bit more power due to the cams and full exhaust and then having to create a custom timing. Tuning just to put an aftermarket filter will do nothing for you if other parts of the engine aren't upgraded as well, and it'll be a nightmare of tuning in the meantime. Like, removing the carbs 50 times and changing jets, float levels, needle positions, slide springs, pilot jets, pilot air jets, etc. Oh, and it'll take a lot of money beyond the jet kit for the extra jets, springs, etc.

IE ... not worth it. I was stupid and did it because I wanted to make the cams and exhaust work.

[92xjunker]

Doh, lol.

[TRPUT]

I'll weigh in briefly too - only cos I'm an arrogant (bullshit it can't be done!), OCD (almost perfect, pull the carbs again) pyromaniac (flame on).

I EVENTUALLY have my 2005 750 Kat running extremely well with a K&N. Air volume vs air vacuum on the intake side along with exhaust pressure on the outlet side are factors that influence carb operation. But, with the sports exhaust restricted slightly (carbs were totally un-tunable / erratic without some back pressure ... I still maintain this was a more significant issue in getting the tune right than the K&N filter) and a "pre-filter" over the airbox intake (something I actually wanted to keep the big crap out - insect screen works great), and with the guidance of an O2 meter, I was then able to lean off - yes lean off - the carbs in order to get excellent results from the K&N. Mixture screws at 2 turns, floats at 14mm, clips essentially higher than top position by filing away the thick spacers below them. It pulls like a train from 3000 RPM and returns remarkable economy at cruise speeds (over 60mpg is achievable). If interested, click on my "Fuelly" link and look at the full graph ("Chart all fuel-ups") to see the results over time.

That being said, in Oz, we have slightly different standard jetting and adjustability from what you guys in the US have.

Are there any power gains? - NO!

My main motivation - apart from proving to myself it can be done - was from a replacement point of view. I don't need to buy another filter, and since I like long rides (8500 kms last Christmas and plan to ride around Australia at the end of this year which will end up being somewhere between 20 000 and 30 000 kms) that means I don't need to source a filter enroute anywhere either. Any decent shop can clean and oil it for me and off I go again.

Would I do it again? No! Although that's a mute point since I don't have to.

Would I attempt it without an O2 meter or a mate offering free hours on a dyno? Never!

Is it worth the hassle? Certainly not if you ride only a few thousand miles a year. Certainly not if you are looking for some magical performance gain. Certainly not if you don't have the patience to pull the carbs repeatedly (frustration initially, but once I restricted the exhaust it still involved about 10 X 2 hour routines - pull carbs / adjust / assemble / test ride with O2 meter) to dial in the tune.

In summary ... since this wasn't so brief after-all ... unless you are in Oz and want to use the above info to save a lot of time, I really don't see the point. I'm sure I could have used all those hours more productively ... like riding the sucker!

[92xjunker]

My comment was correct, you had to modify your carb components ,restrict your exhaust and fiddle fuck around to get them to maybe work. " you can't jet a carb to work with a k&n filter".

[TRPUT]

Not quite

Your comment was mostly correct ... I had to slightly modify 1 carb component, restrict my exhaust (because an open exhaust really fucked things up) and fiddle fuck around to get them to work. " you can jet an Aussie carb to work with a k&n filter".

but it is a helluva lot of screwing around.

Of course, it might have taken someone as anal as I just as long to tune the carbs to a stock filter and stock pipe, but I don't plan on ever finding out. The oft-quoted factory carb settings with 2.5 turns out on the mixture screws were way out with the stock filter and open can. It ran ok but had a couple of minor flat spots and was thirsty as hell. The O2 meter readings mirrored the flat spots with a couple of swings from way too lean to way too rich. I decided to swap to a K&N before I started fiddle-fucking.

[92xjunker]

Seems every gsxf owner outside of the US can run a K&N.....

[GSXFJim]

Seems every gsxf owner outside of the US can run a K&N.....

You can run one... just not run well...

[lncoln]

Thanks for all the responses guys.

I've been hanging out around here, checking things out, reading up...then decided to join...this is my first kat, had an 87 fz750 before. Suzuki is a little different than yamaha, that's for sure.

The reason for the air box question....on my yammy I had rebuilt and jetted my carbs, added a stock 2006 r6 can, and had 4 pods on the carbs...ran fricken great. In reading up in here, there was mention about keeping the air box with stock filter, even if you jet it....so I'll listen to you guys.

Again, Thanks for all the responses...and I look forward to getting to know some of you in the future.