Announcement

Collapse
No announcement yet.

Rear header red hot after removing quiet baffles

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Rear header red hot after removing quiet baffles

    Hi, yesterday night I replaced the 'quiet' baffles in my V&H Longshots with the stock baffles.
    Also I decided to take the heat shields off to tighten all bolts on and around the exhaust, as something was rattling there.

    I ran the engine for about 3 minutes, first with 1/3 enricher on high idle, double-checking intake for air leaks by spraying starter fluid behind carb (I had leak and fixed that over the last days, wanted to double check). Confirmed no air leak.

    I then got on the bike, put the enricher back in and revved it up a couple of times for another 1-2 minutes to hear if anything rattles on the exhaust (I had tigthened all bolts).

    When I got off the bike, to my surprise, the rear header was glowing RED HOT!

    After shutting the engine down, I noticed both pipes had chanced in color- the rear more bluish and the front more golden. They had a bit of discoloring before, but not that much.

    Is it possible the pipes run so hot just because I replaced the baffles? Or is there something else going on? (The carb is stock, the airbox as you can see on pic is stock but has K&N filter element in it which I cleaned and re-oiled)
    Attached Files

  • #2
    To glow red hot indicates a lean condition on that cylinder. Just a blue discoloration in the pipes means nothing unless it is actually red. bluing on the pipe under the chrome shield is normal. On those pipes you usually get a blue spot on the chrome about half way down the pipe. That is caused by a exhaust leak at the joint clamp.

    Comment


    • #3
      Thanks. What could cause my rear cyl to run lean all of a sudden?

      I have fixed my intake leak and have carefully checked for exhaust leaks.

      Comment


      • #4
        A leak that you haven't found and are missing somehow. No other way around it. It is a single carb running to 2 cylinders thru 1 manifold. If the front is running OK the rear must have a leak at the rear manifold connection. Also check the brass nipple on the intake to make sure it isn't leaking. Pull 1 of the spark plugs out of the rear cylinder and it will be snow white. That will show that it is running lean.

        Comment


        • #5
          maybe time for a valve adjustment ?

          Comment


          • #6
            Thanks guys, I have repeated the leak test once more with starter fluid and confirmed there is no leak on intake anymore. I found a leak 2 days ago with that method, it was the clamp holding the carb but no leaks at ports to cylinders. Carefully inspected manifold. Nipple is correctly blocked- see pic.

            I'm thinking valves or carb -PMS jet in particular. I think both cylinders running hot, the rear is just running a bit hotter because it's more shielded and 'in' the engine vs. the front is more exposed.

            I have been advised to leave the valves alone but given this situation maybe reconsider.

            Comment


            • Duke
              Duke commented
              Editing a comment
              If the engine is running smooth and not making excessive noise, then "I would" leave the valves alone.

            • roadiemort
              roadiemort commented
              Editing a comment
              What he said.If you blindfolded this man he could still build an engine.

          • #7
            Ok I take your advice on the valves.

            But should I do anything about the red hot header pipe or just put the heat shields back on and pretend nothing happened?

            Comment


            • roadiemort
              roadiemort commented
              Editing a comment
              Can't answer that until you pull the rear plugs like Dave said.

          • #8
            Sorry I forgot to mention that. I did pull the plugs two days ago. Right hand side plugs looked tan color on the outside ceramic and some black residue on the contacts. Left hand side plugs similar but with more black residue everywhere also on ceramic. I did shut the bike down immediately after coming home from a 30 min ride. Front and rear cyl plugs looked tge same. In my humble opinion that's what I had expected on a bike with 39K miles on it.

            I replaced the pugs with fresh NGK's after that.

            Also, I should point out that I still have an issue with rough idle. What I mean by that is that I have to adjust the idle speed to a 'fast idle' around 1500rpm (sorry just my estimation in absence of a tach). Below that the engine will sputter and stall. When idling at that high idle speed, the bike vibrates quite a bit. When running at speed, everything is very nice and smooth.

            I did perform the air leak test repeatedly until I found the clamp holding the carb was loose and tigthened it. I have inspected the manifold and confirmed it is in very good shape, nipple plugged, and no more air leaks in that area.

            I also gave the carb a Seafoam treatment yesterday, sparaying into it a couple of times and then a long spray until engine stalls, then hot soak for 45 min and then ride. It seemed to improve the roughness somewhat but the idle is still not what I would like.

            In my very limited understanding of this bike I would think it is running lean at idle but I might be wrong. The PMS is still plugged btw.

            Hope this gives some additional pointers. Would appreciate any ideas or further questions to help solve this problem and make this engine run smooth.

            Comment


            • #9
              Looks like an exhaust leak to me. When you messed with the exhaust did you loosen and retighten the manifold bolts? You may just need new exhaust gaskets.

              Comment


              • #10
                Thanks. I did tighten them yes. Also checked there is no hot air/exhayst gas coming from that area by blowing smoke on it. I would think if there was an exhaust leak I'd have some popping, too but it might be a small leak. I'll double check but honestly I'd be surprised if that causes the pipes to run that hot.

                I tend to think the bike runs super lean at idele thats why it vibrates at idle and why it takes long 10-15m to warm up to run without choke. But qgain I'm new to this kind of bike so I could be wrong and appreciate any thoughts!

                Comment


                • #11
                  Are you using 87 octane fuel? My bike runs hot on premium. Our engine is made to run on 87.

                  Comment


                  • #12
                    yes thanks, I have 87 in the tank.

                    The thing that really seems wrong is that I have to keep the idle speed really high to prevent it from stalling. I think its at least 1500 probably more like 2000. No wonder its getting hot. But why does it stall when I bring idle speed down?

                    On really warm/hot engine when I push the enricher in all the way I either have to be on the throttle or adjust the idle speed up to this unreasonable level. I can make a video and you would see what I mean. It will only idle at this ridiculously high rpm it seems totally wrong.

                    How can I make the engine idle at 920-1000 when it stalls always below 2000?

                    What can be wrong here.. spark? Carb idle or pilot? Throttle position sensor? valves? (I did the paper test just to be sure and both pipes blowing not sucking)

                    I'm really at a loss right now. Could use some help!

                    Comment


                    • #13
                      clean the pilot circuit.

                      Comment


                      • #14
                        How? Do I have to take carb off or just clean that orifice lower left when looking into throat?

                        Comment


                        • #15
                          Only reason you would have to keep it idle and that high to keep from dying I would think is that you have obstruction in the pilot jet. At this point I would say pull the carburetor off give it a good cleaning and make sure your main jet and pilot jet are completely clean (carb cleaner and thin wire). Make sure bowl gasket and diaphragm rubber are good (no tears or rips). There's a filter screen on the fuel inlet of the carburetor which also can get plugged blow that out with some carb cleaner . Maybe even blow the fuel line out with compressed air from the end of the fuel filter to the inlet of the carb screen with carburetor off. Also blow the roll over valve out since you'll have the compressor handy.. That's the little rubber line that goes on top of the gas tank as a vent just shoot some compressed air down through there as well.

                          I would think that if I let my bike title at 2000 RPM for several minutes the exhaust would get very very hot Especially with no air flow from just sitting still
                          LET'S RIDE

                          Comment


                          • #16
                            Yes. Thank you. This makes sense. I will take the carb apart and clean tt good. While I'm in there I think I'll re-jet it with #40 pilot and 172 main.

                            Should I check the float level or just leave it alone?

                            I will make this engine run smooth. We are just getting to know each other.

                            Comment


                            • #17
                              Only rejet if you have aftermarket exhaust and air filter. If you rejet with that jetting it also needs the aftermarket adjustable needle. If you still have the stock non adjustable needle that jetting won't work.

                              Comment


                              • #18
                                Like Dave said dont mess with jetting yet...

                                Whatnyear bike and exhaust and air intake?
                                LET'S RIDE

                                Comment


                                • #19
                                  2006 1700 xv1700a v&h longshots and k&n element in stock airbox. If and when I get the basics sorted out I may want to stick a BAK on there or drill the stock box.

                                  I'll need new screws for the bowl anyway and believe they come with the barons kit (ok that was a lame excuse) but more importantly I don't necessaily want ro take the carb off and apart again so thinking about the Barons Needle/Jet Kit BA-2420RDplus mikuni pilot #40 from jetsrus.

                                  Reading the instructions from barons kit https://www.denniskirk.com/dk/pdf/in...7/dk173299.pdf

                                  as well as tech articles here I believe the Barons 172 would be appropriate and 40 pilot at 2 1/4 turns out to start.

                                  Does that sound like a good plan?

                                  Comment


                                  • Shores
                                    Shores commented
                                    Editing a comment
                                    Not all brand needles and jets have the same bore or tape even though they are labeled the same. The carb Gurus should explain that to you here.

                                • #20
                                  Don't know how long you were running the engine with no motion, but were you using a fan blowing on the engine to give it some air during your testing?

                                  Comment

                                  Latest Posts

                                  Collapse

                                  Topics Statistics Last Post
                                  Started by scotcher65, 2 hours ago
                                  3 responses
                                  25 views
                                  0 likes
                                  Last Post scotcher65  
                                  Started by roadiemort, 04-17-2022, 01:19 PM
                                  30 responses
                                  385 views
                                  1 like
                                  Last Post roadiemort  
                                  Started by Lug Nut, 7 hours ago
                                  15 responses
                                  50 views
                                  0 likes
                                  Last Post Lug Nut
                                  by Lug Nut
                                   
                                  Started by Airlordd1, 5 hours ago
                                  2 responses
                                  27 views
                                  0 likes
                                  Last Post Tcontrol  
                                  Started by Sykobox, 3 days ago
                                  17 responses
                                  153 views
                                  0 likes
                                  Last Post Lug Nut
                                  by Lug Nut
                                   
                                  Started by Lug Nut, 15 hours ago
                                  5 responses
                                  83 views
                                  0 likes
                                  Last Post Lug Nut
                                  by Lug Nut
                                   
                                  Started by Sabotage, 1 week ago
                                  10 responses
                                  146 views
                                  0 likes
                                  Last Post Sabotage  
                                  Started by Bnag0, 04-13-2022, 11:05 PM
                                  109 responses
                                  1,368 views
                                  1 like
                                  Last Post Shores
                                  by Shores
                                   
                                  Started by Mad Maj, 3 days ago
                                  29 responses
                                  250 views
                                  0 likes
                                  Last Post Tcontrol  
                                  Started by brianmac, 3 days ago
                                  2 responses
                                  80 views
                                  0 likes
                                  Last Post J89k
                                  by J89k
                                   
                                  Started by dna9656, 1 day ago
                                  2 responses
                                  28 views
                                  0 likes
                                  Last Post dna9656
                                  by dna9656
                                   
                                  Started by KFallsRider, 1 day ago
                                  11 responses
                                  137 views
                                  0 likes
                                  Last Post KFallsRider  
                                  Started by dna9656, 2 days ago
                                  8 responses
                                  78 views
                                  0 likes
                                  Last Post Ahodge75  
                                  Started by Kmartcivic, 3 days ago
                                  8 responses
                                  115 views
                                  0 likes
                                  Last Post Chromepony  
                                  Started by KFallsRider, 3 days ago
                                  16 responses
                                  139 views
                                  0 likes
                                  Last Post Chromepony  
                                  Started by ElVispo, 01-25-2022, 07:34 AM
                                  100 responses
                                  1,764 views
                                  4 likes
                                  Last Post ElVispo
                                  by ElVispo
                                   
                                  Started by dna9656, 2 days ago
                                  3 responses
                                  74 views
                                  0 likes
                                  Last Post dna9656
                                  by dna9656
                                   
                                  Started by roadiemort, 4 days ago
                                  7 responses
                                  52 views
                                  0 likes
                                  Last Post LDofDC
                                  by LDofDC
                                   
                                  Started by Tykes_Place, 11-17-2021, 12:09 AM
                                  122 responses
                                  1,539 views
                                  2 likes
                                  Last Post Shores
                                  by Shores
                                   
                                  Started by 6door7r, 3 days ago
                                  14 responses
                                  96 views
                                  0 likes
                                  Last Post 6door7r
                                  by 6door7r
                                   
                                  Working...
                                  X