Cleaning my carburator result: variable idle speed and stall

2001 SV 650S with 13k miles on it. No performancfe mods.

Just cleaned my carb. Was only having trouble in cold weather. Bike was fine down to about 36oF. Around 32oF the bike would not start or took for ever. Also would stall during idle even when bike was HOT.

Now the weather is not cold, but bike starts great without choke even and runs great, but will NOT start when warmed up without near half open throttle. If throttle is cold bike has to be cold to start. Also the bike will stall during hard stops always. The idle speed will randomly go from 1300 to 2200 to 800(stall) while ridding. What gives?

NOTES:

Choke plunger in front is broken. The thinner part that the metal part(screw goes through one of 2 holes) goes over is seperated from larger/wider piece. Choke seems to work fine though. Give me about 1000 to 1500 more RPMs.

The ports on the bottom of carm may not be 100% secure, but should be close. I can't get a screw driver to seal the clamp.

[jambo]

OK there's a few things you mention that are well worth a look.

I'd take the air box off and try to seat the carbs properly again, if you are in any doubt that they are sealed properly this should be your first port of call as any air leaking in between the carb and engine block will mess the fuelling up quite a bit. I found a good long number 2 Philips screwdriver fine for doing all this though a little WD40 and possibly a 2nd pair of hands help reassembly go smoother.

You say you "cleaned your carbs" I'll assume you striped them right down and re-built them. If re-seating doesn't help you may want to take them back apart to see if something is loose or bent, a loose jet can cause problems for instance (not something I've experienced but it's come up before)

If the choke is mangled I'd get the parts you need to sort it, the curvy choke cable is a little notorious for sticking and causing rough running as there is a Y-piece splitter where the one cable splits to feed 2 carbs. This can let water get in and the front choke cable / plunger where it attaches to the carb can end up sticking. Might be worth a clean / lube.

Thank you for the tips!

Cleaning: I sprayed carb cleaner all over most metal parts.

1) Removed carbs
2) Openned the black plastic capped ends and cleaned needle and other peice with spring.
3)Sprayed inside of end caps with diaphram and needle removed
4)Removed float bowls
5)Removed floats and small cyclinder attatched(plunger type device)
6) removed and sprayed 3 jets; main , needle and pilot(2 brass peices next to each other facing up, one with many holes like flute)
7)sprayed bottom and top of bowl
Sprayed inside tops(intake) and bottom(to engine) of carb
9)Sprayed all with compressed air
10)WD40 on choke plungers
11)Was not able to get to the pilot air jet

Originally Posted by jambo

OK there's a few things you mention that are well worth a look.

I'd take the air box off and try to seat the carbs properly again, if you are in any doubt that they are sealed properly this should be your first port of call as any air leaking in between the carb and engine block will mess the fuelling up quite a bit. I found a good long number 2 Philips screwdriver fine for doing all this though a little WD40 and possibly a 2nd pair of hands help reassembly go smoother.

You say you "cleaned your carbs" I'll assume you striped them right down and re-built them. If re-seating doesn't help you may want to take them back apart to see if something is loose or bent, a loose jet can cause problems for instance (not something I've experienced but it's come up before)

If the choke is mangled I'd get the parts you need to sort it, the curvy choke cable is a little notorious for sticking and causing rough running as there is a Y-piece splitter where the one cable splits to feed 2 carbs. This can let water get in and the front choke cable / plunger where it attaches to the carb can end up sticking. Might be worth a clean / lube.

[Sid Squid]

If the choke plunger isn't right and doesn't shut correctly, you'll get an abnormally rich mixture on that cylinder, giving the exact symptoms you describe. The choke may still appear to function as the other cylinder will be receiving the correct mixture, and the choke action will cause the other cylinder to run quicker.

I have now illiminated the 4 carb clamps on top and underneath the carbs for the carb intake and outlet into the engine. I reseated them all and made SURE they were secure. I even marked the sides with red marker so I could tell how well the clamp was attatched.

Let's revisit the symptoms again:

Great starting when cold; may not even need choke in even 47oF weather.
Will NOT start when warm without about 1/2 throttle
Idle speed varies +/-1000RPMs
Bike WILL stall if you brake too hard

Typical ride:

Go outside and click start button
Bike atarts
idle 1400
Brake hard at light; bike stalls
Go riding for 10 minutes
Brake hard; bike stalls
engage choke
idle 2300RPM
Brake hard; RPM drops to 1300, bike stays on
Rev bike
idle 1400
choke;idle now 1300

Bike performs very well, exept with ablove issue.

Originally Posted by jambo

OK there's a few things you mention that are well worth a look.

I'd take the air box off and try to seat the carbs properly again, if you are in any doubt that they are sealed properly this should be your first port of call as any air leaking in between the carb and engine block will mess the fuelling up quite a bit. I found a good long number 2 Philips screwdriver fine for doing all this though a little WD40 and possibly a 2nd pair of hands help reassembly go smoother.

You say you "cleaned your carbs" I'll assume you striped them right down and re-built them. If re-seating doesn't help you may want to take them back apart to see if something is loose or bent, a loose jet can cause problems for instance (not something I've experienced but it's come up before)

If the choke is mangled I'd get the parts you need to sort it, the curvy choke cable is a little notorious for sticking and causing rough running as there is a Y-piece splitter where the one cable splits to feed 2 carbs. This can let water get in and the front choke cable / plunger where it attaches to the carb can end up sticking. Might be worth a clean / lube.

Originally Posted by Sid Squid

If the choke plunger isn't right and doesn't shut correctly, you'll get an abnormally rich mixture on that cylinder, giving the exact symptoms you describe. The choke may still appear to function as the other cylinder will be receiving the correct mixture, and the choke action will cause the other cylinder to run quicker.

Sounds like good advice to me. I take it that you have checked the choke plungers? Would not be surprised if the front one was seized in the open position, giving all of the symptoms mentioned.

The plunger seems to work fine, it's just the black plastic holder is seperated. By work fine, I mean the brass tip goes in and out as it should.

Bottom line is I know I need to replace them, if not only because I can illiminate it from the equation if I do.

Originally Posted by BigApe

Sounds like good advice to me. I take it that you have checked the choke plungers? Would not be surprised if the front one was seized in the open position, giving all of the symptoms mentioned.

[21QUEST]

Originally Posted by F16Falcon

The plunger seems to work fine, it's just the black plastic holder is seperated. By work fine, I mean the brass tip goes in and out as it should.

Bottom line is I know I need to replace them, if not only because I can illiminate it from the equation if I do.

What you described about your bike in your first post could have been my bike untill this morning. Even though the choke may appear to work fine, I'll put money on the problem being the damage pluger bit.

Mine appeared to be working okay but wasn't. I had already eliminated everthing else but because I didn't want to pull the carbs off in this weather(no garage) I hoped a TPS check/carb balance would sort it. Problem was when I tried balancing the carbs I couldn't get them balanced no matter what and then revs would now not go lower than 2000.

I had to bite the bullet and pulled both plungers out to check. The front one(holder) was actually siezed even thought it appeared to work okay. Seized enough that I had to take drift to it to get it out. Unfortunatey I ended up with a slight fracture on the lip of the plunger holder housing but I got away with it more or less. Quite a bit of crude in the outer part of the housing where the plastic holder (brass in my case) sits. That was the problem. So pluger was moving and appeared to function right but wasn't actually shutting properly becasue the brass holder(plastic in your case) was sitting fully.

All put back, balanced and all sweet now. I also packed the top and bottom ends of the splitter housing with silicon grease to stop the water running into the front again(Apes' Tip).

Whats the point of all this waffle you ask .

Emm... just change the damaged bits at the pluger end and I reckon all should be well. It may look alright but only need to be a little bit off to cause problems Get the carbs balanced while you are there.

Also, if you there is a piece missing off the lower end of splitter housing use a cable tie to hold both front and rear ends together. Not too tight and you should be able to put them back in position into what is left in the part of the housing where they would normally be(then loads of grease in there).
Easy to crack that section especially when working with the carbs still attached to bike like I did this morning .

Cheers
Ben

Thanks for the post. Now I REALLY can't wait for the parts to arive. Can't wait the reap the benifits of the carb cleaning I did over a week ago!! Can't wait to start right up in 32oF weather.

I'm assuming a c;lean carb is all you need to start in cold weather? Anything else I need to consider?

Originally Posted by 21QUEST

What you described about your bike in your first post could have been my bike untill this morning. Even though the choke may appear to work fine, I'll put money on the problem being the damage pluger bit.

Mine appeared to be working okay but wasn't. I had already eliminated everthing else but because I didn't want to pull the carbs off in this weather(no garage) I hoped a TPS check/carb balance would sort it. Problem was when I tried balancing the carbs I couldn't get them balanced no matter what and then revs would now not go lower than 2000.

I had to bite the bullet and pulled both plungers out to check. The front one(holder) was actually siezed even thought it appeared to work okay. Seized enough that I had to take drift to it to get it out. Unfortunatey I ended up with a slight fracture on the lip of the plunger holder housing but I got away with it more or less. Quite a bit of crude in the outer part of the housing where the plastic holder (brass in my case) sits. That was the problem. So pluger was moving and appeared to function right but wasn't actually shutting properly becasue the brass holder(plastic in your case) was sitting fully.

All put back, balanced and all sweet now. I also packed the top and bottom ends of the splitter housing with silicon grease to stop the water running into the front again(Apes' Tip).

Whats the point of all this waffle you ask .

Emm... just change the damaged bits at the pluger end and I reckon all should be well. It may look alright but only need to be a little bit off to cause problems Get the carbs balanced while you are there.

Also, if you there is a piece missing off the lower end of splitter housing use a cable tie to hold both front and rear ends together. Not too tight and you should be able to put them back in position into what is left in the part of the housing where they would normally be(then loads of grease in there).
Easy to crack that section especially when working with the carbs still attached to bike like I did this morning .

Cheers
Ben