greens8 wrote:
Just for the record I don`t know a fraction of what the gurus here know about the triples but I have had mine now for a year and you wouldn`t believe how many differrent settings of all the carby adjustments I`ve tried. Can I just advise that the best way to see if your bogging down is caused by richness or not is the basic method of running the bike fairly hard and stopping pretty much straight away (ie avoid idling) and getting all the plugs out for an inspection. Obviously the black is rich and brown is optimum. I tried so much contrary advice and kits and read manuals till my eyes were dropping out, but the above is the only real test in my opinion and is so easy. Oh, and start out with new or clean plugs. Good luck.
Thanx for the input.
What you are describing is what is known here in the UK as a 'Plug Chop' This will indeed determine how the engine is running but only when its on main jet (Over 3/4-full throttle). The symptoms which I had previously described occurred at between 4-600 rpm at which time the engine is being controlled by the needle and the needle jet and to a lesser degree with the main jet.
This area is difficult to diagnose especially if there are parts fitted within the carburetors that are not OEM parts. In my case I bought this bike after it had had an enthusiastic restoration by someone who clearly knew nothing about the bike and had never set the bike up after the work was completed, I believe its was never even run since the rebuild.
In my particular case the carbs on my machine had been rebuilt using 'Keyster' rebuild kits which I have found to be a 'budget option' that is available owing to the fact that genuine OEM Mikuni carburetor parts are no longer available over the counter as they have been discontinued. Without doubt the Keyster needles fitted to my bike were Keyster Y32 like in this kit advertised on fleabay
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 740318846+The bike ran very rich between 4-6000 which is when the needle and needle jet come into play. By rights the clip on the needle should be on either the center groove or possibly second down from the top (Leaner) My bike requires the clip to be on the top groove (Leanest) and I'm now using part number 95 main jets too. This indicates to me that the bike is rich at this rev range as although it is now much better than it was its still not as crisp as it could be.
Consequently I scanned the internet and found some brand new 5DJ19 OEM needles (Couldn't find any new 5GL3), sure they cost me a lot of money but if I want this thing to run right I had no real option. Second hand needles are risky as other than possibly being bent they are also prone to wear, so 40 year old needles were not they way I wanted to go. All I'm hoping now is that the needle jet is not worn.
Understanding why the engine is doing what its doing is the key to sorting out the carburation, I have found through experience that going to extremes to identify the symptoms can be a great help. In my case I could easily identify the rev range where the issues existed and knew enough to know what part of the carburetor controlled (Or had influence) at that particular range.
Moving the clip on the needle from the very bottom (Richest setting which made things worse) to the very top (leanest setting which made things better) narrowed down where the problem was 'significantly'.
As you will have no doubt noticed the needles are tapered, the amount of taper is what controls the amount of fuel/air at that particular throttle opening and is crucial to the correct running of the machine.
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