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  • 25DC Trouble Shooting.

    Having only recently purchased a 1961 25dc (please see my last posts, here; http://www.greeves-riders.org.uk/for...ead.php?t=2787 ) I am having some problems.On 2 runs, after about 7 miles ,the engine just cut out.Leaving it for about 15 mins it started again so I went back home,not willing to risk being stranded.Also I found the bike quite unwilling to top 40mph and being quite sluggish.I removed the carb. but it looked ok,not sure what the main jet size is though.I have also found that the float chamber overflows if the fuel tap is left on although during inspection everything appears fine.Has anyone got any ideas what could be causing these problems ? Also what type of spark plugs and gap.Thanks for any assistance
    Last edited by Brian Thompson; 18/06/2012, 04:06 PM. Reason: Link to previous thread added.

  • #2
    25DC probs

    Difficult to diagnose without seeing bike, could be lots of reasons, but dirt in fuel (maybe disintergrating tank sealent) may be cause.
    If the carb is flooding the float needle is not seating, may be just dirt but may be worn. Get a new one from Villiers Services with viton tip
    Carb settings for S22/2 are:
    Main jet 180
    Pilot jet 35
    Needle 3 1/2 in groove 3
    Throttle slide 3

    Plugs NGK B-6HS (or equivilent)
    Gap 25 thou

    Comment


    • #3
      25dc trouble shooting

      Thanks John for the info.and I realise that it's difficult to diagnose the sort of problem I have without seeing it. Let me just say that this bike has been fully restored to almost better than when it came out of the factory,with only 62 miles on the odometer, but I don't think it's been run much in the last six months.The engine starts readily enough but seems to be acting like a 125cc instead of a 250cc when on the the road.I have been keeping the speed down thinking that it may need to be run in but when it suddenly stops,for no apparent reason on 2 occasions I start to wonder-hence my call for help.If you have any other suggestions I would love to hear them.

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      • #4
        25dc trouble shooting

        Just a thought FWIW,,but as you are having probs with flooding, have you checked that the crankcases arent full of fuel,by removing the drain plugs?
        if the bike has been stood for a lengthy period,it's posssible fuel may have accumulated there,which wont help matters.Also, check the points havent closed up,(a bit obvious,but it would reduce performance significantly,if thats the case).Best of luck, and let us know what/when/why etc, when you get it sorted.
        Les

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        • #5
          [QUOTE=bryan;8478]
          The engine starts readily enough but seems to be acting like a 125cc instead of a 250cc when on the the road.QUOTE]

          Sounds like its only running on one cylinder, check plugs & points & all electrical connections to coils etc. You say the bike has been fully restored, who did it yourself or previous owner/seller? If you bought it restored have you contacted the seller? if he sold it as a fully restored & running bike he should be prepared to sort it out. Particularly if he is a dealer.

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          • #6
            25dc trouble shooting

            Sounds as if running cylinder ?,after you say 7 miles the bike cuts out I would suspect coil problems,perhaps both coils are weak and one failing once warm.Don't ask me how I know. Have fun when you get it sorted.

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            • #7
              25dc trouble shooting

              Sounds as if running on one cylinder ?,after you say 7 miles the bike cuts out I would suspect coil problems,perhaps both coils are weak and one failing once warm.Don't ask me how I know. Have fun when you get it sorted.Sorry for initial posting,I must be more careful with my grammar.

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              • #8
                25dc trouble shooting

                Thanks for all contributions so far.Plugs,points all ok but how do you check a coil ? Carb. fitted is s25/1 but should be s22/2,as you said John, how much difference will this make-haven't checked jet sizes on s25/1 yet but will fri.am. If I have to buy a s22/2 anyone know where one could be bought-tried the villiers site but they only have a Amal in stock.

                Comment


                • #9
                  S25 carb will be OK, here are the settings for the S25
                  Main jet 180
                  Pilot jet 35
                  Needle 3 1/2
                  Needle set out (distance from bottom of slide to tip of needle) 1.94 inches
                  Throttle slide 3

                  Comment


                  • #10
                    25dc trouble shooting

                    Update,still have same problem with engine cutting out,last time,yesterday,it went fine for 15 miles and then stopped 5 times in the next 11 miles !I did change the main,pilot jets also the needle valve,carb.still flooding now and then.Contacted Villiers services for help.Steve told me to remove carb.and manifold,get the left or right piston above the manifold and pour petrol in in till it floods out,leave for a while,30 mins.in my case,then remove the opposite drain plug,if fuel transfers from one side to the other then the centre seals have gone and basically it's a big bill.Has anyone heard of this before cos I was interested in one of the latest posts.
                    However I have contacted the seller and he's going to come and collect the bike and hopefully fix it ,so I'll post other updates as and when things become clearer.

                    Comment


                    • #11
                      25DC troubles

                      The advice given by Villiers Services is valid. Yes the centre seal could have gone, but unlikely as the bike starts & runs OK for 15 miles. If it were the centre seal failure the problem would be there all the time. ie poor starting & erratic running particularly a low revs.
                      You have done the right thing in contacting the sellor, you bought the bike in good faith as a restored machine & you should not be having these problems. If he cant sort it out, ask for your money back & look for another, preferably being sold by a genuine GRA member.
                      Last edited by John Wakefield; 29/09/2011, 02:18 PM.

                      Comment


                      • #12
                        25dc trouble shooting

                        Thanks John for your reply.With what you said about about V.S. being right how come I'm getting cross over fuel , from pouring the fuel into the manifold and taking out the opposite drain plug,when the engine starts and runs ok,even tick-over is steady, for a number of miles,even got to 22 miles the other day before it came to a halt ! Will post a further update in the future.

                        Comment


                        • #13
                          2T problems

                          I dont quite understand what you are saying here Bryan. Have you actually poured petrol down the manifold & seen it come out of opposite crank case drain plug? If so this would look like a seal failure but it would only need a minute gap for petrol to seep by seal, or crankcase centre plate see No 24 on this drawing http://www.isdm.co.uk/VI62/_VSF6.asp?ID=TXC02&fun=F2
                          so not sure if this is such a good test after all. Again if it starts & runs perfectly well up to 15-20 miles its not a leaking seal. More likely ignition system breaking down, or fuel starvation. Is fuel in the carb when engine stops? Are you sure its not siezing. If its been rebored & a bit tight it will need at least 500 miles before its fully run in. The 2T engine is well known for 'nipping up' after a re bore.
                          Last edited by John Wakefield; 30/09/2011, 01:26 PM.

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                          • #14
                            25dc trouble shooting

                            Yes John that is exactly what I'm saying,ie fuel in right hand manifold,remove left hand drain plug and the fuel comes out.I don't think the engine is seizing because when the bike comes to a halt I can kick it over and it is free.As I said before sometimes when it cuts out the carb. is flooding and sometimes it's not ! I realise this a mystery but hopefully it will be sorted out when the seller visits next week.I will let you know what happens and thanks for your interest.

                            Comment


                            • #15
                              2T probs.

                              Hi Bryan, I'm waiting in suspenders,(!!), here,oops, suspense,I mean, to hear the latest on the ,(hopeful), resolution of your problem episode.
                              Whats happened?, is it fixed now?,was it expensive,or not?,Do tell, we other 2T operators need to know!!
                              Seriously tho, hope you got it fixed OK.
                              Les

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