SuzukiSavage.com - Print Page

SuzukiSavage.com
/cgi-bin/YaBB.pl
General Category >> Rubber Side Down! >> BACKFIRE- STILL!!!
/cgi-bin/YaBB.pl?num=1307055371

Message started by arteacher on 06/02/11 at 15:56:10

Title: BACKFIRE- STILL!!!
Post by arteacher on 06/02/11 at 15:56:10

OK now I'm p*ssed! I re-jetted today, putting in a 55 pilot with bleed holes, and a 150 main. I have done a 2/3 spacer mod and have a Dial-A-Jet installed. I have adjusted the mixture screw till it's just on the rich side of nominal. The exhaust is not leaking. Yet it still backfires every time I shift from 1-2 and 2-3. It does not backfire when down shifting or at shut-off, although it burbles a lot. The Raask exhaust is pretty loud and people flinch when it backfires. I have a K&N slab filter installed.
I don't know what to do next. :-/

Title: Re: BACKFIRE- STILL!!!
Post by Boule’tard on 06/02/11 at 16:17:13

Since you have both the exhaust and airbox uncorked, you could probably do away with the white spacer altogether.

I guess you are finding out, a straight pipe makes the savage difficult to tune. The dial-a-jet claim of "filling in the lean spots" based on a "sonic signal" is something that would be handy about now, too bad it's BS.

Title: Re: BACKFIRE- STILL!!!
Post by Serowbot on 06/02/11 at 16:52:26

If you have an open pipe,... it's gonna' afterfire...

Title: Re: BACKFIRE- STILL!!!
Post by arteacher on 06/02/11 at 18:11:30

7B766C757C6D786B7D190 wrote:

I'm not sure it's BS. I've been running it all spring, set to full rich, with the stock jets, and in reasonably warm weather it's been fine, except for the backfire. I only rejetted to bring the DAJ off the full rich setting, so I wouldn't burn valves if it quit working.

Title: Re: BACKFIRE- STILL!!!
Post by arteacher on 06/03/11 at 04:13:42

I think I might look at the TEV next.

Title: Re: BACKFIRE- STILL!!!
Post by CalisOsin on 06/03/11 at 09:03:45

Taken straight from the Dial-a-Jet site: "You must create a lean condition so that Dial-A-Jet has a window of opportunity to function."

Perhaps you are running to rich to begin with??

Title: Re: BACKFIRE- STILL!!!
Post by arteacher on 06/03/11 at 11:32:12

092B262339053923244A0 wrote:

Taken straight from the Dial-a-Jet site: "You must create a lean condition so that Dial-A-Jet has a window of opportunity to function."

Perhaps you are running to rich to begin with??

According to the boys in Finland (huge Savage club) I should run a 55 pilot and 155 main with the Raask pipe and K&N filter. Originally I had the stock 145 jet in and was running the DAJ at full rich. This was 4 sizes too small! I rejetted to two sizes too small and now run the DAJ at it's mid point, as DAJ recommends.

Title: Re: BACKFIRE- STILL!!!
Post by Staplebox on 06/03/11 at 18:54:18

I don't know if this will help much or not but...

I've got a straight open Hard Krome exhaust. I am running 155 and 55 and the same K&N. And, if I remember correctly, I have 1/2 white spacer and am out about 2 full turns. I'd need to check to be sure, haven't touched it in a while.

I still get some backfiring but usually not. You may not be able to completely eliminate the BF but you can get close. I think you are one the right track. Keep tweaking.

Title: Re: BACKFIRE- STILL!!!
Post by LANCER on 06/04/11 at 08:55:39

I do recommend the 55/155 with at least 1/2 spacer or less for the the K&N and Raask setup.
But as always, the differences in geographic location and variance between engines requires good tuning.
Keep in mind that assuming there are no exhaust leaks it is the pilot circuit that is dominant in controlling backfiring. Be sure the engine is responding when you are adjusting the pilot screw. You should notice a change in engine rpm with each 1/8th or at least a 1/4 turn of the screw.
If not, then you likely have some passage's clogged. It does not take much to clog them... some are almost as small as a hair so they can clog very easily and it does affect it when trying to fine tune the engine.

When I get any carb I always do a complete teardown and check and clean everything until it passes the white glove test. Then I set up a clean "surgical" area for assembly.
That is the only way to know for sure that you have a fully functioning carburetor that will respond to your tuning efforts.

There is a carb cleaning tool (Carb cleaner wires) you can get from Sudco for $10.50 + shp. It is a MUST to have if you are going to get to all of those tiny passageways. Sudco Part # 950-203

Title: Re: BACKFIRE- STILL!!!
Post by Gyrobob on 06/04/11 at 09:14:25

I agree with Lancer a LOT. I treat carb disassembly/reassembly as if it were brain surgery,.. or an industrial "clean room" kind of deal. The tiniest speck of grit lodging itself on a jet or some critical hole somewhere can ruin everything.

One additional way to make sure all the passages are clear (all the old dried-fuel-varnish removed, etc.) is to put the pieces in an ultrasonic cleaner. That process peels off the unwanted coatings/chunks/etc. off of every possible inaccessible nook and cranny way inside the carb body and anything else that you put in the ultrasonic bath.

Harbor Freight and Northern tool have these machines for not all that much money. http://www.harborfreight.com/25-liter-ultrasonic-cleaner-95563.html Once you get one, you might be surprised at how many uses you find for it. For me, I started using it for jewelry, cleaning fired 9mm brass, little tools, carb parts, glasses frames, locks, pistol frames and slides, R/C model hardware, etc.

Title: Re: BACKFIRE- STILL!!!
Post by arteacher on 06/04/11 at 15:22:15

Thanks for the replies guys. I spent an hour or two fiddling with the mixture screw yesterday, took it out today and the backfires are at a minimum, and not as loud- just pops now. I will try tuning the Dial-a-Jet a notch leaner and see if it runs as good as it did today. BTW I also filled the broomstick handlebar with lead shot. I calculated that I put about 12lb of shot in it. I can barley feel any vibration after it revs up to 2000.
I'm a happy camper now. :D :D

Title: Re: BACKFIRE- STILL!!!
Post by LANCER on 06/05/11 at 05:16:15

keep in mind that when you have an open exhaust you will likely have some mild crackling/popping on deceleration, and that is ok; it's just the backfiring that is undesirable
also keep in mind that the dial-a-jet is designed to function in the 1/4 to wide open throttle; it does not work in the low range controlled by the pilot circuit.
If you want to boost the low range take a look at the UFO at Thunder Products; same manufacturer as the dial-a-jet. (this is for a Mikuni VM roundslide carb only)
It dramatically affects the low range.
If you normally do your own wrenching the install is not difficult

Title: Re: BACKFIRE- STILL!!!
Post by arteacher on 06/05/11 at 08:02:41

The UFO won't fit the stock carb-right?

Title: Re: BACKFIRE- STILL!!!
Post by justin_o_guy2 on 06/05/11 at 10:26:24

If mine didnt grumble snarl & pit Id rejet till it did..

Title: Re: BACKFIRE- STILL!!!
Post by RpNSht on 06/05/11 at 12:09:39

have you tried this? http://suzukisavage.com/cgi-bin/YaBB.pl?num=1268545171 i did it along with the 1/2 white spacer mod with stock jets and it solved all my problems. i recently re-jetted the carb and put on a k&n air filter...i havent fired it up yet as my bike is in pieces... but i do recommend the spring mod

Title: Re: BACKFIRE- STILL!!!
Post by Routy on 06/05/11 at 13:56:19

223D3B3C21261727172F3D317A480 wrote:

If mine didnt grumble snarl & pit Id rejet till it did..

Its a Savage, it is suppose to backfire, they are well known for backfiring, I knew they backfired before I ever bought one.
About the time you fixed it, it will backfire,... because of any change in temps, humidity, or elevation,... or.......

If mine didn't backfire, I'd know something was wrong,.....like the morning I left the choke on 1 clik, I knew something was wrong !
Proves its a lean mix that causes it. But its a Savage, its a lean mean machine,..... that what it does !