New Fuel

[skyman_cbx]

Hi,

I just recently received my new old '80 CBX from WI. In shipping, he drained the fuel down to reserve level. When I received it the bike ran fine. took a while to warm up but was nice and smooth.

i filled up (89 octane) last weekend and ran it for another couple of miles.

Today (a week later) i took it out to ride and it had a hard time even after letting it warm up for a while.

Symptoms were:
rough idle
stalling at low rpm (<1200) and idle
not much power in 1st gear
frequent backfiring on acceleration and engine braking

I only took it around the block and garaged it again until i figure out what's wrong.

My (uneducated) thoughts:

1) bad reaction to the ethanol content (supposedly <10%) in the new fuel?
2) bad reaction to the 89 octane fuel
3) potentially gunk in the fuel line or carbs (yikes)?
4) air/fuel mix adjustment needed for higher temperature and humidity levels here in FL?

I notice that there doesn't seem to be a filter on the fuel line so that definitely gets put in (too late?) next weekend.

Any advice would be welcome. Would like to address before i blow someting serious.

sky

[NobleHops]

I'd drain it all into clean glass, let it settle and see what's in there. If it's not full of gunk and particles, install a filter. Water should be visible after sitting overnight. Then drain your float bowls, fill with fresh gas and try again. My money is on water in the fuel.

HOWEVER...

My bike always takes a few minutes to clear out after starting.

N.

[steve murdoch icoa #5322]

Hopefully in riding the bike with low fuel levels you did not pick up any rust/dirt particles from the bottom of the tank. After draining the gas from the floatbowl i would check it for sludge.
Fingers crossed it is just water as Nils suggested.
I do not want to start another gas debate but my bikes their best on ethanol-free 91 octane.

[Houtman]

I always use the name brands but mainly Shell 93 premium in all my bikes and lawntractor and all my other gas engined garden tools.I might be wasting some money but all my engines start and run great.I rather pay a little more for peace of mind .I do know that our bikes do not need premium but with todays gas compared with years ago I play it safe, just my 2 cents ! Safe Riding John.

[skyman_cbx]

Thanks guys,

It was Shell Silver mid octane (either 89 or 91) from a busy station so should have been fresh.

I just got a reply from the seller and he says he used only non-ethanol fuel that he managed to obtain so i'll drain the vegetable fuel. That will give me a chance to see what it looks like. Maybe some water in there . Tank (and the whole machine) is in great shape with not a speck of rust anywhere so i'd be surprised if any flakes.

He redid the carbs using Mike Nixon's book after bringing it out of storage and i trust that he did a good job.

So, task list:

1) Drain fuel from tank (syphon most then disconnect fuel line at petcock and drain out the balance) into a glass container.
2) Drain the float bowls. Is there an easy way to do this without disassembly? Close fuel line and start motor with kill-switch off until doesn't sputter?
3) Check for water (should seperate overnight) or debris.
4) Remove spark plugs to check for fouling.
5) Check plug leads for wear. I notice a lot of the bikes have the new yellow leads.
6) While i'm at it, check the spark advancer for A model upgrade
7) Check inside of the tank. Worth coating?
Install fuel filter.
9) Find a station that sells Ethanol-free fuel
10) Try it again.

Missing anything?

Thanks,
Sky

[EMS]

We have only 10% or 15% ethanol fuel here in NE Ohio and I have absolutely no problem running this in any of my vintage bikes. This includes the CBXes, the CB1100R and the Kawasaki KZ1300 and H1. I also use regular most of the time because the myth that "premium" is "better" than regular is just that, a myth. Some people even believe high octane fuel makes more horsepower
All that premium has, are more ignition retarders to prevent uncontrolled combustion or knocking. Actually, in a bike that doesn't need high octane because of lower compression ratio, the high octane fuel is worse, as it does not burn completely and you theoretically could have unburned fuel wash down oil from the cylinder walls.
I am with Nils and guess water or dirt in your fuel. Hopefully, you haven't clogged up the jets yet.

[Rick Pope]

There is a "strainer" in the fuel petcock, inside the tank. If you're draining the tank anyway, remove the petcock and see what you find on the vertical screen or "strainer".

I agree with Mike, these bikes are engineered for regular gas. I have no issues with 87 octane, and even run 85 when at higher elevations (6000' and up). I've never had an ethanol related issue either, and I have upwards of 25 gasoline motors, ranging from 1927 to 2012.

[skyman_cbx]

Little update (hope these pics work)

Drained the tank last night. Man she holds a lot. Still dizzy from the fumes Note to self...get a pump syphon instead of an oral suction

Jarred a sample to see if any water separation overnight...nada. Urine sample (i mean, gas) looked fine.





Tank innerds looked okay



tank unnerds looked okay...turned turtle



Learned not to do this as the tank top isn't quiet completely sealed and residual will leak out...but had to take the petcock off



Hmmm...new petcock but no strainer in sight will be installing an inline filter just in case.

and just for the heck of it...a belly of the beast shot





Started to check the advancer but was late and didn't want to chance a metal spark with those fumes...


Off to the local marina to get ethanol-free.

Sky

[Rick Pope]

Okay, Dave, Mike, anyone, isn't there supposed to be a plastic mesh strainer rather than that brass stand pipe?

[EMS]

Okay, Dave, Mike, anyone, isn't there supposed to be a plastic mesh strainer rather than that brass stand pipe?

Yes. A strainer fits over the standpipe and is held in place when the petcock is screwed on the tank fitting.

[steve murdoch icoa #5322]

The strainer on mine usually stays with the tank when i remove the petcock.
skyman, you can pull the float bowl on carbs 1 and 6 with out much difficulty. Have a look for rust/dirt particles.

[skyman_cbx]

okay dokie. tomorrow's business.

just made the trek to a local marina to get "recreational fuel". 90 octane @ $4/gallon!! i guess boats don't like the ethanol either. corrosive they say.

S

[daves79x]

Your strainer is likely in the tank still, as the petcock won't seal without it and the o-ring.

Dave

[Jeff Bennetts]

You can attempt to pull the srainer out of the tank but man you have to be careful that you don't crack or split the screen on it, use a dental pick to work around the o-ring and the base of the strainer, if it oesn't want to budge just leave it and spray some brake cleaner through it and rinse your tank out after.

[skyman_cbx]

hmmm. no sign of any strainer. i see the o-ring but nothing else inside. the petcock nut screws directly onto the thread with the brass pipe going into the hole.

Am i missing something?

What solvent should i use to clean the inside of the tank? Is it worth coating? Have read varying opinions. Kreem and Seafoam seem the most popular.