snels516 wrote on 02/04/18 at 10:18:57:



Hmmmm...
*ponders*

I will be back in a machine shop this week...
I may whip something up that I can make a batch for anyone interested.

The break in miles are slowly racking up.
I now have 367 miles on this rebuild.
It's thumping right along!

I have had no further starting issues, and as the ambient temps rise the carb does not puke fuel out the vents. I discovered that I can clear whatever is causing the issue while the bike is warming up by just switching over to prime, then back to on once its up to temp. Once I discovered that, it has worked 100% of the time. A Raptor is definitely in my future.

Are you running a stock air filter?  A 160 main jet is pretty darn big......a #150 is usually big enough with the stock air filter - even at sea level.

If you have to turn the idle fuel screw out more than 2.5 turns to get a smooth idle - you need a bigger pilot jet.  The range of pilot jets us usually between #50 - #52.5 for the stock air filter.....cone filters may need a #55.  You should be choosing the pilot jet based on what the engine needs to idle well - the fuel mixture screw should be proper when the screw is around 2 turns out.  If the screw can be turned all the way in and the engine still run - the pilot jet is too big.  If you need to turn the screw out more than 2.5 turns - the pilot jet is too small.  You need to adjust the idle speed pretty low when adjusting the idle fuel screw - the normal 1,100 rpm is too fast for the adjustment as the needle jet is beginning to add fuel at that speed......be sure to turn the idle speed back up after making the fuel screw adjustment.

Fuel leaking out the vent tubes is a sure indicator that you are either having petcock or carb issues.  Your scenario of needing to switch to PRI and RUN is weird......in the prime setting a little lever moves over and holds the diaphragm open - which permits both the main and reserve fuel ports to be open and provide constant fuel flow.

You should be jetting for how the engine runs when the throttle is open - not for how it runs when you close the throttle.  When you close the throttle the slide drops and closes off the fuel flow - and the high engine vacuum pulls a lot of air past the slide.  The fuel/air mixture goes very lean, and the spark plug can not ignite the mixture in the cylinder - but the lean mixture can ignite in the hot exhaust system.  If you hold the throttle open just a small amount while you decelerate you can cut down (or eliminate) the popping/backfiring when you slow down.  Same thing when you shift gears - don't close the throttle completely between shifts.  There is no jetting changes you can make to correct for the lean mixture scenario when decelerating - the TEV valve is supposed to help...unfortunately I don't believe it works very well with the E10 fuel and the mixture is just too lean when coasting with the throttle closed.  You have to learn how to ride a Savage and use the throttle to control the noise - it is a primitive bike and needs to be ridden like one.  The throttle should not be "cracked" open or "slammed" shut on this motorcycle - you should be rolling the throttle open or closed - and only closing it to the point that the noise out the exhaust allows.  You don't need to open the throttle so far that the bike is accelerating as you are trying to slow down - just far enough that the noise goes away.

Chris, No matter what the petcock is doing , their is only one thing that controls  the fuel level, and if it comes out the vents or not, and that is the float valve/float  ,even if you find a hole in the petcock  diaphragm and thus fuel running down the vacuum line bypassing the carb(which may cause lower mpg).You should check the valve tip for damage and pull the valve seat to check the O-ring that seals the seat to the carb body.If they are good then the only other thing it can be is the float level.
      Your mpg ,may be lower until you reach 1500 miles and the bike has completed full break in, but as Dave said your 160 main jet is likely to big, and if you did the spacer mod you may have lifted the needle too high ,both would cause you to run rich at cruising speeds, and lower mpg. If your running with the fuel mix screw more than 2.5 turns open your pilot is to small , this will also add to back firing when you close the throttle as the fuel mix will become even leaner.
       So I would suggest a larger pilot ,smaller main jet ,needle lift based on your alt. and a good hard look at the  float assembly.(Raptor petcock when you get the chance)

There isn't anything wrong with drilling out a smaller pilot jet - it is just a bit hard to know exactly what you are going to end up with.  The pilot jet has the most effect at idle, and the screw adjustment can account for a variation in size.  You just need to end up with a pilot jet size that provides for the smoothest idle....and also results in the screw setting being out somewhere between 2-2.5 turns out.

Good point Lancer...........the engine does need to be at full operating temperature.

I just finished up with the test ride after buttoning it back up an it is a bit better. It is still backfiring on decel but smaller sharper reports. Much lighter backfire on shutdown. Mix screw has it happy at 2.25 turns out.
I will get a real good idea of any changes tomorrow. I will be taking the exact same 70ish mile ride I was taking before the weather put me off riding a couple days ago. Its supposed to be tolerable tomorrow.

If the numbers go up we'll know something.
If they go down...
We will also know something.

The oil was pretty dark that came out, but still pretty slippy. Very little glitter.

I did get kinda spooked when I went to break the drain bolt loose...
when I put the wrench on it and went to give it a bump and I was met with no resistance. Like, I nearly knocked myself out finding the bolt was completely loose after already setting my arm in good hard motion to loosen it. It wasn't even finger tight! It had not lost a drop. it was all dry around the drain bolt and bottom of the case. It is tight now.

Batz, The factory main jet was in fact a .145.
I wanted to open it up a smidge but smallest twist drill I have on hand is a .060". The main jet that is in the carb now is a .160. so that would kinda defeat the purpose...
I took the smallest drill I did have and shortened the distance between the back of the pilot bore and the nose. Then I swaged it open from both ends with a very small swaging taper with the aid of my fancy airflow test device. It was kinda lippy, but it worked!
I got it to flow just an ever so slightly higher rate than the one replacement 6Sigma sent with their kit.

I will likely order a kit from Lancer as soon as my current situation gets situated.

Once I was satisfied it was fully warmed up, I gave it a little goosing...
Ermagerd...

Er.  Ma. Geeerd!

I have put a higher flow filter on after discovering the RYCA was crushed and junked. It started to develop a new issue when I pulled out of the fueling station yesterday evening. It spit and sputtered like it was fuel starved in first gear just about the 20mph mark. Yesterday it cleared right up...

Now it is persistent.
I have readjusted the float. ..
Swapped between every combination of jets I have on hand with absolutely the same results. Falls on its a$$ at that point in 1st, also running pretty warm...

I'm about fed up with it.