I’ve heard of plug killing problems like you describe as a result of using Dyna Coils of the wrong output. (Perhaps a reason the CCWs were sold on FB). Are you able to cross check any part number of the CCW coils to ensure they are correct for your model?
Thanks guys. I have checked primary coil impedances. Haynes states 3.8 to 6.2 ohms. The OEM coils come in at 3.8 (Horizontal) and 3.9 (Vertical), whereas the CCWs come in at 4.5 and 4.5 respectively. So both sets within spec. For completeness, the secondary coil impedances are 11.98/12.25 kOhms on the OEMs and 11.99/13.20 on the CCW. Haynes says 10.8 to 16.2 kOhms, so again, all in spec. @Desmoquattro - I am starting to think back towards fuel myself now... The fact that it fires up OK on both and will run me to the end of the road, but then only starts to misfire when I wind it on a bit is suggesting perhaps a shortage of fuel. When got the carbs back from their cleaning, the RH (Horizontal) float bowl was sticking and pissing fuel out of the overflow. I had the bottom off the bowl and freed it. When I put it back together it was still leaking a bit but a gentle wallop with a plastic mallet stopped it. I guess it's not inconceivable that it is still sticking, but closed rather than open, or at the least not moving freely. That might explain why it would run for a bit but hen once the bowl is drained will cut out. I will take a look at that. I haven't really had time to get back to it since last weekend's investigations, and am away this weekend again. Will see if I can get some time in the week to have another look at the carb floats. The guy who cleaned and rebuilt them for me reported no problems (e.g. holed floats), so maybe just a sticky pin. Thanks again James
Blimey that really does sound like a fuel issue then from what you have just said about the carbs. Sticking float would explain the misfire. I would suggest pull them off and check all again, a pain I know but sounds like the main culprit!!
Could this be some kind of breather issue? Some piping in the fuel tank? (I don't know much about carbed 900s). I've had similar issues on FI bikes that have been solved by cleaning up the fuel filler cap. But I am no mechanic, sorry if I'm talking rubbish.
Don't know about the SS but, on Monsters with the same engine and carbs, there are some little plastic pods that the carbs vent into. I believe the function is to protect the carbs venting from airflow, causing pressurisation issues, not sure how critical this is or whether the SS has a different setup but maybe it's something related to this, especially if it only happens on the move?
The breather issue is relatively easy to diagnose and fix. If the tank can’t breathe, because the breather holes in the cap are blocked, the effect will be that fuel being pumped out of the tank to the carbs will create a vacuum in the tank, starving the supply of fuel. If this is what is happening, try and open the cap. It should be difficult to do so as the vacuum will be ‘sucking’ the cap closed. If this is the case, simply clear the breather holes in the cap, the collar below the cap and at the breather/overflow nozzle at the top/front of the tank. There were tales of some tanks imploding due to this vacuum, but they may have been urban myths.
