Waffle box query

[jeffen]

About a year ago I purchased a new but unfinished waffle box. One of the jobs that needs doing is to fettle the outlet slots.
 Would some kind soul who has a an original box measure them for me? Thanks

[tck]

If the UK ever creeps above -1C  I will go into the summer store shed and let you know

[eddie]

Hi Jeffen,
              The original waffle boxes only had rough cast slots but they are approximately 1/4" wide by 3 1/8" long.
 As you no doubt know, the exhaust pipes have the ends blanked off and slots cut in the sides. Something most owners are not aware of is the fact that a similar slotted pipe was inserted in the centre of the waffle box (behind the screwed brass plug). By the time most owners investigate this deeply, the entire baffle has rusted away - leaving no clue to it's previous existence!
  Regards,
                Eddie.

[jeffen]

Hello Eddie,
Once again you come to the rescue.  Because the box I have is a new casting it doesn't have a tapping to take a brass plug or baffle tube. Do you think that without the baffle tube the performance will drop off or is it just a case enjoying the extra loud exhaust note?

Jeffen

[eddie]

Hi Jeffen,
               As far as I am aware, the original waffle boxes and the repro's produced by the LDMCC all had the brass plug fitted. There were some other waffle boxes made by a Club member that were an open casting with a flat closing plate welded to the underside - these may not have the facility for the central baffle.
    Bikes that had the original waffle box were probably over silenced, so running without a central baffle shouldn't  result in an offensively loud exhaust (after all, that is the situation when the central baffle rusts away!). Performance shouldn't be adversely affected - in fact a lot of owners think the Mk3 with a waffle box is a much sweeter running engine than the later models with barrel silencers.

   Regards,
                  Eddie.

[jeffen]

Thanks Eddie for your help, perhaps you have a view on whether the pipes going into the waffle box have to be as you stated earlier or can be straight through.

Jeff

[eddie]

Jeff,
       You could try the bike with straight through pipes to see if it is too loud. If it is, it's not a big problem to alter the pipes some time later. The welding/machining will be on the part that is hidden inside the waffle box, so wont affect the appearance of the bike.
     The original pipes were blanked with washer with a 5/16" hole. On the inboard side, the pipe has 7 slots x 3/32" wide going about half way round the pipe - the first slot is 16mm from the end and the rest are pitched at 15mm centres. When milling the slots, I have found it pays to cut the slots prior to blanking the end - then a strip of 1 1/4" wide steel can be inserted into the pipe to support it whilst it's clamped in the milling vice.

    Regards,
                 Eddie.

[jeffen]

Once again Eddie many thanks for your detailed input and your indepth knowledge of the mysteries of the Mark series.
Jeff