Ahh right, gotcha. The standard 'pop' is more like a cat sneeze, more of a fluff than a proper pop, and only at about 3200rpm under a tiny throttle opening. Your problem is clearly something else.
yep definetly some thing else what i dont know :frown: well bike ran fine going to work today managed to have a quick check round again only thing i found was some carbon blacking on the inlet of the front cylinder throttle body as looked down the filter box so thought was valve clearances checked compression with a borrowed tester as the one at work is the wrong thread size borrowed one was push in the hole type (not keen )well showing around 100 psi on both cylinders didnt think it would be that far down when engine was cold tester could be iffy ? so left it at that ................. then the ride home ......shoot me now after a 100 yards it coughed farted and shat itself wouldnt rev died 3 times (on a mile journey ) wouldnt pull more than 15 mph mostly other than a quick burst of revs for a couple of seconds only just made it home well pulled it apart .................starts on the button every time coughs farts and will not rev then dies checked down filter box at same time.................. hey theres flames as it coughs and farts COOL!!!!!!!!!!! not put back together cover on fuck it its friday trying to calm down and not take a hammer to it i think our days as a couple are numbered had the bike for a year now and the longest ride was 25 mile round trip dont think i have done 100 miles :frown: think i might buy a chinese 125 lol
It almost sounds ignition timing related. Don't read too much into compression tester readings, they are more a tool for comparing cylinders than outright numbers, so if both read much the same I'd not be too worried.
Seems to me like wot mine did..........exactly the same symptoms with flames from one of the carbs........Never found out what it was, but I'm thinking multiple things like dirt in the carbs, leaky HT leads, carbs needed maintenance and balancing........Maybe John's injectors are gummed up???
well slept on it had time to think and realized i have been putting off the inevitable should know better as a car mechanic as well ....it needs plugging in to a dam diagnostic tool was thinking timing sensor phil did also think blockage in injectors al but didnt think it would cause firing back in the air box going to check wiring for breaks again and have a look at timing sensor ....dont think there is a way to check the sensor ? should have stuck to 2 strokes and points ignition
well didnt get to do much today to the bike all igot to do was start it up to see how it behaved after being left overnight so started up a ok ticks over fine revs fine ......... left running for about 5 minutes on tick over then tried to rev it up a bit ..................nothing then dies started on the button again try to rev and its like i hit the kill switch back off the throttle and it ticked over as normal after a few more minutes it was getting rougher and struggling to tick over almost like fuel starvation but the engine getting worse when warm still seems like valve clearances ? just getting annoying as cannot see what the hell i am doing properly as my eyesight has gone shit got dragged in to book an eye test today dam getting older
Blocked filter in the tank? Does the pump run all the time? (It should) Beginning to seem like fuel starvation as you say..... Mine did the same thing......playing with the balancing helped, assuming that your injector isn't gummed up.....
shouldnt be blocked filter just done that about a month ago and yes a pig mainly just the filler cap neck whats the best way to check the injector to see if its gummed up ?
ok thinking head has been back on today now i have calmed down a bit (the wife says i am a mardy git ) have been thinking if i have inadvertently caused this latest fault when tensioning the cam belts if there is play in the cam bearings would it be feasible that tensioning the belts would affect the valve clearances ? so as engine warms up metal expands blah blah and such and we end up with no clearance just need a bit of a break in weather to have a look as cannot get it to work now :frown:
John........Thinking back to the issue that I had with my carbed SS, which seems similar to the symptoms you describe - maybe there is a pointer here. 1) I checked out the ignition circuit wiring and the coils 2) I found that the pick up wires to one of the coils had got a hole in the insulation immediately where the wires connect to the coil - caused by the tank rubbing on them, it seems. 3) I checked the coils resistance and substituted other coils as a check. AOK 4) I checked continuity of the pick-up wiring. AOK 5) Although I never checked the pick-ups physically, I also checked their resistance. AOK 6) I wondered if a pick-up had come loose, but as it now runs OK, I didn't inspect this. 7) I changed plug leads and re-routed them, making sure they weren't rubbing against anything. 8) I changed plugs and caps. 9) I stripped the carbs three times and cleaned them, replacing worn diaphragms and float assemblies. 10) Tank filter not changed, because I knew it had been changed before I got the bike - and besides, the symptoms weren't like vacuum or filter starvation. 11) Cleaned out the tank breather pipe - dirty, but not blocked. 12) Checked the belt tension and timing - AOK. By all means check your belts again, but if yours were 'out' enough to cause your issues, I would be surprised. 13) Checked compressions, hot and cold - AOK 14) Ran with and without air filter - No real change. 15) Cleaned out the tiny filter in the fuel supply line Tee at the carbs.......Is there something like a Tee in the line before your injectors? (I can't see anything in the Parts Manual that suggests there is) 16) Found a badly maintained pilot needle and seal - changed it. 17) Adjusted pilot screws and balanced carbs (at least three times before I got it right). When I first got the bike it would sometimes refuse to fire up on the horiz cylinder in damp or cold conditions....the cylinder used to flood and when cleared, it would fire up. It also didn't need choke to start. Now, it will start on half choke, in cold weather; but until it gets fully warmed up, it will occasionally spit back through one of the carbs from idle if easing the throttle open. My gut feeling with yours if it isn't electrical, is the injectors are dirty and need cleaning; but I honestly can't be sure.......I had a similar problem with an XR4i which I traced to dirty injectors - I can't recall how I cleaned them, although I did remove them to do it, but I was bl**dy careful with them. Persevere, mate......you will get there in the end. AL
Just to throw another spanner in the works it sounds like it could be a cold solder joint in the ECU. I had a similar fault with a Renault a few years ago, it would start fine, but after it had warmed up it went into limp mode. The garage spent ages chasing sensors until they finally changed the ECU and bingo. Perhaps someone could loan you one to eliminate this from the equation?
cheers guys food for thought al as for the ecu hmm would a loose wire on the ignition switch cause a problem with that as in an arcing connection maybe as that was one of the last things i fixed other than belt tension
I guess it depends how hot the plastic got when you did the soldering...so I guess there is a possiblity the contacts have got loose and bounce apart.........might be worth another look. AL
sorry al i meant it was loose and possibly arcing before i soldered it once upon a time this sort of problem wouldnt have bothered me all in my stride lol just dont get the time :frown:
well got round to having a look at the bike this afternoon first thing was to check the cam belts didnt look to tight but slackened of a light touch anyway started up on the button as usual revved up spot on left to run for a few minutes .....still ran fine stopped and checked cam belts seemed to tighten up quite tight so slackened off a little bit more ran engine seemed fine nice and smooth no miss fire or cough well thought best thing was at this point was to take it out on the road and see what happens upshot a 2 or 3 mile ride and the bike ran faultless really smooth so conclusion i caused this fault and possibly have play in the cam bearings and the valve clearances need checking at least it doesnt seem to be electrical so looks like next job is belts and valve clearances etc dont you just love the drama
