TOPIC:

Gents
have a problem ive never encountered before which has appeared suddenly basically a complete lack of power, took the bike out yesterday it was a pain to start and keep running but i assumed maybe fouled plugs and it would clear as i went on a run but it actually got worse to the stage where on 3/4 throttle i could just about pull away from the lights and was doing about 15 miles an hour,all the down pipes seem hot but somethings horribly wrong i am wondering if it could be the cdi any ideas?

My first thoughts are, it sounds like fuel starvation. Check the petcock, filter then carbs.

Fuel-cap vent ?. Check vent hose and make certain some "BUG" hasn't made a home. I've found insect pupae in air-mixing intakes in a set I purchased for rebuild, parts of "bugs" in my own fuel filter (recent article) and have seen Mud-Wasps plug up the Pitot-Tube (Air-Speed Indicator) on our jump-plane, within 25 minutes, between loads. Plus McZee's suggestions.

already checked the inline filter, will disconnect the fuel hose from the carbs to check fuel flow[open the fuel tap and drain into bottle] seems to have happened a bit too sudden to be an air lock but will also check, thanks for all the suggestions

Paul, had a very similar lssue recently - initially thought fuel starvation, but pet cock flowed perfectly and float bowls full of super unleaded ( also like your bikle my Z13 had heat in all down pipes).

Thought best to start by checking my recently fitted Dyna Coils - was surprised to find a couple of very loose electrical bullet connection feeding my coils (only me to blame for that): quick bit of contact cleaner and liberal use of my crimping pliers and she was soon singing on all six again. Probably worth checking your coil feeds / connections. Fingers crossed it turns out to be something straight forward.

Cheers Tim

I wish we had more information here. It started but not easily. So you have spark. All the pipes are hot but no power. So it would appear to be running on all six cylinders. 3/4 throttle and only 15 MPh ?
First thing I would do is put the air box and fire it up and watch the throttle chocks rise and fall as the throttle is opened and closed. If they're lazy it suggests low intake vacuum which could be attributed to the camshaft timing slipping a couple of teeth. Hence the reason I ask for more info. Sometimes when an engine is shutdown and it sputters or coughs, it's enough to upset the cams if the cam chain is loose enough. The only other thing I've seen is a new load of bad fuel that won't burn.

I believe something happened and you might have heard it happen and not recognized the issue. I'm merely trying to provoke thought here.

My money goes on the cam timing slipping causing low intake vacuum and the throttle chokes aren't seeing enough vacuum to lift.

Let us know what your find please no matter how bad. It's a learning opportunity for us. Good luck

KB