bambam_n_chunx Posted April 13, 2008 Report Share Posted April 13, 2008 Hello all Wonder if anyone can help. Having a nightmare trying to start my tr77 mar.The plug is sparking and getting wet but it wont fire at all. The carb is clean and all blown through with compressed air. I took the flywheel cover off to check the timing and found its been fitted with motoplat points ignition.The wires that come off all seem to be original and mate up with the connectors so I wondered if these were fitted as standard. The wires that come from the mag are black,white,green and yellow.I think the black is live as it is the only one that makes a spark but perhaps someone knows better. Cheers Andy Quote Link to comment Share on other sites More sharing options...
scotty Posted April 13, 2008 Report Share Posted April 13, 2008 Fit a new sparkplug , Ive had the same problems as described only to find it needed a brand new plug! after much points/timing adjustments thats all it was! good luck. Quote Link to comment Share on other sites More sharing options...
bambam_n_chunx Posted April 14, 2008 Author Report Share Posted April 14, 2008 Thanks for the suggestion. I managed to get the bike running by heating the plug and it runs for a short while until the plug is fouled. I suspect the carb is set up wrong but cant find any info on it. Its a bing 84 carb,I guess its the original but it may not be. Does anybody have a list of jets and needle settings? Thanks Andy Quote Link to comment Share on other sites More sharing options...
swooshdave Posted April 14, 2008 Report Share Posted April 14, 2008 A fouling plug may also indicate the wrong spark plug. Triple check to see that you have the exact one as specified. That being said, it could be a number of factors. If it were me I'd go down the list to see what isn't correct and address each one. Sparking means you're getting the electricity to the right places, now (as mentioned) it's about getting it to spark when it's suppose to. Quote Link to comment Share on other sites More sharing options...
bambam_n_chunx Posted April 14, 2008 Author Report Share Posted April 14, 2008 Thanks I guessed its down to the carb as I`ve checked and double checked the timing.It is fitted with a montesa points stator and flywheel,gap is 0.38 and it opens exactly 3mil btdc.When its running the bike sounds as if its responding perfectly until it cuts out.Then when the plug is checked it is always wet and wont fire up again until it is heated with a gas lamp.I have tried a number of plugs and its always the same result. Andy Quote Link to comment Share on other sites More sharing options...
woody Posted April 14, 2008 Report Share Posted April 14, 2008 Are you sure the stator is off a Montesa? The green Ossas, TR77 and TR Verde did have Motoplat points fitted as standard instead of electronic ignition, then they went back to electronic on the Grippers. Have you replaced condensor also? Bing carbs work well but are very finicky with the float level, are you sure it isn't flooding which is why it's cutting out. I may have the carb specs for the Ossa's Bing, I'll check tomorrow Quote Link to comment Share on other sites More sharing options...
swooshdave Posted April 14, 2008 Report Share Posted April 14, 2008 ThanksI guessed its down to the carb as I`ve checked and double checked the timing.It is fitted with a montesa points stator and flywheel,gap is 0.38 and it opens exactly 3mil btdc.When its running the bike sounds as if its responding perfectly until it cuts out.Then when the plug is checked it is always wet and wont fire up again until it is heated with a gas lamp.I have tried a number of plugs and its always the same result. Andy What is the correct plug for your application? Quote Link to comment Share on other sites More sharing options...
bambam_n_chunx Posted April 15, 2008 Author Report Share Posted April 15, 2008 What is the correct plug for your application? Im going off whats in the book and its ngk b9 or 10 im using a b9 but I think woodys right by saying its flooding I`ll try again tonight. Cheers for your interest Andy Quote Link to comment Share on other sites More sharing options...
bambam_n_chunx Posted April 15, 2008 Author Report Share Posted April 15, 2008 Are you sure the stator is off a Montesa?The green Ossas, TR77 and TR Verde did have Motoplat points fitted as standard instead of electronic ignition, then they went back to electronic on the Grippers. Have you replaced condensor also? Bing carbs work well but are very finicky with the float level, are you sure it isn't flooding which is why it's cutting out. I may have the carb specs for the Ossa's Bing, I'll check tomorrow Thanks for the info on the stator,I couldn`t find any details whether these were fitted as standard,I guessed it was montesa due to the colour of the wires but as the bike hasnt been messed about with much you are probably right about it being the original. I suspect its flooding as once the plug is dried it will start again and it only starts with the choke off. Im using the vintage dirt bike book for references but it doesnt give a measurement for float height just a vague guide with the floats level with the base of the carb. Thanks for sharing my problem with me your help is once again appreciated Andy Quote Link to comment Share on other sites More sharing options...
Guest majestyman340 Posted April 15, 2008 Report Share Posted April 15, 2008 If anyone has a bike fitted with Bing, Dell Orto, or Amal carb, a guy on Ebay is currently selling VM26 Mikuni carbs for Quote Link to comment Share on other sites More sharing options...
pedronicman Posted April 15, 2008 Report Share Posted April 15, 2008 If anyone has a bike fitted with Bing, Dell Orto, or Amal carb, a guy on Ebay is currently selling VM26 Mikuni carbs for Quote Link to comment Share on other sites More sharing options...
bambam_n_chunx Posted April 15, 2008 Author Report Share Posted April 15, 2008 But that isn't going to solve the problem with the electrics is it! The plug should be a NGK BP5ES Thanks very much for the plug info. The banging your head on the wall is perfect thats exactly how I feel. I`m still convinced its the carb. My legs had it all the kicking it can stand. The bikes going back against the back wall for a while. Thanks everybody for trying to help and taking the time to read this. Andy Quote Link to comment Share on other sites More sharing options...
swooshdave Posted April 15, 2008 Report Share Posted April 15, 2008 I've already kicked the crap out of one too many bikes. If it hasn't started by the 5th kick, I'm going to find out why. If you suspect the carb, take it off, clean it and make sure it's to spec. I was working on my cousin's bike and when I took the carb apart the floats were upside down (Mikuni). Needless to say, the bike started a little easier after than. Unless you bought the bike new, there is no saying what a previous owner has done. Quote Link to comment Share on other sites More sharing options...
bambam_n_chunx Posted April 16, 2008 Author Report Share Posted April 16, 2008 But that isn't going to solve the problem with the electrics is it! The plug should be a NGK BP5ES Thanks you are a life saver. I managed to get a b5es plug today and the bike started more or less straight away. Its running a little rich but at least I can fiddle with it now. The bike was found in a cellar and has been there for about 25 years with a collapsed rear wheel. Its now ready to trial. Thanks again Andy Quote Link to comment Share on other sites More sharing options...
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