Backfire help. Apollo beach area

[Kylenav]

   
Backfire for first time...
« on: Today at 10:30:11 AM »
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So I tried utilizing the search first of all... Of course every backfire it turned up is different than mine so here we go!

Noticed month or so ago a puff of black smoke from the right side on start up, not every time and only the first start of the day. So I ran a can of deadpan through thinking this magical can would fix anything. No effect.

Rode to work the other day and about 25 miles in I noticed a popping sound when at about 65-75 mph and just steady throttle. After the highway run is when I knew something was definitely the matter. Backfires under deceleration and acceleration with throttle under 1/2 or 3/4. Soon as I go WOP she clears up and pulls like a beaten bull as always. I've ran another can of deadpan hoping it was a clogged jet or something of the sort but hasn't changed. Best I can tell it's only one cylinder backfiring, furthest back (toward rear tire) on the right side (rear brake side).

I'm in no means an expert, especially when it comes to carbs. I do all my own maintenance such as oil, fluids, rear end maint...  Need to know what to check, and possibly how to check it!

Bike is an '01 tourer, cobra 6X6, k&n filter with pre filter installed. Always use 93 octave from Sunoco.

All help is GREATLY appreciated.

[98pacecar]

Float sticking, or needle valve not seating properly ?   

Seems like,, it's getting excess fuel.....   ???

I'm sure, someone else will come along,, with a better,,,,, answer..     

[FloridaValkRyder]

Kyle, some of the other "Experts", and I use this term literally, will be along pretty soon with lots of ideas and suggestions. There is nothing these guys can't diagnose. There are quite a few in your area too. Be patient..they will come!

[John Schmidt]

If you haven't done so lately, check the hose clamps on the rubber intakes. They have a tendency to loosen over time and will give that type of trouble. Larue had that problem and he found nearly all his were loose, cured it. Should be 12....worth a look at least.

[Kylenav]

Checked the hose clamps, those are supposed to be tight ehy??? Could move 4 of them by hand and were all very lose. Unfortunately however now that they're all tight that didn't change anything. I'm nervous that when I start it now, about 90% of the time I get a puff of smoke, now from both sides of exhaust... Could that possibly be related to using a full can of seafoam in a 1/4 tank of gas? I wanted to ensure maximum cleaning power.

From what you've said first John I'm guessing you're thinking a vacuum leak? Maybe it's time to do the desmog.

[John Schmidt]

Kyle, that's pretty rich on the Seafoam. My wife's car sat for a year in 2012 and into 2013, had to really treat the old gas in order to clear up a miss. For the first couple hundred miles it smoked when first starting up and when I'd goose it a bit. Now that we have it running smooth again and I've run all the heavily treated gas out and replaced it with some good gas, it no longer smokes on start up.

As for the desmog, any time is a good time. The main reason riders do it is to get rid of the possibility of a vacuum leak.

[Kylenav]

I'll go fill it up with gas tomorrow. I will most likely be attempting the De-Smog this weekend then.  John which way are you leaning with your diagnosis?  I've been on this board for a while now, have seen you help solve lots of these issues.  Vacuum leak, carbs or anything else pop into your head?  Just curious, you are an EXPERT!

[Thunderbolt]

Each cylinder has either a vacuum line or a cap on the back side of the intake.  The caps or the lines can crack and suck air and lean out that cylinder.  Have you ever heard a weird whistle from the engine?  The cylinders are 1,3,5 on the right from the front and 2,4,6 on the left.  #3 and #4 have vacuum lines that over time usually split near the connection point on the intake from the heat of the engine.  #6 has a vacuum line that operates the petcock.  All of those are sources for possible vacuum leaks.  The pair valves sometimes don't close properly.  That is one reason that a lot have been desmogged.  You can buy 4 9/16" freeze plugs and some epoxy glue and exhaust gasket and one old bolt to screw into the airbox hole that will be left after the desmog.  That eliminates a lot of vacuum leak possibilities.  Another source is the short vacuum line on the side of each carb that goes to the vacuum cut valve.  These I usually replace when the carb bank is off, they will look good until you get them off, but will have hairline cracks in them when you squeeze the end.  You have already tightened the clamps that get loose.  The intake O-rings are another possibility.  Do you have any brown oily looking residue underneath the intakes?  This usually happens when the O-rings are leaking.
If you pull the carb bank to desmog you might as well clean the slow jets and bowls.

[FloridaValkRyder]

Told ya.....

[larue]

make sure you tighten all 12 intake clamps, 3 apparent on top of the intake and 3 underneath the chrome piece covering the chock linkeage, those need tightened too, you cant see them unless you take chrome piece cover, make sure NOT TO TOUCH the little screws with blue paint on them wrapped in little springs that  you'll see further underneath the chock linkage  cuz you will be sorry...dont ask me how i know  thats why i am joining the carb party at johns place today.
Oh and since its got seafoam in it already, try to ride on 5th gear under 2200 rpm for six miles and so..it worked for me. good luck kyle

[John Schmidt]

Kyle, Terry covered it very good....follow that lead. Desmog is the main reason for eliminating the leak possibilities. As for what's needed, here's what I've done in the past for a quick down and dirty desmog.

Re. the two chrome tubes that go to #5 on the right & #2 on the left. I pull the clip that holds it down, cut the tube off the plug that goes into the top of the cylinder head, fill that hole on the plug with quick setting JBWeld and replace it. Do that on both of them. The other chrome tubes; one goes down the front on the right side and the other down the back on the left side. I cut them at a convenient spot and again with the JBWeld. Pull the vacuum hoses off the back of the carb intakes and cap those ports....except #6 if you're still using it. Later when you're ready to tackle the tank and airbox, then you can pull the Pairvalves and all the extra crap in there. At that time you'll need to plug the one hole in the bottom of the box.

[Kylenav]

First and foremost thank you all for the advice. I will be pulling the tank and attempting the entire De-Smog with the advice you have provided.  I really don't want to have to pull the carb bank off. Not so much pulling it off that worries me, I can pull anything off. More the putting it back together part that seems to give me troubles. 

I'll provide an update this weekend hopefully if I have time to get it all done, or most likely be posting pictures and asking for more help.

Thank you again for taking the time to help. Much appreciated

[Thunderbolt]

Kyle here is a link to Normands Desmog article.  Even has pictures which helps.

http://www.valkyrieriders.com/shoptalk/desmog.htm

[Kylenav]

Well I found the culprit prior to taking the tank off, thank goodness.  Had a spark plug, about 10K miles old, that was bad. The porcelain piece somehow came loose and was causing the plug not to fire. $45 for 6 new plugs and the fat girl is singing again. Thank you all for the input!!

[Thunderbolt]

Thanks for letting us know the culprit.  Sometimes you get lucky.