How do you make an XR200R sound good?

[oldskool]

when i bought mine from my uncle it had his homemade muffler that did very well til i munched the pipe in a race accident

Hiya motorbyclist. Tidy looking XR BTW
Where-abouts down the pipe is it munched? Do you know what bike he modded the can from? Did it have a good snarl and a throaty purr? Would it pass the forest noise nazi's?

[motorbyclist]

Hiya motorbyclist. Tidy looking XR BTW
Where-abouts down the pipe is it munched? Do you know what bike he modded the can from? Did it have a good snarl and a throaty purr? Would it pass the forest noise nazi's?

well when i broke the pipe it broke about where it passes/mounts that rear strut in the frame, so i cut the pipe off and welded on a bit of galv trampoline leg that already had the right bend in it (pictured in the stripped down photo)

then my crappy gas welding broke so i left the muffler cut at the base and built my stainless one. so it needs a new pipe welded to it (basically like any new muffler but without the slip on part)

i'm pretty sure the can was completely home made, and can't remember how loud it was but it was way better than other XR200s with stock pipes that's for sure! didn't get much nazi attention but that was back around 2003-2005 when they didn't really care

will go get a pic of it next time i'm down in the shed

[motorbyclist]

heck i've even got the old trampoline pipe too (welded to original mounting part of pipe)

muffler has no packing - just baffling by the holes in the pipe

i might add that the flange/megaphone part of the muffler may chop off a few knobs from your knobblies if you bend it badly enough and then bottom out - or break the pipe and leave the muffler dangling like i did. otherwise it's fine

that crap on the pipe was my attempt to seal the join to the rusted out header

[oldskool]

holy ####, I can see why you made another one for it. It looks heavy duty. I think there may be a bit of work to resurrect that to something I'd be proud to show to my mates It's given me some ideas tho'.

Do you reckon you didn't get any loss in performance with that on?
What colour was your plug? It looks to me it may have run a little rich if anything...


Hey I see you're doing a mechatronics degree. Is that at Massey? I've recently built some grunty 300mm/sec linear actuators with optical encoder feedback ready for a 2DOF motion platform, they're pretty sweet.

[oldskool]

holy ####, I can see why you made another one for it. It looks heavy duty. I think there may be a bit of work to resurrect that to something I'd be proud to show to my mates It's given me some ideas tho'.

Do you reckon you didn't get any loss in performance with that on?
What colour was your plug?


Hey I see you're doing a mechatronics degree. Is that at Massey? I've recently built some grunty 300mm/sec linear actuators with optical encoder feedback ready for a 2DOF motion platform, they're pretty sweet.

[motorbyclist]

haha yeah heavy duty sums it up well, though it's actually quite light and looks good with a fresh coat of high heat matt black

uncle got the mix right, when he fitted it and she ran mint as. when i built my new one i made it tunable so i could experiment with backpressure and it came out a tad better but not by much. i can't remember exactly which screw it was but if you DO go to play with the mix screw it's really bloody sensitive so 1/8 turns mean big changes in mix

turns out low pressure makes it run lean, and ruins the bottom end of the rev range (along with exhaust valves).
high pressure kills the top end revs and can run her rich.
read into scavenging effects etc and you might get an appreciation for why stock pipes are often so restrictive and are sometimes best left stock (up until the emissions laws came in that is)
both mufflers worked well... high compression pistons made a much more notable improvement on my brother's xr


note i was 15 or 16 at the time - that muffler has been sitting around in the "spares/broken/salvageable" pile for a few years now. got assorted bits to make one for the modern big bore motox bikes but they probably won't do too well on the XR


yeah i'm doing mechatronics at UofAuckland - gots me a whole damn robot i should be finishing

[oldskool]

Well if you think it will sound better than drilling some 10mm holes around the backplate, and if you're offering a donor, then I'll give it a go! Can't look at a gift horse in the mouth specially if it's even got a curved pipe to go with it!

I'd rather low end torque than top end. If I wanted speed I would have got a motorX. As long as I can pop the front up I'm happy. I'm more a zen type dirt rider.

[motorbyclist]

i'm talking top end power in the revs - irrespective of speed

couldn't hurt to try - and i could attempt to weld it back together for you but no promises it'll last forever

[oldskool]

Alright!

If I get a summers riding out of it I'll be happy. I'll reassess whether I want to move to a bigger bore bike come March. It will then depend whether we decide to get a fizz boat sooner than later, and if thats the case I'll stick with the XR - after all it is a legendary bike and the '86 model might just see me into the VMX class?

So you only played with the pilot screw and didn't change the main jet.. Well that sounds promising hey. Should be safe enuff to give it a burl.

The only other thing I may have to consider is a bit of wire mesh for a fire arrestor? Don't know what they are like up at the Sandpit, seems that's the only regular place to play my side of Aucks... Never been there yet.

[arj127]

I had Custom Chambers make one for my XR250 years ago. An awesome muffler and a fair price to i thought.

[oldskool]

arj127 I had Custom Chambers make one for my XR250 years ago. An awesome muffler and a fair price to i thought.

I just heard back from an enquiry I made to MLB Manufacturers - they make the Musket Mufflers brand, they couldn't help me but suggested Custom Chambers too.

Many thanks for your enquiry. Unfortunately we are unable to help with this muffler at this stage, however if you try Custom Chambers in Otahuhu they may be able to help you. Their phone number is 09 274 1155.

But I'm guessing they'd be too exxy and theres no way I can justify pouring hard earned money into a 22yr dirt bike... well not to my better half anyway!

[oldskool]

Just drilled 5 holes into the back plate of the existing stock muffler. Jeez theres about 3mm of fresh steel plate there! The previous owner must have cleaned it up a bit and resprayed it. Anyway 3 holes are at 6.5mm and 2 at 4mm, and only because my bits went blunt! A noticeable difference in dB and more so when you block the holes with your fingertips to compare. A nice throb when idling but it all goes to custard when you rev it. None of that nice snarl, just a lot of noise sounding like just what it is - Noise escaping through little holes. I want a deeper throb and a crackling snarl. I've heard a good one today on youtube. The can is an ARROW, it sounded sweet. It's a short stubby fat can.

[motorbyclist]

So you only played with the pilot screw and didn't change the main jet.. Well that sounds promising hey. Should be safe enuff to give it a burl.

The only other thing I may have to consider is a bit of wire mesh for a fire arrestor? Don't know what they are like up at the Sandpit, seems that's the only regular place to play my side of Aucks... Never been there yet.

yep never had to touch the jets - though mine was an '83 model with the single exhaust valve - i believe yours is the less reliable double valve model ?

They don't check and don't ask - never been asked about arrestors and never ridden with one - one ride i went on up north required a fire extinguisher but seeing as they never checked and the "standard" was one so pitiful it'd struggle to put out a match i've never bothered.

[oldskool]

yep never had to touch the jets - though mine was an '83 model with the single exhaust valve - i believe yours is the less reliable double valve model ?

nup mine is the '86 model which reverted back to the 2 valve motor, and from what I've read it was the model that took the best of the original design and the '84/'85 advancements and from them made major improvements on the total package. I guess they had to, (or had to say they were major improvements anyway!) to regain loss of market dominance from the 4 valve disaster. Mine has still got the longer travel suspension but theres a story of an improvement on the prolink system which sometimes broke on the earlier models.

[arj127]

But I'm guessing they'd be too exxy and theres no way I can justify pouring hard earned money into a 22yr dirt bike... well not to my better half anyway!

Depends on what you call a lot of money. Muffler cost me about $150 i think, shouldn't be a lot more now, theres f all to it anyways.
Gave me the sound i wanted for a small amount of coin.