2005 Thunderbird with a Chewed up Piston... you're not gonna belive this!

[mohsinp]

Hey all, I need your opinion on this:

I have a 2005 RE Thunderbird that has done about 9000 kms. About a month ago I went out on a long tour with the bike and I was riding pretty fast between 80-100 kmph for about 90 kms. When I was ascending Amba Ghat at 80 kmph sustained, I noticed that the bike seemed to be loosing power. I assumed that for some reason, it was overheating or something, even though the oil levels were proper and the bike had been running smoothly. Now before I go any further, let me tell you that the bike has been run in very well and only recently has it been subjected to any sustained high speed riding (that's what cruisers are for). Well, the bike started loosing power and then I stopped to check and shut the engine off. It never started again. I had to get the bike towed to Kolhapur, where I live which is about 80kms from where the bike stalled. It would not start again no matter what I did. I could sense a loss of compression while kicking. I thought that I might have a broken push rod or something. When I had the engine opened, I saw this (please see the attached pictures)

I was shocked. The engine never seized. It was never EVER oil starved and the fuel was always pumped from the best pumps in Kolhapur. The bike was always serviced regularly.

Has this ever happened to anyone else before? I've never seen a piston in this state without the engine seizing. Frankly, I'm very disturbed by this and would appreciate some ideas on how this can happen, if it was my fault or what I'm thinking is that it was some sort of manufacturing defect. Either way, I don't think Enfield would give this a second look, but its very very disturbing. I was thinking about taking this bike to Leh-Ladakh, now, I'm not so sure.

Your opinion/theories on how this can possibly happen would be greatly appreciated!

[darkside_of_d_sun]

I am sorry for you man, I hope this never happens to anyone! But below are my views on this:

Firstly, cruisers are not for sustained high-speed riding thats a business for sports touring bike! And this is not uncommon for Royal Enfields, their manufacturing quality (or lack of it) is well known in the Indian motorcycling circles.

Practically, you have two options,first, rebuild the engine, finish the running in and hope this would never happen again. Second, sell the bike and buy something more reliable which can do 110kmph all day without a hitch a la ZMA.

Cheers,
Shamik

[akshay4384]

I suspect Oil pump failure.
and bullets arent meant to cruise consistently at constant speed.
if not run in properly they sieze even at a constant 70 km/hr
the resolution is to keep varying speeds by 10-15km/hr every few minutes.

How was the bike run in? and for how many kms?

My CI machismo has done 72K kms and I have ripped her hard abused her and she hasnt missed a beat.

[mohsinp]

Thanks for the reply DarkSide and Akshay. The bike was run in very well, and it comes as a surprise that they are so delicate. To me, they have always been the ultimate beast. I am having the engine rebuilt. I've gotten a new piston for the thing, cost me 1k... My mechanic is going to re-sleeve the bore. He insists that we start up the bike and then look for oil pump failures. Should I order him to split the engine and flush the oil channels of the metal that is definitely in the oil circuit? Any pointers on how to run this thing in after the rebuild will be greatly appreciated. Darn it, I love the beast. I don't think that I can bear to part with it. Even though Its a big drain on my wallet getting this thing fixed, I had so many things planned with this monster!

How do you run this thing in properly? And have you ever seen an piston chewed up like that? How can that possibly happen without seizing the engine? It NEVER seized! The kick was just too free, indicating to my n00b brain that it was a lack of compression...

How can I prevent this from happening again?
and Should I have the engine split and inspected?

[anupmathur]

Originally Posted by mohsinp

How can I prevent this from happening again?
and Should I have the engine split and inspected?

Seems to be catastrophic failure of the piston. More specifically the piston crown.
Is the piston crown of the RE cooled from underneath by oil squirted from the gudgeon pin bearing? If yes, then choking of that oil-hole could have initiated this breakdown. Otherwise it has to be considered as materials failure.
I don't think that the oil pump failed. That would have caused serious damage to the bearings and most probably led to a seized engine.

One of the biggest problems will now be to clear the metal dust from all the oil channels. This would be critical towards preventing a repeat of a major breakdown in the future. Please do everything possible to thoroughly wash out all metal dust from the entire engine block and crankcase.

This is all part of the bonding process between man and machine! Long live RE!!

[Yogesh Sarkar]

That’s one thoroughly seized engine, my bike has seized twice till now, once immediately after the Piston Kit replacement (got it fixed for free) and one long time back which I didn’t noticed and went on to clock around 30k kms and two trips to Ladakh on the seized engine, you can view the photographs here, Got the motorcycle engine overhauled | Yogesh Sarkar's Blog

Personally I believe that piston and cylinder block should be changed, instead of going for sleeving or reboring.

Like Akshay and Shamik have already pointed out, Royal Enfield motorcycles aren’t built for sustained high speed cruising and require plenty of care while doing so to prevent things like this from happening. So after the run in is over, make sure you don’t ride her at high rpm for long time.

[anupmathur]

Originally Posted by Yogesh Sarkar

That’s one thoroughly seized engine, my bike has seized twice till now, once immediately after the Piston Kit replacement (got it fixed for free) and one long time back which I didn’t noticed and went on to clock around 30k kms and two trips to Ladakh on the seized engine,

YS, his RE engine did NOT seize! That's a bit perplexing.

And how could you have gone on to make two two trips to Ladakh on a seized engine?

[Yogesh Sarkar]

Sir see the photographs for your self, especially the piston ones.

[anupmathur]

Originally Posted by Yogesh Sarkar

Sir see the photographs for your self, especially the piston ones.

Those piston photos do not have any scuffing or cold welding marks.

Further, from the man himself:

Originally Posted by mohsinp

And have you ever seen an piston chewed up like that? How can that possibly happen without seizing the engine? It NEVER seized! The kick was just too free, indicating to my n00b brain that it was a lack of compression...

[Yogesh Sarkar]

Sir both the times my bike seized, the marks on it were very small, these are the photographs of the piston which I changed at ~53k.





You can see the two places which have scuffing marks, similar mark were also present on the cylinder wall. Similar mark (though larger) is also present on Mohsin’s bike’s cylinder (right hand side):



When my motorcycle seized for the first time, it was due to oil pump failure and yet I was able to complete 1100km ride (though at slow and cautious pace), at the beginning of which it had seized.

So far what I have seen and heard is, when Pulsar's engine seizes up (unless it is a major problem), they restart in a minute or so and can continue running. While incase of the Bullets and two strokes, the piston get firmly lodged up and at times, even results in rear wheel lock.