Driver Teeth Question vs. Track Howl

[The Camp Yeti]

Hey fellas and fellarettes As noted in the title here I am wondering about track drivers. According to the parts diagrams, my 2014 RTX has a 9 tooth track driver. I am currently experiencing the dreaded tunnel howl and wonder if going with a 10 tooth driver might help. But also, what would be the advantages/disadvantages of the 10t vs the 9t? I see that it is an option available for my sled made by Wahl Bros in the Royal Distributing catalogue. I've been searching for answers to this for the last couple of hours now with no real info to go on. All I keep finding is changing from a 121 track to a 144+ and changing gearing as well. I'd like to leave the chaincase alone at stock hoping the larger tooth count might lower the droning levels. I need to check over all the bearings in all idlers too but the droning is enough with a helmet on to about force me to sell it. If I sell the sled, I won't be coming back to the sport. My buddy has the previously mentioned 2009 BRP MXZ 600 TNT carbed sled, his is about half as loud as mine at the most. If I can clear out yhat tone entirely and fine tune the suspension I might actually like sledding. As of right now...not so much. It's very difficult to appreciate when you're super sensitive to migraines and get on a machine that instantly causes them I am going to buy a new helmet too but need to figure out what's good for this issue and not beyond $300

 

[maim]

increase your speed 10 kph and it will lessen or go away completely. i almost never drive at track drone , witch is at 50-56 kph on most yamaha 4 stroke sleds.

 

[The Camp Yeti]

Nope, doesn't work. I went from 43 where it really starts up through 70 with minimal change and I flat out refuse to invest several hundred dollars in parts to eliminate it. If I can't figure something realistic out then it'll go up for sale. It is beyond excessive as far as I'm concerned. Would the 10 tooth drive sprocket do anything to change the track speed and lower the tone or make it worse? I'm thinking it might just be the engine/drive line harmonics matching and doubling the intensity. If changing how they interact by dropping the track speed below or raising it above that harmonic match point I wonder if it help cancel it out.

 

[maim]

it would change when it occurs speed wise. on the one i had, i went to 8 tooth as i went 144 with the track and it would not fit with the 9 tooth drivers.

 

[The Camp Yeti]

I'll be staying with the stock length. It appears according to the parts diagram description that it uses a 9 tooth already. Would a 10 be much bigger? Would going bigger make more noise? I have read so many failed attempts on changing idler sizes, M10 skids, Arctic Cat quiet tracks. It doesn't seem right that all of these attempts have had little to no success and as noted, I really don't want to be dumping a bajillion dollars into this. I can tolerate a little bit of expense like idler bearings of a better kind like SKF, it might even need new idlers. I have to look into that this weekend but loading up on extra parts just to have the same quantity of removed OEM parts kicking around with little to no benefit is just not feasible for me. It's such a foreign concept to me that this has been an issue from back in the late 90's right to current and nobody has found a definitive cross platform cure for it. In the ATV and PWC market, when a common problem has been identified the OEMs would work on curing it for the next model year. But nobody other than Cat has even considered this? Nobody??? lol...just weird.

 

[maim]

usually about an inch bigger in diameter. as you have a rtx, you have enough gear to handle the larger drivers. just make sure that you have enough clearance in the tunnel for the track to clear the front exchanger and the top of the tunnel.

there is a group of students that did a bunch of testing on a rs venture to get rid of track drone and they found porting the track made a big difference.

 

[The Camp Yeti]

I just saw a video about track porting. Mine has studs, if I removed them would the holes have the same effect? I also read that if you put washers under the stud heads to raise them up a touch, preventing them from sinking into the track it will do a lot of good. But that was done to a Venture if I recall. I'm not sure if that would hold true to all tracks or just how the Venture idlers are set up. Personally I'm not keen on studs at all, if removing them makes a huge improvement then I'll get to doing that this weekend.

 

[The Camp Yeti]

I found this very interesting and potentially beneficial university experimental sled. The tunnel stiffener idea looks very intriguing. I'm going to look further into this with my tunnel. Maybe I can find some areas and do little things like this to help isolate the tunnel. Where I work, we develop custom alloys, some are extremely rigid being 7000 series aluminum alloys. Instead of angles, maybe just slightly thicker flat plates will work and be easy to hide.

http://www.mtukrc.org/download/madison/madison_design_paper_2007.pdf

 

[maim]

if it is studded, you should try with the studs out as odds are they are the noise you are hearing hitting the idler wheels.

 

[The Camp Yeti]

I like that plan, I'll get working on that one Saturday afternoon. I'm also revving up the grey matter thinking about options for tunnel stabilization. I'll be getting lots of measurements Wed night after work. I'm hoping to machine up some small but functional parts to help make that happen. If I find anything I build works I will be sure to post up some photos and details. That university study has me enthusiastic about the possibility of a real cross platform correction to this issue. If adding some extra bits for rigidity to the tunnel can cure if not all but most of the sound on my machine, then that will make 2 different brands and tunnels that have benefited from it. That should offer some hope for any other tunnel designs and brands for those of us suffering through it. Here's to hoping for the best results!

 

[blueironranger]

I guess I haven't noticed the track drone on my Phazer, at least anything that isn't louder/more annoying than any other sled I've ridden. I've never had a short track Phazer though so maybe the 144 doesn't make as much noise. Exhaust drone is a different story, cruising at 35-40mph will give me a headache after awhile.

 

[The Camp Yeti]

I think that it's a combination of the exhaust frequency coupled with the tunnel. When looking at the research in the link I posted, they were able to silence the tunnel resonance with small lengths of angle bridging the tunnel seams. They act like little braces to isolate flex and vibration. They reduced resonating tunnel frequencies to near zero with just three small pieces of angle bolted onto the sides of the tunnel with a slight angle front to back, basically like this \ \ \

 

[The Camp Yeti]

I guess I haven't noticed the track drone on my Phazer, at least anything that isn't louder/more annoying than any other sled I've ridden. I've never had a short track Phazer though so maybe the 144 doesn't make as much noise. Exhaust drone is a different story, cruising at 35-40mph will give me a headache after awhile.

Quick question, is your track studded? I'm going to try what maim said and remove the studs from mine. I don't like the damage they do to everything anyway and if nothing else it should help the skid drain off with the holes being open. Maybe the holes will help disperse some frequencies or noise too?

 

[The Camp Yeti]

So it looks like I need a new track. I was out having a look at some possible tunnel strengthening options when noticed about an inch and a half long cut in he center of my track. I'm also beginning to put a lot of faith in the studs as a major contributor in the droning effect. The studs are quite heavily sunk in to the track and do ride in line with the driver cogs. I'm considering heavily of the track porting idea now too. I've read in a few threads elsewhere that they are cutting off the holesaw teeth and sharpening the saw like a knife edge to not pull out cords. I've only seen one video though where they ported a track with an unchanged, right out of the box hole saw spinning in reverse. It looked like it worked. They said it does it all, cuts the hole, melts the sides and no frayed cords. I think this will be how I do it too. My plan is to remove the studs and put the hole saw to work. Maybe it will be enough to cut out the slit opening up in the center of the track? I know on plastics for ATV's, if you develop a crack in them, just drill a little hole at the end of the crack and it will stop any further damage. This should apply to the track too I hope. I noticed on my track that the cut line looks to be very centered, hopefully it is then I can cut the entire bad spot out and maybe get through this season. Any thoughts about the porting being done in reverse? Will it work out well?

 

[maim]

the only track i have ported was a closed every 3rd ripsaw 136" track that i put on a 1990 et400t/r that i pulled all the studs out of and used a hole saw to open up the closed windows. i then used a propane torch to melt any cords hanging out and seal the rubber where i drilled.