Carbs got to come off again

[Ken4004]

The old bikes are a present that keeps giving so sorted the issue out with the bike not pulling properly and over heating which now seems to be fixed so please with that but now the bike is harder to start and won’t idle so looks like there is an issue with the pilot jets being partially blocked so got to take the carbs off again and give them a good clean.
I thought if I am going to all this trouble I’ll buy some more quality fuel hose and replace the whole lot, empty the tank and give it a slosh round with fresh fuel (e5) .

Just in case ( I know alot of people don’t like them but I am going to replace the sintered fuel filter with a paper one.

So just as a question what’s the average amount of times you have to remove your carbs over a calendar year ?

[Johnwebley]

Normally zero

Just an idea

Put some carb/injector cleaner in the fuel every so often

Help keep the carb internals clean

Redex or similar



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[exvalvesetdabbler]

About 10 year ago for me, when I got tired of a sticky float and puddles on the floor after it had been stood for a week or more. Float valve was ok, the frame on the float had been bent and was getting stuck once it rested on the bottom.  Substituted another float and no problems since.

I do drain and flush  the carbs out before a winter lay up. Just feed it from a remote reservoir  of white spirit down the fuel pipe.

Regards
Dave

[Ken4004]

About 10 year ago for me, when I got tired of a sticky float and puddles on the floor after it had been stood for a week or more. Float valve was ok, the frame on the float had been bent and was getting stuck once it rested on the bottom.  Substituted another float and no problems since.

I do drain and flush  the carbs out before a winter lay up. Just feed it from a remote reservoir  of white spirit down the fuel pipe.

Regards
Dave

Hi Dave

Do you leave the white spirit in the carbs or are you Just driving out all the fuel with the white spirit then drain it out ?

[exvalvesetdabbler]

Leave it in.  I do put about 3 spots of engine oil per 300 ml.. just drain it out in spring, connect up to the fuel tap, turn it on and it's fires up 3rd kick.

Regards
Dave

[Athame57]

So just as a question what’s the average amount of times you have to remove your carbs over a calendar year ?

So far not in 2026 at all.    That said, 'too often' is all I can say, definitely a bit of bad luck and lack of experience involved  and then there are the plenty of times that someone else did it.

[Ken4004]

Thanks for the feedback guys I’ll try some preventative measures to try and keep my carbs in fine fettle and keep my fingers crossed.

[Mikep328]

  2+ years ago, just after acquiring my 400, I pulled the carbs. It idled badly and bogged severely when given full throttle.  I pulled/cleaned/adjusted the carbs, reinstalled them and found the bogging reduced considerably though still present and the idling was still poor.

So I pulled them again and found that one of the idle jets was still clogged.  This time I used a piece of wire and thoroughly cleaned all passages with that/carb cleaner.  Put the carbs back on.  Still didn't idle well.  Took the carbs off again and looked carefully at everything - using magnifier glasses.  I discovered that two of the slow jets had distorted "holes."  It appeared they had been longitudinally crushed and some of the holes were now egg-shaped/smaller than the original holes.  I replaced the two slow jets.  Carbs have been fine ever since - idles perfectly/takes the throttle with no bog at all.  As far as how often they "need" to be pulled," - I owned a 550 and three 750 fours back in the day and never had to pull the carbs on any of them the entire time I owned/rode them.  BUT they were ridden almost every day. One of the worst things for mechanical devices is sitting unused...

FWIW,  my 400F sits for approximately 4 months every year; I put some StaBil fuel stabilizer in the normal (E10) fuel for each layup.  I use Stabil in all our vehicles during storage.  One motorcycle sat for 2 years in storage and started immediately with no problems.  All of our vehicles (cars and bikes) sit for a minimum of 4 months unused, some sit for nearly 8.  Been doing this (fuel stabilizer) for MANY years now and all the vehicles will start after storage as if they had been running yesterday.  We only use "normal" fuel - typically E10; I have never made any attempt to find/use non-ethanol fuel.

[exvalvesetdabbler]

I have some  miller oils ethanol protection fuel stabiliser and carry a small 8ml bottle in my jacket pocket and empty that in the tank when filling up.  Never used E10, the cost difference to E5 isn't worth worrying  about given the small amount I used.

Regards
Dave

[Ken4004]

Well I stripped down the carbs and have found light brown deposits in all the bowls, some in the form of fine particles and some a little larger.

Not sure what this is , might be rust but there’s no sign of it in the filter, so new hoses and a new paper filter purchased and as Dave suggested once I have flushed out the tank I will add some fuel stabiliser and see how I get on.

Cleaned the bowls with carb cleaner and removed the pilot jets and have them a blast  with cleaner , Also blasted the pilot jets and galleries do will fit them back on the bike in the next couple of days.

Hopefully adding the fuel stabiliser will prevent it coming back but only time will tell.

[exvalvesetdabbler]

Probably fine rust particles from somewhere. Did you reuse old fuel line which could have had a coating inside that's come loose. The fuel stabiliser prevents oxidation of the fuel and is also supposed to prevent it going corrosive once it's absorbed moisture. Oxidation of ethanol eventually makes vinegar(acetic acid).

You can usually tell if the fuel has gone corrosive when the brass ware looks like dull copper where the zinc has been strippe away from the surface. Dezincification of brass is well documented.

Regards
Dave

[Ken4004]

Probably fine rust particles from somewhere. Did you reuse old fuel line which could have had a coating inside that's come loose. The fuel stabiliser prevents oxidation of the fuel and is also supposed to prevent it going corrosive once it's absorbed moisture. Oxidation of ethanol eventually makes vinegar(acetic acid).

You can usually tell if the fuel has gone corrosive when the brass ware looks like dull copper where the zinc has been strippe away from the surface. Dezincification of brass is well documented.

Regards
Dave

Hi Dave yes I did use some of the old fuel lines but have now bought all new fuel lines so as you say it must have come from the old fuel lines as I cleaned everything else.
Another lesson learned !

[Ken4004]

The carbs are back on and the bike is running and idling well now, starts first kick so  let’s see how long this lasts fingers crossed.

[Mikep328]

 "starts first kick so  let’s see how long this lasts fingers crossed."

So next is fixing the electric starter?   

[Ken4004]

"starts first kick so  let’s see how long this lasts fingers crossed."

So next is fixing the electric starter?   

Electric starter works fine I was just seeing how many kicks it would take to start