Hi, When the headlight is on & you switch to Hi beam or Flash/Pass the headlight dims - Ideas?
   Cheers   Dale

Assuming the low beam is unaffected I would think it is probably a bad connection somewhere in the hi beam wiring.

Could be in the handlebar switch, the big connector under the tank, or the connection at the bulb.  Might even be a dying bulb, although they usually get brighter just before they burn out.  Possible, but not likely, the ground connection under the tank is dirty.

I would go for the connection at he bulb first and work my way back to the switch.

+1

sounds like the earth wire connection at the bulb to me ....the h4 plastic connection there have been seen to have been distorted from heating effects on many occasions
hint check the wattage of the bulb
supposed to be 55-60 ...but many install higher wattage types

just a heads up
there are many posts in the forum about upgrading to relays ...to alleviate switch and connector issues

good luck

Thanks for the quick reply's. 
      A bit more investigation - bear with me - 
   Right hand switch block - The light switch in the headlight position.
   Left hand switch block - When the headlight switch is in the Lo-beam position its brightness is greater than when in the Hi-beam position. When the flash/pass is operated it's brightness is as when on Hi-beam.
   Right hand switch block - The light switch in the Park position. When the flash/pass is operated it's brightness is also as when on Hi-beam. 

   Could it have the wrong headlight globe?  
   The wiring harness looks original. 
   I've had the L/H switch block of and all looks original, About to try to remove R/H switch block.
      Cheers   Dale

Hi beam comes on so the bulb has to be OK and the earth has to be connecting so I'd say its gotta be in the left switch block.
Gaz80 wrote a post on the repair of the contacts in that switch just recently. Might be helpful.

Opened up the wiring harness behind the headlight plug and another plug has been fitted. So, three wires - Brown, Yellow & White - Assuming P/O had wired it up wrong, which wire should activated Hi- beam & Lo-beam?
   Appreciate your time.   Cheers   Dale

just remember that its European .....so brown is always the earthy side of the connections
white = high and yellow = low beams power


good luck ...you may have found the issue

Thanks. 
   Reading through the Forum there is reference to having Relay's in the headlight system, one for L/beam & one for H/beam?  
   So, while i'm in there, What sort of relay's am i looking for & where would you suggest the relay's go?
      Cheers   Dale

look for "eastern beaver " relays

he's an Japanese supplier of relay kits to suit ...made exceptionally well with good components

you can gleam from the the kits how the system works ....  

but in essence ...a relay is fitted so the headlight switch wiring switches the relay ...rather than the load to the headlight

there is an additional positive supplied from the starter motor relay (battery side ) that supplies the relays then the headlight as the relays are switched on and off

there are quite a few posts with diagrams throughout the forum

have you found the search function yet ?

addition recommendation is to fit an ceramic headlight connector

I use 3 relays ...as I have additional running lamps ...like many others

While i had the Left hand switch block of i noticed one of the contacts looked low. It was loose in it's position. Others have commented on this being a problem. 
   Gaz80, has a good repair & pictures. I followed that but using a brass bolt i had.
Cut the outer flange of existing pin & punched it out. the brass bolt screwed in, but [as Gaz80 did] i also used epoxy as well. The silvery bit is what came out.

   Dale

yes that's the issue with our switches ....heat from arcing on a relatively small contact area

did you tap the plastic before inserting the screw ?
nice solve
love to see it finished

Hi, charlie99,  In solving it, it was a 'leg up' by Gaz80.

   No i did not tap the hole. It was a firm fit, it did not slip in but needed only needle nose pliers to wind it in. Used the Epoxy glue as a precaution against it working loose.   
   The brass bolt was 3.mm dia.


   The drill bit was 1.5mm. [smaller would have been better]


   The end to attach power was done by filing a flat spot, punching a mark then drilling. When i tried to drill all the way through the bolt broke. So, at the forth attempt, i drilled but not all the way through and turning the bolt over, filed away the brass to expose the hole.




   With reference to have i 'found the search function yet'  i'm only aware of the 'Portal page, Forum google search'.
   
   Dale

yep that's the "search"

good work on the replacement

cheers for the pics as well

Word of advice for anyone replacing these pins and soldering on new wires: the plastic will heat up and deform very quickly.

Don't use anything less than a 25 watt or greater than 40 watt soldering iron
Make sure that the pin you are soldering to is absolutely clean
Tin it with solder as quickly as possible and allow to go cold (yes! let the heat out of the plastic)
Tin the end of the wire
When forming the joint, apply just enough heat to melt the solder properly and then get the soldering iron out of there. Don't apply any pressure to the pin with the soldering iron.

The original pins are actually slightly barbed. Having looked at the angles on some of the wires in a number of K-series switches, I suspect that the wires are soldered to the pin and then the pin (complete with wire) is punched into the plastic.

with that type of replacement I guess the best thing to do is tin the new lug ...before it goes back into the plastic dai

Good idea.

Good tips Dai and Charlie!