Knocking During Start on 88 Katana

[Tomasz]

I am a new rider and have a 1988 Katana which is difficult to start. I have checked the plugs and they were covered in a dark brown liquid (presumably gas). I cleaned them up and the bike started very nicely...the first time. The tank is full of new fuel. It has backfired (literally fire out the pipe) a couple if times during the difficult starts

Recently the bike has started knocking intermittently quite noticeably when trying to start it. (Not the alternator solenoid clicking) Once it starts it runs without the knocking.

Any advice would be appreciated before I take it into the mechanic.

[Kreylyn]

I am a new rider and have a 1988 Katana which is difficult to start. I have checked the plugs and they were covered in a dark brown liquid (presumably gas). I cleaned them up and the bike started very nicely...the first time. The tank is full of new fuel. It has backfired (literally fire out the pipe) a couple if times during the difficult starts

Recently the bike has started knocking intermittently quite noticeably when trying to start it. (Not the alternator solenoid clicking) Once it starts it runs without the knocking.

Any advice would be appreciated before I take it into the mechanic.

Black plugs, backfiring, easy to start with clean plugs, but then hard again after it's run a while....

All points towards a rich running enviroment to me. I would suggest a carb cleaning and basic tune up. Put new plugs in after you do.

Be sure to check the jets for sizes and compare to stock, verify you don't have a jet kit, make sure all the orings are in good soft round condition... not flattened or hard/cracked. Replace as nessasary. Also check your emulsion tubes for wear. Double check the floats are right and the float needles and seats are in good shape, sealing off properly.

Krey

[Tomasz]

Thanks Krey,

Before I tear into the carbs. Is there any benefit to trying liquid or spray carb cleaners? Anything else I can do? Despite a knack for mechanical things, I have no experience with carbs so I'm a bit hesitant.

Tomasz

[Kreylyn]

Thanks Krey,

Before I tear into the carbs. Is there any benefit to trying liquid or spray carb cleaners? Anything else I can do? Despite a knack for mechanical things, I have no experience with carbs so I'm a bit hesitant.

Tomasz

I think for this situation that the can of spray cleaner will be fine. I don't think you have clogged jets, I think you have a possible float issue. The needle seats could be dirty, but your getting lots of fuel from somewhere... The cleaning is a "while your there, migth as well" aspect. It's more important right now to find out why your running rich. Bad orings? Bad foat needles? Worn emulsion tubes?

Krey