drilling stock exhaust baffles

[strom]

Originally posted by xj11john
Strom,

If I had an original I doubt I would drill it, as I think they sound good. But I have a 4 into 1 and it sounds like junk, especially at passing speeds, sounds kind of like an old RM80 when the power band kicks in, but not that good!

Now thats easy.... get an aftermarket muffler.... (akrapovic, wings, arrow...) and stick in on there... but save the old one if you ever feel like quieting down is in order. Akrapovic exhausts are expencive, but a bit scrached used one could be a nice find. Just make sure it was made for a big cc bike. 750-> should do. Now THAT makes a great sound. Even the street legal ones.

BTW: I don't know how much you know about those exhausts... Igor Akrapovic used to race in the open class till they banned it in the 80s. He turned to making performance exhaust systems. Here are the references: http://www.akrapovic-ai.si/main/refe...cing_teams.htm
Now he makes the thingies for the teams above, he was asked if he would make F1 exhaust systems for williams, ferrari etc, but he turned them down... They were not able to afford his... services (korean workers are cheap). Well, their loss. Anyway, to sum it up, those exhausts make the nicest sound ever! Not to mention the performance gain. BTW: Older Akrapovic mufflers were sold under the Scorpion brand. He had to change to Akrapovic later due to some copyright crap.

LP

PS: As you all know, I'm also a moto guzzi nutcase. So a few days ago a 1976 LeMans 850 shows up in the classifieds. I called the guy, he wanted about $5000 US for it. It is the bike Igor used to race before the class was cancelled. Now I wasn't interested - I'm searching for an everyday use bike... that bike was later set up for roal-legal (almost) use, but the engine seized a few times. He is not much of a wrencher, so a shop did all the work (I know the shop, it sucks).
But a collector might find a place for it in his/her collection... and the time to restore it to the original look. Due to the look it certanly isnt worth the asking price. But there is so much tuning stuff in the engine,... well... ask a racing team how much they spend on one of their bikes! I found a photo of the bike from one of the local guzzi rallies, I can send it via email, pm me if interested. And dont forget, the bike is in yurp.

[xs650mike]

let's see it Strom

Post the pic. I like Guzzis. My old boss had an 850 El Dorado ex-San Francisco Police Dept. bike with a Fontana 4 leading shoe front brake, police floorboards, cop bars and solo seat. I rode it regularly and it rocked! Handled great for a big dresser too. It had the rear baffles punched out of the mufflers and sounded really fine. Splitting lanes was great fun on that thing. I wore a white helmet, people would see me coming up in their mirrors with the 4 way flashers on and with that police sillhouette they would just move over out of my way. LOL!

[xj11john]

Strom,

I was thinking about just getting a muff to slip onto my 4-1, but as I said money is tight now with the purchase of the ss brake lines and a "new"- used seat , so I am again concidering drilling my "not-stock" muff on my 4-1.

Cheers,

[strom]

Well... heres a link to the pic... drool, Mike, drool!

http://www.motosvet.com/tabla/index....=post&id=67153

Heres another one, 78 LeMans 850 still original with lafranconi copetizione exhaust. Im still after this guy bout selling his bike. Hes not interested at the moment tho... Now I would trade my XS for this bike. For the silver one below too.

http://www.motosvet.com/tabla/index....=post&id=46925

Here is another tuned 76 guzzi LeMans (the chrome/alu one, most fun bike I ever ridden), my XS behind it and the lovely thing on the right is a 76 750 S3 in a showroom better than new condition. Me and SWMBO on the pic too.

http://www.motosvet.com/tabla/index....=post&id=47757

John, drill away then... just do it step by step... drill a hole, try it (hi revs too), repeat untill happy.

LP

[mason79]

i looked but i could not see;do the stock mufflers unbolt or are they welded on?

how loud are the mac 4 into1 vs. stock and the what is the sound they make?

how about the mac 4 into 2 with no crossover, does it loose torque? and what does that sound like?

[DiverRay]

The stock muffler is welded. one header pipe is a welded peice to the muffler on each side, and the second header bolts to it. The stock exhaust will give you more overall power than any header. Yamaha did a GREAT job on the design of the exhaust system on this bike. The headers will give you more at top end, but have a "flat spot" in the middle of the RPM range.
The reason for drilling the stock muffler is reduce the back pressure at high RPMs. A lot of the people on this board don't like doing that, but it will help. I now have a header on my "daily ride" as the exhaust system that was on there was from a special and rusted out all over.
I don't think the MAC pipes are all that good. The stock system works better, and you can cut off the old mufflers and weld or clamp on "new" mufflers.
Ray

[mason79]

thanks diverray,

the po hit somthing hard and #3 and #2 luckyly were crimped pretty tight and not 1 and 4, yaeh but 1 don't run, that another story,

,i'm looking for those pipes, they are on ebay right now and #1 AND#4 pipes come with it, but no muffs, he says they were unbolted hence my question...

[xs650mike]

Originally posted by strom
Well... heres a link to the pic... drool, Mike, drool!

http://www.motosvet.com/tabla/index....=post&id=67153

Heres another one, 78 LeMans 850 still original with lafranconi copetizione exhaust. Im still after this guy bout selling his bike. Hes not interested at the moment tho... Now I would trade my XS for this bike. For the silver one below too.

http://www.motosvet.com/tabla/index....=post&id=46925

Here is another tuned 76 guzzi LeMans (the chrome/alu one, most fun bike I ever ridden), my XS behind it and the lovely thing on the right is a 76 750 S3 in a showroom better than new condition. Me and SWMBO on the pic too.

http://www.motosvet.com/tabla/index....=post&id=47757

John, drill away then... just do it step by step... drill a hole, try it (hi revs too), repeat untill happy.

LP

Really nice. Thanks Strom! Like that chrome one a lot also. Pretty wife you've got too.

[mason79]

another thing is if i replace muffson the stock system and lose the crossover, what are the effects?

my muffs are good anyways just courious

[strom]

lol, tnx Mike.... she looks awful on this photo lol
But shes got red hair, so I guess Dragonrider would like her too LOL. But stand in line!

Exhausts... I had a homemade 4in2 with a crossover, got an original system, but it was pretty kaka, so I took off the mufflers and put my home made ones on (the guy who has the chrome guzzi made em, his guzzi ones too). I lost the crossover, I get a stutter at 3k, but I have a carb job planned, so well see...

LP

[TopCatGr58]

Put that in your pipe and smoke it!

Hey Mason,

Like DiverRay said, the stock pipes with the crossover provides the best low end response and still gets you decent in the upper rpms! The 4-1 headers scavenge better, and reduce backpressure, which promotes the topend when more volume of exhaust is flowing thru the system.

I put a cheap 4-1 black chrome system from JCW on mine about 18 years ago(they don't sell them anymore), but I think they were made by MAC. They sounded a bit tinny. I drilled four 1/4" holes in the end of the baffle plate and it really lowered the tone and gave it a nicer growl!

I've heard an XS11 with the Mac 4-2 turnouts WITHOUT Baffles, and it sounds like a HARLEY!! I'm sure you could tune the sound with simple modifications to the baffles in them to attain the sound your looking for! But without the crossover, you'll probably loose a "little" lowend grunt. I don't miss it, but I've also got a 1179cc big bore, and I don't run it much in the low rpms !
T.C.

[mason79]

thanks topcat,

i like lowend, but maybe there will be an abundance and i can stand to lose some, by going the mac 4 to 1 way,


regardless the pipes will have to be addressed, i'll try to get the inside pipes on ebay and keep it stock, i like stock looking...

[skids]

I have two bikes with Jardine 4-1's. The must be made with different internals. One gets more low range torque than stock and drops off quickly at about 95 mph. I have tried jetting it differently...

Originally posted by DiverRay
The headers will give you more at top end, but have a "flat spot" in the middle of the RPM range.