SuzukiSavage.com - Carb cleaning questions

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Carb cleaning questions
12/08/19 at 20:41:25

Hi all

2012 s40 with about 8500 miles. Just bought it beginning this last summer. Had a great time riding it throughout the summer. Well maintained bike, very clean, everything worked perfect to start out with. But around August or so it started having problems where it would stall and die at 40 mph when I pulled in the clutch to come to a stop. This progressed to where any time I was at a stop light I would have to constantly rev the engine or it would die. Sometimes even this wouldn't help. I started using a little Seafoam in the gas and that seemed to help but only for a while. The problem came back to the point where the bike was almost unrideable.

Previous owner said carb had never been cleaned so I decided to take a stab at it this weekend. I am not very mechanically inclined but I like to learn so I have been reading up on this web site and watching videos. Getting the carb off was quite a learning experience but finally managed it and started taking it apart and cleaning today. Had a couple of questions for you all that I am hoping you might be able to help me with. Pictures attached here for reference:

https://imgur.com/gallery/ZF2Wgna

1) This is my first time at this so I don't really know what "dirty" looks like, but when I opened things up I didn't think it looked bad at all. There was some build up, but it wasn't like some videos I watched where spraying carb cleaner on it left a pile of grime on the bottom of the bowl.

Anyway, when I detached the float bowl, I got the jets out fine and I have them soaking in carb cleaner. But I could not figure out how to detach the float itself. The pin would not move and I did not want to force it. My question, though, is: do you think this is absolutely necessary? Like I said it doesn't look all that dirty to begin with and if the float weren't working I would think the symptoms would be different but I am not sure. The action of the float seems good. Seems to move up and down ok. I put 3 pictures of the float bowl area in the link above. Wondering what you all think.

2) I screwed up a little (hopefully not a lot). I removed the fuel/air mixture screw (jet?) from the side of the carb (see picture #4). I noticed the spring but somehow missed a tiny washer and o-ring until I looked down and noticed them in my work area (arg!). Anyway, I am not sure the order they fit back together now. Can anybody help me?

Oh yeah, before I removed the fuel/air mixture screw I did tighten it all the way and counted how many turns to full stop. So I know to back it out that much on reassembly.

Thanks in advance!

Edit: I should have done a little googling before posting question #2. Here is a parts diagram for the carb:

https://www.suzukipartshouse.com/oemparts/a/suz/506b36ccf870022ba8af9ea5/carb...

This confirms that the order of fuel/air idle mixture jet is (starting at threads) spring, washer, o-ring.

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« Last Edit: 12/09/19 at 08:13:18 by SilliusSoddus »

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IslandRoad

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Re: Carb cleaning questions
Reply #1 - 12/09/19 at 00:33:42

Someone with more experience will likely give you advice on the carb. But, while you're waiting you might find it useful to read up on the stock petcock (fuel tap). It's notorious for playing up and causing 'carb-like' issues. There are threads on this forum about how to test it and a recommended replacement ... (the Yamaha Raptor) ... it's inexpensive and really easy to replace. Just make sure it's the genuine Yamaha part and not a cheap copy.

That would eliminate one possible cause.

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ohiomoto

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Re: Carb cleaning questions
Reply #2 - 12/09/19 at 07:00:00

Carbs usually don't get "dirty" or go bad unless they have been sitting unused for a few years. The slide is about the only wear item in there and your symptoms don't match a sticky slide. So "cleaning" the carb will not fix anything.

Your carb looks spotless. I would just put it back together. Make sure you install the jets in the correct spots (top and bottom of the carb) and take care when seating the diaphragm.

Don't try and "jet" it while you are in there. The bike ran fine before the problem, so now is not the time to change anything. You want to get it back to where it was so you can fix the actual problem.

As IslandRoad pointed out, you probably have a bad petcock. The OEM unit is vacuum operated and it fails often. Check the petcock and replace it if needed.

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SilliusSoddus

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Re: Carb cleaning questions
Reply #3 - 12/09/19 at 07:46:59

Thanks for the replies. I did pull the stock petcock out to examine it. Didn't see anything obvious but don't know what to look for either. But in any case I went ahead and ordered the yamaha petcock last night. Ordered it from Partzilla here:

https://www.partzilla.com/product/yamaha/5LP-24500-01-00?gclid=EAIaIQobChMIhs...

Hope that is the right one. Should arrive in a couple of days. Will install and test once the carb is back in place. I guess I should have tried that first.

ohiomoto, yes, I have been very careful about keeping track of the jets and have them in separate bowls. Wish I had been more careful w/ the fuel/air idle jet Undecided

. My best guess on that is (going left to right starting at the threads) spring, washer, o-ring. Hope somebody can confirm.

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stewmills Serious Thumper Offline Imagination is more important than knowledge Posts: 2641 Auburn, AL Gender:	Re: Carb cleaning questions Reply #4 - 12/09/19 at 09:50:35 See image. Needle, spring, washer, o-ring.
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Re: Carb cleaning questions
Reply #5 - 12/09/19 at 10:02:44

On cleaning the carb, do not use carb cleaner on any plastic parts (float needle, diaphragm). Carb cleaner is bad for plastic parts. Clean anything plastic with a good dose of WD40 or other similar cleaner.

The float pin slides out, but it may only slide one way (can't remember). If you have a small pick, you can get it on one side of the pin and gently tap to see if it will start to wiggle loose, and if not try the other side. Just be gentle, don't wham on it.

On the slide, make sure that the slide itself as well as the slide body of the carb are free from debris as well as cleaners/oils. Remove any loose oils and fingerprints using a lint free cloth before reinstalling the slide. It only takes a tiny bit of oil or fingerprints to attract dirt and make the slide stick over time.

This is irrelevant with the raptor, but in the event that you don't convert to the raptor make sure to also clean out the TEV, which is behind the small plate on the passenger side of the carb with the three screws, which is where the vacuum line from the stock carb connects to the carb. If this is clogged OR the vacuum line itself has cracks or leaks it will lose its vacuum and cause loss of fuel flow.

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SilliusSoddus

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Re: Carb cleaning questions
Reply #6 - 12/09/19 at 10:17:44

Thanks for the picture and advice, stewmills. I saw on the video I was watching not to get the carb cleaner on the diaphragm. I think did get a little on there at one point but I quickly wiped it off. I will use some wd40 tonight to clean it up some more and get any residual carb cleaner off of it. Also I have been using rubber gloves as I clean so hopefully no fingerprints.

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batman

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Re: Carb cleaning questions
Reply #7 - 12/09/19 at 12:31:00

I see a dent in the float in the first pic ,unusual , make sure it isn't a hole, if it is the float would tend to sink and the float level to be to high ,flooding the carb ,even more so at idle .
The float pin only comes out one way ,if you look closely ,you'll see a rounded head (like a tack ) on one end and the pin needs to move in that direction. You should pull it ,as you need to look at the tip of the valve to make sure it's not worn (noted by a ring around the tip) and so you can remove the screw which holds the" horseshoe " shaped clip . This allows you the pull the float valve seat straight out ,where you can inspect the rubber O-ring (that seals the outside of it to the valve body (another thing that will cause float bowl flooding) and the small fine domed screen above it (it pulls off ) which may be plugged. You still need to adjust the float level after reassembly of that area ,just before replacing the bowl.
Returning the fuel mix screw to the number of turns you found it ,may be a good starting point , but it should be tuned to your own motor's needs ,you should read up on it.

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Gary_in_NJ Serious Thumper Offline LS650 Cafe Racer Posts: 2633 Amongst the Twisty Roads	Re: Carb cleaning questions Reply #8 - 12/09/19 at 19:22:11 I see that dent too. When you remove the pin, take the float and put it in some water with the dent up. If you see bubbles, you need a new float.
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batman

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Re: Carb cleaning questions
Reply #9 - 12/09/19 at 20:05:18

From the pictures it 's also apparent that you haven't removed the needle jet , the jet needle rides inside this tube , and it has small holes that could be plugged, it 's the tube the main jet screws into, and is removed by pushing it up and out the top of the carb ,just as the slide does.
Go to a site like Ron Ayers , they have expanded pictures ( to show how things are assembled ) and factory part numbers -handy to have to order the correct parts even from your local dealership, for almost every component on the bike .

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SilliusSoddus

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Re: Carb cleaning questions
Reply #10 - 12/10/19 at 08:02:15

Batman/Gary, thanks for the heads up about the dent. I wonder if that is a trick of the light or something. I inspected the float pretty closely and didn't see anything. Unfortunately, I didn't see your responses until late last night and I had already reinstalled so I can't verify. Also, didn't see your tip about the needle jet in time.

In any case, I got things reassembled and at the very least it started again and idled for a minute or so without a problem. That obviously doesn't prove it's fixed of course. I need to ride it around a bit. Too late wet and cold last night to do so, though. Will give it a proper test drive soon, though.

I plan to change the petcock this week too. If I still have problems after all that, I will open up the carb again and check those two things.

Thanks for the help and advice.

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Gary_in_NJ

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Re: Carb cleaning questions
Reply #11 - 12/10/19 at 11:14:29

SilliusSoddus wrote on 12/10/19 at 08:02:15:
Batman/Gary, thanks for the heads up about the dent. I wonder if that is a trick of the light or something.

It very well could be the lighting or angle. What makes it look like a dent is the darker color below the lighter portion. It makes it look like a shadow, but it could just be a dark spot.

The new petcock will resolve your running issues. Be sure to change the oil after you swap out the petcock and before you start the bike. Fuel in the oil increases the overall volume of fluid in the crank case which is bad for the seals; and as the fuel in the oil vaporizes as the temperature rises, it causes the air:fuel mixture to go rich as the vapor makes its way past the rings. That's the part that is making to bike run so poorly.

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Re: Carb cleaning questions
Reply #12 - 12/10/19 at 12:04:06

The new petcock will resolve your running issues. Be sure to change the oil after you swap out the petcock and before you start the bike. Fuel in the oil increases the overall volume of fluid in the crank case which is bad for the seals; and as the fuel in the oil vaporizes as the temperature rises, it causes the air:fuel mixture to go rich as the vapor makes its way past the rings. That's the part that is making to bike run so poorly.

Could you expand on this? I don't quite understand. How would there be fuel in the oil? Are you saying that is a symptom of a bad stock petcock? And then it vaporizes and makes it way UP the cylinder past the piston rings and into the combustion chamber?

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Re: Carb cleaning questions
Reply #13 - 12/10/19 at 13:34:55

The stock vacuum operated petcock fails in two ways.

The first way: the vacuum operated valve that is shuttled by the diaphragm in the petcock gets gummed up when the bike lies idle for a long period. Then, when the bike is started, the vacuum opens the valve but the gummed up condition prevents the valve from closing when the engine is shut off. Now, fuel can gravity feed into the carburetor. Leave it sit that way overnight and the fuel leaks past the needle & seat in the carburetor and starts to slowly overflow into the engine. The fuel drip, drip, drips into the engine, migrates past the rings, and slowly starts filling the crankcase. Its not uncommon to end up with the entire contents of the fuel tank migrating into the crankcase.

The second way: The vacuum diaphragm in the petcock gets old and develops a crack or hole. Now fuel can leak through the diaphragm into the vacuum side. The fuel continues past the diaphragm, through the vacuum hose, and into the intake manifold. When the engine is running it will be very rich, and the excess fuel washes past the rings and into the crankcase.

I guess its also possible to have both failure modes at once. The double whammy.

Check your oil level. If the sight glass is totally full, you know what's up. If the sight glass shows normal oil level, it's no guarantee that the petcock is OK. If fuel is getting into your oil, it will be evident upon the tried & proven whiff test.

When the oil is fuel diluted, the fuel flashes off when the engine is operating. The fuel vapors exit via the engine breather. The breather hose is connected to your airbox. The fuel vapors enter the airbox and are then consumed by the engine. Because the fresh air charge is contaminated with fuel vapors, the engine is consuming more fuel and less air, essentially a rich mixture. The degree of richness is dependent on how much the oil has been diluted with fuel.

Vacuum & petcocks are a match made in Hell.

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Re: Carb cleaning questions
Reply #14 - 12/11/19 at 07:34:03

Thanks for the explanation, DragBikeMike. Very helpful. I also found this as well:

http://suzukisavage.com/cgi-bin/YaBB.pl?num=1251932429/1

This suggests there is a third failure mode where the vacuum does not hold open the diaphragm, or doesn't hold it open wide enough, so you get fuel starvation.

In any case, I think if I my issues are due to a petcock problem, it is either your #2 or the fuel starvation mode above. I have not seen high oil levels in crank case. In fact, just the opposite. It seemed a little low when all this was happening so I added 2/3 of a quart or so to top it off.

In any case, I will be sure to change the oil after installing new petcock as suggested, just to make sure.

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