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lucas octane booster #591881 03/25/15 8:27 pm
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LeonGustus Offline OP
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So after I suddenly lost compression on the left cylinder, I took the head off and found a glass/ceramic like coating on the face of the exhaust valves. There were bits of ceramic on the tops of the pistons that would flake off with some prodding and looked as if that was the source of the ceramic that was stuck on the valve seat holding the exhaust valve open. This is all on an N.O.S. cyl head with new guides and exhaust valves with 2-3 thou miles. I have never seen anything like it and am tempted to blame the Lucas octane booster that I stopped using a while back. Now I'm busy with a re-lap of the valves and cleaning up the pistons. So why did I go with an additive instead of some high octane real stuff ? My source dried up. That's my rant. ( I'll re-polish the piston tops too but meanwhile I'll look for a thicker head gasket)Leon


October of 69-A50R
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Re: lucas octane booster [Re: LeonGustus] #591967 03/26/15 10:52 am
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Rusty Goose Offline
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What does the plug look like? Whatever got in there sounds like some naasty stuff.


1967 A65 Lightning
1967 Moto Guzzi V7
1969 B44 Victor Special
1966? Royal Enfield Interceptor
Re: lucas octane booster [Re: Rusty Goose] #591973 03/26/15 11:20 am
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GS DAVE Offline
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Has the inside of your fuel tank been lined with ethanol tolerant coating ?

Re: lucas octane booster [Re: LeonGustus] #592016 03/26/15 5:29 pm
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LeonGustus Offline OP
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Thanks for asking. When I first experienced the cyl cutting out I replaced the ngks. Since the problem was intermittent I couldn't tell if that fixed the issue and didn't notice the crap on the pistons. Neither old or (now new) plugs looked problematic. As far as the tank - It got a coating of Por15 when I first got the bike 14 years ago and as I said, head was done with no strange issues just 2 years ago.My issue with pinging is what prompted me to start adding race gas to the mix years ago. I was still in that habit even though the original problem of carbon build-up was solved. The original head had sloppy exhaust guides. When my race gas dried up -I looked for a replacement - even tho I now rarely had pinging. I believe EI would solve the occasional pinging -as my A65T with Boyer didn't ping. I bet I won't put additive in my gas anymore. Well-maybe a little Marvel Mystery oil.


October of 69-A50R
Re: lucas octane booster [Re: LeonGustus] #593106 04/02/15 11:37 am
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LeonGustus Offline OP
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So I got everything disassembled and found tiny dings in the exhaust valve seats that I was able to lap out. Looks like the combustion chamber was chucking out small bits and some got stuck under the valves -mostly left exhaust. This lesson has cost me many hours of riding time - but part of the joy of this hobby is fixing the bike. Right? When it's out of stupidity - not so much. Back on the road soon. Leon


October of 69-A50R
Re: lucas octane booster [Re: LeonGustus] #593120 04/02/15 12:56 pm
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Why was the engine pinging in the first place? What is the compression ratio and what bike is this?


Bill B...


Boomer
Re: lucas octane booster [Re: LeonGustus] #593163 04/02/15 4:05 pm
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Allan Gill Online Happy
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Whilst others on here may have a different view, it is possible that the high octane race fuel has loosened the carbon deposits in the combustion chamber, this causing the problem you had.

There is something in the UK called Terraclean, it is a super high octane fuel which is pumped into the engine ( bypassing the fuel supply) it cleans the system from inlet to tip of the exhaust and the result being it restores power and fuel economy.
The prolonged use of the race grade fuel may have had the same effect over a period of time, a decoke at an earlier time may have solved the issue, any possible pinging could have been the carbon working loose and getting too hot, pre-igniting.


beerchug
Re: lucas octane booster [Re: LeonGustus] #593170 04/02/15 4:39 pm
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kevin roberts Offline
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Originally Posted by LeonGustus
When my race gas dried up -I looked for a replacement . . .


http://www.racegas.com/fuelfinder


every day you do not take a chance is a day of your life that you will never get back.
Re: lucas octane booster [Re: LeonGustus] #593366 04/03/15 8:37 pm
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LeonGustus Offline OP
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Allan, I used your piston radius/polish when I de-coked and replaced exhaust valves last time. I have a totally stock A50r (castanets and all) but carbon build up was the culprit last time. This time it was this nasty ceramic stuff. I found no solvent that would dissolve it - only elbow grease. I've always believed that race gas was a good thing, but I strayed. I forsook the right path. Now I must amend my ways. Leon


October of 69-A50R
Re: lucas octane booster [Re: LeonGustus] #593368 04/03/15 9:03 pm
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LeonGustus Offline OP
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btw, I was using 115 octane leaded and adding a quart to two gallons of 93 unleaded. Five gallons lasted a long time. I believe that most of our late 9/1 compression bikes wanted 98 oct leaded fuel, so sonoco 260gt may be the only legal fuel now. No love for tetra-ethyl lead mind you but I do have a pilot friend who might get me hooked up with av-gas. Hmmm E.I. vs. av-gas. What to do. Leon


October of 69-A50R
Re: lucas octane booster [Re: LeonGustus] #593424 04/04/15 11:23 am
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kevin roberts Offline
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i have found that the carbon on piston tops can be dramatically loosened for cleaning by soaking the piston crown in water and laundry detergent overnight.


every day you do not take a chance is a day of your life that you will never get back.
Re: lucas octane booster [Re: LeonGustus] #593555 04/05/15 5:48 am
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Keane Lucas Offline
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Originally Posted by LeonGustus
btw, I was using 115 octane leaded and adding a quart to two gallons of 93 unleaded. Five gallons lasted a long time. I believe that most of our late 9/1 compression bikes wanted 98 oct leaded fuel, so sonoco 260gt may be the only legal fuel now. No love for tetra-ethyl lead mind you but I do have a pilot friend who might get me hooked up with av-gas. Hmmm E.I. vs. av-gas. What to do. Leon
In my experience- "octane boosters"( laughing Lucas? laughing ) are useless. Avgas works just fine mixed with 93 pump premium.100LL has an R+M/2 AKI of about 103.I have run a 50/50 fuel mix 100LL/93 on 9:1 bikes. You may be able to cut it even more.Here are REAL jerry cans<www.deutscheoptik.com/cart.php?m=search_results&headerSearch=Y&search=jerry+cans>


1969 BSA A65T w/A70 engine
1970 Royal Enfield Interceptor S ll
Re: lucas octane booster [Re: LeonGustus] #593559 04/05/15 6:11 am
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Allan Gill Online Happy
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I used an octane booster in my A65 a while ago, it made zero difference. I put the rest in my car... It had a noticable difference in that! I could only assume that the modern car mapped its ignition timing according to the fuel grade where the bike was at a set timing and already running at its optimum ( advancing the ignition further might have made a difference)


beerchug
Re: lucas octane booster [Re: Keane Lucas] #593582 04/05/15 11:03 am
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Gary E Offline
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Originally Posted by Keane Lucas
...Avgas works just fine mixed with 93 pump premium.100LL has an R+M/2 AKI of about 103.I have run a 50/50 fuel mix 100LL/93 on 9:1 bikes. You may be able to cut it even more...

I've used straight 100LL Avgas for years.


1967 BSA Wasp
1967 BSA Hornet (West Coast Model)
1967 BSA Hornet (East Coast Model)
1968 BSA Firebird Scrambler
1968 BSA Spitfire Mark IV

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