Full throttle just to start

[Romanousky]

Hello All,

I am having some starting issues with my bike. I can't seem to find anyone else with the same problem.

Here it goes: First, my bike is a 1981 XS650 that is kick start only. In order to start the bike, I have to hold the throttle atleast half way open (usually full throttle for first 2-3 kicks). At this point, I can usually smell a little gas so I back down to 1/4-2/3 throttle and kick until it fires up. As soon as it catches it revs way up since I'm holding the throttle open. If I don't open the throttle at all, I can kick it all day and it won't fire.

Another note, I do not use the choke at all. It does not start with the choke on or even 1/2 on. I have also tried firing up the bike and before it warms up and turn the choke on and it immediately dies.

Other than this, the bike runs great, idles perfectly, pulls strong through mid-range and top. The plugs are a light tan color closer to white than brown but I don't feel that it is overly lean (no flat when running through the RPM range).

Carbs are stock (34mm Miks), pod filters, high flow X-pipe, mild porting (just smothing contours).

Jetting: 137.5 Mains
45 Pilots
Needle is stock (fixed position)

Anyway, this is a pain in the butt because I don't like to be sweaty from throwing 25 leg kicks at 6:30 in morning on my way to work

I would appreciate any help that you can give me.

 

[5twins]

Sounds like your chokes aren't functioning properly. Besides fuel, they add some air as well. Your choke feed jets may be plugged so you're just adding air when you put the choke on - and it kills the motor.

Remove the float bowls and visually inspect that the choke jets are clear .....

 

[Romanousky]

Hey 5twins,

I appreciate the information. I took out the carbs over the weekend and found that I do not have this particular hole in the float bowl???? Is it possible that i have a different version of the BS34? Is this a photo of the canadian model or elsewhere? Anything else to check? Thanks again for the help.

 

[5twins]

Actually, it's a photo of a Virago float bowl but BS34s have the same (or very similar) set-up. Most CV carbs do. Here's a pic of the 34s. The brass take-off tube along the front edge of the carb body sticks down into the bored hole along the front edge of the float bowl. When you turn the choke on, the brass tube draws fuel through the feed hole or inlet and up through the choke jet - IF the jet is clear. If not, the choke won't work .....

 

[Romanousky]

It took me a while to get around to it but I pulled the carbs again and found there to be NO obstruction blocking the choke jet. The take off tube was also not blocked. I filled the take off tube with carb cleaner, then hit it with compressed air and the fluid shot through a hole on the backside (engine side) of the carbeurator. I assume this is correct. It seems to be functioning fine. The carbs are in great shape and look borderline brand new. Could there be O-rings or other seals that are missing around the mechanical choke shaft (the actual pull rod) that may be required so that a vacuum is created to draw fuel from the float bowl? Also, there are holes in the take-off tubes very close to the top of the tube. It seems that this would just draw air as the fuel level in the carb does not reach the top of the float bowl. I figured this was normal since both tubes have these holes. Any ideas?

Thanks again.