Hey nyroc,
Good to see another rider from the same general area. It sounds like you are one of the most helpful members in the forum.
C-YA, Diggler

 

There is nothing like a nyroc modified muffler. Late in the summer my son went to the local lake with canoe. I went quading beyond lake, yep i was traveling about 50 kph along a road about 1 1/2 km to 2 km. from lake along a ridge at least 100 yds above lake. son said he could hear the high pitch plop plop plop of wifes hondu, and the deep grunt of kawi climbing hill. He said he could tell it was me all right. Ah !just the thought of it can give a guy a woody.

 

mastrblastr, I finally got it cut off today. I did use the reinforced wheels, they are great. They are the only wheels I have bought for years. The other wheels are junk and break as soon as you use them. I do have one other question for you and everyone else though, did everyone cut out the packing at the end of the cap the same way nyroc did ? I ran mine today without the cap on it and it seemed kinda loud. I held the cap up to the pipe after I drilled it out and gave it a little gas and it sounded pretty good. I was just wondering if I was gonna still get a decent power gain if I leave it in there. It also seemed, in the very short distance I rode it, that there wasnt much mid range power. It took off well but didnt seem to pull very hard. Im sure I have to rejet it, I drilled 5 7/16" holes. I am just hoping that the rejet will bring it back to life.

 

JJS, I drilled six 1/2 inch holes in mine, another guy I know drilled ten, as long as you get more flow through your exhaust, that is where the power is gained. I did remove the silencer in the end cap. It makes your exhaust hole 1 1/2 inches so there is even more flow. It sounds cool.

Nyroc, thanks for telling all of us 650 owners about this easy power gain. You were the originator of the muffler mod that has gained us some serious power for little money. Cudos!!

 

You guys are all opening up the tip (removing fiberglass packing) right? That was the hardest part for me. I used a hole saw and it took a while. I then trimmed the rough edges with a metal rasp thingy (using high speed drill). Doesn't look bad. I wish I had drilled the holes a little larger.

Dirtigger, I go to henrietta to shop all the time, I live in Chili. Should I bring the 650 next I need to go to the mall or best buy? Any good places to ride there?

Mastrblaster, thanks for the pat on the back. I got a little encouragement from a 650 owner who removed everything from his muffler. He told me about the shape of the baffles in the first chamber (flat) which gave me the idea that drilling holes into the first chamber would relieve pressure. I removed the tip because it was real small and I had also seen 660 owners doing it.

 

nyroc--- I just measured my long 3/8" drill bit: Overall length is 10". I took the muffler off the bike and put it in the Marvel bandsaw at work, and cut right through the factory weld, gutted and drilled it, re-welded the factory bead. Results: You can't tell that it has been touched, except for the larger outlet hole, and of course, the mellow tone. BTW-- I welded a piece of S.S. sreen(1/8" grid) in the outlet to stop "prying" inspectors from shoving a rod up it, while looking for a spark arrestor screen.
PS--- My near-totaled P-650 is back in service, WITH new frame. It runs out perfect. I am happy once again! Final bill= $4628.00.!!!!!!!!!

 

Nyroc,
I don't ride or keep my wheeler in Henrietta I do think it would be cool to see a p650 pull into marketplace mall though. I have a friend who lives in Livonia where I store my quad with 7 acres and another friend in Victor with 25 acres. They are both forum members (SparkyEX, jmoney45). We also know of some places where everyone rides in Clarendon and Geneve. We ride a couple of the local mx tracks occasionaly. A relative of one of my main riding buddies owns Silver Springs mx track.
C-YA, Diggler

 

Hey guys, how much louder does this make the P650. I want to do this to have the power, but I still want it to be on the quiet side. I don't want a loud bike, how noticeable is it?

Also, does this mod eliminate the spark arrestor? Can you explain how the spark arrestor works for me? I ride in USFS well over 50% of the time, so this is a big concern along with the noise.

I have done a search and found out more about the noise, sounds like it is not much of a difference if you only do the 3/8" holes, but no one has mentioned the spark arrestor, I am a rookie, need a little advice.

 

The 3/8 holes and removal of the tip baffle make it as loud as a stock grizzly 660, but deeper and much better sounding (I'm not biased, it's true). I did a side by side test.

Bigger holes give better performance but noise increases.

I don't know if there was a screen in the muffer like some have, I never looked that far in, couldn't see that far in. Although I don't believe there was a screen, the baffles made the exhaust go around to the outside and back through the center many times. This would stop sparks too. Drilling holes straight down technically destroys spark arresting capabilities. The park rangers may check your muffler for modification if it is loud by sticking a rod down a hole to see of it goes all the way. If you drilled a hole down the center, they could put their rod all the way down. However, I did not drill a hole down the center, just six holes down the sides. They can't stick any rods down the holes in my muffler, the angle of the outlet won't let them. I still feel that my muffler will stop most sparks. There is too much cross flow going on to allow any spark to go straight down a hole.

If I rode in a state that was prone to forest fires, I would not mess with the stock muffler. We have a tough enough time starting a fire in NY (rain, snow, green trees, vines thorns, swamps) and they aren't overly cautious here about spark arrestors most of the time.

 

The spark arrester is right at the outlet. You will notice a littlle canister/cylinder with some packing, and some very fine brass screen on the inside surface of this canister. This part is removed, to open up the outlet port size.I would NOT recommend the mod if you ride a lot in fire prone areas. I checked into after market mufflers with this fact in mind. I was told by HMF factory, in Cleveland Ohio,(in Sept '02) that thier arrester is NOT U.S. Forest Service approved. Besure to inquire, if you go with an aftermarket muffler. Good luck!