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Message started by PhantomII on 07/27/13 at 17:13:51

Title: having carb problems again
Post by PhantomII on 07/27/13 at 17:13:51

I thought I had my savage running perfect I had it where it wouldn't backfire and had plenty of top end power, until I put a tach on it this weekend and found out I was idling too slow, so when I set the idle screw to run at 1000 rpms I loose all control of the mixture screw if I turn it all the way in the rpms don't drop I can turn it 8 turns out and nothing happens and it back fires all the time now even when I shift. I am running a stock air filter, stock muffler with 8 1/4" holes drilled in it, a 150 main jet, a 57.5 pilot jet and 2 metal washers on the needle. I am thinking the pilot jet needs to be changed to a 55 but I would like to have some verification on this first.

Title: Re: having carb problems again
Post by Serowbot on 07/27/13 at 18:16:58

Yarp... :-?...

Title: Re: having carb problems again
Post by LANCER on 07/27/13 at 19:37:39

6A525B544E555773733A0 wrote:

Your engine is stock/stock/stock and you have a 57.5 pilot jet in it ? Dude, that is waaaaay too much. Drop back to a 52.5 pilot jet and then try the pilot screw adjustment again, starting with 1.5 turns out.
Note: There is no need to go beyond 3 turns out on the pilot screw. If you get to 3 turns out and the rpm is still increasing then go up to the next larger size pilot jet and start tuning the pilot screw at 1 turn out again.
If there is no change in engine rpm from 0-3 turns out then your pilot circuit passageways are clogged and the carb needs to be disassembled and EVERYTHING cleaned.

Title: Re: having carb problems again
Post by Dave on 07/29/13 at 05:10:10

I agree with Lancer.....sounds way too rich to me. I found that my bike with the stock air cleaner and a DYNA muffler ran best with a #50 pilot, #150 main, and 2 washers. My idle mixture screw was out about 2 turns.

Title: Re: having carb problems again
Post by PhantomII on 07/29/13 at 06:01:28

I put the 52.5 pilot jet back in after I cleaned the carb. again and set the idle to 1000 rpms tried adjusting the mixture screw and it still back fires all the time including when I shift. I have a 55 pilot jet and a K&N air filter on the way hopefully I can get this fixed then.

Title: Re: having carb problems again
Post by justin_o_guy2 on 07/29/13 at 07:24:54

Have ya checked the header flange screws? Look for leaks.. ?

Title: Re: having carb problems again
Post by Oldfeller on 07/29/13 at 07:34:15

Please excuse this thought, please -- he has a stock stock bike and he's just started to modding it.

When you start to mod your bike you should yank off the stock vac petcock as your eventual air filter mods will affect the system's vacuum levels causing the vac petcock to misbehave badly. They misbehave enough when stock stock stock -- giving them additional excuses to play tricks on you is crazy.

If you don't get rid of that stock vacsucker petcock, you will be posting here a lot with strange intermittent problems nobody can figure out .....

Hey, just getting ahead of you a bit -- right now your stock stock stock bike is misjetted a bit (Lancer is the expert on jetting). But sight unseen I bet you have some mild petcock issues muddling up your water too, causing you to do strange jet selections and other things.

Lower your muddy water pro-actively -- get rid of the vac petcock.

Then you can see more clearly to fix your real issues (whichever ones remain).

=============

Constant backfire and popping on decel, it can be caused by low float bowl gas levels, which comes from -- you guessed it -- the stock vac petcock misbehaving.

Title: Re: having carb problems again
Post by PhantomII on 07/29/13 at 07:49:01

When I first bought the bike I had to replace the petcock straight away because the original one leaked, I put the Raptor one on after reading all the posts about the stock one's issues. I have been reading the posts and trying to learn from everyone's experiences on her for about 6 months, but I didn't want to start posting anything until I studied the tech sections and started exhausting the suggestions I read first. I ordered the jet kit from 6sigma and gave them the specs of what my bike had and the altitude that i live at and they sent me a 150, 155, and 160 main jet, a 57.5 pilot jet, some metal washers and one plastic washer for the needle. Their instructions said to put in the 150 main jet, the 57.5 pilot jet and 2 metal washers. Then they said to set the mixture screw to 2 turns out, and adjust the idle screw to where it idles smooth and then adjust the mixture screw to where the idle start to increase and that should be pretty close to stop the backfires. I thought I had it running pretty good it didn't backfire and when i shut it off it didn't pop or poof anymore, but I put a tach on it and the idle was was just at 750 so when I adjusted the idle screw to bring it up to 1000 I could no longer get the mixture screw to make any difference as a matter of fact I could screw it all the way in the the motor wouldn't even slow down. I put the 52.5 pilot back in but I can't get the back fires to stop and have turned past 3 turns and nothing changes. I will check the header pipe and make sure it is tight but wouldn't it backfire not matter what?

Title: Re: having carb problems again
Post by justin_o_guy2 on 07/29/13 at 08:02:07

Be caerful on that, Only When Cold, & Dont get crazy with those skinny things,,
Its easy to check, it could be the problem, look for leaks up & down the exhaust,,
Its cool you already ditched the petcock.. You got a Genuine Yamaha Raptor replacement?

Title: Re: having carb problems again
Post by PhantomII on 07/29/13 at 08:11:54

Yes on the Raptor I bought it from a online Yamaha dealer.

Title: Re: having carb problems again
Post by justin_o_guy2 on 07/29/13 at 09:37:05

Good to hear,,

Title: Re: having carb problems again
Post by LANCER on 07/29/13 at 17:42:02

Are you making sure the engine is completely warmed up before adjust ing the carb ? If not, ride it for several miles before stopping to tune.

Title: Re: having carb problems again
Post by PhantomII on 07/29/13 at 19:39:56

Yes I usually jump on the interstate ride 2 miles and come home then make a small change and try it again.

Title: Re: having carb problems again
Post by justin_o_guy2 on 07/29/13 at 19:46:16

To get that air mix screw I grabbed a small screwdriver & went for a ride. Rode in town. Small adjustments at lites,

Title: Re: having carb problems again
Post by PhantomII on 07/30/13 at 06:02:15

Can someone explain to me how the "enrichment knob" works? I rode to work (27 miles) today with the knob pulled out to the first position for 14 miles and not once did my motorcycle backfire or pop, as soon as I pushed it back in and rolled off the throttle the backfires and pops returned. Does this mean I am running too lean, too rich?

Title: Re: having carb problems again
Post by Oldfeller on 07/30/13 at 06:18:42

The enrichment knob is named correctly. At a first click position you have added a very minor amount of fuel continuously to your fuel flow.

Title: Re: having carb problems again
Post by PhantomII on 07/30/13 at 07:05:09

So with that being said and the symptoms of my bike running with and without the enrichment knob pulled out my bike is running lean, which is causing it to backfire every time I decelerate or shift gears?

Title: Re: having carb problems again
Post by Dave on 07/30/13 at 11:11:12

192128273D26240000490 wrote:

Your bike may not be running lean.....it might be running well. When you close the throttle the fuel supply through the needle jet and main jet is shut off, and only the pilot jet can supply fuel in this scenario. The mixture does go lean - but by increasing the size of the pilot jet or opening up the mixture screw you are making the engine run rich during acceleration or steady cruise - in an attempt to supply some additional fuel when you close off the throttle.

If your bike runs with the enrichment knob out when the bike is warm, that does indicate that something is wrong. Your enrichment circuit could be plugged, your idle speed could be too high, your float level too low. I am not sure what tach you are using to check your idle speed, and if you can move the idle mixture screw in and out without affecting the idle mixture, and the fuel enrichment knob does not affect the idle....it makes me think that the throttle butterfly is open too far and the bike is idling too fast. Go to YouTube and check the 500 bpm (beat per minute) metronome and see if that is what your bike sounds like at idle.

Title: Re: having carb problems again
Post by PhantomII on 07/30/13 at 12:01:02

Thanks Dave, I am planning on pulling the carb off again tonight and firing up my air compressor and taking every thing off the carb and blowing air thru every passage way. I am using one of those Tiny Tach digital tachometers for my testing, I don't know how accurate they are though. I will re-check everything on your list and let you know what I find tomorrow.

Title: Re: having carb problems again
Post by Dave on 07/30/13 at 13:07:50

The tiny tac should work fine...as long as you have it set for the fact that the ignition sparks every revolution. Since there is not any distributor to limit the spark to once every two revolutions. If you have your Tiny Tach set for a 4 stroke that fires once every two revolutions....you may have the idle speed set at 2,000 rpm instead of 1,000 rpm.

Title: Re: having carb problems again
Post by PhantomII on 07/30/13 at 13:26:55

Dave my tiny tach doesn't have any settings but I do wonder how many twist I should have it wrapped around the spar plug lead, right now I have it wrapped around it 4 times.

Title: Re: having carb problems again
Post by PhantomII on 07/30/13 at 13:43:09

Dave I think I figured it out I think my tach is reading too low I just looked up a gearing chart and according to the chart my bike should be running at around 4000 rpms at 60 mph but on my tach it is only reading 2000. I just went out and readjusted the idle to 550 rpm's and I was able to make good adjustments to the mixture screw and the bike no longer pops when I shut it off, I was unable to drive it very far or get it up to speed because I'm at work but I will let you know when I get home tonight how it did.

Title: Re: having carb problems again
Post by PhantomII on 07/30/13 at 16:14:09

I just got home and the bike didn't back fire once and it even shut off without the annoying pop too. Now the problem is when I chop the throttle while coasting to a stop, when I pull the clutch in and the motor drops to idle it slows way down and then recovers it actually stalled twice on me. I think I might need to put the 2/3 or 1/2 spacer back on the needle can someone confirm this?