hughandjen Posted February 6, 2014 Report Share Posted February 6, 2014 Hi New to this group and need some help please. I've recently bought a 1970s montesa 247cota and having problems getting it running. I first had it firing occasionally, then the throttle got stuck and it fired and revved until I turned the fuel off. Now I can start it after squirting easy start into the inlet, it fires after second kick but will not run for more than a few seconds. I've tried opening the throttle, screwing the pilot jet screw in or out to no avail. It has an amal carb with push tickler thingy to get the fuel through. What do people think, is it a blocked pilot jet or any other ideas please. Thanks Quote Link to comment Share on other sites More sharing options...
woody Posted February 6, 2014 Report Share Posted February 6, 2014 You don't mention whether it was bought as a runner or whether it has been laid up for some time. Does the carb flood as it should if you hold the tickler down? Essential for cold starting as that is effectively the choke and even after it fires you need to flood it a couple of times whilst running until it warms and runs on its own. From what you're describing, yes the pilot jet or pilot circuit itself could be blocked, especially if the bike has been lying unused for some time. Remove the jet and check if blocked. Even if it is, also remove the air screw and use aerosol brake/carb cleaner to flush through the pilot circuit, spraying it into the air screw housing, pilot jet housing and pilot intake in the rear of the carb. Once you're happy the circuit and jet are free from blockage, try the bike again. Quote Link to comment Share on other sites More sharing options...
keychange Posted February 7, 2014 Report Share Posted February 7, 2014 You have over-tightened the carbie - that causes the slide to jam and can deform the carbie and cause air intake. Back off to just tight and see how that goes. If carbie is deformed it is easy fixed - just ask. Almost certainly a blocked pilot jet - guitar strings are good for removing stubborn blockages. Make sure your plug is good and the gap is not too large ie: standard plug setting is too large gap should be 0.4 mm Suggest you get a decompression valve before you bugger the kick start gears which are unobtainable. My Cota took me months to figure out but now that I know the beast it is a terrific and reliable old mount so stick with and don't be scared to ask as there is no such thing as a silly question just impatient responses 1 Quote Link to comment Share on other sites More sharing options...
hughandjen Posted February 7, 2014 Author Report Share Posted February 7, 2014 Thanks foe that help guys. I agree it looks like a pilot jet problem. I will buy some carb cleaner and a guitar string and have another go. I fitted a decompression lever a few weeks ago, how do I use it? Am I right in kicking it over a couple of times with the lever to prime it then give it a kick with full compression? Will keep you guys informed of progress. Thanks again Quote Link to comment Share on other sites More sharing options...
hughandjen Posted February 7, 2014 Author Report Share Posted February 7, 2014 Thanks pro sport for the offer of help Quote Link to comment Share on other sites More sharing options...
keychange Posted February 8, 2014 Report Share Posted February 8, 2014 gently move the kick start until it gets to top dead centre ie:becomes very hard - then give the compression lever a squeeze and take it just past TDC then release the lever and kick normally. Once you get the hang of it - it becomes part of a natural kicking action. Quote Link to comment Share on other sites More sharing options...
hughandjen Posted June 18, 2014 Author Report Share Posted June 18, 2014 Thanks for the help guys, pilot jet at fault. Quote Link to comment Share on other sites More sharing options...
pro sport Posted June 18, 2014 Report Share Posted June 18, 2014 Great stuff Hugh I rebuilt my Amal with new main, needle, and pilot jets a new needle and throttle valve for about £30 from Burlen . Probably the best spent money on the bike so far as it was running very rich before and four stroking with no pickup, now it running with a strawberry brown plug and really responsive on the throttle. Cheers Dave Quote Link to comment Share on other sites More sharing options...
alchemy84 Posted June 21, 2014 Report Share Posted June 21, 2014 You have over-tightened the carbie - that causes the slide to jam and can deform the carbie and cause air intake. Back off to just tight and see how that goes. If carbie is deformed it is easy fixed - just ask. I believe the 247 I picked up has a deformed carb, it is hard to remove the slide and it sticks at WOT, and I read somewhere that is a sign of a deformed carb. Could you please share the fix you mentioned? Thanks and much appreciated Quote Link to comment Share on other sites More sharing options...
keychange Posted June 23, 2014 Report Share Posted June 23, 2014 Firstly make sure that your carbie isn't simply over-tightened. Back of the bolts so that they are just done not over-done and see if the slide is working smoothly. Otherwise remove the carbie and get a sheet of glass ( I pull the pane out of my shed window ) place a sheet of say 600 wet and dry on the glass leave it dry to begin with and rub the face of the carbie in circular motion over the wet and dry for say 20 seconds. Then have a look at the surface of the carbie face and if it is deformed you will see clearly that patches ( usually around the bolt holes) have been scuffed by the wet and dry and the rest is untouched. Now continue with smooth circular action on the wet and dry until you can see that the entire surface is making contact with the wet and dry and you should now have a flat surface. Then make sure you don't bugger it by over-tightening again Quote Link to comment Share on other sites More sharing options...
thats_a_five Posted June 23, 2014 Report Share Posted June 23, 2014 Be a little careful with the guitar strings. Nylon strings should be OK but steel can scratch the brass jets. I had a Honda with a sticking slide. A previous owner had assembled the slide wrong and it damaged the small index pin that keeps the slide from twisting in the bore. It took some very careful handwork with some tiny needle files to clean up the pin to stop it binding the slide. Quote Link to comment Share on other sites More sharing options...
keychange Posted June 24, 2014 Report Share Posted June 24, 2014 (edited) Yes I suppose many guitar strings are quite stiff - I use a very fine soft brand of guitar strings ( Thomastik ) and so not a problem but certainly you want to be sure that the string is smaller than the jet. They are available in .011 .010 and .009 . I always carry a 6 inch length of .010 in my kit just in case - as it is useful for unblocking all sorts of orifices As for the sticking slide - this is very common with Amal carbies and almost always due to being over-tightened - the quality of the aluminium is pretty ordinary and so really too soft for the job. But as long as you know and work within the limits then the Amal does a great job. My 247 goes like the clappers/ Edited June 24, 2014 by keychange Quote Link to comment Share on other sites More sharing options...
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