On my '99 Xplorer 400 4x4 I installed an Aaen top-end pipe, MSA Spark Arr Muffler, Aaen Green Primary, Aaen Blue Secondary, mod. S55 flyweights, new belt, rejetted to 210.

First observation was the higher engagement rpms and a very tinny, "new sound"

First chance to get her out was very cold, wet and some snow. I wasn't immediately impressed with acceleration gains although I will know for sure when things dry out.

I feel I should give the new mods some time, but I am already thinking about a quieter muffler and getting some punch back into the low end. Questions are:

The muffler didn't fit very well on the end of the pipe - seems like it should be tighter fitting. All that is holding it on is a spring and the frame attachment. Is there a way to fasten the muffler better? Should it be loose? Is there a seal material that would still allow me to remove it easily?

Can anyone name a quieter muffler that wouldnt affect my performance too much? I believe the current one is an MSA from Aaen. I would really like to get rid of the "tinny" sound - is this possible? Any advice?

Would V-Force reeds help me out at the bottom? Would it help or hinder at the mid and top?

Does a clutch tool help alot?! I couldn't believe how hard it was to pretension the secondary and hold it long enough to get the snapring on. I actually had to have my wife "help". What is the best tool for these snaprings? I bent two tools before finding a screwdriven one that barely worked.

Is there any breakin for mods like this? What should I know/expect?

Thanks - Dave

 

Dave, the tinny sound comes from the pipe. That is the same effect as putting headers on a car. You are replacing the thick heavy unit with a thinner lighter unit, so that is common. About the only thing to quiet it down would be some header wrap or kevlar straps. That is pretty funny,though. Most guys love that sound. On the silencer fitting the pipe, use some high heat silicone to seal it with, but it just slips on and is held by a spring like you said. Give the belt some adequate break in time. Vary your speeds and keep it easy for the first bit of driving. If you stick with it, I believe you will love it when you start riding alot. It will backshift like a dream and hang in lower ratio while climbing. I have always liked to have the trail bikes to have a higher engagement. Even my stock bike has the higher engaging spring. You can buy the tools to do the primary and secondary clutches with, but if you dont use them all the time, it might not be worth it. A good set of reeds will only benefit you in every aspect with a big gain in throttle response. Buy the 2 stage Boyensens to put on the stock cage. They are 1/3 of the cost and still have the carbon fiber outer petals.Also increasing the compression will pick up the bottom end. Hope this helps, Bubba

 

Hello Dave. I spent much of the weekend doing the same, although my pipe selection was already done and in. You've had a busy weekend.

The tinny sound is likely the result of the single wall pipe you now have compared to the double wall pipe you had. I suppose it could also be lean, as "tinny" is a way to describe that, but most people think of lean as sounding "Shrill", or "shreiking". Lean sounds like your weed eater does as its runs out of gas. Kinda nevous sounding. The lean isn't to likely as I'd assume you're following aaen's jetting advise.

You probably should have done the pipe change, tested, and then done the clutch settings step by step, with testing in-between. so you knew the affect of each. The value is not only in deciding what did how much for you, but you can then decide what yoo want to change later.

I've found most FMF and DG spark arrested mufflers to be fairly quiet, and most of these guy's make a "quiet" version of same. Further, any rebuildable/packable muffler (all aftermarket 2 strokes are), can be re-packed. I've tracked down a product called "Silent Sport" and was amazed. I've given some to buddy's and they too have been amazed. Seems to help big bore 2 strokes the most, and that's what you've got, so.... I'll be packing my 400 the weekend with some as I want my quiter too!

I'm gonna stay outa the whole clutch kit thing. I do wish you well, and I suggest you get a tach. I did find the sun pro to work well. After some basic math and etc.. I've concluded it has to be at least resonably close, and so went ahead and did my testing assuming it was correct.

I can't comment on the fit of the muffler. It does need to be pretty airtight or you'll get pipes, leaks, and odd sounds. I've never seen a loose one, but I've no idea of the MSA.... Most folks use the highest temp silicone sealant they can find on the pipe to cylinder junction (for other quads. As I recall the polaris has its own ring gasket, kinda like the 250r), and that might might might work to seal up slop. It might also blow out. I use a permatiex's Ultra Copper High Temp.... 101br and it works for me. YMMV.

Compression is a WONDERFULL thing, and it helps most on the bottom. I'd have had you do that from the start, as it relieves some of the need to clutch so high. Reed mods to get talked about lots, and god knows I've bought plenty. I've never felt anything I could swear to, but I promise a pipe and head work are both clearly feelable.

I used my 17 year of clutch tool (teenager) to help. Once you do it a few times you can change preload or rear spring in nothing flat. Course I did all my testing with the cover off and etc... I do own a good screw type snap ring plier (hadn't I told you you'd need one? I meant to. Sorry. Maybe that was a different thread). I know that one I own can be bought at a napa. I think I saw its $50 bucks, but I might remember wrong, and hey, it works great. I've actually had mine for 20 years, so...

Your wife won't like helping as her hands are likely not strong enough to hold the preload. If she'll still help, get a wood shop double screw wood clamp (ya know, two long wood handles on threaded rods that tighten up to long blocks into each other. Ask a lowes or whatever lumbar yard around you if this is news to you.). That will likely provide enough grip to hold it. she can screw the clamp closed while you hold it pre-loaded. If it wants to twist anyway add a few small dowells set into the jaws. then it can only untwist a little.

No, no break-in.

Back on tinny, I did notice a sorta tinny sound @ idle once when I was really rich on the pilots... Could this be...

Talk to Rick about head mods. He gave me real good advise, took good care of me. In fact, I over-rode his advise, asked for a bit more compression (170) then he preferred, and he's was likely correct. I'm afraid to run less then 100 octane, and will likely step back down to about 150 lbs.

FWIW, the compression makes a HUGE improvement on the bottom. I tend to suggest it as my top 2 or 3 mods for almost any 2 stroke. I can not can not can not pin the throttle from a stop or even slow speed unless I want to mount a wheelie bar. And I didn't, and won't, alter my engagements or springweights. (I know you needed to do something @ 8000').

Send me a private email if you want talk about any of the above. I'll PM you back my phone number.

Good luck.

dan

 

Thanks Bubba and Dan! I really appreciate your advice. I think I will invest in a new head to increase compression. I noted HPD has a billet head to do so. Seems like a simple bolt-on - am I overlooking something?! It seems to me that I should be able to replace the head without removing the cylinder, etc from the frame.

While I'm at it... Can I get by with the stock piston with a higher compression head? I would love to go to a Wiseco piston if that's not too hard. I assume I would remove the head and cylinder but is that all? What is involved in replacing the piston? Do I have to replace the crankarm as well? Can I do this without removing the engine from the frame? An overview of changing the piston would be great, including any special tools needed. I have the '99 ATV Service Manual which seems to be good but it notes a few special tools.

Thanks for the info on the muffler. So it sounds like I might be able to repack the MSA muffler with a quieter material. Where did you hear about this Silent Sport material Dan? Also, I didn't see a PM button on this forum but would be interested in talking to you.

Thanks - Dave

 

PM button is the "lock" icon top right of the thead window. send me you're mail address and I'll send you my phone #.

I don't personally do my own piston work as I don't own the micrometers or the boring eqp. anyway. Plus when you swap pistons you really outa check and record rod side play and etc.. anyway. You can pull the plastic and save a few bucks, and I've even brought my own piston in.

If the quad is new to you the piston needs to be changed. the stock cast piston has a weak skirt and a bad failure rap. I'd quit having my pistons domes coated with swain tech and etc... but have decided that's a mistake. Again, Rick Ritter can sell you pistons pre-coated. In fact, you could send him the cyl and he'd bore it for you.

If you forgo the mic's you'll need a ring squezer (I've heard some guys do it by hand. Never tried, as again, I...

The head's a good idea too, although in candor I've spend a damn fortune on domes for me 'she, so that's a trap in itself. You'll note that for my 400 I just had rick cut it. Course you'll also note I've changed my mind already, and its a bit harder getting compression back out...

you WILL need a good torque wrench. I used a cheapie for a while but I finally bought a craftsmen dial/clicker 3/8 drive and LOVE it.

Changing heads is normally easy stuff. no need to remove engine, no no need to replace rod, unless bearing play in crank is getting bad (that's the end-play I said to measure and record)

I don't remeber where I heard about SS anymore. Been to long, but here's a link:

http://www.motorcycle-superstore.com...662&Division=6

Also, as I recall silent sport was a german product, so I think its the "secret" in
http://www.accwhse.com/big_gun.htm

In fact, its spelled out:
http://www.motovan.com/cat/2003atv_e...tv_en_430.html

Anyway, I like it...

luck...dan