jack_the_lad Posted May 18, 2012 Report Share Posted May 18, 2012 Having followed this article for a few weeks to me it looks like your going round in circles. You seem to be spending a lot of time messing with the carburettor. You mention that you have strobed the timing. What you have not mentioned is the position you static timed it too. I think your problems will be timing related. Quote Link to comment Share on other sites More sharing options...
brucey Posted May 18, 2012 Author Report Share Posted May 18, 2012 Good news at last! I took the bike around Henry Boudrey's house this evening (he's the guy who's carb I borrowed last time) and showed him the problem. "That's a carb problem" was the immediate response from the Orical! We then refitted his (supposedly identical) carb onto my bike and hey presto, it ran perfectly again. On stripping my (new) carb, Henry found the pilot jet to be partially blocked. The lesson being don't be happy just seeing carb cleaner squirting through the hole, poke some wire through as well to make sure! Long story short, I now appear to have a Cub I can actually ride instead of fix! Special thanks to the legend (in my books), Henry and to all those who helped with advice and words of encouragement. I don't know if it was the drizzle or just the excitment, but I arrived back home a little damp! It still blows through the breather pipe a bit, but somehow that doesn't seem to matter any more! I'm planning to do a practice session with the Cub on Sunday to see if I can remember how to ride it. Bruce Quote Link to comment Share on other sites More sharing options...
bashplate Posted May 19, 2012 Report Share Posted May 19, 2012 YEEEEEEEeeeeHAAAaaaaaa Quote Link to comment Share on other sites More sharing options...
totalshell Posted May 19, 2012 Report Share Posted May 19, 2012 (edited) happy that you ve sorted it. whoa though.. poking wire through carbs is NEVER a good idea niether is squirting liquids through. blow them through with compressed air or air from an aersol (available at all plumbers merchants for about 3 quid) and actually look through the thing to check its clear. Edited May 19, 2012 by totalshell Quote Link to comment Share on other sites More sharing options...
bashplate Posted May 20, 2012 Report Share Posted May 20, 2012 hi totalshell, I agree in most cases compressed air is enough....BUT in this case... and a few others I've read regarding older carbs that have not been used for a while, you can end up with HARD deposits in the pilot system which air willnot blow out, only careful persuasion with piano or guitar wire will shift it. Bloody marvelous you got it sorted at last Brucey, have some fun now with your riding. Quote Link to comment Share on other sites More sharing options...
stork955 Posted May 20, 2012 Report Share Posted May 20, 2012 Gday Bruce, regarding your breather - remember that the same capacity change happens under the piston as it does above - so you will roughly have the same amount of air movement through the breather as you have through the carb, but in 2 directions. If there is little black smoke then you are heading in the right direction. No black smoke, clean running and a nice brown plug is what you are after, it is carb so concentrate on that and dont allow external non issues to be confusing! Hope this helps, Cheers, Stork Quote Link to comment Share on other sites More sharing options...
brucey Posted May 20, 2012 Author Report Share Posted May 20, 2012 (edited) Good evening gents, Well, what a fantastic day! I'm now convinced that although my carb was new, it probably had a used pilot jet fitted as I asked for a non standard item. The bike started and ran really well but according to Henry was running a little bit 'heavy' when the throttle was opened quickly. I was just happy the thing was still running when the throttle was opened at all! We refitted the original 100 main jet but this introduced a slight hesitaion when cracking the throttle open, so we raised the needle 1 notch (now 2nd from bottom) and it ran even better! The plug is a dark straw colour and there is virtually no smoke. I tried to upload a couple of photos of the days activities but I'm having 'issues' with photobucket! I swapped rides with my mates 08 Beta 4 stroke and was having trouble following my own Cub! I will be entering the next pre 65 trial on a bike that starts first kick, ticks over like a clock, pulls like a train and revs out as it should. It's amasing what a well set up bike does for your confidence! As an aside, I also had my first ever go at driving and being passenger in a trials side car outfit. I thought 'how hard can it be?' after about 2 minutes, I found out and after 10 minutes, I was completely knackered. Brilliant fun but bloody hard work! Once again, thanks for your help and comments, maybe I'll see you at a trial to say thankyou personally. Bruce. Edited May 21, 2012 by brucey Quote Link to comment Share on other sites More sharing options...
goudrons Posted May 21, 2012 Report Share Posted May 21, 2012 It's always a good idea to write down your setting once you get the bike running as you like it. Carb jets, float height, needle postion, timing setting etc. So when you get lost doing your next mod, you always have a base set up that you know works to refer back too. Quote Link to comment Share on other sites More sharing options...
brucey Posted May 21, 2012 Author Report Share Posted May 21, 2012 (edited) Photos added in above post, however, looking at the last one, I either need to loose 2 stone or go for a 250cc upgrade! Bruce Edited May 21, 2012 by brucey Quote Link to comment Share on other sites More sharing options...
bashplate Posted May 24, 2012 Report Share Posted May 24, 2012 a very tidy cub that Quote Link to comment Share on other sites More sharing options...
brucey Posted May 29, 2012 Author Report Share Posted May 29, 2012 Goudrons, All settings written down in my little black book! Trying a slightly smaller air filter and a Champion Platinum plug as I'm hoping I won't have to change it so frequently now. Bashplate, thanks for the kind comments. I live about 10 miles from Canterbury UK. I have really enjoyed building it and have a few improvements planned already! I think Big Red Bike gets the prize for 'nearest to the correct diagnosis' award! I'll know for next time! Bruce. Quote Link to comment Share on other sites More sharing options...
old trials fanatic Posted May 30, 2012 Report Share Posted May 30, 2012 Goudrons, All settings written down in my little black book! Trying a slightly smaller air filter and a Champion Platinum plug as I'm hoping I won't have to change it so frequently now. Bashplate, thanks for the kind comments. I live about 10 miles from Canterbury UK. I have really enjoyed building it and have a few improvements planned already! I think Big Red Bike gets the prize for 'nearest to the correct diagnosis' award! I'll know for next time! Bruce. Just a question. Obviously it's your bike so you do what you like but why would you want to fit a smaller air filter when most people are striving to fit a larger capacity airbox to improve performance. It goes against basic principles. A large, as large as is practical considering space available, plenum chamber is a prerequisite to getting an engine to breathe properly so why do you want to strangle it? Just wondered Quote Link to comment Share on other sites More sharing options...
brucey Posted May 30, 2012 Author Report Share Posted May 30, 2012 OTF, Fair question. I have been 'advised' that foam filters perform better than K&N type filters as they have a slightly better air flow. The orange filter in the photo came with a pit bike Mikuni Carb (one of an increasing collection of carbs and filters I've aquired). Unfortunately it hits the frame, forcing the carb down slightly (Goudrond advised against this), so I have purchased another foam filter the same diameter but slightly shorter (and not quite so....orange!). You've probably guessed it also happens to be the same as the one fitted to Henry's Cub. I'm now trying to decide if I should spray the new filter with air filter oil or just leave it 'fresh and airy'. Bruce. Quote Link to comment Share on other sites More sharing options...
old trials fanatic Posted May 30, 2012 Report Share Posted May 30, 2012 As long as youre happy Bruce. Think i would have fabricated a large capacity alloy airbox to take a modern filter in the top giving a much better plemum chamber and better water proofing when riding deep water. K&N filters are a total waste of space if you want a bike to actually perform and are a nightmare to jet. Strictly for the chopper squad who wouldnt understand the question never mind the answer. Good luck with your foam filter. Deffinately not the route i would take but then again it's not my bike. Quote Link to comment Share on other sites More sharing options...
brucey Posted May 31, 2012 Author Report Share Posted May 31, 2012 OTF, If I was riding in water that deep, I think I would be looking at arm bands as well as plenum chambers! I was rather anticipating the continuation of the current drought conditions down here in the south for the forseeable future :-) I have fitted a Champion L-6G platinum tipped plug and Ramair MR-003 Foam Filter as these all work really well together on Henry's 250cc Cub. It started first kick and immediately settled down to a nice even tickover which is encouraging. However I turned it off before I irritated the local residents too much. My local farmer has kindly given me permission to ride the Cub up and down a farm track in a nearby field as long as there are no cows there (apparently cows get spooked more easily than sheep) I also promised to I pick up any sheep I find laying on their backs. Can't ask fairer than that! Bruce. 1 Quote Link to comment Share on other sites More sharing options...
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