NSR125 Another Problem! Knocking

[RichP]

Hey guys,
finally got the engine back in, everything hooked up, radiator plumbed in etc.

Now I read in the top end rebuild guide on 125cc Sports forum that you top up the cooling system with 1.1l of water, top up the overflow bottle to the min line, run till warmed up and then top up as necessary.
Well when I added the water it wouldn't take 1.1l, more like 750ml, but thinking nothing of it I went ahead and started up.

Engine was fine for about 1 min and then i started hearing tappety noises that got progressively louder towards knocking, so i switched off.

After its cool again it runs great till warming up slightly, suspect the problem is cooling system, any ideas on what I could have got wrong..?

Cheers

[taz4626]

hi there the best way i have found to fill up the radiator is to pour in the glycol (anti freeze/coolant) and water mix till it reaches the top then squeeze the rubber hoses that attatch next to the water pump. Then lean the bike side to side i found alot dissapeared at this point. Then squeeze the pippes again quite quickly to try and get rid off the air in the pump as the pump needs to have water in it to be able to work if its full of air it will just spin. The book also recommends a couple of blips on the throttle upto about 5000 revs to get the water round but make sure you squeeze the rubber pipes first to ensure the pump fills with water

[RichP]

No chance I could have blocked it by something stupid like headgasket wrong way around...?

[RichP]

Just had another go, with squeezing pipes and revving... No better...
And when I pull the clutch in I start hearing weird grating noises........
I feel like breaking down and crying...!

I've completely fucked this whole job up!

[evoboy]

[RichP]

If the engine where overheating...?

I'll have a listen tonight when i get back from work but it sounds like from around the barrel / head area.

[RichP]

Ok i braved it out and ran it till the temp came up, i don't get the tapping at certain rpm's where its very smooth...
But i do at tickover.

When put into gear the engine dies with the kickstand down but the clutch in, and when put into gear with the kickstand up the clutch doesn't seem to be gripping at all, i can hold the sprocket from moving whilst in gear...

I guess this means i put something in wrong and didn't tighten something up!

[taz4626]

there is a certain amount of tappy sort of noise at idle on mine which i think is normal and as for the engine cutting when put into gear with the stand down thats also normal as i still forget about that now

as for no clutch engagement is it adjusted correctly? can you feel the tension on the cable when pulling it in. If all is ok with that I would drain the oil and take the side cover off and check the clutch basket is together properly etc

did you check the length of the springs before you put them in to make sure they were in service limits?

did you put the top hat piece back into the outer casing as i nearly missed that when i had mine off as it had fallen out and also is the race bearing in the compression plate ?

Also with the friction plates did you put all 5 friction plates in with another one which is slightly different, also the two judder rings ? im guessing you have the manual to follow?

[RichP]

All the friction plates where there and i remembered the top hat thing.

Its adjusted correctly... When i pull the clutch i get a scrapey noise.... Sigh! I'll have a look!

[taz4626]

yeh i would check the basket is together properly and the top hat is seated correctly in its hole also lube the clutch cable

let us know what you find should be pretty obvious when you get the side off if there is some noise from the basket when you use the clutch

[RichP]

https://www.youtube.com/watch?v=fL43BeL-jDU

Thats it in action... Almost sounds like something rolling inside but at high revs it can't move?

[taz4626]

def not right mate sounds as if something is lose i would say side covers off and have a mooch!!!!

[Billing]

clutch bearing? and just as a thought, did you put the clutch plates in the right way round? i.e friction, plain, friction not plain,friction, plain?
____________________
'84 TS50X, '91 TZR125, '89 CBR400RR, '91 VFR400R NC30, '98 R1
"Hey copernicus! Why don't you navigate yourself to the back of the line with your feet and stand there with your shit."
BCF Eastern members map here ---> g.co/maps/2tm8b PM me to be added to it!

[baldy]

The bearing in the clutch was ok, i would say that there is something loose around the clutch. Did you time the balancer shaft? It could be that.

I definitely think that something is loose, it was quiet as a mouse when i had it running many moons ago.
____________________
One day i will rule the world, just not today.

[alains]

baldy
Rich , i made a zip file for you with the 9 related pages of the workshop manual
https://www.geneva-racing.ch/~alains/balancer.zip
____________________
the worst day fishing is better than the best day working

[RichP]

Thanks very much i'll look through that!

I checked the balacer shaft and the two dots as good as lined up when you turned it, maybe a tiny bit out, but since you don't have infinite adjustment due to the cog on it, it looked as close as it would go.

Engines coming out again tonight!
AAAAAAAAGGGHH!

[taz4626]

a little confused on the comment on the clutch plates friction plain , friction "not plain" whats the not plain ??

[Billing]

you misunderstand, not 'not plain' its not, as in one way NOT another if plain plates are 1 and friction plates are 0 then what i meant was;

1010 instead of 0101
____________________
'84 TS50X, '91 TZR125, '89 CBR400RR, '91 VFR400R NC30, '98 R1
"Hey copernicus! Why don't you navigate yourself to the back of the line with your feet and stand there with your shit."
BCF Eastern members map here ---> g.co/maps/2tm8b PM me to be added to it!

[taz4626]

ah right makes sense now made me think i had done mine wrong for a min then lol

cheers for clearing that up

[RichP]

Cheers guys!
Sorted now, i took it apart and reassembled it.... seems fine now!

[taz4626]

what did you take apart ? all of it or just the clutch?

[RichP]

Just the clutch...

I'll post up a video, it drives now but in my mind doesn't sound 'right'.
(but ive never owned a 2T before...)

Powervalve not connected because i stupidly put the radiator in now can't reach it... DOH!

[taz4626]

it is possible to do the powervalve with the rad in just takes a bit of patience a UJ socket and some sticky tape but you do have to lift the bottom of the rad out, but you can leave all the hoses attatched.

without the powervalve i must admit the bike would probably be quite boring as this is where most of my fun with the bike is had.

to be honest when i first got mine it didnt seem to sound right but apparently its just the way two strokes sound it was mainly atb idle always sounded as if it were struggling.

get the power valve sorted asap and you will have a grin on your face!!

[RichP]

Well gotta get the Pvalve sorted there a huuuuge flat spot at 5K, in some gears it can't make it past it!
It can't maintain 60 in high gear so it really does need it methinks!

When it hits about 8 the bike takes off, but nothing till then!

[taz4626]

the power valve doesnt come in until 7k unless because its got no cables on it it is more shut than it would be normally but yeh def not right if you cant get over 60 mine does that in a flash