Need advice.. 2002 Yamaha YZF R-6

[Iowawegian]

Thought there used to be a thread section for "All other bikes" but couldn't find it so I just put it in the Watering Hole.

My son just put a new straight pipe on his bike. It has no baffles. He wants to know if he needs to have it rejetted.

Appreciate any advice.

[pegscraper]

Very likely. But to what is anybody's guess. He'll just have to ride it and see what happens and work with it.

[Iowawegian]

Thanks Pegscraper,

I'll let him know!

[pegscraper]

But then again, if that's a fuel injected engine, and I'm not going to know whether it is or not, he might be in for even more fun than a simple rejetting.

[lonestarmedic]

The usual thought on rejetting is air in versus air out. The straight pipes change the air out. Did it change the air in? Or, did he put on a different air filter system? If so, he probably does need to rejet. Best way is to put in a fresh set of spark plugs and then read the plug color. White looking - too hot from too lean. Dark brown or blackish - too cold and too rich. Nice buckskin tan - leave it alone!! Most bikes don't really require a rejet if only the exhaust muffler was changed. Now, if it is an exhaust system, it probably changed the airflow towards the wide open throttle. And maybe a bit at the lower RPM area. I use the plug method and an IR temp reader. You can get those at Norther Tool or Harbor Freight for $50.00 or less. I run the bike stock, then check the carbs and sync them. Then I will make 1 change at a time and compare. Please keep in mind that most modern bikes run a bit on the lean side to make the EPA happy. I know that the H-D will run a lot cooler and make more torque/hp with just fuel adjustments. They are set very lean from the factory. Also, air-cooled bikes are more prone to air/fuel changes and heat.

Just my dis-jointed thought on the matter.

 

JB

[MAINEAC]

My guess is yes it will need to be re-jetted... Usually those sport bikes are so highly tuned that any exhaust change requires re-jetting... I don't get the straight pipe thing though... If he see's any improvement at all it's going to be at the very top revs... His lower end and mid-range RPMS are going to be crap... Mid-Range is where the bike is going to be run 90% of the time so the straight pipe is definitely NOT an upgrade and will hurt performance... JMHO

[lonestarmedic]

Mark-

I agree with the straight pipe. I really didn't question why he went that route. Most sport bikes seem to run better with a bit of restriction. Especially on the low and mid-range area. I bet the straight pipe runs a bit lean on the top end and even a bit rich on the bottom. That straight pipe won't help the exhaust scavenging at low RPM. My experience on sport bikes has been that they are pretty well tuned for the street from the factory. If you change air in, air out, and jetting you can get a few HP. However, the louder it is doesn't mean the faster it is:hihi:. And on my old KZ900, I lost some of the driveability when I went to a Kerker 4-1 and started messing with the air and fuel. Heck on wheels from 5000 rpm and up. It really hated around town. Loaded up and ran rich, throttle wasn't as smooth, and took more fiddling than riding. However, at 19 that Kerker and the Super Trapp sure would howl!!

 

JB

[WIKD]

It's been said already but to get the best performance it needs to be checked. Might not need rejetting but I'd still check it out. My 2000 R1 needed changes just from changing baffles. Not sure what he wants from the bike but the open pipe is just going to give him more noise, not any more usable power.

[Iowawegian]

He's 22. Howl is all he wanted and he got it!!!!

I will print out all of your posts and let him figure out what he wants or needs to do. Thanks for you input. I appreciate it!

[Squeeze]

My Question would be, straight Pipe, that means no Exhaust Can, just a plain 2 Inch Pipe ??

 

Or is it a Can without any Baffles ? If so, post up the Manufacturer and we will figure it out.

[Iowawegian]

He got it from ebay. Item 390012718528

Thanks again!

[MAINEAC]

Ok it's not a straight pipe... It does have a baffle... It kinda looks like a little chrome cherry bomb... Probably not going to increase performance but it's probably not going to hurt it as bad as a straight pipe... Probably a pretty cheap way to make some noise... I think it will need some tuning tho... And make sure his passenger isn't going to cook their feet.

[Iowawegian]

Ok it's not a straight pipe... It does have a baffle... It kinda looks like a little chrome cherry bomb... Probably not going to increase performance but it's probably not going to hurt it as bad as a straight pipe... Probably a pretty cheap way to make some noise... I think it will need some tuning tho... And make sure his passenger isn't going to cook their feet.

 

Thanks for the info!! You should have seen he and his brother Christmas Day!! I think the words were ..."Mom, doesn't it sound sweeeeeeeeeeeeeeeet"?

 

His xmas list year was:

That exhaust

Chrome "pig mirrors"

Eliminator kit

Some kind of new blinkers

and a new brake levor

The boys were like kids in a candy store putting everything on!! Didn't have a clue what I was ordering, especially the "pig mirrors" but he's tickled with all of it!!

Thanks again for all of your help!

[Squeeze]

I think he might need to enrich the upper End to get the Air/Fuel Ratio right. And i believe this Thing cost him 4-8 hp, due the Size of the Thing, or better said, the Lack thereof.