SuzukiSavage.com - Carb question

Stefinstein YaBB Newbies Offline Mad Scientist Posts: 46 Vancouver Gender:	Re: Carb question Reply #15 - 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 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.
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Stefinstein YaBB Newbies Offline Mad Scientist Posts: 46 Vancouver Gender:	Re: Carb question Reply #16 - 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.
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Re: Carb question
Reply #17 - 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.

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buster6315 Senior Member Offline SuzukiSavage.com Rocks! Posts: 353	Re: Carb question Reply #18 - 03/25/17 at 14:46:17 justin_o_guy2 wrote on 03/20/17 at 17:17:50: Stock petcock? Before I changed the stock petcock, I was calling the Savage 'stinky'. Now I just call it the SAVAGE!
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norm92de

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Re: Carb question
Reply #19 - 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.

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2014 S40. Raptor. idle mixture adj.Needle raised one notch. 4000' altitude. Stock jets. Shell Rotella synthetic.

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Re: Carb question
Reply #20 - 03/25/17 at 17:56:23

Dave wrote on 05/05/16 at 05:22:50:

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.

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Re: Carb question
Reply #21 - 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).

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« Last Edit: 03/26/17 at 08:52:58 by batman »

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norm92de

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Re: Carb question
Reply #22 - 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.

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2014 S40. Raptor. idle mixture adj.Needle raised one notch. 4000' altitude. Stock jets. Shell Rotella synthetic.

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Re: Carb question
Reply #23 - 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 .

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justin_o_guy2 Serious Thumper Offline What happened? Posts: 55279 East Texas, 1/2 dallas/la.	Re: Carb question Reply #24 - 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.
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norm92de Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 1180 El Paso TX Gender:	Re: Carb question Reply #25 - 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
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batman Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 3806 osceola new york Gender:	Re: Carb question Reply #26 - 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
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justin_o_guy2 Serious Thumper Offline What happened? Posts: 55279 East Texas, 1/2 dallas/la.	Re: Carb question Reply #27 - 03/26/17 at 16:52:04 Ha! And after only twelve years,,,
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Re: Carb question
Reply #28 - 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.

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norm92de Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 1180 El Paso TX Gender:	Re: Carb question Reply #29 - 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.
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