Since I suppose no one else had done it I decided to take it upon myself to do the exhaust mod. It consisted of cutting the end off and cutting through the spark arrestor as well. Then take off the cover and pull out all the stuffin. Then drill your holes I did five 1/2" holes and plamsma cut out some of the inner spark arrestor. Then took a hole saw to the cap to get rid of the spark arrestor still attached to it and then welded it back togther and sprayed a little BBQ paint on it and then listened to that nice twin sound.

 

Did you have to change any cab settings?

 

Thats great! Did you notice any difference in performance? Did it require rejet? I think Im sending back the suppertrapp and doing this mod to the stock exhaust as well. Me and suppertrapp just arent getting along. We will have to get together sometime so I can hear that beast run.

 

Rivermud: IMO, don't waste your time trying to gain performance on a Prairie or a BF by modifying the exhaust. I have yet to see any proof of significant hp gain (maybe 1 hp?). Some riders say they can feel 'seat of pants' gain with full Penland package, but no dyno before and after tests. The nyroc mod makes gains in noise and sparks only. (The exhaust mod does help sport quads from what I hear.)

BS to the exhaust dealers who say 3-5 hp gains. One dealer told me on the phone 5-7 hp gain and it would only cost me ~$400, parts only.

I am irritated since I did spend significant bucks on my 650 exhaust mod, only to find no improvement at all on my dealer's dyno test or time tests.

FYI, a forum search will reveal one of our credible members wound up having to buy a replacement Prairie exhaust on ebay after doing the nyroc mod, because of more noise to riding buddies behind him, neighbors, and not being legal to ride in the woods.

Not trying to be a wet blanket, but Kawi has done a good job in OEM muffler performance w/o setting the woods on fire and unnecessary noise. I have done almost all the usual mods on my trusty '02 Praire, but am disappointed in my expensive and worthless exhaust mod (new address: trashcan).

No offense to nyroc and other modifiers; just trying to save people like rivermud from spitting into the wind, tugging on on Superman's cape, or pulling the mask off that old Lone Ranger.


P.S. The old rumor is the Lone Ranger and Tonto split up when Lone Ranger found out kemo sabe meant big white turd.......am I the only one who still knows who Tonto is? Gittum up Scout.

 

What about the muffler bearings, did you reinstall those? [img]i/expressions/face-icon-small-wink.gif[/img]

 

I cannot tell any performance increase but I need to take it back to get irt richened up to get rid of the low speed miss andway. Maybe something then? I didn't really do it to get more power (it would be nice) but rather for the extra sound. Twins really just sound awesome with different exhaust. Physics would say there will be some power difference since it is more free flowing now. I have no idea what exhaust bearings are???

 

The muffler berings are just behind the spark arrestor. They actually keep the spark arrestor from seizing up when too many sparks get introduces tot he spark arrestor. The arrestor actually has to spin to put the sparks out and the berings keep that motion nice ans smooth.

I would suggest repacing them as soon as possible, OR removing them. the bloody things weigh 5 pounds a piece and there are two of them.

 

I know its just a "seat of the pants" thing, but when mine was stock, I could barely wheelie it, exhaust mod was the first thing i did, and then i could lift the front end easy.

Just my experience. Oh yeah, I love how my 650 sounds with it done.

 

Thanks for your honesty kawiyowee. The only reason Im considering this mod is due to the headwork and cams. With more air flowing Im thinking it probably needs to exit a little better. I feel the stock exhaust flows a stock or slightly modified engine just fine and wouldnt expect to see any gains. Maybe the free exhaust would allow the cams to be more effective though? Just a thought, your probably right.