carbed monster won`t start, fuel isse

[samuraibiker]

first of all, Happy New Year to everyone. Safe riding and let`s hope breakdowns are few and far between!

My 97 monster 400 won`t start...have checked the battery, all good, checked plugs etc... have a good spark at each cylinder so it`s a fuel issue.

What is the best way to check fuel delivery to the carbs ( I had the carbs overhauled 18 months ago so I`m pretty sure they aren`t the problem ) and how can I check that the vacuum pump is working?

The fuel filter was last changed 2 years ago so that may be ready to be replaced.

Thanks

Mike

[koko64]

What kind of fuel tap does it have?

[samuraibiker]

hey koko

this type



happy new year!

[koko64]

Happy New Year.
It's worth replacing that vacuum tap with an in line manual tap. Those vacuum taps either jam shut or leak fuel into the cylinder via the vacuum line to the manifold. Hondas used a similar type which often starved motors.
Bypass it and see if fuel flows. Otherwise it will be your pump but that's less likely. Check the tap's vacuum line is ok.
I have seen a few float needles glued shut by old fuel congealing in the bowl. Strange but true.

[samuraibiker]

hey Koko

thanks. will bypass the fuel tap and see what happens. I will drain the float bowls too. It`s a 1997 monster with most of its original parts so I am expecting some issues to crop up.


safe riding
Mike

[samuraibiker]

bypassed the vacuum fuel petcock...no joy.....
fuel filter changed too but still wont start. double checked battery etc..all good there
vacuum fuel pump? should i bypass this and run the fuel line directly from the tank to the carb to see if this is the issue?

[Howie]

For test purposes, yes.  Just make sure the fuel level in the tank is higher than the carbs.

[samuraibiker]

thanks Howie

do i need to remove the air filter housing to get to the fuel inlet? I really hope not as it is a major pain.....

[samuraibiker]

jan 30 th update

too cold to work on the bike recently..... wimp i am!

anyway....installed new fuel petcock ( non vacuum ), new fuel filter, new vacuum pump, all new fuel lines...... bike still won`t start. checked battery, all good and good spark on each plug...... engine cranks but just wont fire...so could it be a carb issue? I had the carbs overhauled by ducati 2 years ago and have only done 2000 kms on the bike since then......... any ideas before i called the most excellent motovita bike shop in north osaka and ask them to take a look?

[ducpainter]

Have you verified that you're getting fuel to the carbs?

How long did this bike sit since the last time it ran?

[Howie]

Try priming the carbs with gasoline, a drop or two down each venturi.  It can take a long time for the float bowls to fill.

[koko64]

Stock carbs have floatbowl drain screws that can confirm fuel is reaching the carbs. Very handy. +1 on the carb priming.

[samuraibiker]

hey guys

thanks for the replies...

fuel is definitely reaching the carbs as when i remove the fuel line from the carb, gas comes out. I will double check via the float bowl drain plug as suggested.

bike stopped running in mid december so hasnt been fired up for 6 weeks

i will try and prime the carbs tomorrow and see what magic ( or not ) happens.

fingers crossed and thanks again.

[samuraibiker]

update.... checked the battery again, all good... undid the float bowl drain screws...lots of gasoline... checked spark...both good....but still doesnt start.... carbs bunged up? i want to take it to my local duc guy but wifey has just bought airplane tickets for our summer hols and i have been given strict instructions not to spend more money on bikes so any suggestions as to what to check next? i was thinking could it be fouled jets or some gunk clogging the carbs internally somewhere?

[ducpainter]

Did you try putting some fuel in the carb mouths as suggested? Are you using the enricheners/choke?

It's likely the pilot jets are clogged if the bike fires with some fuel dripped in.