Metal plug cap covers.

[LesterPiglet]

Around 1969 the H1 Kawasaki was fitted with the first CDI which evidently interfered with TV's as the bike rode past.
The metal cover was probably intended to eliminate the RFI created when the plug sparks (the internal resistor in the plug cap reduces this too). The manufacturer's were probably more bothered about eliminating RFI than they  were preventing their bikes cutting out in wet weather !!!

This is the reason I believed those metal contraptions existed. I didn't give a sh1t if your TV buzzzed when I zoomed past. 

[AshimotoK0]

Around 1969 the H1 Kawasaki was fitted with the first CDI which evidently interfered with TV's as the bike rode past.
The metal cover was probably intended to eliminate the RFI created when the plug sparks (the internal resistor in the plug cap reduces this too). The manufacturer's were probably more bothered about eliminating RFI than they  were preventing their bikes cutting out in wet weather !!!

This is the reason I believed those metal contraptions existed. I didn't give a sh1t if your TV buzzzed when I zoomed past. 

I know, in the late 70's I worked for a large company and it was all doom and gloom about redundancies and everyone was moping around doing nothing but look miserable. I though boll***s to this and gainfully employed myself for a week designing and building a CDI system for my 1st 400/4. It basically inverted the 12v to 400 VDC, then charged a  0.5uF capacitor to 400v and discharged this using a thyristor   across the coil each time the standard contact breaker operated. It took a bit of perfecting though, the first attempt nearly blew up the silencer when it misfired!  It ran great for the next 20k miles (apart from 1 capacitor failure - these were the type used in old Pye valve colour TV sets and I uprated from 600v, to 1,000v type, as they did in the TV design). It was still fitted when I sold it (in the tool tray ) and the original points still looked like new. BUT -  god knows what the RFI was like!!  and yes I did not have the crappy tin covers on. Wonder if its still fitted, as the bike is still out there and was licensed last time I checked XDN128R. I can still hear those twin inverters, 1 for each coil, singing together now!

[RGP750]

My Point in possibly making these was to supply a service NOT suggest everyone should rush out and put them on their bikes.
Until i had been informed that you can get them I have seen a lot of bikes "original/ concourse"in articles and books without them.
Judging by the comments sorry i even mentioned them.
I'll think again before posting.
safe riding

[UK Pete]

For what its worth Rich if i had a UK bike and i wanted it be to original i would use the metal plug caps, it was a good idea to try and offer a service to us, some of the comments were a little harsh but dont be put off posting, some subjects get this reaction on forums
pete

[mickwinf]

don't take offence, keep posting!

[LesterPiglet]

Don't take offence, everyone has an opinion or story. Sometimes these threads take on a life of their own.

[AshimotoK0]

+1  Please don't take offence!! Fitting them for originality is fine, a concourse bike will probably never see much wet weather anyway. To my knowledge  there wasn't a safety  recall on them by Honda. On all of the bikes I had, they had been removed so I can't speak from personal experience how bad they were in the wet. However, parts on the sandcast 750 which WERE safety recall (e.g. carb tops) items are sought after, for refitting - scary, but that's just my view unless they are just used as museum pieces.
Please keep posting -- this is a very    friendly forum !!!!

[Green1]

+1
What was the recall on carb tops don't think I'v herd that one
I'm glad I don't have tin plug caps as it rains every time I use the bike.
I do remember touching one of those caps once when the bike was running and I can tell you it made me swear somewhat 

[AshimotoK0]

Don't want to hijack thread so please request I  move this SteveD, if necessary. The Service Bulletins were on the internet but must  have been removed due to copywrite  issues. The SB was no 15, (see below '750 #15   4-70   Throttle Cable Recall') I think there were issues with the cable jumping out of the carb top and increasing engine revs but I may not be exactly correct. Real shame those SB's were removed!

All I can find regarding SB#15 is "This bulletin covers the replacement under warranty of the throttle valves / cables on machines up to frame number 1017342, and the rear wheel dampers on machines up to frame number 1016997. It requires that after replacement of the rear wheel dampers, that three centre-punch marks are made on the rear wheel flange just outboard of the driven sprocket.
is this"

Cheers AshD

Honda SOHC Four
Bulletins and Notices
This table merely enumerates the bulletins. The bulletins themselves are not on this site.
They are copyrighted, and requests to Honda for permission to use the material have gone unanswered.
350/400   500/550/650   750   General

TITLE   DATE   SUBJECT
350/400F #1   1-75   Disc Brake Mounting Bolts
350F #2   6-74   Correct Cam Chain Tensioner Use
350/400F #3   12-74   CB400F Wiring Harness Strap
500 #1   7-71   Tendancy of Exhaust Valves to Stick
500 #2   7-71   Oil Pump Precautions
500 #3   8-71   Cylinder Stud Removal
500 #4   7-71   Revised Shift Mechanism
500 #5   10-74   Oil Consumption
500 #6   11-73   Muffler Warranty Extension
Field Memo   1-3-75   Excessive Wear of Rocker Box
Field Memo   6-25-75   Revised Alternator Field Coil
Field Memo   7-11-75   Vibration Affecting Regulator
550 #7   3-76   Instrument Mounting Cushions
Field Memo   4-76   Anti-vibration Regulator Mounting
500/550 #8   8-76   Revised Rockerbox
Pts News   8-3-76   Revised Rockerbox
500 #9   8-76   Revised Clutch Adjuster
"Wrench"   6-80   CB650 Valve Cover Installation
650 #1   8-80   Poor Acceleration
"Wrench"   5-81   CB650 Head Torquing
"Wrench"   7-81   CB650 Faulty Exhaust Valve Guides
"Wrench"   9-81   CB650 Cam Chain Installation
CB750 #1   6-69   Charging System Diagnostic Tips
CB750 #2   5-69   Pre-Delivery Service
CB750 #3   6-69   Setup Particulars
CB750 #4   9-69   Drive Sprocket Recall
CB750 #5   9-69   Drive Chain Maintenance
CB750 #6   11-69   Cylinder Head Damage
750 #7   10-71   Air Filter Box Fasteners
CB750 #8   11-69   Bent Advancer Shaft
CB750 #9   11-69   Manometer Use
750 #10   12-69   Loose Alternator Bolt
750 #11   11-71   Front Brake Lever Freeplay
CB750 #12   1-70   Revised Break-in Procedure
750 #13   1-70   Revised Oil Filter Case
750 #14   10-72   Main and Rod Bearing Selection
750 #15   4-70   Throttle Cable Recall
CB750 #16   5-70   Camshaft Tower Caution
CB750 #17   5-70   Revised Drive Chain Oiler
750 #18   6-75   Drive Chain Type Caution
CB750 #19   7-70   Correct Cam Chain Adjustment
CB750 #20   7-70   Crankcase Breather Fitting
CB750 #21   7-70   Drive Chain Maintenance
CB750 #22   8-70   Chain Guard and Oiler Mods
CB750 #23   9-70   Excessive Front Brake Pad Wear
CB750 #24   8-70   Revised Output Shaft Bearing
Cust Letter   12-28-70   Throttle Cable Recall
750 #25   9-71   Linkage Type Carb Adjustment
CB750 #26   12-70   Brake Disc Mounting Bolts
750 #27   3-72   Spark Plug Fouling
750 #28   2-71   Drive Chain Installation
750 #29   4-71   Revised Crankcases and Output Bearing
750 #30   5-71   Drive Chain Oiler Adjustment
750 #31   8-74   Connecting Rod Weights
750 #32   8-71   Chain and Crankcase Recall
750 #33   11-72   Wiring Harness Routing
750 #34   5-72   Shimming Front Brake Caliper Mount
750 #35   11-72   Revised Oil Tank Feed Hose
750 #36   4-73   Rear Brake Wear Indicator
750 #37   11-73   Sprocket Manufacturing Tolerances
750 #38   11-73   Muffler Warr Extension
750 #39   2-74   Use and Removal of Revised Head Gask
750 #40   4-74   Revised Shift Drum
750 #41   4-74   Revised Fork Seals
750 #42   7-75   Intro of Head Gask Stud Seals
750 #43   1-75   Revised Pos Batt Cable
750 #44   4-75   License Plate Bracket
750 #45   3-76   Instrument Mounting Cushions
750 #46   3-78   F Model Brake Pad Recall
750 #50   4-78   Automatic Fuse Box Recall
SL #83   11-72   750 Master Cyl Reserviour
SL #87   6-71   750 Final Drive Bearing
Service Rem   5-75   750F Fuel Tank Caps
"Wrench"   3-76   750 Clutch Chatter
Service Rem   8-76   750 Rear Sprocket Dimensions
"Wrench"   12-76   750 Clutch Chatter
Service Rem   1-77   750 O-Ring Chains
Service Rem   4-77   750 Pipe Bluing
"Wrench"   4-77   750 Cam Breakage
SL #108   10-77   750 Wheel and Tire Matching
SL #124   10-78   750 Speedo Cable Alignment
Pts News   6-4-80   750F2-F3 Fuse Box Recall
SL #84   5-71   Stellite Plated Valves
SL #85   9-72   Factory Chain Riveting Tool
SL #90   6-71   3-Phase Charging System Explained
SL #93   5-74   Battery Vent Hose Routing
SL #98   6-73   Batt Vent Hose and Drive Chain
SL #99   7-73   Availability of Manometers
SL #107   2-75   Sidestand Maintenance
SL #110   7-75   Bleeding Hydraulic Brakes
"Wrench"   11-77   78 550, 750 Carb Specs
SL #120   4-78   Fuel Filler Latch Recall

[Bryanj]

Didn't know they had been taken down from the uS site, I have most of them on paper if anybody wants a copy of one or two ---PLEASE don't ask for them all, I'm working 60+ hours a week at the moment and sleep is rather important too (along with the wife!!)

[AshimotoK0]

Found them!!!

New Link   is

http://www.sohc4.net/cb750-faq/

Scroll down and click on the relevant one