What is your "choke" RPM when starting

XS400NJ

XS400NJ

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Hi guys,

when I start my bike in the morning with choke pulled-out all the way bike usually starts from first kick and rpm goes over 4000. It is a bit noisy so after few seconds I push the choke in and use throttle to keep bike running until it's warm.

Also, pushing choke half way in does not seem to do anything(should it?). It's like no choke, cold bike just dies.

Is it how it supposed to be?

Thanks.
 
Last edited:
Thanks, this post suggests that I have carb out of sync. Very much possible... will sync them and see what difference it makes.

I figured your rpm is pretty high on choke as well, how high?

Thanks again.
 
I try to keep the RPMs around 2000, for about a minute, using the choke. The longer the engine runs, the less choke it needs to do this. After about a minute, I let it idle while I'm getting my helmet and gloves on. Then I ride gently for a few minutes to get the oil warmed a bit, and to get away from home. After that, I enjoy the ride. ;)
 
High rpms on full enrichener, it's not a choke, is somewhat normal. But pushing it in should slow the rpms. Try not pushing it in to halfway. Try 3/4.
You can put it most anywhere, not just the notches.
In the float bowls there is a jet that controls the amount of fuel drawn by the enrichener. It may be partially plugged. This could cause you to not get enough extra fuel except at fully open.
Leo
 
I have a '77. Full runs about 4000 rpms when cold, half runs just under 2500. I typically ride around the corner at half before reseating the enrichener.
 
No, they knew it was an enricher, or a cold start circuit. They also know that most consumers are relatively ignorant and resolutely arrogant in their refusal to read owners manuals. So the manufacturer labeled it a choke, because that is what the ignorant and arrogant consumer would understand.
 
16VGTIDave said:
No, they knew it was an enricher, or a cold start circuit. They also know that most consumers are relatively ignorant and resolutely arrogant in their refusal to read owners manuals. So the manufacturer labeled it a choke, because that is what the ignorant and arrogant consumer would understand.
Click to expand...

I'm not sure the manufacturer cared about the ignorance or arrogance of consumers. I think it's just a lot easier to put CHOKE on a small plastic piece instead of EN-RICHENER.
 
For practical purposes I think the two names are interchangeable, as a compromise on this forum we could use enrichoke or (chokerichener) :)
 
mmcdx said:
I'm not sure the manufacturer cared about the ignorance or arrogance of consumers. I think it's just a lot easier to put CHOKE on a small plastic piece instead of EN-RICHENER.
Click to expand...


Sure they did then, as they do today. The Yamaha service manual refers to this as the "Starter Circuit". They could have easily put "Start" on the SOHC knob or beside the DOHC lever. But they chose to use "Choke" because most people back then kinda/sorta understood what a choke was for.

The point to be acknowledged is that the starter circuit it is NOT a choke, and it does NOT work like a choke. The starter circuit performs a similar function as a choke, that is all. Twisting the throttle, especially while starting, will defeat the cold start circuit. Not so with a choke.
 
i still have some tuning issues to button up, but i have been able to start half "choke" relativity quick... RPMs stay near 2000 until it heats up and the RPMs raise a bit after revving once warmed up.
 
Today after work finally had some time to look into carb synching. Differential manometer made from two empty cambucha bottles, aquarium tubes, water, and some acrylic paint. I could not figure out how to synch carbs with gas tank on, but to my luck I had plenty of gas line left...

It was surprising how little turn on the "synch" bolt it would take to make water to move from one bottle to another. I was able to synch carbs and it made a noticeable difference to how the bike rides, especially at low rpms.

I am yet to see what difference it made to morning warm-up, but wanted to share this. Here are some pics...
 

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Well done :) It really is amazing how much difference it makes, hey? I found out the same thing the first time I synced my carbs.
 
XS400NJ said:
Today after work finally had some time to look into carb synching. Differential manometer made from two empty cambucha bottles, aquarium tubes, water, and some acrylic paint. I could not figure out how to synch carbs with gas tank on, but to my luck I had plenty of gas line left...

It was surprising how little turn on the "synch" bolt it would take to make water to move from one bottle to another. I was able to synch carbs and it made a noticeable difference to how the bike rides, especially at low rpms.

I am yet to see what difference it made to morning warm-up, but wanted to share this. Here are some pics...
Click to expand...

You set the petcock to pri and gas will flow without being hooked up to the vacuum.
 
Yes, I turned it to "pri" for the tuning, it is not hooked to vacuum. The picture is before starting the bike.
 
I thought the same thing xchris, then I was thinking does the cap need to be air tight? If so maybe glue, or plumbers putty?
 

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