High rpm's on start up?

[Spide4x4]

When I fire up my 79'xs1100sf, the rpm's immediately race up. With the choke in full mode there is just to much rpm's, I have to hold the choke back manually between the half and full just to keep it running. I'm the 2nd. owner of this bike, which I bought from my dad. He tells me, it's always been like that. Has anyone else encountered this problem?

[hollywoodxs1100]

The choke raises RPM on my bike as well, but not to a point where I feel I need to manually hold it back.

On our bikes, the "choke" circuit isn't a choke at all, but rather a fuel enrichment circuit. It doesn't restrict airflow as on a conventional choke. It instead sends more gas into the airstream. If you are getting to much RPM on choke, maybe your mixtures/fuel level are incorrect? What RPM do you run at with the engine warm and the choke off? What color are your plugs?

[TopCatGr58]

Hey Spide4x4,

Are you saying that you are running the bike with the choke engaged to keep it running after it warms up?? IF so, then you need to do a serious carb cleaning, not to mention probably needs to be vacuum synchronized.

Go to the MAIN FORUM PAGE, and scroll down to the TECH TIPS, also to the MISC section, and read what to look for in a neglected XS11, you'll find lots of things that you'll need to check to get the bike into proper running condition and road safe!
T.C.

[oseaghdha]

On our bikes, the "choke" circuit isn't a choke at all, but rather a fuel enrichment circuit. It doesn't restrict airflow as on a conventional choke. It instead sends more gas into the airstream.

I believe there is also additional air introduced by the "choke" circuit. Could be the seals on the end of the plunger are defective.

[HobbyMan]

How are intake manifold boots? Does it run ok when it is warm? With the "choke" and extra air introduced(from air leaks), doesn't it seem that the rpms would increase. I don't know if this would really happen or it is your case, but it makes sense. If this isn't it, sounds like a carb cleaning/inspection job.

[Spide4x4]

After the bike warms, I turn choke off and she runs good.
All my carb boots are brand new, the rpm's are so high on start up that I know that's not good for a cold motor. I've had the carbs off and cleaned them, also checked float levels and so fourth. Thanks for the replies.

[DiverRay]

When cold on a full "choke", the bike will start at 3.5 to 4K, and after just 30 to 45 seconds, go to 5K in our area. I usually let my bike, '79F, warm on full for 30 seconds, and then shut down to 1/2 choke. It will then idle at about 1500, and I usually start driving after about 1.5 to 2 minutes.
Ray

[Spide4x4]

Yeah, that's close to what I'm looking for on start up.
$hit mine jumps right up to 6 or 7 g's, I don't let it keep going to see just how far but it's crazy! Thanks for the help

[DiverRay]

I would put a carb sync on the bike. When cold, you can have just one carb pull up the RPM.
Ray

[BLUEJEEPLAB]

Mine depends on the air temp for the day. At lower temps, full choke and he runs at around 1800. Mid temps (50 to 70) he runs at 1500 or so then creeps up to 2000. Never higher than 2K. At 70 or above, I can start him without the choke, though I usually opt for the half choke for about a minute then go no choke.

[HobbyMan]

Normally, on a chilly morning, I let it run on full choke until it hits 2K. Then I knock it down to 1/2 choke. When I blip the throttle and it holds at 2k, then I know that it is warm enough to ride. If I leave it at full choke, it will eventuallly rev to 3500-4000 RPM.