Cylinder cure?

[oldstarfire]

My 350 GTR just seized at 60 mph on the weekend.
Pulled the heads and the right piston feels solid in the bore, but will know better when I get it apart (somehow).
The barrels were nikasyl(?) coated about 1000 miles ago. Yuk.
So....the question
Anyone have a "better" solution?
Anyone ever installed a thinwall cast iron sleeve in the barrels?

This the second go-round for me, first was a melted piston due to poor fuel.
Getting tiring........
Any advice would be appreciated.

[coxy]

that sounds nasty .  how is your oil pump.   i have had a few seizures on two strokes and all were oil related 

[Sno Jet]

I don't believe an aluminum piston will work with a cast iron sleeve.  Different metals don't go well together.

That has got to be frustrating.  I assume the first meltdown took place with the original cylinders.  Sufficient lubrication is suspect.  Could be one of many things unfortunately.

[oldstarfire]

Aluminum pistons are used regularly with cast iron engines - cars and M/Cs.
My Ariel Square 4 had cast iron sleeves and alum pistons.

The first time poor fuel caused detonation, and the center of the piston melted, the bits sprayed into the bottom and then seized the piston, scored the chrome.

Oil pump may be the culprit, but have ridden about 1000 miles, some amount at highway speeds without a problem till now. How to check the pump? Would it (single pump) not affect both cylinders?

First task is to get it apart, I guess.

[ztnoo]

What have your plugs looked like (color) during the "run in"?
Good "plug chops" can reveal lots of info as to fuel mixture.......i.e., lean or rich.
Ignored or not observed......this can lead to the failure you site.

Did the seizure just bog down, or did it put you on your back rolling along the pavement?

[Mike Anderson]

Hi,
You need to make sure your check valve on the bad cylinder is not stuck. This is a common problem, especially if the bike has set with gummy oil.
Later Mike

[oldstarfire]

Thanks for the suggestions, guys!
The plugs look good, some carbon on them, not dry and/or burnt.
At speed, the engine made a slight "rrrr" and by the time I dumped the clutch, the rear wheel started to slide (maybe 4 feet or so).
A very quick engine death!

[RayK]

Hi
Just to make sure there is some oil getting to the motor, even though the oil pump appears to be working - I add around 40-50:1 synthetic two stroke oil to my petrol (gas) in my 175DT.
Cheers
Ray

[OldSwartout]

Thanks for the suggestions, guys!
The plugs look good, some carbon on them, not dry and/or burnt.
At speed, the engine made a slight "rrrr" and by the time I dumped the clutch, the rear wheel started to slide (maybe 4 feet or so).
A very quick engine death!

It could be many things, hopefully you will find a cause and not have to wonder about it.  Along with all the other suggestions, check for a pinched or split oil line, crankcase/intake air leak, plugged carb jet, etc. 

Since you had 1000 miles on the build, it probably is something that changed just recently, unless this is the first time you ran it that hard (seems unlikely).

Your cylinder is probably OK once you get the piston out.  That nikasil is pretty tough stuff and even if there is some piston material stuck, you can probably either sand it off or use acid without damage to the bore.

[Jimmy]

I,m new around here but old everywhere else.I grew up in my Dads bridgestone dealership.I had a ruined Sr100 barrel that I got a sleeve from L.A.Sleeve co. out of SR Angeles,Ca. It was a lot of work but I was playing with port timing and didn't want to ruin a good barrel.Usually when a two stroke seizes it will free up when cooled down.I have seen a seizure from forieign material that would stay solid from a piece of material jammed between the piston and barrel. Take it apart and see what happened.Let us know what happened.Good luck  90k Jimmy

[reed]

Oldstarfire
When you get some time to strip down the top end let us know how you get on!
Thanks.
Steve.

[oldstarfire]

Well, managed to pull the right barrel.
Some Kroil and a bit of persuasion with a rubber hammer worked quite nicely!
The piston had smeared onto the barrel and seized it up. Appears to be insufficient lubrication.

AND the nicasil looks ok!!!!Wow!

Will check the oil lines, check valves, pump, and pump cable adjustment for sure.

But, some help please.
1. Was using Castrol 2 cycle oil - Is a synthetic oil really better - any thoughts?
2. What is the best way of cleaning the aluminum off the nicasil without damaging it?
3. Will need a new piston and a set of rings. Ebay or?

[OldSwartout]

A synthetic oil is probably better than the Castrol, but I don't think that synthetic would have prevented the problem.

I've cleaned a cylinder with a combo of sandpaper and sulfuric acid.  Sand off the heavier sections of aluminum, then finish up with sulfuric acid to get the remainder.  The Nikasil is so hard that you will just barely mark it with sandpaper (I generally use 3M wetordry, 180 or 220 grit wrapped around a cylindrical object so that you just hit the high spots until you get down to the end.  Use the sulfuric acid carefully with gloves and goggles. You can even use modelling clay or something similar to dam it up into the area needed.  Don't leave the acid on too long; keep an eye on it. The nikasil is porous enough, the acid could get through it if left for a long period (many hours). You may be able to do a satisfactory job by sanding and not need the acid.

Richard still has pistons and rings, I believe.  He's been selling piston/rings in pairs on ebay.

[reed]

oldstarfire
I put new check valves in on my Bridgestone GTR you can get them new from Richard.
And i would run a hone down the cylinders as well wont do any harm etc.
And i agree with Karl synthetic would not have prevented this problem.
If you get some time talk to Millennium Technologies 920 893 5595.
Great people to work with.
Thanks.
Steve.

[bsforever]

Reading this post made me think about the 'poor fuel' , would the choice of octane level be of a concern for the engine seizing? Also i was running an old antique vehicle ( car) for a few years, and because of the change made to gasoline years ago (used to be leaded or unleaded) i did buy a gasoline lead additive to the tank when putting unleaded fuel in the tank. Would this be a concern to the motorcycles as well, not sure , but i believe the change to the leaded/unleaded gasoline was after 1971?  Just a thought that could be a 'safeguard' preventing more seizures??

[coxy]

i dont think the fuel would be a problem seeing its a two stroke? if you dont put a additive in a old four stroke  you can damage your valve seats . i do know the reason for 2 of my bikes seizing one is still a bit of a mystery pretty sure that was the oil cable .but all happened on extremely hot days . coincidence?