atocp Posted September 25, 2012 Posted September 25, 2012 So I got to the stage of putting in fuel, oil and a well charged battery. And then, kicked the poor wee thing to death. I started to get angry. I really shouldn't have, it didn't deserve it that much and it went from 6.7v down to 4.3 very quickly, so I had to stop. It has a new air filter, the fuel is coming out the excess drain tube (I know that isn't a sign its getting to the cylinder, but im going to check that tomorrow) and the battery when I started was 6.7v. It did pop a few times, and its a new spark plug, so there is a spark (again, i'll check the quality and wetness tomorrow). This question is really more of a way to set the scene for the innevitable question i'll be asking tomorrow. I don't trust the wiring loom that is in it. Does dropping down in the voltage so quickly (6.7-4.3v in 3mins kickstarting), and a severe lack of any sound of starting point to a possible wiring problem, like a grounding wire? Secondly, I have the haynes manual, and the 3 wiring diagrams it supplies doesn't seem to fit what I have. What are the chances that mine would be different from all of the 3 that are printed in the manual (no modifications)? Unfortunately it's going to be hard to get a brand new wiring loom, but if need be, im going to get some new wire and rewire the entire bike at the weekend. So close, I can almost smell the oily smoke coming out of the 'silencer'. But right now, all I can smell is pure unleaded petrol, kickstarting induced sweat and the stench of failure. Its not a good mix. Thanks to anyone that can offer up a possible problem this 2-stroke is having. As I say, new filter, fuel is flowing and it should be sparking. Many thanks, atocp
Moderator Airhead Posted September 25, 2012 Moderator Posted September 25, 2012 Have you put new rings in the piston...perhaps It's a bit down on compression? Take out the sparkpug tonight and leave it out It's a good bet you have flooded the engine after todays endeavours!...let it evaporate off. tomorrow squirt a bit of oil in through the spark plug hole...about 1 1/2 teaspoons full...if the rings are a bit worn it will help seal them to gain some compression to start...full choke and no throttle (or hardly any) is the key
atocp Posted September 25, 2012 Author Posted September 25, 2012 Hey Airhead, thanks for the evapouration tip. Completely forgot to do that! I put on a new piston head and rings, as I accidentally broke one of the rings when I was inspecting the small end bearings recently. So new piston head and two new rings. Someone once told me that if I liked it I should put a ring on it. So i put two on, just in case. It hasn't started in 2 years. And back when it did, the timings and everything were so far out that it wasn't ticking over for long. So its been stripped and put back together clean. I didn't have any parts left over, so Im pretty sure its all together right. Cheers, atocp
Moderator Airhead Posted September 25, 2012 Moderator Posted September 25, 2012 its small enough to try a bump start too eh?
atocp Posted September 26, 2012 Author Posted September 26, 2012 so. it turns out the cylinder wasn't flooded. in fact, no fuel was getting to it. the fuel was flowing down to the carb and then out the over flow pipe. which to me suggests dirty jet/carb?? unfortunately, while trying to start it today i got a loud sharp pop....and oil started dripping quickly out the bottom of the crankcase. looks like the gasket, as I can't see any cracks, but Im going to have a strip down at the weekend when i have some more time. if its not one thing, its another!! atocp
Moderator Airhead Posted September 26, 2012 Moderator Posted September 26, 2012 so. it turns out the cylinder wasn't flooded. in fact, no fuel was getting to it. the fuel was flowing down to the carb and then out the over flow pipe. which to me suggests dirty jet/carb?? so the carb is overflowing! just turn off the fuel tap for now...if the bowl is full theres enough in there to start the bike and some Just because it was overflowing why does this mean it isnt being drawn into the engine? unfortunately, while trying to start it today i got a loud sharp pop....and oil started dripping quickly out the bottom of the crankcase. looks like the gasket, as I can't see any cracks, but Im going to have a strip down at the weekend when i have some more time. if its not one thing, its another!! atocp I really dont like the sound of that!!
atocp Posted September 26, 2012 Author Posted September 26, 2012 I really dont like the sound of that!! Hahaha, yeah, you and me both!! I don't mean because it was overflowing it isn't being drawn in, I just meant I can eliminate everything from petrol cap down to the float chamber. My problem with the fuel starts there, so between float chamber and cylinder. So im thinking blockage or something. I stuck my nose right into the spark plug hole and couldn't smell any fuel, and the spark plug was bone dry. As I say, I can't try and start it now, as Im going to have to strip it down and possibly get a new gasket in place. Least it'll make it easier to get to and clean the carb while the engine is off. atocp
Moderator Airhead Posted September 26, 2012 Moderator Posted September 26, 2012 If you are taking your carb off take the reed block off also, check they are not stuck or bent while you're at it Have you had your flywheel magneto off?
atocp Posted September 28, 2012 Author Posted September 28, 2012 Ok. Will do. As I say, I'll have it off at the weekend if im not hungover. Yeah, I've had that off a few times. Replaced the contact points and condenser. And set the gap to 0.35mm @ 1.8mm BTDC, as it says in the haynes. Getting a good spark, so even if the timing was out slightly, the fuel would still go pop. Everything else in there was in very good condition for the age. atocp
Moderator Airhead Posted September 28, 2012 Moderator Posted September 28, 2012 Its a points ignition system is it? Tell you what my train if thought is. With a points system you may still get a good spark even if the timing is way way out, you could perhaps get a spark that will burn fuel/air in the crancase...perhaps giving a loud sharp 'pop'...maybe (just guessing here) how could it be that the ignition is so far out that this would happen you may ask yourself? Simple...you dont torque up the flywheel tight to within specifications, then you try starting the bike...there is a backfire...this shears the flywheel key and the crank rotates some inside the taper now your timing is way out and all your efforts to start it are in vain!!! Check your ignition timing...if its good then all well and good, if you have torqued up the flywheel to spec...ditto but if you didnt?!!!!
atocp Posted September 29, 2012 Author Posted September 29, 2012 How did you get 1.8mm. Where did I get it from or how did I measure it? I got it from the Haynes manual, and I measured it using a dial indicator positioned inside the spark plug hole. I took the side off the engine and found that the gasket had torn and wasn't in great condition since I last replaced it. Strangely it hasn't been run since it was fitted. Anyways, I've ordered up a new gasket set (may as well change some others over while the engine is off. However, I did notice that the oil wasn't too clean, and it was brand new oil in 2 years ago. I know that sounds like a long time, but bear in mind for almost 2 years its been sitting in a garage and hasn't moved. So, I'm going to dissasemble the clutch plates and surounding bits and just have a general check over to make sure there's no damage causing the build up of 'shavings'/dirt. atocp
Moderator Cynic Posted September 29, 2012 Moderator Posted September 29, 2012 Motorcycle oil always gets dirty because of the clutch. I only asked on the 1.8 because i have heard a few imaginative ways of trying it but only 2 work that i know of. I pull thr head clean the piston then mount a bar on the head studs set at tdc. Then i set the ig with 1.8gap using feeler gagues. Totally accurate no errors to mess things up. A good quality dial gague will also do it with the proper adapter. Its probably the one thing that dt's do need to be spot on the ig setting.
Recommended Posts