Mech

Oh ok. Thanks. I better get under there and have a look.. which isn't my style at all...

I've got an old LT.. can you tell me where the crack is so I can check mine.. They probably all crack in the same place if they are going to.. Cheers.

And the same to you Dave.. Especially the happy. Safe and prosperous if you manage them.. Don't forget.. Ya gotta have fun.

Howdy Scrappy.. Cracks aren't so bad. A lot better than rust.. If the plastic's all ok then pretty much everything else can be fixed. Have fun and keep that girl happy..

"Onya" stands for "good on you", and it's common over here.. And If I call anyone "mate".. it means "pal", I believe.. not lover.. Just to clarify before there's any embarrassing misunderstandings ! Or is it "buddy" over there.

Ha... Onya Dave.. I forget.

Ha.. Could be.. I'd try and disconnect the switches and check they are adjusted and working right first thing though..

The cooler should have signs of oil, but it might have drained away by the time you got to it. You need to clean that cooler out, and when you put the motor back together you want to leave the return of the cooler off and in a bucket to check it's flowing and to flush it out with clean oil. For one crank it's barely worth setting up the stuff you need, for ongoing work it's cheap though. You'll need a thick steel plate(14/16mm) with a wide slot gas-axed in it that will fit between the two crank webs and around the con rod nicely, a dti gauge and stand for it(not too dear and handy for lots of stuff), and some sort of set up that has two "centers". Centers are just round rods with 60 degree tapers on the ends that fit into the ends of the crank so you can spin the crank on them without any wobble. The centers don't have to be anything fancy at all, you could just grind them with a bench grinder if you are careful. To do the pulling/pressing you can use threaded rods or a hydraulic puller and a bit of box section or chunky angle iron, or a twenty ton press. To set up a "center" arrangement you could make the two centers and fit them into the gudgeon pin holes of two big conrods off some truck or old car, then use the cap holding bolts and two steel plates to clamp them to a long steel strap or angle iron, the idea being that you can slide them along the strap to get the crank in between the centers and then together so the crank spins by it's ends between the centers. They need to slide nicely so you can get them a bit tight in the ends of the crank so there's no wobble, and you need to be able to get the crank in and out easily because you are going to need to take it out of there after every measure to hit the crank with a hammer to do the adjusting, then back in for another measure. You'll also need some drills to make holes in the thick steel plate for the 14/16mm threaded rods. The thick plate with the conrod slot has to be wide/big enough to poke out the sides of the crank far enough that you can drill two holes that will be directly in line with the crank pin you want to press out, or so the two legged puller can grip it on opposite sides of the crank pin. I use a round plate about 160mm diam, but it could be square.. As long as it's strong still after the slot is in it. Once all these things are arranged you can do most cranks. The actual work involved to overhaul the crank is quite minimum. As little as an hour and a half once you've done a few and got the idea about what you are doing and how hard to tap them to align things.

Oh yea well if it's puffing out the inlet you do need to adjust the valves. The compression won't be as good as it could be, and also that puffing prevents the full charge of fuel getting pulled in.

Yeah well that wasn't very successful now was it... I see there is a service manual in here though.. and that the circuit's got diodes in it.. and several switches.. Out with the test light..

Hope this Paste job works...

Yeah I'm suspicious of the cdi too...

Oh ok, and hi to you Kuba. From 135 to140 isn't much, and it's richer which is the safe way to go. It should be fine.

In that last post it sounds like it's better in higher gears now, but earlier it sounded the other way around... better in low gear. Has it changed ? And.. you have changed the spark plug now ? You mentioned you were planning to. It doesn't sound like the plug because plugs mostly play up with high compression and engine load, which is highest at mid or lower revs, and higher gears rather than lower. . The blackness on the plug seems to mean it's getting plenty of fuel, perhaps just not firing every time and so burning heaps when it does.. If the motor was flooding for some reason, like the carbies float chamber vent/hose being blocked, it would sort of burble and stumble/surge and not rev, but not really rev cut. Have you driven a flooding motor before ? They run and sound different to one starving or missing from spark issues. If it's a diaphragm type carby, have you checked the diaphragm on the slide, and also the needle in the slide, I've seen the needles not have their clip on them for some reason or another and the needle could jump up and down in the slide.. and they ran erratic and rich. And you say a rev limiter.. rev limiters cut the ignition momentarily right, so the engine goes from full power to cut, then abruptly back to full power.. and the bike jerks and bucks. That is what it's doing right.. It's how I read your description.. as opposed to getting to high revs and then fading the power away .. If it's fading the power away/going flat, that's a whole different thing.. Maybe flooding. If it's the rev cut sort, the voltage regulators can cause that on some bikes. They are meant to get to a certain voltage and then reduce the voltage by shorting a certain amount of it out through a resistor to ground, but still let a bit of power through to keep the voltage about thirteen volts. If there's no battery or a bad wire the regulator sends some power to earth, then detects that that hasn't lowered the voltage enough and so shorts it fully to ground, killing everything momentarily till the revs and volts drop again. Sometimes putting the headlight on will let you get a few more revs out of them, which gives a clue or confirmation.. The sitting for a month and then having the problem sounds sort of like a clue perhaps, but we don't get freezing conditions here. Perhaps someone knows of something that happens when things freeze.. like fuel or electrical things that go bad. Hope that gives you a few more ideas to consider..

Couple of general rules.. If they spit/backfire out the carby, it's usually too lean, so air leaks into the manifold, lean mixture, tight inlet valve etc. If they backfire out the exhaust while going downhill or with the throttle off, it can be an air leak at the head to exhaust connection or back between the front pipe and the muffler. If they backfire out the exhaust as you are throttling on, it's likely to be caused by an intermittent lack of spark or incomplete combustion, which is letting unburnt gases into the exhaust. Then you need to check the ignition system.. and secondly the mixture. Just general rules... but it's mostly right.. But hey.. for every rule, there's an exception !

Kuba... That jet you changed.. When we are fine tuning bikes we adjust the size of that jet by 5 at a time normally, so like from 180 to 175. Going from 180 to 140 is a huge change and may make the bike run far far too lean at full open throttle. Running mixtures lean makes bikes overheat very quickly. They might know you need that 140, or perhaps you've read in the manual it does.. I don't know.. So.. That jet controls the mixture at full throttle and you need to be very careful about doing that(running full throttle) until you are sure it's going to be ok. Before you change that though you have to check that the throttle slide's needle is in it's correct setting. It's best to have a new spark plug in there to do it, or a nice clean on anyway. You do the test by giving the bike a run on a long flat road for about twenty or more seconds at more than one quarter throttle, and less than three quarters throttle. The nearer three quarters the better. At the end of the long straight you have to pull the clutch in(if it has one), or throw it into neutral, and switch the throttle off immediately. Don't let it go into overrun or idle. Roll to a stop and then take the spark plug out and see what colour it is. It should be starting to colour up the new whiteness. If it's too white the needle jet in the throttle slide too low. If it's black or dirty, the needle jet in the slide's too high. Adjust it one notch down or up with it's circlip and try the test again. Keep testing and adjusting until the sparkplug is a nice light tan brown or grey colour. This adjustment will probably already be correct but you have to be sure before you do the full throttle adjustment. Once that setting's correct you do the same testing and adjusting process but at full throttle. So full throttle for at least twenty seconds(If you can, it can get tricky, find a quiet road), then out of gear and switch the motor off as you are knocking it out of gear. Roll to a stop and check the colour of the plug. It should be starting to show a light brown/tan or grey colour. If it isn't, you need to change that main jet, the 140 one. Depending how (presumably) white it is going to be you are going to have to make a judgement call on how much to change the jet by. As I say five or ten is a good change. Be careful not to run it to hard if it is lean.. It's better to err on the side of rich rather than lean.

And yeah... replace the oil pump if you are at all concerned about that !

If you are really keen, and feel confident to do it, and have the gear... I'll tell you how the crank job's done.

The crank is in three parts, left, right and the pin. You have to replace the pin, because the rollers run on it, and the conrod because the rollers run in it. Getting it apart and together you might do with pullers and/or threaded rods, and a thick steel plate with a wide slot cut in it to go around the conrod, which is how I do them, but you need two centers or a lathe to spin the crank between, and a dti gauge to check it for runout and alignment. If you don't have the centres and dti gauge then it's better to get it done by a bike shop or precision engineer. And.. given the choices between engineer and bike shop, you're better off with the bike shop. The engineer will be scared of it and try to tell you it's a tricky business, the bike shop will be doing them all the time.. and will charge you a fair price. Yeah ignore the heat marks... the new rod when you get it will have heat marks from it's manufacture already probably. And the crank throws are just soft steel.. no worries.

And would the lack of travel from the change cable be because there's an interlock button to stop it going into reverse.. perhaps you need to press some button or something to get full travel.

Good work with the excellent pictures and descriptions pokolbinguy. It helps a lot if people describe things really well and not expect people to guess.. To get the drain bung out, were you using a six sided socket ? If not, grab one and try that. The other standard way mechanics get things like that out is to use a small not too sharp cold-chisel, or nice sharp good condition regular round pin punch, and tap it around out on it's outer circumference.

Yeah you have to replace the conrod.. You don't replace the whole crank, just a new pin the conrod runs on. So rod, roller bearings and pin get replaced. And unless you have a good workshop you need someone to press the crank apart and together and lined up. Don't get conned into getting the crank balanced.. that's a bit of bullshit you might get hit with. If the people doing the pressing do a good job, that's all that's needed. And it doesn't take much to do a good job.. My sons were doing them for themselves when they were fourteen.. There's probably an oil restricter in the crankcase oilway that stops too much oil pressure/flow going to the head and cam. Make sure you find that and blow it backwards.. It gets blocked easily and people overlook them and the cams run dry. The wrist pin should press out with a palm push so yeah it's seized.. You'll get the new one in with your hand.

Well to tell you the truth, that doesn't particularly look like a motor that died from overheating. Mostly if they overheat they seize the piston in the bore, but not smash the piston to bits like that. Does the bore have signs of it locking up, like aluminum stuck to the walls of ? And which bit was seized ? It wouldn't have been that piston/bore I'd bet. I'd assume that it was just an old worn out motor that was making noises and eventually got a big rev and broke the side of it's piston because of the way it was rattling around in there. And the top ends often smell like overheated oil.. I'd inspect everything for the usual signs of wear and damage and then go ahead and overhaul it. I've done heaps of motors that looked like that, and worse, and they all rebuilt just fine.

It sounds like a broken ring, but, if there's really heaps of smoke.. and I mean if it's just pouring out, and white not blue tinged.. change the oil. I've seen motors with the wrong sort of oil in them that run good, but just streamed white smoke out the back.. the whiteness of the smoke being the clue. In those cases the motors had just had an oil change and it was easy to guess what it was. Changed the oil and they came right. The noise could be caused by the oil detonating. Doh... I really must start taking better notice of the dates. Probably worth mentioning (now we are here), that in one of those cases, and suspected in the other, it was chain bar oil that had been put in by mistake..

Hi. Can you tell us what that red light is for ? Have you checked the fuses ?