HRC high flo end cap for XR400R. What a difference.

Just installed the HRC/OEM high flow end cap for the stock 2003 XR400R pipe. All I can say is Wow what a difference. I do have a few questions with regard to power and sound for those who have done this change or just happen to know.

1)This end cap is marketed by Baja Designs as HRC/OEM high flow spark arrestor. Is it the same as the OEM 96 version of the end cap re-marketed by HRC?

2) Does anyone know what the approximate power gain is from adding this end cap over stock 3/4 diameter welded in version?

3) It is definitely louder, does anyone know the decibel level produced with this end cap. My guess is that it would test out at around 100db.

This really seems like a great way to help exhaust flow for the money.

Thanks in advance for the feedback.


Sorry- I don't have any info for you but rather a question. Isn't the unit that BD sell *just* the spark arrestor? My understanding is that this PLUS the end-cap silencer is the OEM setup from the early XR4...



I think the spark arrestor (HRC Racing) sold by Baja Designs is the same as the OEM 96-97 unit with the internal baffle removed. I may be wrong. Thumper Racing used to sell a Stealth insert for the 96-97 400 that had the small baffle removed. I had one on an XR600 and it was not too loud. BD sells a baffle to insert in the HRC spark arrestor that quiets it down. On your original 2003 spark arrestor, had you done the Gordon's mods?

You are right, it is just the spark arrestor (HM KCY A1). As for the tip Honda put in with that to dampen the sound I don't Know there are however two small holes meant to recieve an insert. BD and probably others sell their insert for the stock cannister(that inserts into the spark arrestor (as far as i can tell, and seals with a heat activated o-ring). I know of at least two. The one at BD which you have probably already checked is about $100.

I on the otherhand don't want to add any more restriction to my outflow than I have to. I am jetted reletively rich and pose no danger to the engine currently. A portion of my messge was to get an idea about sound levels and the likelyhood of getting a ticket here in Northern California(thus i am interrestd in exatly how many db i am over according to the dyno.

I will probaly buy the BD baffle or at least carry the stock arrestor with me (in the truck) if I get stopped i can revert back in 2 minutes in stead of having to go home.


Yup (i take it you mean drill out the stock arrestor (up to four holes) and keep the set screws around for tuning). I have done most of the mods with regard to intake and exhaust. I still wanted more flow but was to lazy to take the header pipes of and grind out the extra weld material (heh heh heh). Snorkel yanked Jets are big 160/60. I got the okay for the mikuni pumper in a few days.


I was told the HRC Racing end cap was "damn loud" when I was shopping around.

If you are over 96 db, you can be ticketed at most California OHV riding areas, National forests, etc.

Here is recent thread with my experiences;

I ran the HRC high flow spark arrestor by itself for one ride. Was a little too noisy for me. Then installed Quiet-is-cool baffle into HRC high flow spark arrestor and this combination tests at 92 dba. I could not feel any significant power loss with or without the Quiet-is-cool baffle.

Great info oldturtle, I thought there could have been a thread for this topic.

Exactly what I was looking for in the way of information.

Yes I agree, the spark arrestor is a bit loud by itself. But seems to REALLY perk things up.

Just checked out quiet is cool. The tip that they sell is cheaper than that of BD by half. :thumbsup:



Along with the 400 I have a 01 650R with the HRC insert. My understanding is that the 650R with the HRC insert will just pass the sound test, some pass, some don’t. My 400 with the 96 insert is louder than expected, but not as loud as the 650. If anyone has had their 400 with the 96 insert tested I too would be interested as to the outcome.

I have a 04 xr 400 with the larger late model end cap that I got from the dealer , alot better than stock and more zip , no problems at any parks or rangers.. do the 160/60 jets and adj . the valves, remove air snorkel and enjoy...

Don't attract attention to yourself by doing anything stupid and you should be alright

Don't attract attention to yourself by doing anything stupid and you should be alright

Thanks J very helpful.......

Thanks J very helpful.......

Yeah all the people I've seen checked for sound were people spinning donuts with their quads in the camp/staging areas or the jackasses wheelieing down the main road or guys that rev the piss out of their bikes when they're warming them up first thing in the morning. I have loud pipe and haven't had any trouble with rangers or sound because I don't attract attention to myself

I agree,

I see that mostly from teens on quads and posers.

I never been to a sound test, but I can compare to other pipes I have. I have used the 96' SA on 4 XR400's, also tried a BigGun Race, White Bros pro meg, FMF MegamaxII.

The stock 96 w/o baffle runs really good and was by far the quietest. I would guess borderline on the 96db test.

FMF next up the sound list, Best compromise if you don't have to be 96db,unfortunately they don't make it for the 400 anymore.

Biggun is real loud, throttle response is much better than others.

WB is real loud, mid-top power is much better than others.

None of these is as loud as my WR426 w/o baffle was.

At Dual sport rides I run the 96 cap and take the Vortex baffle that I can stick in it if I need. Sticking the stock 98-up cap on would require jet changes.

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