kevbn2
L plate rider.
Posts: 43
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Post by kevbn2 on Jun 21, 2013 17:19:07 GMT 1
took my N2 out last night for a spin. running ok through gears but not really pullin in top past 7 thousand! rode about a mile on dual carriage at about 70ish 6 thousand then as coming down the slip road changing down when bike seized!pulled clutch in quick then stopped, bike would not kick over it was solid. got it home stripped both cases off nothing that you can see wrong, clutch was really heavy to pull in though but no signs of anything wrong.
tried turning over by hand and after initial resistance engine turned over with no problem.im able to change up and down through the gearbox no probs and took head off there's no sign of damage to rings or barrel!!!
Can anyone suggest what it could be that seized the bike?
cheers
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Post by bare on Jun 21, 2013 17:34:54 GMT 1
Shame.. Also fairly typical to seize after a High rpm run.
Time to take it apart and fix the damages. It will only get worse (cost even More$ ) if you wait.
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Post by rickbrown01 on Jun 21, 2013 18:07:41 GMT 1
Agreed, no point running it until you fix the cause. Got to be too hot to seize so running too lean, or not enough oil, or cooling not working. Problem is there are lots of possible causes for each.
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kevbn2
L plate rider.
Posts: 43
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Post by kevbn2 on Jun 21, 2013 18:37:18 GMT 1
thanks but bike was not running hot i had fitted new billet impeller and was impressed with low temp at time of seizing and not running lean either just up jetted as fitted allspeeds that why its such a mystery and now all seems ok and working (when not running) apart from clutch was tight to pull in but stripped that now and looks ok!!!!
#HAD ENOUGH pass me the really big HAMMER!!!!
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Post by airbraker on Jun 21, 2013 18:46:46 GMT 1
Probably no help but had an X7 do that to me on the motorway once. It seized up for about 3/4 hour and then I could kick it over and it started and I never had a problem with it again it was all very strange. It made a sound like running a stick along a fence first. As I said it never happened again ! Did it make that noise before it locked ?
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Post by icarus001 on Jun 21, 2013 18:54:46 GMT 1
Check the oil feed to the carbs.
Had the same problem years ago on an old 125LC, me and my mate used to use it to muck about on and it kept seizing when it got warm, then the next day it would run fine, then seize. Turned out to be partially blocked oil feed from the two stroke tank, it was coming through but nowhere near enough. Once it was cold (i.e. the next day) it would start and tick over, but then once it got warm it would seize again.
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kevbn2
L plate rider.
Posts: 43
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Post by kevbn2 on Jun 21, 2013 19:40:23 GMT 1
it would not kick over when cold still seized only when i turned by hand on stato but had to wiggle both ways with a with a bit of force seemed to crunch a little bit then turn ok gears worked all the time and oil gettin through ok and when i took the head off it was a bit oiled up
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matt7
Thrash Merchant
Smell of the 2 stroke & the roar of the crowd
Posts: 445
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Post by matt7 on Jun 21, 2013 19:58:30 GMT 1
Are the cases full of fuel ? LH most likely.
Could have hydraulic locked ?....
Fuel tap wnet other week on my N2, i've now fitted a 350R tap - manual on off reserve.
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kevbn2
L plate rider.
Posts: 43
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Post by kevbn2 on Jun 21, 2013 21:34:27 GMT 1
no fuel in cases
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Post by marsbar350 on Jun 21, 2013 21:42:00 GMT 1
7k only part throttle could be an oil pump problem
send it to arrow for confirmation
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Post by steve h on Jun 21, 2013 21:53:52 GMT 1
Looks like you need to split the cases, if the barrels and pistons look ok. Just keep stripping till you find the problem, and don't tear your hair out, it will fallout naturally after 40yrs of 2t ownership.  Sounds like the crank or something amiss in gearbox. |
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kevbn2
L plate rider.
Posts: 43
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Post by kevbn2 on Jun 21, 2013 22:12:26 GMT 1
thanks will send off oil pump and continue stripping and hope i find something!
will let u know if i do
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Post by LC_BOTT on Jun 21, 2013 23:39:52 GMT 1
My guess would be the gearbox or clutch bearing, but that is just a guess. Didn't someone else just have the same problem??
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Post by icarus001 on Jun 22, 2013 9:25:48 GMT 1
Someone dropped a bag full of washers into the gearbox  |
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Post by bryan on Jun 24, 2013 23:19:31 GMT 1
If the needles are set too weak it can seize as you roll off from the main jet could also be the pump having no stroke on a closed throttle like mine had. |
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Post by bryan on Jun 24, 2013 23:23:23 GMT 1
thanks but bike was not running hot i had fitted new billet impeller and was impressed with low temp at time of seizing and not running lean either just up jetted as fitted allspeeds that why its such a mystery and now all seems ok and working (when not running) apart from clutch was tight to pull in but stripped that now and looks ok!!!! #HAD ENOUGH pass me the really big HAMMER!!!! timmimg out or twisted crank could mean combustion chamber temp could rocket and you temp gauge would show no high temp. |
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Post by arrow on Jun 25, 2013 17:18:39 GMT 1
If the needles are set too weak it can seize as you roll off from the main jet could also be the pump having no stroke on a closed throttle like mine had. The pump was found to have a minimum stroke of around 1 thou. This could have easily have caused the problem with high revs and over run condition. The pumps I have seen come here most of them are like this. Now fully re-built and sorted. I'm not saying there are not other issues, but the pump was not right. |
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Post by rich on Jun 25, 2013 19:24:16 GMT 1
I also had it on a 125LC - nipped up on the way to work at exactly the same place on 2 different days going up a hill. That was the oil feed pipe from the pump to the engine and it was pinched between the outer cover and the top of the water pump housing. I sorted that and it was fine afterwards until I sold it.
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kevbn2
L plate rider.
Posts: 43
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Post by kevbn2 on Jun 30, 2013 11:53:30 GMT 1
after changing pistons,rings,small ends,clutch plates and springs,oil pump refurb (by the pump god Arrow), banshee coils,plug caps, plugs, jets, allspeeds added and stripping and rebuilding different parts several times I have now found the cause of the problems a totally shagged main bearing.(see picture)that when was stripped of clutch the crank turned and the seal covered the problem to the eye ive had my N2 6 weeks now and aged 20 years in that time but hopefully now i can rebuild and enjoy at last!! fingers and everything else crossed. I'll keep you all updated as things progress  |
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Post by bryan on Jun 30, 2013 12:17:59 GMT 1
Thats ba shame, however bnow you will have a good engine when you have fixed the problems. If you want to ever check you crank, simplest thig to do is remove the primary gear off the right end, tou are then only turning the crank ,providing the top ends off that is. Could this have been caused by the pump not oiling enough, as this was what had happened to the blown up YPVS engine I got hold of to put in my LC. You may see blackening on both ends of the rods and on bearings where they have over heated because of the lack of oil. I know its a pain in the arse and will cost you about £500 for new crank, rebore (if needed) and pistons, gaskets and oil, but you should now have a trouble free bike.  |
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kevbn2
L plate rider.
Posts: 43
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Post by kevbn2 on Jun 30, 2013 14:44:16 GMT 1
By the look of everything i should get away with main bearing and seals pistons and top done and ok now (fingers crossed) but will fit lightwieght flywheel while its off trying to upgrade as i go but im going a bit fast for my bank balances liking but when finished it should be worth it!!!
Thanks for all the help and input from everyone Kevin.
im just off to fit all new bolts to engine and bike!!! im a glutton for punishment i know
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Post by steve h on Jun 30, 2013 18:07:08 GMT 1
Was the crank the only thing you haven't had rebuilt? Sods law strikes again.
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kevbn2
L plate rider.
Posts: 43
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Post by kevbn2 on Jun 30, 2013 21:08:34 GMT 1
you not wrong there steve i now have a very good knowledge of the bike never having done my own mechanics before im having to learn very quickly but i must admit im enjoying it but the list of things i want to do to her grows even though i have done an awful lot already!!!
now just ordered a billet radiator!!!!
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Post by steve h on Jul 1, 2013 0:08:51 GMT 1
That's the beauty with machines of this age, they are hands on. Not like modern machines where you need a laptop to adjust the tickover
and fuelling etc. I was amazed when a mechanic recently told me that most bike owners now, haven't a clue how to change the spark plugs.
You'll have her back up and running "sweet as" shortly.
If you can, get her on a dyno when she's back in one piece. It wont do her any harm, but may save you plenty.
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