Loud 300

[wheeler]

I have an '04 GG 300 that I bought last year, maybe ridden 6-8 times, like new. When I bought I noticed it was louder than what I expected and louder than the other trials bikes that were around that day. On a ride later that week I ran into a another trials rider on a Montesa, who rides a lot of trials and the first words out of his mouth were "why is that thing so loud?". It has a real throaty "pop" to it. Anyway, I started riding some events this year with a lot of other GG's and the sound level is starting to get annoying. I took the silencer apart last year, went through all the o-rings, etc. The packing looked virtually new.

The other night I took the entire system off, including the middle pipe. The sound almost seems to resonate from the middle pipe as much as it comes from the silencer end. The inside of the mid pipe is pretty basic, about 6" of perforated tube on the big end and maybe 2" of the perforated pipe on the small end and nothing in the middle, just the aluminum can, other than some frayed fiberglass looking stuff on the small end, there is no other damping material. I have never seen a stock new one so I don't know if this is normal or not.

The stock packing in silencer seems pretty tightly packed, not as loose as I would pack my KTM silencer. Any thoughts on packing material and technique?

Also, is it possible the compression had been raised? Maybe a thinner base gasket?

I am stumped. In competition the sound is fine. I just find it a little loud for riding around the house/neighborhood areas and certainly not the quiet putter the other GG's make.

Thanks,

Scott

[wheeler]

I think I may have figured it out, but someone please confirm this...

It looks to me like the midpipe has been split, gutted and tig welded back together. Around the perimeter of the midpipe you can see what looks like a seam showing through the weld here and there. And weld certainly DOES NOT look like any welds I've seen from a factory....more like something I would do myself. Like I said in my previous post, there is nothing inside that midpipe that resembles packing or baffling.

If this is indeed the case, do buy a new midpipe, take a chance on repacking the old one somehow?? I imagine this is far from an economic part.

Scott

I have an '04 GG 300 that I bought last year, maybe ridden 6-8 times, like new. When I bought I noticed it was louder than what I expected and louder than the other trials bikes that were around that day. On a ride later that week I ran into a another trials rider on a Montesa, who rides a lot of trials and the first words out of his mouth were "why is that thing so loud?". It has a real throaty "pop" to it. Anyway, I started riding some events this year with a lot of other GG's and the sound level is starting to get annoying. I took the silencer apart last year, went through all the o-rings, etc. The packing looked virtually new.

The other night I took the entire system off, including the middle pipe. The sound almost seems to resonate from the middle pipe as much as it comes from the silencer end. The inside of the mid pipe is pretty basic, about 6" of perforated tube on the big end and maybe 2" of the perforated pipe on the small end and nothing in the middle, just the aluminum can, other than some frayed fiberglass looking stuff on the small end, there is no other damping material. I have never seen a stock new one so I don't know if this is normal or not.

The stock packing in silencer seems pretty tightly packed, not as loose as I would pack my KTM silencer. Any thoughts on packing material and technique?

Also, is it possible the compression had been raised? Maybe a thinner base gasket?

I am stumped. In competition the sound is fine. I just find it a little loud for riding around the house/neighborhood areas and certainly not the quiet putter the other GG's make.

Thanks,

Scott

[peterb]

Hi Scott,

Noticed you weren't getting too many responses.

I had a look inside an older GG middle box, it looked like it had fibreglass packing around the perforated tube. I would say the packing in the mid box should be packed similar to the silencer. I remember some years back, Codina saying that the mid box should be re-packed frequently to give optimium performance (not exactly in those words) - so kind of confirms that the mid box should be packed.

Usually, the end silencer on the GG blows away the packing on the curved section of the inner perforated tube, approx 70mm from the start/entry part of the silencer. You can easily turn the packing around at this point to fix the problem - best to wear gloves as the packing can become real itchy. The packing is usually reasonably tight.

Bye, PeterB.

[ikb]

I seem to remember there was a a problem with some of the ally centre boxes on the 04's such as the baffles coming loose or something. Some people got replacements under warrany and usually opted for the steel 03 version.

Any one had this?

[wheeler]

I ended up getting a new midpipe. I tried to mod the old one, but I wasn't too happy with the way the core fit, it was going to come apart eventually. The new one was slightly different, there are no horizontal spars or supports like the old one that hold the sides together. This new one appears to be more free flowing because of that. And some of the mounts are beefed up. Of course it didn't fit right and took over an hour of tweeking and grinding with a Dremel to get the silencer to fit on. The lower mount, that uses the rear brake reservoir bolt doesn't match up at all. I'll need to make a much thcker spacer/bolt combo to get it.

It was $265 US plus shipping. I guess it was worth it. It does sound better. Not quite as stealthy as a 280, but much better than it was. We don't have a lot of 300's to compare to in our club.

IKB - That's interesting on those ones that came apart, that could have been the issue. I also found the gutted muff was nearly a full pound lighter than the stocker too.

Edited April 26, 2007 by Wheeler

[bilco]

muff

What a wonderfull word.