RM125M/S - Too Loud?

[Graeme M]

In light of all the discussion about sound levels, I am wondering what my chances are of racing the RM125M. I started it today to have a listen and it is pretty loud - standard little muffler on it after all. But I love the look of that pipe - long stinger and little muffler, just looks so cool. What does everyone think - will I get pinged for it?

My options for changing it are to find another pipe and add an aftermarket muffler. But where would I find a pipe? I've never seen one advertised... Anyone got a spare they don't need? Minus muffler is fine of course.

Alternatively, what is the likelihood my TM125's Circle F pipe would fit? I could go try it of course, but thought someone might know before I do that.

Or do I just do what I think I probably will. Go ridin' and worry about it when and if.

[jimson]

G'day Graeme the bike might sound loud because its the only one going if you were lined up with 10 other bikes you might not hear yours. Can you take the bike to a place that does rego checks they might have a sound metre. jimson

[LWC82PE]

get some silent sport muffler wool and speak to lozza! ive got silent sport muffler packing in a DEP muffler and it sounds pretty good for a straight through job. lozza thought that brand packing made some bikes too quiet!

[Graeme M]

I hadn't thought of repacking the standard muffler... I guess I could cut it open and the weld it closed. Possible, though I do like the idea of the Circle F pipe. If I lived near GMC I'd just take it down and get a new pipe made up.

[Lozza]

Simply the silencer is just to small to be effective.Attaching a 250mm or so long ali end can would go a long way to solving the noise problem.

[GMC]

I have cut a few of those sorts of mufflers open to repair & repack them. The packing becomes fossilised and ineffective after a decade or 2.
These are usually done to preserve the original look more than meeting sound tests.
I do like the look of the pipe reducing to a stinger with the muffler on the end as well & I first built my downpipes this way, however they were often prone to breaking as the small stinger becomes the week point.
A longer muffler will help your problem but beware the extra weight will cause problems if not supported properly.
I was led to believe the TM pipe was interchangable, seems you would be best able to confirm this.

[Doc]

Geoff, the RM125M or S pipe will fit the TM but the TM pipe won't fit the RM, it interferes in the frame lower crossbrace area just before where the pipe kicks up. Minor mod required

[cyclegod]

Vintage iron "Retro-Rocket" pipes list a specific 1975 RM125, pipe possibly jemco too, are your only option short of retiring the bike or modifying (vandalizing!!) the original pipe with a more restrictive muffler.

[Maico31]

Graeme i would think that the TM pipe would fit because when i had a TM125 i put a RM125s pipe on it. Bolted straight on.

[Doc]

call me a little argumentative but still for the life of me don't see why we should be modifying vintage bikes away from standard. Folding footrests fair enough but to have to change pipes is for want of a better word..BULLSHIT! I'll be hanging out till the last before I spend too much on new pipes that aren't even period  grumble grumble..I feel a little better now and I didn't even breach 96db  nice M by the way too Graeme 

[halo1963]

So how loud is a TM250 72 or 73 because they do not have silencers

What do you use as a silencer when build your own down pipes to keep them under 96db

Regards
halo1963

[Doc]

Halo, you'll have to either make something or scour the wreckers and for sale ads. I've come to the conclusion that I will have 1 bike that will scrape in under the 96db but as for the rest they will remain unchanged and now most likely un-ridden. Yet to see an effective muffler for an older bike that

A. silences without robbing too much power
B. that looks the part..the newer oval DG and stuff like that are nice (nice price too!) but in my eyes they look way out of place on a pre75 and even so I doubt they'd muffle the sound any better than stock.

I don't want to have to buy expensive accessory pipes when my stock pipes are perfectly good, I don't want to have to fit bazooka sized mufflers and there aren't a lot of other alternatives so it really does make things ridiculously difficult when you have more than 1 bike. I can see people being turned away from vintage mx over this issue. Riders/owners/potential competitors and spectators alike come to enjoy racing vintage the way it was. If this sound limit was enforced right across the whole bike racing spectrum then it wouldn't be such a bitter pill to swallow. Because it singles out vintage motocrossers only it really gets up my nose even moreso..an' I have a big nose too! 

[cyclegod]

Get a safety products store to sponsor the race meetings, and supply FREE ear plugs to whomsoever requests them.

LOUD BIKES SAVE LIVES

[LWC82PE]

you can always get one of those little aftermarket repacable alloy mufflers eg a DG or one made by GMC or Lozza and then paint it black to hide the alloy colour.

[oldfart]

Hey Doc ...I may have it solved with a piece of 20mm copper tube inserted down the singer with holes drilled on angles ( Pssssst  its still early days ) its knocked the loud crack crack at idle & taken a fair bit off full noise on me Tm 250