NC30 rings/piston kits

[lostinflyz]

the oil thing can never be good. gotta keep a close eye on the oil in these. have heard a few stories of them going bang if you get slack and rev the guts outta them.

in terms of smoke ive all of mine blowing all sorts. Black from my old one. white (and fuel) from one of the race bikes. They often run like shit when you first start them and move for a bit. They will often blow a bit of something every now and then. Often its just winter and hot/cold air mix.

If your worried about rings run a compression test. OUtside that i doubt i would bother unless something is really a miss. In terms of cylinders unless its gone bang what you got will be fine. may need a bit of a hone but thats easy. Its not like a 2 stroke where you can just change the barrel. If it fucks the bore royally its easier to just find a new engine. Or you need to find a sleeve i guess.

Valve clearances i think are shimmed in these i think and requires you have a nice set of shim stacks to do. Easier to get a shop to do it. I dont know the price but its a pretty simplistic job so i doubt it would be stupidly expensive.

but either way it sounds like what you got runs good. 1st law of vfr's is if it runs good, it more than likely is good. Going and touching anything is more than likely to bring rivers of tears and frustrations. If it sounds good (no really loud tapping (valves) and no rivers of smoke after its run for awhile i would just let it be. Keep the oil up and fresh and just listen for anything that may change. They arent like dirt bikes and need rebuilds and kisses at night every few hours. Shit my dirty old Nc21 VFR has 90000kms on the clock and i still ring the guts out of it and im sure its never been opened in its life. Ive put 20+ thousand kms on it and all ive done is a minor adjustment in the carbies cause i changed the air filter and changed the oil and filter every now and then.

[motorbyclist]

heck my bike even splatters my car behind it with black carbon, washed out the muffler from all the steam. had a friend ride it while i followed friday night and a bit of steam came out the whole way. mix is good, plugs are good, wait till summer when it's too warm for the water vapour to condense into visible steam and it'll be fixed

Does that mean new rings most likely? How likely does it mean new cylinder?

it's fine, i can tell from here:P


this is what i was talking about earlier. heck i've run three bikes now without oil;
my first oil change was an '83 xr200 when i decided to check it. it was empty, and no-one had looked for the 5 years we had it til then
next was my motorcross bike. ran for a minute, thought i'd check and LOL no oil. no problems either.
after that was an '89 ttr250, got a good 5 minutes before i got a funny noise and thought i'd check. still went hard, told mate about it and sold it with personal guarantee and it's still got no problems

turns out a 4 stroke bike still holds a lot of oil in the passageways up into the head and through the crank etc, which is what spawned this thread lol, and even then there is a lot still stuck to the metal

obviously it's bad for them, but not "oh no low oil now it's fucked"

blue smoke means either rings or valve stem seals. lack of compression means rings (or possibly head gasket). pistons/bore ultimately need examining to determine anything.

dark or black smoke means she's running rich, but check plugs to confirm. pays to learn the smell of it

white smoke is steam. put your hand there and find it gets moist, might smell a tad of petrol if she's rich

lean engine a bit trickier but she might get hard to start cold and run extra hot, check plugs unless you have a better way (do tell if you know one)

valve damage in my experience is pretty hard to do provided you have an air filter. if you manage to have a valve contact the piston it's easier and cheaper to get a new engine as would've had to seize the thing anyway. if the pistons mash valves, or if pistons stop dead, the crank may bend a bit. then run bent crank at 14500rpm and BANG she's snapped in half. whatever you do don't be a dick. had a mate buy an fzr that seemed mint, 3 days later it snapped the crank. we reckon the previous owner had seized it, fixed the top end and expecting problems sold it on.


that ttr250 i mentioned earlier had an issue in the distant past where my brother forgot to check oil and ran it till it stopped, started it again and got another few minutes before it wouldn't start again. he said it was making funny noises in high revs and losing power.
valves eventually stuck open enough and did get bent but we managed to get them back to operating condition (within tolerance too!).
extreme example but does show the difference between what you "should" do and what you can actually get away with.

Alternatively, if anyone could show me for a first time that would be absolutely awesome! Is anyone interested?

I have haynes manual but it seems a bit daunting a...

dude, i'd be keen as

the valves have shims, so if we can't mix/match we may have to wait for some new ones from a shop

could open both our vfr's at the same time to improve our chances

Easier to get a shop to do it. I dont know the price but its a pretty simplistic job so i doubt it would be stupidly expensive.

simple job but a shitload of labour

would be cheap if you dropped off the bike with open engine so all they have to do is stick in the feeler guages and swap shims

but either way it sounds like what you got runs good. 1st law of vfr's is if it runs good, it more than likely is good. Going and touching anything is more than likely to bring rivers of tears and frustrations

+1

[racefactory]

just broke my sump!! it was leaking oil from the sump so lol patched up the crack with some exhaust gasket sealer and epoxy glue. Looks like it will hold though! Until the next oil change. need a new sump tho anyone got one???

looks like she had plenty of oil in there so thats good. at least 2 litres, so i guess shes not burning much if any. I realise now i was just taking dipstick measurements with a cold engine instead of warm and upright. topped her up with 2.4 litres castrol gps part synthetic and new filter before over tightening my sump bolt!! crack- ouch...

found out i have one tiny hole in my exhaust and water is leaking from it! hooray- just water then! I guess there is quite a bit of moisture in there from the cold weather- i feel great now that it definately wasnt ''smoking''. You guys were right. the hole doesnt seem to effect sound or anything though.

hey motorb i'm thrilled to hear it! Let's do it then. My bike isnt legally roadworthy at moment though so im afraid i cant bring it out far. if it's possible for you to come over that would be great though id really appreciate it. Im on north shore. anyone else keen to bring their VFR over for a tune?? My garage can only fit 3- 4 bikes with space to work thougj. we could have some good tuning/maintenance and comparisons.

how much are shims?

[lostinflyz]

the hole in the exhaust is supposed to be there. Its to help drain any water that gets in or condenses inside the exhaust pipe. stops the pipe from filling with water and corroding from the inside out. It should look like a perfectly round hole. unless the pipe has hada rough life but even then it will still be sweet. just leave it alone.

woops on the sump bolt. shit happens. theres plenty of stuffed engine bits about.

Good luck with your valve clearance checks. let us know how it goes.

[racefactory]

oh thanks man.

by the way i dont need to be worrying that the water might be coming from my coolant right? I would have seen the water in the oil if there was a head gasket leak a?

[motorbyclist]

the oil would look milky

exhaust hole is a drain, meant to be there

can you weld up the case perhaps?

chrislost is on the north shore with his two NC30s, i wouldn't come out as i'd need to get home somehow and know i have all the required tools... my viffer is my primary transport, without it i need to steal another family member's bike to get to uni. old man has a ute and trailer though

[motorbyclist]

so, my viffer got nicked today...

[racefactory]

your fucking kidding me?

[motorbyclist]

see sig

:'(