Air box

[pgnz]

A 78E is easy to soup up, if you've got a good  free-flowing 4-1 or 4-2 pipe setup with the early model carbs,  a K&N air filter,   the airbox re-breather removed,  extra holes drilled BENEATH the lower airbox,  one or two sizes larger on the main jets and possibly one size larger on the pilot jets,  drill the carb-slide suction holes out to 3.0mm,  advance the timing 3 deg,  gives the bike some extra kick,  throw in some crackly Dynacoils for a hard-out spark,  it's all good       

[wiz]

I will restore the air box to it's stock configuration, thanks guys.

[Christian Raith]

Yamaha did a lot of work to get the XS1100 correct.

[melbxs]

Drilling airboxes was a well known home tuning technique. Very bad idea on the XS which ran beautifully with a stock airbox and the carbs well balanced.

[Jonesy]

Yep, all air via the snorkel. sounds like an experiment gone wrong by a PO

[wiz]

Thanks for the reply, the bottom half # 39 has got 4~1" dia in the back, (not shown on the parts diagram, are they an unwonted addition? I figure all the air should go via the snorkel, right~wrong ?

[Jonesy]

is this any good to you?

[wiz]

81 xs 1100 some PO has stuck gaffer tape over the 4 holes at the back of the air box, what should it look like ? just 4 open holes ? Thanks.