bigshineybike Posted January 2, 2012 Report Share Posted January 2, 2012 Happy new year everyone. I was out yesterday on my 348 Cota, I have just fitted 10t to 38t chain and sprocket kit, so the bike seems to have so much more torque and runs so nicely clutch out. As a wobbler I am finding this helps my riding. The engine is running better than its ever run in my ownership its able to tick over while I walk a section. It does sound like all the bearings are shot but so many old guys tell me they all sounded like that when new! So my problem this week began after about two hours riding. it began to rain and I went to pieces on any steepish climb, loss of traction had me using too many revs and having dropped the bike several times the exhaust began to emit too much smoke. (normally when cold it smokes but a hard rev seems to clear things.) The smoke is mid to light grey. I suspected that dropping on its side had caused a temporary smoke effect and gave it a bit of a hard rev up. At this point within the smoke cloud a worrying amount of sparks were visible in the smoke. Luckily it was all downhill to the car park. Someone that was watching suggested crank seals, can these fail so suddenly? when I got back to the car I also found that I had used half a tank of petrol in about 20 minutes, its most likely I spilled it when the bike was on its side, but could this be related? Finally not something that troubled me too much but I also found the bike would stall if left facing downhill while ticking over. Thanks all. Alex Quote Link to comment Share on other sites More sharing options...
belldane Posted January 3, 2012 Report Share Posted January 3, 2012 Sounds like you should have stayed in bed ! It is hard to work out what is causing all your problems without actually riding and hearing the bike running but I will give you my thoughts anyway. When you dropped it going up that hill did your fall accidently turn the choke on? That would explain more than average smoke and the fuel usage. The sparks I have no idea unless something has gone terribly wrong in the combustion chamber but it does not sound good. As for the crank seals, huge amounts of smoke is a tell tale sign the seals are bad but I doubt they would have packed it in after a couple of falls. The problem with the idling could also be choke related ie running too rich. Just a few ideas. Hope that helps Quote Link to comment Share on other sites More sharing options...
keychange Posted January 3, 2012 Report Share Posted January 3, 2012 Sparks could be simply carbon build up in the pipe knocked loose by the fall - have you ever cleaned the pipe? Or it could be nasty - if in doubt take off the barrel and have a look at your piston. Quote Link to comment Share on other sites More sharing options...
bigshineybike Posted January 3, 2012 Author Report Share Posted January 3, 2012 Sparks could be simply carbon build up in the pipe knocked loose by the fall - have you ever cleaned the pipe? Or it could be nasty - if in doubt take off the barrel and have a look at your piston. I am hoping its this. the exhaust system is very oily, I repacked it only about 6 hours (running time) ago. I have a riveted plate in the silencer middle box which maybe letting air in (supporting combustion?) I am taking the engine apart this week as new crank seals are probably due anyway. I will let you know what else I find. Thanks. Quote Link to comment Share on other sites More sharing options...
jimbo349 Posted January 3, 2012 Report Share Posted January 3, 2012 I am hoping its this. the exhaust system is very oily, I repacked it only about 6 hours (running time) ago. I have a riveted plate in the silencer middle box which maybe letting air in (supporting combustion?) I am taking the engine apart this week as new crank seals are probably due anyway. I will let you know what else I find. Thanks. The crank seals can be replaced without splitting the motor or taking the crank out as they are fitted into seal carriers behind the flywheel and pinion gear on either side of the motor. Don't forget to get new gaskets for the carriers and don't loose the shims. When the seals went in my mont it threw oil out of the exhaust and ran like A bag of crap good luck with your problem. James Quote Link to comment Share on other sites More sharing options...
bigshineybike Posted January 30, 2012 Author Report Share Posted January 30, 2012 I changed the seal on the gearbox side only. It was a differnet design to that which was fitted. (came in a Honda packet with double lips blue rubber from InMotion) I think the oily exhaust was contributing- I found this which sums this up http://www.advrider.com/forums/showthread.php?t=731048&page=9 Also I discovered that the fuel isnt getting through at full revs so I guess that was leaning it out causing overheating. That was caused by having an inline paper filter as well as tank strainer and filter bowl strainer. the old grp tank had left a lot of bits of red stuff blocking everything. this last weekend I managed 4 laps at Bagshot heath without any bike related issues so all seems well now. Quote Link to comment Share on other sites More sharing options...
nelly1 Posted January 30, 2012 Report Share Posted January 30, 2012 this might sound daft and i dont mean to insult you but when i was 16 i had a puch m50 gp a quick little bike and to save money i packed the baffle with wire wool it ran great till i got it hot then exactly as you describe loads of smoke and sparks Quote Link to comment Share on other sites More sharing options...
taylo63 Posted February 1, 2012 Report Share Posted February 1, 2012 I changed the seal on the gearbox side only. It was a differnet design to that which was fitted. (came in a Honda packet with double lips blue rubber from InMotion) I think the oily exhaust was contributing- I found this which sums this up http://www.advrider.com/forums/showthread.php?t=731048&page=9 Also I discovered that the fuel isnt getting through at full revs so I guess that was leaning it out causing overheating. That was caused by having an inline paper filter as well as tank strainer and filter bowl strainer. the old grp tank had left a lot of bits of red stuff blocking everything. this last weekend I managed 4 laps at Bagshot heath without any bike related issues so all seems well now. How did you remove the pinion gear ? did it come off easy ?..I'm trying to get the pinion off my cota 247 without success at the moment. Any comments would be gratefully welcomed.. Thanks Quote Link to comment Share on other sites More sharing options...
bigshineybike Posted February 4, 2012 Author Report Share Posted February 4, 2012 How did you remove the pinion gear ? did it come off easy ?..I'm trying to get the pinion off my cota 247 without success at the moment. Any comments would be gratefully welcomed.. Thanks I am trying to post a pic of the puller I used. here it is on my flickr feed this is based on a GM steering wheel puller. Google it there are loads the legs snapped off first time I used it so I threaded the ends of the pull bars. then Screwed these into an 8mm thick steel plate with a u shape slot. the plate is 8mm thick steel. this is then ground back to clear certain bits of the engine casing. It was a bit of a game to make all this but now I can whip the pinion on and off with some ease. Its important to re torque everything afterwards as they can come off easily enough being that the only fit is the taper. Also make sure the flywheel weight has a good fitting woodruff key as it is common for vibrations to cause the crank to snap where the keyway is deeply machined into the crankshaft. Quote Link to comment Share on other sites More sharing options...
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