How restrictive?

Now, we all know that KH500s were strangled restricted shadows of
their H1 forebears. It wasn't until just now that I was aware how
restricted.

On a H1E/F the entrance to the airbox silencer is approx 65x35mm, or
<tap, tap, tap> 2275 square millimetres.

As we know, the smallest diameter of an intake system should be that
of the carburettor. These are Mikuni VM28s, which gives (3xpix14x14)
or ~1850 sq mm.

So the H1E/F had a correctly sized airbox intake, then.

The intake to the much deeper, and more convoluted KH500 airbox, is a
single hole, some 23mm across, or just 415sq mm in area. Or, to put it
simply, around a quarter of the size it needs to be.

No wonder they had to jet down from 92.5 to 75.

Right then; anyone got an H1E airbox intake for sale?

<Ebays furiously>
--
| ___ Salad Dodger
|/ \
_/_____\_ GL1500SEV/CBR1100XXX/KH500A8/TS250C
|_\_____/_| ..62743../..14719.../..3157./.19406
(>|_|_|<) TPPFATUICG#7 DIAABTCOD#9 YTC#4 PM#5
|__|_|__| BOTAFOT #70 BOTAFOF #09 two#11 WG*
\ |^| / IbW#0 & KotIbW# BotTOS#6 GP#4
\|^|/ ANORAK#17
'^'

 

Salad Dodger said:

Jolly common trick too. The Pan (not the same I agree) has a
teeensy-weeensy intake to the airbox - about the size of one carb. I
have heard that drilling holes around the airbox on the Pan (and
rejetting) is a fun thing to do...

Can you drill extra holes in the KH airbox?

 

Simon Atkinson wrote:

Completely the other end of the scale I know, but we have carried out a
similar mod to the airbox and jet on the TS50, the original air intake hole
was tiny.

--
Dan L (Oldbloke)
My Bike 2000 Honda CB500
M'boy's Bike 1990 Suzuki TS50X

BOTAFOT #140, DIAABTCOD #26

 

Simon Atkinson posted ...

Yes.

Actually this was well-known, and was the most common mod (in those days),
along with re-jetting and exhaust tampering, to get extra speed from them ..


The exhaust baffles are also way longer than they should be for free flow of
gases .. and are pretty easy to remove, cut off about 2" or 3" of baffle
tube, refit and get some more horses .. it wasn't necessary to cut much off,
and indeed cutting too much off screwed the bike down again ...