Help! please.....carb issues ?

[JWillyG]

Who can help me with this....

....my front two cylinders are firing good.....rear right cylinder fires when i spray a little carb cleaner in the carb. but the rear left does not fire. Took out the spark plug , started the engine and I have good spark. Where to start ?

 

[a113ycat]

Who can help me with this....

....my front two cylinders are firing good.....rear right cylinder fires when i spray a little carb cleaner in the carb. but the rear left does not fire. Took out the spark plug , started the engine and I have good spark. Where to start ?

My '85 was doing that when I first bought it, Check to make sure that your plug boots and wires are not compromised ie any cracks from the coils to the cylinders. Check the boots with an Ohm meter. Check the carburetors to make sure they are getting fuel to them, and clean them the quick way. ( there is a video on youtube )
https://www.youtube.com/watch?v=xItRzty9_hA

If everything checks out and you are still having that same problem then take the airbox off and check your vacuum lines to make sure that none of them are cracked. ( turned out to be an issue for me )
This is what I did and it worked

 

[adambweird]

When were your carbs last torn down and cleaned? And when did you last sync your carbs?

 

[blaxmax]

More than likely your pilot jets in the jetblock inside the fuel bowls are clogged.

 

[Traumahawk]

More than likely your pilot jets in the jetblock inside the fuel bowls are clogged.

Yep....time for a shotgun...which is easy to do. The pilot jets clog up EASY due to the E-10 fuel. This will walk you thru it.

http://vmax.lvlhead.com/tips/shotgun.htm

 

[JWillyG]

thanks guys ...got the left rear firing ....right rear has a stripped brass screw, cant adjust the idle mix . I am going out to do the Shotgun cleaning............

 

[jagco1]

I been through this 3 years ago, Pull the carbs 3 times - 1st time bad gas rusty gas tanks orange dust in the carbs floats sticking clean the carbs but did not take them apart completely . 2nd time the 1st and 3rd cylinders started back firing through the carbs pull the carbs and clean them bike ran found for 6 days stated again I did the pee shooting to. 3rd time pulling the carbs then completely pull them carbs apart - and found the block jet assy gasket over hang was breaking off and clogging the jet block assy. So this time was going to do it right. All carb metal parts I boiled in lemon juice for about 45mins and let the carbs sit in the juice for another 30mins and then clean the parts off with WD-40. I been doing the lemon juice clean on parts for a long.

I completely rebuilt the carbs with new parts, I did not like pulling them off again... My bike is 1992 so new parts in the carbs was needed.

I never had any more problems out of the carbs....
Every now and then, I run WD-40 through the carbs - motor running each vent hose / 1 at a time shoot some WD-40 through the vent hose until the motor start to idle rough mixing with the gas - this helps keeps the floats from sticking and flush out the white gas dust that kinda stick to the bowls and floats.

And bought lot carbs screws

This work for me.

 

[one2dmax]

Don't forget something as simple as a carb sync will cause what appears to be a cylinder not firing.

 

[D-Max2012]

Just a little tip, if you feel so inclined.
Be aware that once you go through all this cleaning and pea-shooting, you can eventually get the same crap happen again, unless you kill it at the source. Your gas tank.

BELIEVE ME, It is a ROYAL P.I.T.A to get that tank out, clean it, coat the inside with a well respected brand of tank sealer, and put it back in. (I used the 3 step KBS Tank Sealer kit).

After that main part is completed, you can take out your fuel lines and clean them. Take out your fuel pump and clean out the orifices and rubber diaphragms.

Once that's done, get into those carbs.
Give them a good cleaning (I broke down each carb and place all parts into an ultra sonic cleaner (I picked up the large one from Harbor Freight Tools).

I was completely shocked, to see how much **** the ultra sonic cleaner removed.. Even after pea-shooting my carbs 4 times earlier. The parts came out looking like new.

last time I took my carbs apart to try different mains, the carbs looked like pure water had been running through them. NOT A SPECK of grit anywhere and the fuel was 100% clear.

After all that work, my crazy *** would take a 5 gallon fuel jug to get fuel.. Just so I could look into the container to see the fuel is clear before putting it in my bike.

I did all of this because one day I fueled up and went riding.. Bike died on the side of the road. I had to get it towed back home. it cost me $175.00 to get a tow less than 1 mile from the house.
Once I got home, I took a look the fuel line and it was completely clogged with this brown **** that looked like rust. I could not even blow air through it. My friends was claiming that it was rust from my tank.. I was like, No Freakin way, I could not have that much rust in my tank, all of a sudden. I would have no metal left if it was rust from my tank.

After trying for 2 weeks to siphon this **** out of my tank, I had to break down and take the tank out. All together, I collected about 5 coffee cups full of this rust looking ****, that clogged up my fuel system. Some of these pieces were big.. Biggest piece was 6mm by .5mm flat. Out of curiosity, I put some of the particles under a microscope and found that these things were flat and shattered but all of them were like .5mm in thickness. like a giant jigsaw puzzle. Also, NONE of these particles had any magnetic properties what so ever.. Rust, grows like a plant spore off of metal, and rust is magnetically attractive. So the only thing that would make sense, is, the liner coating on the inside of the underground fuel tank, degraded after the introduction of Ethanol in our fuel.

Thinking about it later, I remember the tanker was there at the gas station.. All of this could have bee avoided by going to another station if the tanker was there.

 

[JWillyG]

thanx for all the input,,,I am going to pull the tank and re-coat the inside. I found that some one has stripped the head of the brass adjustment screw on the carb that's giving me troubles. Can I drill and use a tiny easy out tool?

 

[Traumahawk]

Dannymax (BRC carb shop at the bottom) can probably answer that.

 

[dannymax]

Dannymax (BRC carb shop at the bottom) can probably answer that.

I can Eric, and we've been talking off thread about this situation. unk:

 

[sdt354]

thanx for all the input,,,I am going to pull the tank and re-coat the inside. I found that some one has stripped the head of the brass adjustment screw on the carb that's giving me troubles. Can I drill and use a tiny easy out tool?

Very doable. A center should be drilled first. I use a bit that fits the screw tunnel tight to get a good center. I want to say 1/4". Then I drill it until just a shell remains of the screw head. An easy out will then get it out. I usually put the easyout in a vise and turn the carb. The pointed end of the A/F screw will usually fall out with a tap or two.