[robert s.]

Seems my two vintage Brit bikes, T120R & B44VS are getting harder to kick start after I began running 100 fuel. With 89 fuel, they'd usually start cold on first kick; now it takes more kicks, many more sometimes.

While it's possible both bikes have fallen out of tune at the same time, I am thinking that 100 fuel (less volatile) could contribute to the hard starting.

That's my conclusion, anyway?

 

[knallert]

fill them with the other stuff and se if it gets any better...

why run 100 in them?

 

[dhallilama]

i can tell ya right now my sporty was a proper bitch to start cold with 110 octane in it... fires right up with 91/92 octane.

with the 110, i'd kick it over at full timing advance which made it fire up a lot easier when cold. still retarded it when hot.

now i just run regular old pump super unleaded shite. kicks over easy when cold.

when the motor was hot, i didn't notice much of a difference between the 110 and the 92 as far as starting goes.

 

[Glider]

Funny, for all the talk about how crap the new ethanol-cut gas is, all my old bikes run fine on the regular, no carb or tank problems either.

 

[dhallilama]

as far as running? my sporty runs like a raped ape on E85 when jetted/timed/tuned for it...
never a problem with carbs or anything else. works fine.

 

[Hoofhearted]

Some years ago I had a '70 750 Honda and it ran fine on regular gas. Going to work one day (in a rush as usual) I noticed it was low on gas and I wouldn't have the time to stop. So I dumped some VP C15 race gas in it. It ran like shit and I struggled home on three cylinders. Dumped the gas and put some regular back in and all was good again. I ran the C15 in my Weslake speedway engine in the Norton and it loved it but the Honda hated it. Go back to what you were using and see what happens.

 

[scottto93]

Do you know your comp ratio?

 

[robert s.]

Compression ratios:
T120R Bonneville: 9:1
B44VS Victor: 9.4:1

I started using 100 octane due to some detonation symptoms, mainly in the Victor.

Perhaps I can mix fuels to ease starting and lessen detonation. I am in California.

 

[kllrjo]

i had a bitch of a time cranking my 10;1~68 tr6c with anything near 100 o.......this engine would heat up in traffic and ping, so i started running the higher octane fuel to cure this,,,,,and it did! just wouldnt hardly start the next day. prime and fire. prime and fire. would run for a brief second then die.....so, i dumped the fuel from the bowl, through the drain plug and ran a pc of .035 alum mig wire through the jet w/throttle open....fired right up and ran fine all day.....multiple restarts,no problem!
thought that i might have just got some trash in the main, until the next day!
prime and fire. prime and fire! clean the main,once in the morning, fire and ride. fire and ride. all day!
funny thing is, on reg gas it fires up whenever i want it to! so i dialed the timing back a scoce. and now it doesnt heat up and detonate[ping]
i gotta wonder if the heat wasnt "cooking" the fuel after shut down and leaving a "sugar crust" sealing up the main???? funny thing is, the t140 and the stock comp `64 dont do this,only the tr6c! been running 89 in all three ever since!