Quieter Q4 solution!

http://www.kawasakiforums.com/forum/klx-250s-71/pictorial-custom-fmf-q4-quiet-stock-35239/
http://www.kawasakiforums.com/forum/klx-250s-71/fmf-q4-how-make-quiet-stock-35221/

Poster claims that the powercore quiet insert will further quiet down a Q4. Anyone tried this on a WR?

Was just looking for ways to quiet the Q4.
Leaning toward the first way... don't like to mess with the spark arrestor feature by trimming stuff.

Thanks for posting this! I have been wanting something about as quiet as stock, but much lighter.

If you try it, just be sure to order the insert that is 1-1/8", which I believe is part number 040630. There is another one that is wider diameter and probably no different from the standard Q4. Mine should be arriving in the mail today, so i will try to post pics.

It raises the question of mapping changes, but I will deal with that once I am happy with the noise level.

So I got the 1-1/8" insert installed today. Did not take long at all. The new insert just needed about an inch of the screen trimmed off and then I bent the rest of it around the baffle so it should still function pretty well as a spark arrestor.

The results are noticeable. It has been a long time since I have ridden a stock WR, but the noise drop is massive, especially at higher rpms, but still has a nice growl. No noticeable power difference, except it may not have revved *quite* as crisply. That is probably more of a mapping thing. The bike smelled a little rich when it was warming up, but was not noticeable once everything was warmed up. If anything the bottom end power felt a little firmer. If I can find a shop to help me remap with the PCV I will, but its not doing any harm as is.

HIGHLY RECOMMENDED!!!


Tomorrow I will try to get the Megabomb installed. I have the Powerbomb now, so it will be an interested comparison.


The part number from FMF is 040630. Mine was $44 shipped from Dennis Kirk.

Gundy Let us know how this works. I am very interested in this. I have a Q4 and still have to wear earplugs to keep my ears from ringing on rides. I don't have to on my girlfriend's XT225 though.

I have looked and the 040630 part number seems to be for the Titanium Powercore models. It this correct. How is the fitment on the regular Powercore models?

Gundy wrote:

So I got the 1-1/8" insert installed today. Did not take long at all. The new insert just needed about an inch of the screen trimmed off and then I bent the rest of it around the baffle so it should still function pretty well as a spark arrestor.

The results are noticeable. It has been a long time since I have ridden a stock WR, but the noise drop is massive, especially at higher rpms, but still has a nice growl. No noticeable power difference, except it may not have revved *quite* as crisply. That is probably more of a mapping thing. The bike smelled a little rich when it was warming up, but was not noticeable once everything was warmed up. If anything the bottom end power felt a little firmer. If I can find a shop to help me remap with the PCV I will, but its not doing any harm as is.

HIGHLY RECOMMENDED!!!


Tomorrow I will try to get the Megabomb installed. I have the Powerbomb now, so it will be an interested comparison.


The part number from FMF is 040630. Mine was $44 shipped from Dennis Kirk.

You get the megabomb installed? Curious to hear about performance, and the claimed 1.5db noise reduction.

No megabomb yet - hopefully I can get that on sometime this week. It will probably be quieter than a stock header, but not be a lot different from the Powerbomb in terms of noise. If it delivers more low/mid power as advertised then maybe that means less need for high rpm screeching...we'll see.

I ran errands around town with it on Sunday with the new insert and can say that I did not need ear plugs like before. With the standard Q4, everyone would turn around and look when driving by and cars would hang back at stop lights (maybe a good thing?), and I would feel like I walked out of a loud bar after riding. Now its much more tolerable; not as quiet as my KLR, but it sounds like a motorcyle at least. It seems comparable to my stock DRZ, maybe a touch louder. I think the noise is more of an issue with the WR simply because it gets revved to much higher rpms than other dual sports. It is quieter at idle but you really notice the improvement when you start to get on it more.

The only thing left to do at this point is get the mapping perfected, but honestly its not that bad, just running the slightest bit rich, which is better than lean.

And yes, the part is not listed to fit the Q4 since it does require a small amount of trimming on the screen to fit, about an inch or so right off the end. My guess is that it would fit a Powercore without modification, but that is just a guess. With a hacksaw, good bolt cutters or some other like tool it takes 2 minutes. Otherwise it fits like a glove.

is this what you bought? <-- clicky

motokid wrote:

is this what you bought? <-- clicky

NO! That one looks like it is pretty much the same diameter opening.

The one I bought is tapered more.

https://www.denniskirk.com/435531.sku?utm_source=google&utm_medium=cse

Quote :

The new insert just needed about an inch of the screen trimmed off and
then I bent the rest of it around the baffle so it should still function
pretty well as a spark arrestor.

Say again, you bent the end of the screen "around the baffle" - could you be a little more clear?

Depending on how much screen you leave on, there may be some extra that you can fold over the baffle disk to close the gap. In the pics in the Kawasaki link in the first post, the guy just cut the screen off flush with the baffle disk. I left some screen sticking out and sort of tucked it down around the edges. Not a precise thing at all....

I went ahead and ordered mine but from another site because Dennis Kirk seemed to out of stock. I went ahead and ordered some muffler packing too while I was at it. I looked inside the Q4 and saw the baffle that is the problem. I might take the muffler off and do the whole thing when It comes in. Or I may do one at a time to see the difference each makes. I am excited about making my WR quieter. I have thinking about going back to stock for a while. This may keep me from having to.

Remove Spark Arrestor.
Cut a 3/4" x 1"-1-1/2" tab in the stainless steel. (cut opposite the spark arrestor screen to not disrupt it).
Bend the tab in with a pair of pliers (etc).
More bend = Quieter
Less bend = Louder.
Replace spark arrestor.

With the bend I have in it... it is much quieter. IMHO: Sounds like a Q4 should.

I got mine from Powersport Superstore for $30.86 and installed a day ago. Took it for a ride and it is maybe quieter at higher throttle levels and not so much at lower throttle levels. There was maybe a little more low end torque with it. I rode for about 45 minutes without ear ringing but it was still pretty loud. I had not installed the new muffler packing at that time. I installed it tonight and will try it out in a day when the RTV has set up. I had to modify the insert to fit like this. I used a vice to flatten it and bend it over as I wanted to keep the spark arrester intact.

Alright, so finally got around to getting the Megabomb installed. It replaced a Powerbomb.

Sound difference:

Not much different. The Megabomb has a smoother, lower, softer tone to it, so I guess its a little quieter, but we are not talking much here. Pretty hard to detect unless you hear them back to back. For me, its easier on the ears. Especially true at high rpms. I initially had the MB on with the quieter insert, and it sounded very reasonable. I then re-installed the standard Q4 insert. It added some bark, but I have to say my impression is that it was a noticeable amount quieter than it was with the Powerbomb.

So: listed from loudest to quietest:

Q4/Powerbomb/No insert
Q4/Megabomb/No insert
Q4/Powerbomb/standard insert
Q4/Megabomb/Standard insert
Q4/Powerbomb/Quiet insert
Q4/Megabomb/Quiet insert

Power difference:

Again, not a big difference. The Megabomb basically shifts the power curve down a bit and smooths it out. It allows for lazier riding and shifting. I wouldn't really say there is more overall power, its just a little easier to use and feels a little fatter in the mid rpm range. The Powerbomb is probably more aggressive of the two in the higher RPM range. So its really a question of money and what your riding needs are.

Verdict:

For just the header, I like the Megabomb a little better. Will it make me a faster rider? No, but it suits my more casual pace a little better, and the softer noise is important to me.

For now, I am going to run the Q4 with its standard insert and the Megabomb. When the off-road season gets underway, I will probably throw the quiet insert back in and play with the mapping a little more. For now, on the street, the bike is running great the way it is, and the Megabomb deadened the noise just enough to make it tolerable for shorter trips.

All that being said, does anybody want a good deal on a Powerbomb header?

I need a good deal on a powerbomb.

Already sold in the classifieds, sorry!

Anyone figured out some settings for a PCV with this insert?

Gundy wrote:

So I got the 1-1/8" insert installed today. Did not take long at all. The new insert just needed about an inch of the screen trimmed off and then I bent the rest of it around the baffle so it should still function pretty well as a spark arrestor.

The results are noticeable. It has been a long time since I have ridden a stock WR, but the noise drop is massive, especially at higher rpms, but still has a nice growl. No noticeable power difference, except it may not have revved *quite* as crisply. That is probably more of a mapping thing. The bike smelled a little rich when it was warming up, but was not noticeable once everything was warmed up. If anything the bottom end power felt a little firmer. If I can find a shop to help me remap with the PCV I will, but its not doing any harm as is.

HIGHLY RECOMMENDED!!!


Tomorrow I will try to get the Megabomb installed. I have the Powerbomb now, so it will be an interested comparison.


The part number from FMF is 040630. Mine was $44 shipped from Dennis Kirk.

Anyone else do this to the Q4 and feel that it made a big difference?

I installed a Q4 and power bomb 2 weeks ago and it is way too loud but im liking the performance. This may be a great solution if it actually makes it a bit quieter. I noticed after an hour ride through the canyons my ears feel like i just came out of a banging night club.

iFlyLow wrote:

Anyone else do this to the Q4 and feel that it made a big difference?

I installed a Q4 and power bomb 2 weeks ago and it is way too loud but im liking the performance. This may be a great solution if it actually makes it a bit quieter. I noticed after an hour ride through the canyons my ears feel like i just came out of a banging night club.

I have 2 of the 040630 inserts that I had bought for an adventure bike of mine that turned out not to need them. I was thinking of doing the modifications to shorten one of these inserts to further quiet down the Q4 on my WRR. If you are interested in one of them, I can modify both.
Let me know. It would motivate me to finally do this versus having the inserts sitting on the shelf.

i would be, i would like to keep the spark arrestor functional instead of chopping it like the guys above did. Maybe cutting the netting shorter and soldering/welding it back shut again so its cleaner. what did you have in mind?

msged you.

I wanted to make my q4 quieter so I did this to the baffle.




I basicly copied the hindle quiet core design I bought for a hindle pipe I had on another bike.

I cut out the sa screen as we dont need them in canada and I dont want to have to remove and clean it once and awhile. If your some wheres you do need one you can do this and leave it alone.

I welded a washer over the end of the baffle then drilled the center of the washer out to 3/4 of an inch, then I drilled 8 3/8 holes in the sides of the baffle as some exhaust flows around it, this helps flow without adding more noise.

Its quite a bit quieter and the bike bikes seams to run exactly the same.

Gundy wrote:

http://www.kawasakiforums.com/forum/klx-250s-71/pictorial-custom-fmf-q4-quiet-stock-35239/
http://www.kawasakiforums.com/forum/klx-250s-71/fmf-q4-how-make-quiet-stock-35221/

Poster claims that the powercore quiet insert will further quiet down a Q4.   Anyone tried this on a WR?

Thanks for the info Gundy bought the quiet insert trimmed the spark arrester so much quieter & no loss of performance...your a star..