Triumphrat

gatornapper

I have to be honest. I haven't been around because I've been both sick and in hiding.

Not physically sick. Sick because for the 2nd time in a little over a year, the Bonnie has a hole in a piston. A brand new piston.

My 23 yr. old Navy son again asked to ride it, and about 4 miles from here on the interstate at 70mph, blew a hole in a piston. For one thing, he hadn't warmed it up, and it was a cool day. This is over 2 months ago.

I guess I've been so upset about it I didn't want to discuss it with anyone.

What happened? Only idea I've heard is that because the bike hadn't run in about a month, water had separated in the tank because of the ethanol, and when it hit the piston on the interstate she leaned out so much the hole was burnt.

And for the first time on one of my bikes, I just wasn't up to rebuilding the top end again so soon in the middle of too many other critical projects.

So, I took it to my friend Ray way out in the country to let him to the work.

Now I'm half afraid to even take the Bonnie out when she's rebuilt for fear of it happening again.

__________________
gatornapper

My sweet '72 T120V Bonne
'73 Trident T150V, '72 Bonneville T120V, '71 Trophy 500 T100C
"A Dream Collection" (w/apologies to all '60's purists)

DCrider

Well that's a real bummer Gator but glad to hear you have a plan to get her back ready for the road. That story makes me worry a bit as still not sure I have my carbs adjusted right, but been riding it every week for last month trying to cram in riding time before it gets too cold. Dumb me ran out of gas the other night, will spare the long story but after pushing the bike to 3 different gas stations finally found one open, pumped gas and made it home only 1.5 hours later.

dl.allen

All you can do is try to keep the carbs clean and run slightly retarded to protect the pistons and hope for the best. Dont let it get you down just ride. Maybe an opportunity for a big bore kit?

Chuck95642

Wow I'm sorry to hear about what happened to your lovely ride. That breaks my heart to hear of this and about the Ethanol Issue too. I keep telling others that Ethanol is the Devil's own creation but many will not believe me. My bet is that it was only E-10 at that but still.

Maybe ask your friend when you get it back from him about using one of the racing fuels available or ask about a Av Gas w/normal Unleaded mix perhaps add in some Stabil if she is going to sit or better yet just drain the tank and the Carb Bowl(s) but no more Ethanol if you can help it. This just makes me more leaning towards race fuel or the Av Gas/Unleaded mixture(4 glns Av Gas to 1 gln Regular Unleaded 87 Octane in a 5 gln can gives you about a 98 Octane mixture, it is just enough to dilute the Av Gas down). Ask around though first.

OMG this just breaks my heart hearing about this tragedy.

loctitekid

Just the other day I was wondering if you were OK. Glad to hear you are still in the land of the living.

Good that you're only half afraid. Now conquer the other half.

These bikes have been around a long time already, and will probably outlast us. Particularly those of us who are 21 with many years experience.

Keep the revs up, live a little, push it a bit, the old buzz is very likely to come back.

All the best,
Neil.

__________________
We can't always control what happens to us.
What we do about it is always up to us.

Snakeoil

I'd be curious to hear what others think regarding your fuel separation theory, Gator. My understanding is when the fuel goes into what they call phase separation, what settles to the bottom is a corrosive goo, not water. And from all I've read, you really need a lot of water to get into the fuel for this to happen.

If you had water getting into the fuel mix, it would have lowered combustion temps as it took heat out of the process when it flashed to steam. Heat of vaporization, remember that from school? Water injection is one way of lowering combustion temps for turbo or supercharged engines.

I suspect something else is going on. Too advanced, something leaning out the carbs (air leaks) or maybe it was too lean and just took this long to do it's nasty work.

If you did indeed suffer from phase separation, then perhaps some of that goo got into the carbs and I would think it is pretty viscous, might have caused the carb on that side to run lean. I could see slow flow thru the flow bowl valve or perhaps the needle or high speed jet. I've never read any articles on what happens from the goo other than it plugging up fuel lines. But I suppose if you had small amounts in the fuel stream, it could stick and partically restrict small orifices like those.

You should be able to clearly see phase separation in the tank if it happened, Gator. My understanding is it really does not happen from moisture aborption from the air under normal conditions.

regards,
Rob

Chuck95642

All great points.

Rathlindri

Hey Gator old friend, I'm just glad to see you posting again, like some of the others I was worrying something serious had happened!!
Now, let's get this into perspective, the main thing is you're okay and your family are okay. No-one crashed the bonnie and no one got hurt.
The 'bike will be fixed and it will be as good as before. As to the cause....I'd suspect two possibilities

1/ Ignition timing...slightly advanced maybe? I can't recall if you're running points or electronic ignition? I tend to run very slightly retarded on the timing these days to cope with todays fuel.

2/Carburettor Mixture... again I'd tend toward slightly too rich than too lean. Did you put new mufflers on it recently by any chance? I put less restrictive pipes on my tiger and found the 'bike running much hotter and leaner so had to raise the needle one notch to get it just right.

One thing....was it the same side as before this time?....just curious.

Glad to have you back!

gatornapper

Thanks for the welcome back guys. Missed being here.

I'd been riding the bike occasionally, every few weeks a short ride, enjoying thrashing her once in a while when warmed up - no problems.

The diagnosis was by my friend Ray - I'm clueless. I'm pretty sure the timing was dead on. A year ago I was running 200 main jets, but the plugs were fouling in a short time so I cut back to the 180's. Even with the 180's she seems to be running rich.

As I haven't seen the bike (it's an hour SW of me), but rode out there Tuesday but Ray wasn't home....probably out hunting on his 150 acre farm.....he doesn't do much bike work during deer season.
So I don't know which piston holed. He said it was tiny.

The previous one was huge, and totally my fault for putting in too much carb cleaner.

All you pointed out makes sense. It had been sitting only a month, and while I've heard that water can separate in that time, it usually takes longer. I know water injection cools from the old days, but not sure what would happen if at high revs just enough goes in the carb to lean it out a bit.

I'll have Ray retard the timing a bit. And I'll be the only one riding her from this point on.

__________________
gatornapper

My sweet '72 T120V Bonne
'73 Trident T150V, '72 Bonneville T120V, '71 Trophy 500 T100C
"A Dream Collection" (w/apologies to all '60's purists)

Chuck95642

Yes glad to have you back. Lots of great info posted. If all else fails drain the tank and float bowls if she is going to sit a long time. For me and my Bike I will be riding year round in between the storms. In my area of Nor Calif we can do that but only the hard core and properly geared up ride year round.