jono035
1st June 2009, 12:07
Was having a major problem with my bike bogging down and stalling at anything under 7k rpm when trying to get moving. The guy who I bought it off said it was just running rich on idle and needed the mixture adjusted. Just finished completely disassembling them only to find that the problem was a jammed-then-snapped choke cable...
The carburettors on the bike are 2x Mikuni BSW-27 dual-throat things, of which I took a few pictures quickly after figuring out where everything was. Figured I'd post what info I found out here in case anyone else might find it interesting/useful.
The choke is a single slide/needle for each carb (not a butterfly) that is located on the engine side of the carb just behind the main cap, easy to spot due to the cables sticking out of it. This jammed open for me and was pouring fuel down the bore causing it to run way too rich and bog down really bad until about 7k rpm.
The idle adjuster is a flat head screw on each carb that sits next to one of the balancing hoses (the 2 air hoses that loop between the engine-sides of the carb) and should be accessible from the top of the carb. This only adjusts the amount of air/fuel that gets through and into the engine, to adjust the mixture it appears that you actually have to replace the idle jet, which is accessible after removing the float bowl at the bottom.
I have pictures of all this if you need but nowhere to post them as of yet, so PM me if you'd like em.
I also couldn't find the main jets (the service manual that is available online is no help, the pictures are terrible) so anyone who knows where they are, feel free to point them out!
Anyway, the choke has now been converted to a pull-on-the-cable-with-pliers style choke and the bike is running much nicer, just have to put the fairings back on and take it for a buzz.
The carburettors on the bike are 2x Mikuni BSW-27 dual-throat things, of which I took a few pictures quickly after figuring out where everything was. Figured I'd post what info I found out here in case anyone else might find it interesting/useful.
The choke is a single slide/needle for each carb (not a butterfly) that is located on the engine side of the carb just behind the main cap, easy to spot due to the cables sticking out of it. This jammed open for me and was pouring fuel down the bore causing it to run way too rich and bog down really bad until about 7k rpm.
The idle adjuster is a flat head screw on each carb that sits next to one of the balancing hoses (the 2 air hoses that loop between the engine-sides of the carb) and should be accessible from the top of the carb. This only adjusts the amount of air/fuel that gets through and into the engine, to adjust the mixture it appears that you actually have to replace the idle jet, which is accessible after removing the float bowl at the bottom.
I have pictures of all this if you need but nowhere to post them as of yet, so PM me if you'd like em.
I also couldn't find the main jets (the service manual that is available online is no help, the pictures are terrible) so anyone who knows where they are, feel free to point them out!
Anyway, the choke has now been converted to a pull-on-the-cable-with-pliers style choke and the bike is running much nicer, just have to put the fairings back on and take it for a buzz.