When I rebuilt the carbs on my 400 it worked out fine, runs well, no hanging throttle issues - I used the full Keyster Kit that came with the bike when I bought it from the PO. I know some folks have had issues with Keyster Kit - mine were new boxed, purchased by the PO many years ago.
Fast forward almost three years - my 500 seems to be giving me some unexpected problems - not helped by my superficial knowledge of understanding the carb design arrangement.
A bit of background is worth a mention as they were sent by the PO to Gerben so had quite nice shiney tops & bowls.
On dismantling the carbs I found one of the two bearings in the manifold mounting bracket was half broken presumably when the locking pin had been removed. I replaced the bracket with one sourced from Ken plus a much better shaft from Florence as mine was quite pitted. The four needles were set one groove lower than the centre position so the needle was effectively raised a notch - set slightly richer. One of my needles was bent near the tip - I do not belive it was bent by me but cannot be 100% certain only 99% certain it was not me. I purchased a set of 500 needles & emulsion tubes from DS as the kit was not too expensive. I have fitted the needle clips into the centre position of the five grooves on all four sliders. Carbs only bench sync at the moment.
On first start up the bike ran reasonably well but by the next day I noticed that my petrol pipe that came with my temporary tank kit was sticky on the outside. When I started the 500 the next day it was clearly not running properly on number one carb as the manifold was almost cold, plus the float valve was now leaking. I've binned the crap petrol pipe, removed the carb bowl on number one carb only & cleaned the screw in jet that had a small amount of muck in it. I opened the petrol tap with the bowl off and a bit of muck was washed out as well.
At the moment I am mentally resisting taking the carbs off - as Roo has said I need to take them off and do a proper check on the other three carbs. I'm now resigned to taking them off when I'm in the right head space. I hate having to do things twice.
I fired her up again yesterday and there was some heat on number one exhaust manifold but nothing like the other three. At the moment I have all four carbs set with the side screw 1.5 turns out. After about 5 minutes of engine running with my Stand Fan blowing air over the front of the engine I removed the spark plugs to find 2,3 & 4 all sooty.
I understand the basic principale of the main jet/slider needle - it's very similar to the old SU car designs.
I am not sure when you adjust the Brass coloured side screw what that actually does - is it just essentially for the engine idle mixture?
The other jet that screws into the carb body inside the bowl - the Pilot Jet - is the Brass coloured side screw linked to this internally?
I know we understand what a sooty plug looks like but added the photo to show how mine looked.
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500 plugs by
Macabe Thiele, on Flickr
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