Seizure?

**koba** · 18th August 2008, 10:40

I seized the RG at a test day on friday.
I Have taken the barrel off and determined it was the piston.

I have an old used but ok high kays piston I will prob put in for the next race while I sort a more permanent fix but I don't want to fuck that with whatever condition caused this still existing.

The powervalves look ok, they had a wee bit of what was probably sicky aluminium on them but no signs of impact or damage, just the bad wear that was there before. (its a bit flogged out)

I was initially worried it was powervalve related because I have been pissing about with them for ages trying to cure all the play in the pulley system from it being worn out, I thought I may have gone to far and made them drop too much.
I had previously thought this was impossible because the fork but that lifts them doesn't SEEM to ocate them and even with it disconnected they seem to stay in place.

Anyway, powervalves are probably clear of guilt coz they look fine.

What seems to have happend is the piston is munted and seized to the bore, it happend once and I let the clutch back out gently once I had slowed to walking speed and it must have broken a weak bond the piston and wall had made.
Gave it another blat. (Yes I know that was silly)
Bang, same thing happened.
Broke loose again too.
This time it has got thru my head that it really ain't right.

The piston and rings were relativley new, inserted into a standard bore that was measured to be within limits.

They had been gently broken in over time and altho still quite new have run fine in two meetings.

The air was COLD - It hailed just before I went out .

The bike was warmed up but not as much as it would normally get sitting on the dummygrid before a race.

There was plenty of oil in the tank and the oil was getting at least as far as the pump.

It has marks good and propper all around the piston, the main one where it has even rubbed over the rings is on the inlet side near the pegs.

The pegs are still in place.

So my Questions (finally!)

What is likley to have caused this?

Could it be that it was just too cold for such a constant thrashing and the piston expanded much faster than the bore?

Is the situation above what a "cold seize" is?

Am I correct in thinking I should warm it up much more now!?

Was that a stupidly lengthly read?

**Ixion** · 18th August 2008, 11:12

Is it a Wiseco (forged) piston?

**oyster** · 18th August 2008, 11:21

There's about 60 down here and pretty well know the hisory over several years. Only once have we had an unexplained seizure, and it was at zero ambient at Teretonga.(The second half of the loop still had frost on it during racing!!!) Our baseline is assuming 95,96 or 98 fuel, Castrol TTS, 185 main jet, needle in centre groove. Also, I shouldn't ask, but I assume it's not modified as I've found MANY NI ones to be when we buy them. Gutted chamber, airbox mods, no filter etc. If so, that's your secret, but it could affect your problem!!!
Re temp before racing, we rountinely fine a $34 temp gauge called 'slimline" from Dick Smith. Effective and the RG always runs around 54deg. A good way to spot a prob before seizure too, as we've had the odd water[pump gear break (quite common actually) Also only once, an oil pump drive failure.
Take the clutch cover off to check both.
Before you refit another piston there must EVERY TINY trace of the melted on Aluminium gone completely, otherwise, instant seoize again.

**racefactory** · 18th August 2008, 11:40

hey man. sorry i cant help you.

just wondering if your cylinder is fucked? Do these have nikasil bores?

Did your rings stay intact?

**Tony.OK** · 18th August 2008, 12:14

Yeah it was a pretty shyte day wasn't it, hope you get it sorted soon

**koba** · 18th August 2008, 15:42

Originally Posted by Ixion

Is it a Wiseco (forged) piston?

Nope, Standard Genuine replacment suzuki one from the man below.

Originally Posted by oyster

There's about 60 down here and pretty well know the hisory over several years. Only once have we had an unexplained seizure, and it was at zero ambient at Teretonga.(The second half of the loop still had frost on it during racing!!!) Our baseline is assuming 95,96 or 98 fuel, Castrol TTS, 185 main jet, needle in centre groove. Also, I shouldn't ask, but I assume it's not modified as I've found MANY NI ones to be when we buy them. Gutted chamber, airbox mods, no filter etc. If so, that's your secret, but it could affect your problem!!!
Re temp before racing, we rountinely fine a $34 temp gauge called 'slimline" from Dick Smith. Effective and the RG always runs around 54deg. A good way to spot a prob before seizure too, as we've had the odd water[pump gear break (quite common actually) Also only once, an oil pump drive failure.
Take the clutch cover off to check both.
Before you refit another piston there must EVERY TINY trace of the melted on Aluminium gone completely, otherwise, instant seoize again.

Bog stock, Its done at least 48,000 kays but probably a fair bit more (the engines in the two bikes I've got have been swapped a few times.)
Temp on the standard guage was the same as usual - nothing!
It was still connected so all that tells me is it prob didn't overheat as far as the cooling system goes.
Coolant and everything seemed ok and stayed in the right place.
Will check waterpump and oilpump drive.

If I drive the oilpump by hand with the cover off and throttle open im guessing I should see oil come out?
Best check that and all.

Could it be from not being run in long enough?
I HAVE done two races on it with no probs tho...

The temp was COLD - must start measuring it all proper but it wouln't have been over 10 for sure and most likley around 5, no frost although maybe only coz of all the hail and rain!

Cheers for more great advice

Originally Posted by trademe900

hey man. sorry i cant help you.

just wondering if your cylinder is fucked? Do these have nikasil bores?

Did your rings stay intact?

No idea on the Nikasil, Cylinder needs to be carfully cleaned and measured yet.

Rings intact in the sense that they are still in the grooves and in one piece but there are bits of piston wiped over them...
Must try get some pics sorted.

Originally Posted by Tony.OK

Yeah it was a pretty shyte day wasn't it, hope you get it sorted soon

AHHHH, so that was you braving the rain on the thou!

Well done and cheers man.
I wasn't finding it all THAT bad out there and if the bike didn't die I would have been happy with paying the fee because it was cool having SOOO much track space!

**koba** · 18th August 2008, 22:03

In preparing the barrel for sanding I thought it prudent to find a hose to see if I could blow air thru the oil hole thing.
I couldn't.
Cranked up the compressor..
The old man got a piece of wire and tried to poke it thru eace end (it has a right angle bend.)
Fine on the outside, didn't seem to go all the way in from the inside tho.
Compressor full....
Blow.
POP.
Blue TTS oozed out of the hole.

hmmm, may be an expalination there.
Guess that means I should strip and clean the whole oil system.
A real bugger seeing as it is full!

Question:
What should I clean it with? Obviously I would flush it with twostroke oil when done.

**koba** · 21st August 2008, 10:32

Hehe thinking the oil pump would pump oil by hand was a bit much.
Battery drill wroked nice tho.

Some of the oil in the system was a but milky, dunno if it was from water or just from air bubbles when I blew down the hose to clear it out.
It seemed all clean and with the oil pump set to full throttle position and a battery drill cranking it over it pumped oil out nice and cleanly, not as much as I thought it would but looks about right with the book saying 2.3mils over 2 minutes or somthing at 2000 rev engine speed.

Because I don't have the fancy tool I was thinking If I turn the engine over by hand to determine the ratio of engine revs to pumpshaft revs I can work out how fast I need to spin the pump to = 2000 engine revs, that way I can do it off the bike and into a container.
I'm not sure I will have time tho and a nasty risk of not checking it thoroghly may be in order...

I am worried that the blockage in the barrel oil hole may have happend from aluminium blocking it up during the siezure and may not be the cause of it.
There was minimal aluminium in that area on the barrel with the main siezure piont on the intake side but still....

Should at least get to start it up tonight, had to finish early last night because I couldn't feel my hands enough to work.

Swapped batteries with str8's bike mine being farked may explaing the atrifical revlimiter that has showed up recently.

I really need a proper garage....

Fark I natter on don't I!

**Racey Rider** · 21st August 2008, 19:23

All good 'learn as we go' info mate.

Originally Posted by oyster

.... I assume it's not modified as I've found MANY NI ones to be when we buy them.

Is that why I can't keep up with some of them down the straights!
(and they said I was Fat...

)

I was interested to see I was able to match the speed of your Patrick's bike when you were up here at Manfield last year. We were having a great battle till I got the squish and wiped out. Is he still racing SS? I have unfinished business with that Lad!

Racey

**koba** · 22nd August 2008, 10:40

Originally Posted by oyster

Also, I shouldn't ask, but I assume it's not modified as I've found MANY NI ones to be when we buy them. Gutted chamber, airbox mods, no filter etc. If so, that's your secret, but it could affect your problem!!!

Originally Posted by Racey Rider

[COLOR="Blue"][COLOR="Blue"]Is that why I can't keep up with some of them down the straights!
(and they said I was Fat...

)

Mine definatley seems to be down on power no matter hao careful I am in making sure everythign is running perfectly but I do believe the older KRs are a slightly slower bike.
I am also a wee bit bigger than most of the riders up here tho...

Had a moment of despair last night, after spending a week of late nights carefully getting everything sorted I started the bike up, it ran ok and started

even better than usual but then I noticed a terrible sound...
Its going clunk, sounds like a bigend or somthing.

I had a quick check of it when I had the bike apart and it felt ok, I didn't dwell on it as much as every other bit of the bike tho which is silly considering the pressure that would have been on it in a siezure...

While it was running I VERY gently played with the powervalve adjustment to see if it was the touching and I did end up touching them to the piston.
I can confirm that I't aint the powervalves, but now I know what that sounds like. They check out ok, just a nick on the end.

I worried for a while about what to do, decided a full proper look was in order but due to lack of time I was steeling myslef to sit this round out...

But I rang AJ to see if he still had a spare bike I could borrow, he was going to be ridindg it but still said In could have it for one of the two races, the old bugger is far to generous and must be going senile in his old age!

SO this weekend I will be on ANOTHER RG....

**Str8 Jacket** · 22nd August 2008, 11:42

Originally Posted by koba

SO this weekend I will be on ANOTHER RG....

Just try not to blow *this* one up, eh?!

**oyster** · 22nd August 2008, 11:50

Yep, Patch won the senior (over 19yrs) class in SS support class these nationals, but has now done 2 meetings on Pro Twin. About 15 at least will be coming up again for the 2 day meeting, just off the phone talking to AJ bout it. When are you guys coming South in Jan for Nationals? Too chicken???