The International CBX Owners Association

I keep reading about SeaFoam on these pages and just assumed I wouldn't be able to get it here in the UK, but actually you can and I've ordered some to try and cure a problem that has just occurred on my 82 low mileage CBX.
My bike runs beautifully at idle and up to about 4,000 rpm but then just bogs down so I assume blocked jets. I do realise that I may have to pull the carbs but if I can possibly avoid that I would obviously like to!

My question about Seafoam is this - can you actually run the bike on it neat? (ie no fuel). The instructions seem to indicate that "more is better" and obviously going for a ride with just seafoam would be horrendously expensive but what I was thinking was setting up an auxiliary fuel supply of just Seafoam and let it soak for a few days and then running it through the engine.

Or failing that I could just follow the instructions!

Simon

SeaFoam is nothing more than well-branded fuel injector cleaner, a petroleum distillate, and very hard on orings and other rubber parts. It is NOT a good idea to soak anything in it, add it as no more than 2X recommended dilution and run it through. It will swell rubber parts and like so can temporarily seal a leaky carb. Given your symptoms, before you go looking for a miracle in a bottle, remove your ignition cover, pickups, and remove and inspect your mechanical advancer. When holding the base and twisting the collar, it should smoothly and crisply snap back. If it’s stuck or super sticky (not uncommon) then there’s your culprit. Hose it down well with carb cleaner, actuating it as you to do to clean it up, lubricate it with lithium grease and reassemble. Protip: remove the right-side crank cover and rotate the engine clockwise with a wrench till the tip of the rotor precisely aligns with the pickup point on one of the the black plastic pickups, doesn’t matter which. Reinstall in the same position (without touching the crank position) and that will save you retiming it if that’s a concern.

Report back!

N.

P.S. For an even quicker test, loosen your gas cap and go for a ride, in case a plugged tank vent is causing starvation. Half a tank of gas or less is recommended

One other check-point: Check the little filter in the fuel petcock bowl. It's a quite small thing. AND, very fine mesh. Has the bike sat for log time periods without being run? You may have to remove the carbs and remove the large vacuum caps for cleaning. These can accumulate considerable 'gum' over time that may be preventing the slides from fully lifting. Just an after-thought.

Thanks chaps - I will take a look at those things

Another reasonably quick(-ish) test is to pull the seat and temporarily remove the air filter element and take it for a short spin.

The idea here is to allow more air to be pulled into the engine (vs with the air filter element in).

So, does it run better, or worse?

If it runs better, then your bike is running overly rich with the filter in.

If it runs worse, then it is running overly lean with the filter in.

May give you a clue on how to proceed next.

(and don't forget to reinstall the air filter!)