Fuel problems

[guyver1]

Ive just stripped dowen the fuel tap on my CB700 cos it was leaking out through the main tap part, i fitted a new rubber O ring as the old x ring was knackered, stopped the leak no problem, but now the bike doesnt want to start, it takes forever where it used to be first press of the start button before, seems to be flooding, any ideas???

oh yeah .....and the revs have gone to 1500 now when they were around 1200 before???

[BlackPig]

Is the "o"ring thicker/thinner than the original "x"ring?

[guyver1]

not really, its a nice tight fit but not too tight, the tap moves just as freely as before but the x ring just didnt seal properly, not much help i know but im a Brickie not a mechanic

[Bosun]

im not wonderfull on mechanics, but sounds as though trapped a cable on refitting tank whatever

check all is where should be..

[guyver1]

done all that too, only thing i can thing of apart from **** in the carbs is that the bike might have been tuned up with the fuel leak already there but not pissin out, now the leaks are sorted the bike isnt getting the right amount of air.........possible???

[Dougie]

Float heights may have been altered to compensate for the leaky tap,check 'em just in case,as you'll be getting more juice now.Invest in Haynes' Carb manual,it'll save you money in the long run.

[guyver1]

Im out training all day Saturday so ill see if i can borrow a training bike and get them to fiddle with the carbs, dunno why they make em so bleedin difficult to remove, cheers for your help everyone :)

[Wolfen]

Guyver1,

You said its a CB700, have you only just got it?

If so, are you the first owner after it was imported from USA.

If so the seals in the carbs could be perished if left stood for a long while or damaged by petrol going off in the carbs.

[ollie]

take the petrol cap off and start/run the bike if it runs ok you've got a blocked breather in the cap or the breather pipe itself you tend to get a lot of probs fuelwise with yank imports due to the laws on vapour venting in some US states

[guyver1]

had the bike 8 months now, this is the third set of carbs that ive had fitted, first set had no choke linkages and were badly damaged, second set run superb but bike wouldnt start with out flattening 2 baterries

tried to start it with fuel cap open but still the same, takes forever to catch and refuses to start atall with any choke

[Dougie]

If it refuses to start with any choke it's most likely running FAR too rich on the pilot circuit.Is it a standard airbox,what pipe do you have on it and do you have a manual?

[guyver1]

Apart from a clock the bike is standard, no manuals were ever made for this bike as it was only built for 3 years

[Wolfen]

Have you checked the air filter, a clogged filter causes all sorts of fun.

If I remember rightly a CB700 is basically a CB750 with a reduced cc, made to get round US import taxes/laws.

[BlackPig]

At the risk of appearin' a bit daft,has the fuel tap got a vaccum(spelling? :o ) pipe?
If so maybe it's blocked/missing/not connected ?
Failing that I would go with the "carb's balanced for the leak" theory. :)

[Dougie]

Without a manual you'll have problems finding the standard settings for the carbs,float heights,jet sizes,mixture settings etc.If you can find them,check that the carbs are set to standard and take it from there.You could see if there are any Honda forums on the net,you might get more info there.Sorry I can't be any more help.

[guyver1]

well i think i fixed the problem, i swore at it tonight before i hit the start button and the bloody thing fired up no problem, a little bit rough till it warmed up but then it was fine, really got me stumped this one

[Dougie]

It may be worth your while to invest in a Gunson's Colourtune,a see through sparkplug you can use to check your mixture at tickover.It's not especially cheap,but it can save you loads of grief.Halfords used to sell 'em.