Muffler Can Drilling, why?

A

alswagg

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Does drilling out the muffler can do anything but make it louder on a 700sx? I have seen several threads saying no, just makes slightly louder. If only makes louder, I would rather have a sleeper sled than a machine which sounds good but doesn't perform better. Also what about the 90* nipple on top of the can?
 
drilling will gain some HP. Along with reed mods, thin head gasket and clutching will get you some good extra power for little money.
 
I have already milled the head to boost compresion. Similar to head gasket mod, I believe just better to mill. I am using Turks clutching and gearing guide also. I have not done anything to the reeds as in spacer block. I really do not see any inprovment done to the muffler by drilling. If any inprovment can be had, where is it at, high, mid or low rpm?
 
Its supposed to be good for a couple horsepower.I'm gonna be trying a bored muffler soon and I still have my stock one to compare too.I'll let you know what I think after I try it.
 
The clutch mods were like going to a larger engine, better take off better midrange, maybe not any faster on WOT but definatly better performance for trail riding.
 
OK thanks, I was going over Turks chart yesterday and it seems like a lot of parts are needed to do it. I've never played with clutches before so I was hesitant. Did you change the jetting too? He lists only one jet size and stock is one size in one carb and another in the other two carbs.
 
I drilled the can on my 01 SXR that I used to have. Found out about it from betheviper, he lives in the town I work in. As far as performance gains I dont know, but it isnt much louder than stock and has alot better tone or note after being drilled imo.
 
I have a drilled silencer off my '99 600 SX triple that I would like to sell. The sled is now the wife's sled so I put it back to stock because she didn't like the louder noise. I would like to get $50 + shipping for it.
Yes I did notice some HP gain from it but got more for the $$ when I did the head gasket mod and Turk's clutching.

Mills
 
Clutching is everything in that sled from stock. Mine when I got it wouldnt break 60mph in 660'. Now runs about 80ish with clutched, new one size mains, needle adjusted, and a 1.25 ripsaw. Bored my can, sounds very nice, not too loud, should see something whether measurable or not. Going to change gears and add t-rods for more 0-50. Did lose alot of top end with the track though.
 
Ondatrail, I used all of Turks recomendations except the jetting, I kept the jets stock, which is fat, I know, but we also travel alot in very cold conditions, ie -15F. I really don't like rejetting while on a trip. I called Kevin at Port Yamaha and he looked up all part numbers and sent within a week. The toughest part of the clutch / gear upgrade is replacing the rivets. I already had the track and front axle out of the sled.
 
removing the axle is not needed to replace the gear, I can not find the invoice for the top gear but I thought it was about $20

Helix, $85.58
lt wt rivits $1.97
hv wt rivites $4.96
primary spring $19.99
secondary spring $16.93

I also replace both clutch springs since cost was minimal
Do you have a clutch puller? If not I would advise of getting one and a clutch holder to retorque the clutch bolt. Both can be had from Dennis Kirk, I truly would advise anyone to use this set up, have fun and be carefull on the trails. Al
 
Save your muffler and keep the trails open. Reclutch, regear, rejet and do the head gasket mod it will run really well.
 
XSIVHP, that is what I was hinting at, By boring silencer can, their is minimal to no gains in performace, Why do it. I prefer to have sleeper sleds, quiet and quick.
 
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