Surging RPMs When Choke Is Set - Page 2

NoTyme · 07-23-2009

Pulled the carbs off and adjusted the floats for a fuel level right close to where the bowl and carb body meet... She runs once again, but now she keeps stalling whenever I drop the idle down below 2000... I did adjust the fast idle a tad so I may have went too far... Could that be keeping the engine from idling?

brown recluse · 07-23-2009

In the last pm you said the bike you are working on is a 305. I sent you some more links and according to another source the gas should be at 1.5- 3.5 mm below the carb body.

brown recluse · 07-23-2009

Some things are not quite adding up. If your floats were low, then that would lead to a lean condition. If your spark plugs are showing rich, then there may be something wrong with your mixture. According to the other links I have sent you, the pilot screws should be 1 3/4 turns out.

I am not sure about your idle settings. You shouldn't really adjust the idle down until the bike is warmed up.

NoTyme · 07-23-2009

I decided to try to raise the fuel level a bit more after I studied the image 8.18 which showed the fuel level at and above the point where the float bowl and carb body meet. I have the fuel level as in the photo and she is running fine. I did re-adjust the fast idle cam once again and after sliding the carbs back on she ran fine. At first the gas started flowing out of the overflow hoses, but as soon as I shut off the fuel, started the bike and turned the fuel back on, all seemed fine.
It took a good 15 minutes to warm up the bike so it would idle but she idles about 1200 and takes off without any bucking or hesitation. I almost don't want to touch a thing. I took the bike for a ride about 5 miles and performance was as good, if not better than before I started fiddling with it because of the surging issue. I won't make any final decisions until I have a chance to start it after a good night set.
As for the pilot screws I need to do some additional adjustments, but for now the fuel level for the floats are set at the point where the bowl and carb body meet and she seems to be running fine... go figure.
I am not done by no means but I simply proved to myself that a critical issue with these carbs was the float level. It seemed that I have been through the carb 3 times now, and except for the diaphragm I am pretty sure its is good clean shape. I am going to study the additional links.... I'll keep you posted.

brown recluse · 07-24-2009

Well it sounds like you should be proud of yourself. I know you have got to enjoy being able to put the bike on the road. I hope everything continues to settle in and you keep the bike.

Post pics.

NoTyme · 07-31-2009

I have have been a bit busy as I will also be for the next 7 days, but after a 18 mile ride yesterday I find she is stalling after dropping to an idle, and I more than likely will need to go back in and try adjusting those floats again. I know I have them set high, but the stalling keeps happening unless I keep the idle up at 2000... Shes still not right.
I'll keep you posted: Thanks for the PM.

OKC_Kent · 07-31-2009

Since the floats were re-set last, did you set the pilot screws back?

Does it just stall at idle when the engine is hot, or does it stall on a cool-warm engine too? If it just stalls when hot, it's time to check the valve clearances. You should do that anyways before further adjusting the carb screws.

Take a look at the attachment, it has good tips that apply to many bikes; setting the pilot screws

NoTyme · 08-01-2009

Just got in from working the fireworks here in Bedford and checked your posting. I wanted to adjust the valve clearance once the carbs were set: so maybe I need to look at them now.
Gonna be busy for the next week as the fair starts on Sunday so I hope to get another cold start maybe tomorrow and confirm the stalling only on a hot engine. I do know that I am not happy with the engine response as it seems the rpm's seem to drop slowly when I wrap the throttle. I think it should drop faster. I am almost thinking multiple issues here now.

ironyankee · 08-02-2009

If the rpms don't come down right away(hanging idle) you have an air leak at the manifolds or air box or a torn diaphragm ($100.00+)(possibly hanging slide-check for bent needle and polish the slides with car wax.) You could try a quick carb synch but you should check the valve clearances first-that is more critical than carb issues.12.5 volts at the coils minimum.You say you keep it on the choke for 5 minutes? If its above 60 or 70 degrees you shouldn't need the choke whether the motor is cold or warm.If you choke it it should only be for a minute or two at the most. Pilot jet adjustments may or may not affect your idle if you have air leaks.Set your pilots at 1 1/2 turns out and leave them for now. Check and reshim valves,set fuel level 1/8" below carb body. Check the diaphragms for tears by holding them up to a light-small holes can be fixed with Gorillla Glue.An inline filter is a must.My 650 with CV carbs and 44,000 miles starts without the choke 90% of the time and has the valves set at .005-.006 Runs like a bandit and gets 40-45 mpg.Stay with it and you'll get it straightened out.(These inline 4 cylinders run best past 4000 rpm-don't keep them idling for too long-keep 'em hot and strung out.)

07-23-2009	#21 (permalink)
NoTyme Ride Safe But ride often Join Date: Sep 2008 Location: Ida, Michigan Posts: 35	update Pulled the carbs off and adjusted the floats for a fuel level right close to where the bowl and carb body meet... She runs once again, but now she keeps stalling whenever I drop the idle down below 2000... I did adjust the fast idle a tad so I may have went too far... Could that be keeping the engine from idling? __________________ Big Boys Ride, not drive

07-23-2009	#24 (permalink)
NoTyme Ride Safe But ride often Join Date: Sep 2008 Location: Ida, Michigan Posts: 35	I decided to try to raise the fuel level a bit more after I studied the image 8.18 which showed the fuel level at and above the point where the float bowl and carb body meet. I have the fuel level as in the photo and she is running fine. I did re-adjust the fast idle cam once again and after sliding the carbs back on she ran fine. At first the gas started flowing out of the overflow hoses, but as soon as I shut off the fuel, started the bike and turned the fuel back on, all seemed fine. It took a good 15 minutes to warm up the bike so it would idle but she idles about 1200 and takes off without any bucking or hesitation. I almost don't want to touch a thing. I took the bike for a ride about 5 miles and performance was as good, if not better than before I started fiddling with it because of the surging issue. I won't make any final decisions until I have a chance to start it after a good night set. As for the pilot screws I need to do some additional adjustments, but for now the fuel level for the floats are set at the point where the bowl and carb body meet and she seems to be running fine... go figure. I am not done by no means but I simply proved to myself that a critical issue with these carbs was the float level. It seemed that I have been through the carb 3 times now, and except for the diaphragm I am pretty sure its is good clean shape. I am going to study the additional links.... I'll keep you posted. __________________ Big Boys Ride, not drive

07-31-2009	#26 (permalink)
NoTyme Ride Safe But ride often Join Date: Sep 2008 Location: Ida, Michigan Posts: 35	I have have been a bit busy as I will also be for the next 7 days, but after a 18 mile ride yesterday I find she is stalling after dropping to an idle, and I more than likely will need to go back in and try adjusting those floats again. I know I have them set high, but the stalling keeps happening unless I keep the idle up at 2000... Shes still not right. I'll keep you posted: Thanks for the PM. __________________ Big Boys Ride, not drive

08-01-2009	#28 (permalink)
NoTyme Ride Safe But ride often Join Date: Sep 2008 Location: Ida, Michigan Posts: 35	Just got in from working the fireworks here in Bedford and checked your posting. I wanted to adjust the valve clearance once the carbs were set: so maybe I need to look at them now. Gonna be busy for the next week as the fair starts on Sunday so I hope to get another cold start maybe tomorrow and confirm the stalling only on a hot engine. I do know that I am not happy with the engine response as it seems the rpm's seem to drop slowly when I wrap the throttle. I think it should drop faster. I am almost thinking multiple issues here now. __________________ Big Boys Ride, not drive

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07-23-2009	#22 (permalink)
brown recluse Vulcan 500 Rider BTK Intermediate Join Date: Oct 2006 Location: South East US. Posts: 153	In the last pm you said the bike you are working on is a 305. I sent you some more links and according to another source the gas should be at 1.5- 3.5 mm below the carb body.

07-23-2009	#23 (permalink)
brown recluse Vulcan 500 Rider BTK Intermediate Join Date: Oct 2006 Location: South East US. Posts: 153	Some things are not quite adding up. If your floats were low, then that would lead to a lean condition. If your spark plugs are showing rich, then there may be something wrong with your mixture. According to the other links I have sent you, the pilot screws should be 1 3/4 turns out. I am not sure about your idle settings. You shouldn't really adjust the idle down until the bike is warmed up.

07-24-2009	#25 (permalink)
brown recluse Vulcan 500 Rider BTK Intermediate Join Date: Oct 2006 Location: South East US. Posts: 153	Well it sounds like you should be proud of yourself. I know you have got to enjoy being able to put the bike on the road. I hope everything continues to settle in and you keep the bike. Post pics.

08-02-2009	#29 (permalink)
ironyankee Still On The Kickstand Join Date: Nov 2007 Posts: 27	If the rpms don't come down right away(hanging idle) you have an air leak at the manifolds or air box or a torn diaphragm ($100.00+)(possibly hanging slide-check for bent needle and polish the slides with car wax.) You could try a quick carb synch but you should check the valve clearances first-that is more critical than carb issues.12.5 volts at the coils minimum.You say you keep it on the choke for 5 minutes? If its above 60 or 70 degrees you shouldn't need the choke whether the motor is cold or warm.If you choke it it should only be for a minute or two at the most. Pilot jet adjustments may or may not affect your idle if you have air leaks.Set your pilots at 1 1/2 turns out and leave them for now. Check and reshim valves,set fuel level 1/8" below carb body. Check the diaphragms for tears by holding them up to a light-small holes can be fixed with Gorillla Glue.An inline filter is a must.My 650 with CV carbs and 44,000 miles starts without the choke 90% of the time and has the valves set at .005-.006 Runs like a bandit and gets 40-45 mpg.Stay with it and you'll get it straightened out.(These inline 4 cylinders run best past 4000 rpm-don't keep them idling for too long-keep 'em hot and strung out.)

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