Montesas At AHRMA Glen Helen

[Tahitian_Red]

Here are some pics of a few Montesa seen at the AHRMA Glen Helen National:

[cappra]

All motors built by Southwest Montesa 

[mx250]

#38, he's got it bad ain't he .

and does great resto's .

These VB360's are get as common as muck. Is that an original muffler Jared? I know the one I have, and the manual shows, has a built in muffler along thr stinger but this one looks 'factory'.

[cappra]

Stock pipe and silencer on the VB 360.

[montynut]

Second year model of VB360 had additional silence exactly as the picture shows the first model only had the stinger silencer biult into the pipe under the seat. The recond model had both. The original model would not pass the noise tests hear in Australia without some 'help'. The 'help' disappeared during the races.

[mx250]

Second year model of VB360 had additional silence exactly as the picture shows the first model only had the stinger silencer biult into the pipe under the seat. The recond model had both. The original model would not pass the noise tests hear in Australia without some 'help'. The 'help' disappeared during the races.

Ahhh! That all fits and makes sense. I sussed the original arrangement as an effective muffler (small diametre). I would also suss the arrangement for it's effect on chamberdesign (no singer, straight into the muffer).

[mike1948]

I'm running the original 77 pipe, with short stinger silencer, and it does have a bit of a bark.  I haven't had it tested yet for sound level, but listening to most at cd5, I don't think it will be far off, if at all.

[montynut]

The reason the original VB360 had problems with the noise test used in 'the day' was that the test was taken at a set "mean piston speed" they used a device which touched the cylinder finning and had a spring which resonated at a set frequency (bloody crude really) which was set by the then ACU for each bike. The problem for Monty riders was that the VB 360 has a very short stroke so during the test it screamed its bloody head off. The revs required for the test was much higher than a YZ400 or Husky 360 etc. Once on the track without the 'help' no one ever questioned it. The second model passed the test without 'help' and did not seem to be affected by the extra stinger length although the second muffer did have a larger bore than the original under seat muffler.