SuzukiSavage.com /cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> Carb question /cgi-bin/YaBB.pl?num=1489950053 Message started by Stefinstein on 03/19/17 at 12:00:53

Title: Carb question Post by Stefinstein on 03/19/17 at 12:00:53 I got one for the gurus, 2009 with 5595 KM's Free flowing petcock K&N cone filter Dyna pipe 150 main 1/2 spacer 55 pilot (?) The main problem is my engine is cutting out when the throttle is closed. With a 52.5 pilot at 2.5 turns it starts and idles fine but revs like turd. I get a very weird choking (sputtery) sound at 1/8 throttle and backfires through the air filter. Once past the pilot jet it revs fine, but getting past the "choke" is laborious. So that being said I thought *lean* and moved up to a 55 pilot With a 55 pilot at 1 turn it starts, idles and revs great. However, when the throttle is released or let off completely idle drops and the engine cuts out. I can blip the throttle a bit in order to keep it from stumbling to low and then the idle stabilizes. I've cleaned the carb, as well as the TEV (tried my luck with a washer/spacer), checked the float (which was a bit low of spec.), new sparky, fresh gas, and sealed the pipe. Maybe an air leak or cut the TEV spring? Anyone have ideas?

Title: Re: Carb question Post by batman on 03/19/17 at 15:44:34 I believe you set the float level to high.AT idle your  ok but when you bring the needle off seat  your getting a slug of gas ,making the motor stumble,due to running to rich. when you rev it your using fuel and the bowl level drops a bit , and when you return to idle the vacuum in the carb goes high pulling extra fuel through the TEV valve and the main jets as the slide is run by vacuum and doesn't close right away because the RPM is still costing down.(again your running to rich flooding the carb). the larger idle jet isn't helping!Back fires through the carb can only happen if there's to much fuel,lean carbs only cause after firing out the tailpipe usually at shutdown, or closing the throttle between shifts.

Title: Re: Carb question Post by Stefinstein on 03/20/17 at 13:04:08 Sorry, when I said "a bit low of spec" I meant the float height not the fuel level. I adjusted the float from 25mm to 27.5 (off of the gasket). I will give it a shot, bump back down to a 52.5 and see if it makes a difference.

Title: Re: Carb question Post by justin_o_guy2 on 03/20/17 at 13:36:51 Before you fix it, test it. Clear tubing on the bowl drain held up by the carb will show exactly how much is in the bowl.

Title: Re: Carb question Post by Stefinstein on 03/20/17 at 14:19:17 JOG- How far should it be from the seam?

Title: Re: Carb question Post by Stefinstein on 03/20/17 at 14:25:50 It only takes me a few minutes to pull the carb. I have now drop the fuel level even more (float sits just above spec) and popped the 52.5 back in to no avail, it's doing the same thing. Should I try raise it?

Title: Re: Carb question Post by justin_o_guy2 on 03/20/17 at 14:32:02 Not above it, IIRC, right at it. I doubt being 1/8" below is a problem. Bet someone here knows Egzaklee.

Title: Re: Carb question Post by Stefinstein on 03/20/17 at 14:59:56 K I'm way low like 3/8"-1/2". I'll raise it up to the seam and so how it does.

Title: Re: Carb question Post by verslagen1 on 03/20/17 at 15:24:42 I don't think we've ever determined what causes shutoff at throttle chop. Normally we just say increase the idle speed. TEV is meant to prevent backfire at shift with extra air throttle chop for shift.   And playing with the spring can get you into trouble really quick cause we are way to heavy handed. Adding a washer is the safest route, but maybe the opposite way is the way you need to go. Don't shorten it unless you got a backup.

Title: Re: Carb question Post by Stefinstein on 03/20/17 at 15:39:52 So I raised the fuel level to 1/8" below the seam and have a 52.5 in place which has the choking minimized (not quite gone) but still dying. I pulled the carb off again the raise a bit more but in the process I found fuel in the intake, am I too high now? Maybe a 50 pilot?

Title: Re: Carb question Post by justin_o_guy2 on 03/20/17 at 16:12:42 If it's dumping gas in the intake it could be in the oil. Snotta good thing.

Title: Re: Carb question Post by justin_o_guy2 on 03/20/17 at 16:16:45 ulled the carb off again the raise a bit more but in the process I found fuel in the intake, am I too high now? Check it with the tubing. Above the top of the bowl is too high. I'm not a carb Goo Roo, I don't even understand why having the float set up to never allow the bowl to get over half full would be a problem.

Title: Re: Carb question Post by Stefinstein on 03/20/17 at 17:05:26 I have checked it with clear hose through out the whole process and it has never gone above the seam of the bowl. It was actually 1/8" under the seam this last time which is the highest its been so far. No fuel in the oil that I can see or smell. It does correlate with what batman is talking about though it's sucking fuel in from somewhere at high vacuum.

Title: Re: Carb question Post by justin_o_guy2 on 03/20/17 at 17:17:50 Stock petcock?

Title: Re: Carb question Post by batman on 03/20/17 at 17:19:05 Did you replace the main jet?you should check to see that you placed the brass washer that fits between it and the needle jet body (the cylinder with all the tiny holes in it)If not the jet can fall the thickness of the washer and that could dump extra gas in the carb as well, causing the same symptoms .the washer fits around the threads on the main jet and fits up inside the carb body.It gets missed sometimes because it tends to stick to the old jet and take on the same color as the jet.

Title: Re: Carb question Post by Stefinstein on 03/20/17 at 19:56:34 JOG- the petcock is not stock and gushes fuel when I forget to turn it off and pull the line of the carb :o the vacuum port for the stock petcock has also been plugged. Batman- I did upsize the main to 150 and the brass washer is present.

Title: Re: Carb question Post by Stefinstein on 03/24/17 at 14:37:27 Could this be a result of raising my needle a washer too high? I'm a 2 washers at the moment.

Title: Re: Carb question Post by batman on 03/24/17 at 17:30:21    A short while back one member put the float in upside down,it fit but did not work at all well.2 washers on the needle will not make the carb flood ,If you have fuel running out the carb without the motor running it has to be the float has a hole and is sinking, the tip of the valve is grooved and leaking by ,the float level is incorrect, or the above, float installed upside down .I would go to wwwRon Ayers ,site he has exploded views of the entire bike,check the one for your carb -LS650p---S-40(I would not include the gasket when measuring the float height)When you first reinstalled the float and found the level low you may have had it upside down.

Title: Re: Carb question Post by buster6315 on 03/25/17 at 14:46:17 312E282F32350434043C2E22695B0 wrote: Stock petcock? Before I changed the stock petcock, I was calling the Savage 'stinky'.  Now I just call it the SAVAGE!

Title: Re: Carb question Post by norm92de on 03/25/17 at 16:19:12 I'd like somebody to "splain me". My understanding of the TEV is that when the throttle is opened the manifold pressure rises and the TEV, "accelerator pump" supplies a temporary enrichment  to prevent the engine from stumbling. The reduced vacuum allows the diaphragm to do its thing and supply more fuel? I remember that you could shut down a British single by simply snapping the throttle open. Amal carbs did not have any provision for this situation. The engine would spit through the carb and stop. Because the engine would go extremely lean. Second observation spitting back through the carb, in my experience, is a lean mixture. not a rich mixture. I hope I am not wrong but I am prepared to be educated :) I don' want to be wrong.  If so all I think I have learned is for nothing.

Title: Re: Carb question Post by verslagen1 on 03/25/17 at 17:56:23 6A515C4B5A564D4B5058554A390 wrote: When I installed an Oxygen Sensor to jet my carb, it taught me a lot.  I was surprised to learn that even when jetted to run at the proper mixtures when at a constant throttle setting- the fuel mixture goes lean when you are opening or closing the throttle.  When you add throttle the amount of air coming in increases, and the vacuum drops and it pulls just a bit less fuel out of the float bowl.....once you stop moving the throttle the flow stabilizes and becomes normal again. When you close the throttle, the engine vacuum increases - but the fuel jets are being closed off and limiting how much fuel can flow (The TEV valve is supposed to help that situation - but does not eliminate it entirely).  When you roll off the throttle, the mixture will remain lean until the engine rpm drops to a speed that matches the available fuel/air flow......you will never be able to completely eliminate the lean condition when you are coasting. You might want to take the TEV valve cover off your carb, and see if anything in there needs to be cleaned, or if the diaphragm is still flexible. Jetting may help your bike run better - it made a big difference on my bike, as it had a lean surge just off idle when accelerating.  If I pulled away from a stop and slowly accelerated, the bike did not run smoothly and I could feel it surge as I rolled on a a small bit of throttle - and if I increased the amount of throttle to about half throttle, the engine smoothed out.  After jetting the best results for me was a #150 main, #50 pilot and 2 washers on the needle in place of the white spacer....I first tried the normal 3 washers recommended and the lean surge was still there - removing 1 washer made the lean surge go away. I don't have any really long/steep hills around here that require a lot of coasting - but we did have one member from Colorado that had a steep downhill that lasted for miles.....and he reported that his bike banged and popped and surged the entire time.....I don't think there is much you can do in that situation - except to open the throttle a slight bit to help cut down on the amount of popping/banging out the muffler.

Title: Re: Carb question Post by batman on 03/25/17 at 22:42:54 Norm,sorry but you have it backwards ,the TEV opens when you close the throttle to add fuel to help prevent after firing in the exhaust pipe,a lean condition .There is no accelerator pump on our carbs .backfires through the carb are caused by a to rich condition,as the piston moves upward to TDC the intake valve starts to open and the exhaust valve has not fully closed,(valve overlape) the heat in the exhaust and the compression from the piston  ignites the unburned fuel in the  to rich exhaust gases and the incoming fuel mix ,which sends the flame front burning back through the intake valve and the carb (backfire).

Title: Re: Carb question Post by norm92de on 03/26/17 at 10:12:52 I guess I have to try to defend my honour. Can we agree that the T.E.V. diaphragm has manifold pressure on one side and atmospheric pressure on the other side. If this is acknowledged, the diaphragm is pulled/sucked to the right when the throttle butterfly is closed. Fuel from the float chamber then flows into the other side of the chamber, about a teaspoon full? This fuel doesn't go anywhere it just sits there, no flow in other words. Then, when the throttle butterfly is opened, manifold pressure rises, to what degree  necessary I don't know but Mikuni engineers figured it all out with the spring tension and diaphragm diameter. Anyway, at this point, the T.E.V. spring does its thing and pushes the diaphragm over, therefore supplying a "teaspoonful" of fuel to the engine to help prevent it from going lean. My reasoning is that the passageway from the carb throat to the spring side of the T.E.V. is drilled on the engine side of the carb butterfly. I hope I am not all flipped up but for the life of me I can't come up with anything else. There you go guys. Shoot me down! I hope at this point that I am not wrong but when Dave Batman and Versy get through with me I may wish I had kept my mouth shut. :)

Title: Re: Carb question Post by batman on 03/26/17 at 11:05:48 Norm, the only time the TEV has has atmospheric pressure on the diaphragm is when the motor isn't running!The spring pressure normally holds the valve closed,when you close the throttle  vacuum builds on the same side as the spring ,defeats the spring pressure and opens the valve ,at which point the higher vacuum draws extra fuel from the carb bowl to enrich the flow down stream of the carb, to the cylinder.some have cut about a third of a turn off the spring to make the valve open farther and deliver a bit more fuel,to calm banging  or loud poping coming from the muffler which is it's purpose,     but I think it to be iffy ,(you could cut to much off)I would instead go to a larger idle jet/or turn the mix screw farther open, as it is at least can be reversed .

Title: Re: Carb question Post by justin_o_guy2 on 03/26/17 at 12:08:40 When you chop throttle you get a high vacuum moment with air through the carb suddenly stopped. The engine is spinning like you're running fifty and it's getting Idle Fuel through the jets. Without the TEV,it flames out. That's my understanding, but I can't prove it. Vacuum drops as throttle goes up.That I know.

Title: Re: Carb question Post by norm92de on 03/26/17 at 13:35:01 Batman, Thanks for the "splainin". I had the valve misunderstood. It actually flows fuel. Duh! I had it as a diaphragm pump which would of course only work when the throttle was opened. I was reluctant to open up my carb to look since the bike is running great. You learn something new, at least some days :)

Title: Re: Carb question Post by batman on 03/26/17 at 16:10:14 JOG you got it only it ignites when it enters the hot exhaust  pipe,unless the TEV adds extra fuel to the cylinder allowing the motor(sparkplug) to fire normally

Title: Re: Carb question Post by justin_o_guy2 on 03/26/17 at 16:52:04 Ha! And after only twelve years,,,

Title: Re: Carb question Post by Dave on 03/26/17 at 17:34:25 The TEV may have been calibrated to work with "real" gas, and it may not have ever been altered to work with E10 fuel....and it is possible that it just doesn't add enough E10 to help the issue. However....with the stock muffler it doesn't do too bad of a job - but adding a less restrictive muffler sure does make the popping/banging worse when the throttle is fully closed while shifting gears or coasting. You can help the TEV by holding the throttle just a little bit open when you shift or decelerate - just hold it open enough to richen the mixture up and quiet the exhaust noise down.

Title: Re: Carb question Post by norm92de on 03/27/17 at 13:57:58 I live at 4000' but anyway I never have popping during gear changes. And I never have the need to coast down long down grades, thus no popping. The only thing I have is Versy's belch of power on shutdown but not always. However it can be quite loud.

Title: Re: Carb question Post by Dave on 03/27/17 at 18:23:54 33322F30646F39385D0 wrote: The only thing I have is Versy's belch of power on shutdown but not always. However it can be quite loud. Cool....ain't it!   :)

Title: Re: Carb question Post by Ruttly on 03/27/17 at 18:59:29 My bike has never backfired , just a lean pop on decel during jetting.

Title: Re: Carb question Post by norm92de on 03/27/17 at 19:56:07 Sometimes it makes me feel powerful! ;D

Title: Re: Carb question Post by Stefinstein on 04/17/17 at 10:57:35 Ok so I had a bit of a weather window to do some carb work yesterday and came out of it with a bit more insite. 150 main (brass washer is there), 52.5 pilot (I also have a 50 and a 55), half spacer mod, Float doesn't leak (drowned it in gas for 5 minutes), valve pin and valve body seat are clean and immaculate, valve body Oring replaced just in case, float height set at at highest spec or lowest fuel level which is up to the bowl bolt. Fuel level is consistent, doesn't creep. 100% not the bowl flooding. After a minute or two of idle and choking again, I pulled the carb off to check the intake boot and bottom of carb to see if it was flooded, no pooling or major flooding, just wet. So this time around I took off the filter and managed to get a look down the barrel of the carb as I started and revved it, I see fuel bubbling. The main jet is splashing fuel around the needle at idle but when the throttle is opened the slide seems to be the culprit of the sputter/choking as it jerks up and down and pisses fuel from the main down the floor of the carb. When throttle is closed (even slowly from 1/8) the slide snaps shut rapidly causing the stall. This happened before I did the spacer mod and I did a thorough inspection of the diaphragm in the process and saw no issue there. Any thoughts?

Title: Re: Carb question Post by justin_o_guy2 on 04/17/17 at 11:05:13 I'd probably spray some soapy water, in the stream, not fan spray stream, around after I used a hose in the ear, hunting for a vacuum leak.

Title: Re: Carb question Post by Ruttly on 04/17/17 at 12:07:58 You will get your brains sucked out that way ! :-?

Title: Re: Carb question Post by verslagen1 on 04/17/17 at 13:40:37 153223202F283532232F28460 wrote: So this time around I took off the filter and managed to get a look down the barrel of the carb as I started and revved it, I see fuel bubbling. The main jet is splashing fuel around the needle at idle but when the throttle is opened the slide seems to be the culprit of the sputter/choking as it jerks up and down and pisses fuel from the main down the floor of the carb. When throttle is closed (even slowly from 1/8) the slide snaps shut rapidly causing the stall. This happened before I did the spacer mod and I did a thorough inspection of the diaphragm in the process and saw no issue there. Any thoughts? The slide is sensitive to dirt and sticks with as little as a fingerprint. I would start there, clean the slide and barrel and check again. Then I would check all the jets as we recently found that you can interchange some of them.

Title: Re: Carb question Post by batman on 04/17/17 at 20:46:58 Stefinstein, In your first post you said "cleaned the TEV and tried a washer /shim" If you mean you added a washer to the spring side of the TEV then it is not sending fuel to the motor when you close the throttle ,spring pressure holds the valve closed .Higher vacuum formed when throttle closes defeats the spring pressure ,and opens the valve and pathway to send fuel down stream of the carb to keep the motor firing until the RPMs drop to idle speed.Without the TEV the motor will stumble and could stall.If you've added any thing to the spring side of the TEV it won't open.

Title: Re: Carb question Post by justin_o_guy2 on 04/18/17 at 05:43:47 Handle the slide like a halogen bulb. Clean, dry,, no fingerprints.

Title: Re: Carb question Post by LANCER on 04/18/17 at 07:09:40 Interesting.  I've always taken a drop of machine oil on my finger and spread it around inside the slide tube of the carb, then wipe it with a clean shop towel (paper type), then wipe the clean dry slide with that same towel.  It removes finger prints and leaves a nearly dry slide and a nearly dry slide tube.  I've never had one stick. Then again, that halogen light inside has never worked either.   :D

Title: Re: Carb question Post by justin_o_guy2 on 04/18/17 at 07:58:14 Then again, that halogen light inside has never worked either.   Cheesy Yeah, like you have seen in there when it was open. It's not a refrigerator, dude.. I gotta admit, I was sorely tempted to oil mine,but came in and asked.. It's really strange that oiled and just wiped down doesn't stick. Too bad about the light. It would be great to see how it works.

Title: Re: Carb question Post by batman on 04/18/17 at 22:18:43 How much slack is in your throttle cable?

Title: Re: Carb question Post by Stefinstein on 04/19/17 at 12:49:52 Batman - the tev shim was only used once and taken out, as it made no difference, the throttle has been left off for ease of pulling the carb but generally I do have a bit of play in the throttle (1/16 turn?) Versy - all jets are proper size and in proper locations the slide was pulled again and found to be as clean as a whistle (cleaned it again just in case).

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