Siezed.

Yup, it happened. Went down a half size on the jetting as it was running great but I could tell it was slightly rich. Only just. Took it out. Perfect. No dead spots, bogging or lean hesitation. Perfectly linear. Then it died. I pulled the clutch in and it slowly stalled. I thought it was my fuel cock playing up again. Got it started and three k's happened again. Not cool. Rear wheel did not lock, thankfully.

Got it started with poping and blue flames coming out the front cylinder, but no smoke! Immediately killed it and checked the injector lines. Yup, the front cylider oil line had slipped off. So much for those **** wire clamps. Connected it, got it started and rode it the two k's home very docile like.

So maybe I'll get away with a new piston... However, what would this have done to the right side crank bearing? Will I get away with just a new piston and maybe a cylinder or does the crank need replacing?

Gah.
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If you managed to get it home, it's very likely that you'll get away with just a piston and rings. I've seen a number of barrels clean up, and the plating is rock hard, so it's often not damaged by a light seize.

I have to say, I've never ever seen an oil pipe come off in 15 years! I suspect it wasn't actually fitted all the way on to the union. Their length, shape, and their relative inflexibility means they can't really move around much (if at all!) once in place.
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Glad to hear, Andy. So the crank should be okay? I did 20km dry on it.
will order a piston from TYGA soon.

It must have slipped off when I changed the jets. They were only held on by those crappy wire clamps that dont do much but are a pita to remove/replace.

Btw, got the Hel lines, thanks! Had a bit of trouble bleeding them but that's for another thread.

Thinking I'll go premix. It's more guaranteed that you've got oil in your fuel if the fuel contains oil at all times. I've had enough premix bikes and have never forgot to add oil. The pump has always worried me.

So, at a 30:1 mix, 1/31*150 (where 150 is, for example, the current hyperthetical jet size = ~5. So going up about .05mm in size, i.e from 150 to 155 sounds about right, atleast mathematically.

Hmmm... always ran a pump, never had one fail, never had a hose come off, and never replaced a spring clip... in over 15 years.

I have forgotten to close float bowl drain screws after a jet change though!

I think you're probably worrying about nothing! I personally wouldn't run premix on the road unless I had no other option, mainly because it's a pain in the backside, but also because I like to know the pump's still injecting on a closed throttle. It's also injecting (although not in this case) if you seize, and the motor's still rotating!

Again, personally, I've never seen a pump fail. I'd have to put this down to operator error, rather than mechanical error! Sorry.
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Well okay. Partly it was my fault for not checking the lined were still on. Though they did slip off on me, I didn't remove them when I changed the jets today. Partly my fault, partly the clamps and partly gods too.

I always pull the hoses off so I can get as much access to the carbs as possible. That way, they always have to be re-attached... and when re-attaching them, you are obviously 100% sure they are pushed all the way home!

A similar principle when topping up my 2T tank. I refill it to max after every ride, no matter how short. I can't remember how many years it's been since I've seen the warning light come on, and had to worry about where I'm going to find a close source of fully synthetic on a Sunday afternoon!

I make a point of doing one "thing", to ensure a more important "thingy" is how it should be! It makes sense in my mixed-up daydream world! I'm usually far too busy thinking about dancing girls else!
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Never had an oil pump problem in my 11 years of NSR ownership either. That includes racing and many trackdays. Can't blame Honda for bad maintenance practices!
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Well, they did slip off while I was jetting the carbs. I'm going to see about replacing those **** wire clamps with something substantial.

Would the crank have been damaged in the 20 km ride? I hope not

Are you saying you rode it 20kms with no oil pipe on? I find it hard to believe it took that long to sieze!

If you mean you rode it 20kms home after finding the problem, and had already reattached the oil line, then the pump would still have been pumping 2T into the crankcase. StephenRC45 rode a dead 300 home from my place (twice I think) on one cylinder, and that's about 70kms! Crank was still a goer both times!

Who knows until you take it apart. It's all speculation until you've got it in bits. And in my opinion, you're still barking up the wrong tree regarding the wire clips. If those pipes are on properly, they simply cannot come off!
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I suspect the wire clipped hoses came off while I was changing the mains. They were definitely on last weekend! It's not like pulled hard on the carbs, I just removed them from the inlet rubbers and tilted them so I could remove the bowl/mains. If those clips are as good as you say then they shouldn't have come off. I never suspected they would either.

I then rode about 15 - 20 km before it siezed. When I figured out the problem, i.e blue flames + no smoke I checked the injector lines as that is the only reason as to why only one pipe was smoking. Reconnected the line, got it started and rode it home keeping it under 5,000 rpm.

Is there a way to tell if the crank is ok without pulling it out?
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As I say, I recommend pulling the hoses off, and lifting the carbs up as far as possible to get the best access whenever you do a jet change. That way you know you have to reconnect them, and are sure to push them all the way back on each time! Their length, shape, and construction makes it quite impossible for them to just "work loose" -- there just isn't enough flex in them.

As for the crank, who can say?! You're just going to have to use your own best judgement. StephenRC45 did at least 80 miles, probably 100 miles on one cylinder over at least two trips on the same crank, and it never failed. Admittedly though, he never lost the oil feed. If you caught the siezure quickly, then I expect you never ran the crank for more than a few seconds without an oil feed.

Personally, I'd do the top-end and risk it for a biscuit!
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Yeah, there is no way they worked loose while riding. Though I'm suprised I got as far as I did with no oil feed! Pulled the cylinder off just now and the piston is really stuffed as you'd expect. The cylinder looks fine though! Just a lot of aluminium from the piston stuck to it, so I suppose some 1000 wet/dry grit should do the trick. A big relief. The head looks good, no pitting from detonation or shrapnel, and the piston crown and head have no carbon build up to speak of in the 7,000 k's they've been on. Impressive.

So, I'll be ordering a new piston kit from TYGA asap for $70. Hopefully a cheap lesson learned. I can't believe my carelessness.

Don't unserstand what you mean about Stephen riding 80+ miles?


Last edited by anonymous.shyster on Sun Aug 07, 2011 6:31 am; edited 1 time in total

What's the best way to remove the alloy from nikosil?

How thick is the nikosil anyway?

Here's a photo of my trophy. Notice the cracked skirt and the lack of carbon on the crown. You'd think there'd be some.


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