Anyone with straightpipe+baffle experience??

[thielb]

Driving an 82 xs400j maxim. Stock exhaust is still on and I am not a fan. However I am a student so I cant afford to buy nice exhaust for the bike so I'm leaning towards the cheapo route: straightpipes. I've been reading other threads on pipes but I cannot find any discussion of throwing these on.

http://www.lowbrowcustoms.com/p1329/buy/m-c-parts/exhaust/universal/emgo-baffles-for-1-3-4-quot-exhaust-pipes-universal/

I'm just looking for some advice on if these actually do the trick for a wee bit o' backpressure and maybe lower volume? I guess the loudness isn't an important factor, I'd just like to know if these actually help with the backpressure/tuning. I really hope so because I'd be looking at a pretty cheap exhaust job then.

All part of a pods+jets+exhaust upgrade. Would really appreciate some wisdom on the baffles before I go and buy something that does nothing for me. Thanks guys

 

[xschris]

If your stock system is not broken I would just leave it alone. The bike will perform its best with it. Going to strait pipes with those kind of baffles will only make it louder and not perform better, plus all the headaches with the carb jetting. Save you time and money and get a nice aftermarket set when you can afford it. But its your bike and thats just my 2 cents

 

[cafenewb]

^ I should've done that, but in haste, I chopped off my mufflers with a cutting wheel. So now i'm forced to rock straight pipes or toss some mufflers on there.
So, I'm curious if these will work well. I bought some washers to try to weld up some of those butterfly baffles you put in... we'll see how that goes.

 

[thielb]

If your stock system is not broken I would just leave it alone. The bike will perform its best with it. Going to strait pipes with those kind of baffles will only make it louder and not perform better, plus all the headaches with the carb jetting. Save you time and money and get a nice aftermarket set when you can afford it. But its your bike and thats just my 2 cents

Thanks for the tip. I guess i was under the impression that with the proper jets, performance would increase along with the volume. So there's no power to gain with straight pipes even if they're baffled and the carbs are jetted correctly?
Plus I'm a freshman in college so I've got a loooooong way to go before I can can afford nice exhaust

 

[Scorpio1963]

If one of my mufflers wouldnt have been rusted off with gaping hole at the crossover and in good shape I would have left it alone.I was going to install new mufflers afetr I installed a new crossover peice but being on a tight budget im just runing straight pipes and rejetted accordingly.I hope to have pod filters to go with my setup in a couple of weeks.

 

[thielb]

Scorpio, everything running smoothly with the straightpipes? Any noticeable change in performance?

 

[Scorpio1963]

Well yesterday was the 1st time I got to test the setup I have.Right now everything is tuned flawlessly.Yes I noticed a performance change but probaly not from the straight pipes themselves.Im sure the jetting helped.Last year I had the same exhaust but hadnt jetted it ran ok but I was running on the lean side.For a while I just ran the down pipes without the crossover pipe and with out jetting and It seemed I lost alot of low end to mid range power.What I havent figured out yet is if Im going to get better or wose fuel milege

 

[brownie44]

Scorpio..
What sizes did you re-jet to? Im in the same situation. Bought a bike with straights all ready on but its running very lean and is prone to backfires.

 

[MechNewb]

Well yesterday was the 1st time I got to test the setup I have.Right now everything is tuned flawlessly.Yes I noticed a performance change but probaly not from the straight pipes themselves.Im sure the jetting helped.Last year I had the same exhaust but hadnt jetted it ran ok but I was running on the lean side.For a while I just ran the down pipes without the crossover pipe and with out jetting and It seemed I lost alot of low end to mid range power.What I havent figured out yet is if Im going to get better or wose fuel milege

How do they sound volume-wise? Any chance of getting a sound clip?

 

[thielb]

I'd also be interested in your rejetting. I'd like to eliminate the trial and error process if I go with straight pipes so it'd be nice to get a ballpark rejet size right off the bat.

 

[Scorpio1963]

Sorry i cant do a sound clip my camera is dead.Its loud but not to bad in my opinion,Too me it sounds good,As for the jetting I went from 135-to 145 mains 37.5 to 40 on the pilots.This is going to be different on your bike.Loook up the manual on your carbs to find out what they are.I may not be done jetting yet its possible I may go up 1 size more on the mains.It all depends on the air flow from my pods that Im getting.I modified my air boxes for now to get better flow.I cut the ends off and drilled holes on the side of them.

 

[thielb]

Thanks Scorpio. My manual lists two different mains, is that right? Every time I see anyone posting in a rejet thread I see a single size for mains and a single size for pilot. Am I going to have two different size mains when I rejet?

 

[Scorpio1963]

Yes this correct about having different main jet sizes.The sohc bikes are asier to jet cause they run both same size mains and pilots.Your bike shouldnt be that bad though.I just kinda guessed from the info that I learned reading up on this subject here.I didnt realy follow the guide per say.I know today I took it for the longest ride since I got it back together.iM very happy with the results.

 

[XSLeo]

Maybe. No two bikes, even with simular set ups respond the same to jettying changes.
The best way is to test things as they are, make one change, test, one change, test.
On the difference in jetting was because of the way the stock airfilter box was designed. Again testing is the best way to figure out whats best.
Reading the plugs is an important skill to develope.
Not just color but the smoke ring down deep in the plug.
If your bike needs different sized jets on each side it will tell you.
Googling CV Carb Tuning will lead you to many guides to help you tune your carbs.
Good luck
Leo

 

[thielb]

On the difference in jetting was because of the way the stock airfilter box was designed. o

I plan on installing pods too so would that perhaps lead to the main jets being closer in size? I understand I'll have to get a few jets for multiple sizes for trial and error, just looking for a little more understanding on the reason for the difference.

 

[XSLeo]

I have an XS650 that I have used several sets of carbs on. A 74 set, a 76 set a 79 set and an 82 set. They all worked well with Uni Filter foam pods. 1.5 inch headpipes and Emgo short megaphone muffs. I found that one or two up on the pilots with two or three up on the mains works well. It all depnds on what the bike wants.
I would start with jets as I have listed and test them all.
If you look around your area and find an independent shop that works on dirt bikes, atv's, snowmobiles and such they often have an assortment of mildly used jets. They might even let you try a few sets and buy back the ones you don't use.
Leo

 

[Scorpio1963]

Im very fortunate that I have 2 local bike shops that stock jets for mikuni`s or can order them within a couple of days.A 2 upsize mains 1 size up pilots works on most bikes but not all.I just got lucky my setup worked out with having to do alot of experimentation.I also had my carbs apart for cleaning when I done the jetting.Not that these carbs are difficult to take apart and put back together but for me timing was everything.

 

[thielb]

I found that one or two up on the pilots with two or three up on the mains works well. It all depnds on what the bike wants.
I would start with jets as I have listed and test them all.

Would you recommend trying the mains with that difference bewteen the right and left even after i replace the airbox with pods?

 

[Scorpio1963]

You have rejet if you go with pods period.When you use pods they increase the airflow into the carbs.Then they run very lean.To compensate for running to lean increasing fuel into the carbs resolves this.If you dont you run the risk of burning a hole in your pistons.

 

[thielb]

Right, I understood the necessity of rejetting with the pods, I was just wondering if I can go with the same size main for each side or if I would still need to use different sizes. If the need for different sized mains was the design of the stock airbox, would matching mains be acceptable after installing pods?