Worried about damaging exhauset valves

[Cafe650]

So ive been doing alot of reading on these forms about valve damage and modifying exhaust. I have a 81 GS 650 and want a more aggresive sound and have been told that simply drilling out the blocked holes in my stock exhaust baffels will achive a more agressive sound and will not require jetting of my carbs and wont damage my valves. Im wondering if this is true and if anyone else has exp with doing this i did some form searching and didnt quite find what i was looking for any info would be great...thanks

[tkent02]

Mostly they sound like crap that way, if you want a better sounding pipe, buy one. Save the stock one for when you get sick of sounding like a jackass.

[Octain]

Mostly they sound like crap that way, if you want a better sounding pipe, buy one. Save the stock one for when you get sick of sounding like a jackass.

Wow, nice welcome mat you got there.

[tkent02]

That's cliff's thing.
Drilled out stock pipes sound like crap.

[Big T]

That's cliff's thing.
Drilled out stock pipes sound like crap.

Tom needs to take his pills tonight

Welcome aboard here. You've probably noticed it's a bit of a nuthouse, but a very informative one.

There's no simple answer to your question about drilling the pipes. A 650 will never be very aggressive anyway, so for me, I wouldn't bother.

You really won't know if it needs to be rejetted afterwards until you do it. I wouldn't take anyones advice who hasn't actually done it.

If rejetting is your concern, I'd skip it. You'll gain zero performance with that mod.

If you want, you can spend $500 on pods and a pipe and gain about 5 HP

And you still won't be able to keep up with a newer bike

It may Take Cliff a day or so to get to you, he's still out on the road.

[don]

The 550 in my sig has the centers of the stock pipes drilled, then knocked out the rest of the way with the correct size rod to get that " plug" out completely, (3/4" or 7/8" if I remember correct). If you look closely, the actual " muffler" portion of the exhaust is pretty short, like a foot at most. I kind of like the way it sounds with them " knocked out". I can do a short "go-pro" vid if it would help. When I first did it, it didn't sound like it does now. Don't know why, gussing some of the " stuffing" got blown out over time.

To answer your question of jetting, no. I didn't rejet mine and it idles smooth like a modern fuel injected bike, ( BRRRRRRRRRRRRRRRRRRRRRRRRRRR), and has consistant pull from idle to 10k, ( wwwWWWaAAAAAAHHH).

PM me if you'd like to hear it..............

[MisterCinders]

Mostly they sound like crap that way, if you want a better sounding pipe, buy one. Save the stock one for when you get sick of sounding like a jackass.

Tom's posts are the best. F**k the haters.

[tom203]

Mostly they sound like crap that way, if you want a better sounding pipe, buy one. Save the stock one for when you get sick of sounding like a jackass.

A 650 is designed to be mellow- "aggressive" is not in its vocabulary.

[FiremanBob]

Hah, talk about "the mouse that roared". Why would you want the motorcycle equivalent of a punk putting fart cans on his Honda Civic? An "aggressive" sound that is merely obnoxious is not a laudable goal. In fact, an "aggressive sound" on any streetbike is pretty much just obnoxious.

[Cafe650]

Hah, talk about "the mouse that roared". Why would you want the motorcycle equivalent of a punk putting fart cans on his Honda Civic? An "aggressive" sound that is merely obnoxious is not a laudable goal. In fact, an "aggressive sound" on any streetbike is pretty much just obnoxious.

Well I do thank all of you for the fast response, idk how many forums ive posted to in the past about various things and taken days to get replys.
Now back to the matter at hand lol. Maybe i worded it wrong when I said a more aggresive sound, because surley i dont wanna sound like a punk with a fart can lmao nor do I wanna sound like a anoying jackass.
Also im not really looking for a major HP increase or trying to keep up with newer bikes although more HP is always fun .
I was just looking for a way to get less of a stock sound and make it sound a little more aftermarket with out making major changes.
and without burning up my engine from what i understand these bikes are very tempermental when it comes to exhaust mods and such.
So far ive gotten very mixed opinions ive even seen people saying they cut the exhaust just behind the foot pegs and ran straight pipes and never rejetted or had trouble where as some say they have burned valves doing that because it shortens the exhaust to much and doesnt allow cooling. Not that i wanna cut my exhaust im just looking for info. I think that would be far to loud.

[FiremanBob]

You might also consider a possible advantage of the relatively quiet stock mufflers - a cop who isn't ****ed off by the sound is more likely to cut you a break, and you're less likely to be noticed at speed if you're not advertising it all over Creation.

Another: when you pick up a girl to ride on the back, she's likely to be more comfortable on the "friendlier"-sounding bike.

[Cafe650]

So ive found a set of stock pipes on craigslist I can play with guy only wants 25 bucks for them they rusted but perfect for testing to see what what i like, now that i have something to experiment with lets say I remove the baffles dont like the sound and go further and put straights just to to see what she sounds like, How long do my pipes need to be in order to not damage my valves from what i under stand its the cold air from not having your pipes long enough that does the damage. Is this correct? if so lets use the foot pegs as a marker can i cut them at the pegs a few inches after the 2 into 1 weld or do i need to run them back much further? Im not worried about mangeling the ones im buying as they are very rusty and unsightly and intend to put my pipes back on after i find what i like im gonna look for another set as well to do the actual mod to.

[Octain]

Be careful not to bust a bolt off in the head when changing the pipes.
These bikes are notorious for this sorta thing.

[Cafe650]

Be careful not to bust a bolt off in the head when changing the pipes.
These bikes are notorious for this sorta thing.

Thanks for the advice, I will becareful. I hope i get some info on my pipe length and valve damage after I test the drilled and removed baffle id really like to test the open/straight pipe. I dont run the bike on long trips or anything short runs all under 50 miles or so around the local area, and with the amount of harleys around here and LOUD trucks lmfao I doubt anyone will even think twice about it being to loud. Unless its really extreme. but idk how my 650 could be more extreme then all these 1100 & 1200 harleys with straights that are running around here all day. Im from a very small town area and everyone owns a frikin harley lol. Oh look there goes one now