749S firing on one

DJ749s · 23-08-2008, 06:01 PM

Hi ,
went to take the bike for a rap the other day and noticed that it wasn't running at all well,the vertical cyclinder wasn't firing properly, after some investigation I found the plug (champion RG59V) had black oily crap on it, I check the other one and it wasn't as bad, so a new set was in order (NGK CR9EIX) put them in and she runs a beaut, I was thinking that maybe I wasn't revving the bike well enough and that fouled the plugs as I have been gentle with it considering that I am still getting used to the machine.
First question is : would a set of NGK CR8EIX's be better for street riding as they are a hotter plug and would they perform better at lower revs?
2nd: is it normal to change the plugs in these things often (ie: 6 monthly)?

Thanks in advance

DJ

Evolution · 23-08-2008, 06:12 PM

Plugs every 10,000km isn't out of the ordinary. Make sure you always use a premium fuel when you can.

Had a miss on mine recently. Thought it might have been plugs. Turned out to be a clogged fuel filter.

If it keeps fouling plugs a little bit of tuning migth be the answer. Should be able to trim the fuel back a little. Also maybe check your air filters.

Nero Diablo · 23-08-2008, 06:29 PM

Back in the days of leaded fuel we used to chuck them every 5000kms the good thing about a twin is you only have to buy two each time. But it seams your Italian bike is in need of a Italian tune up I can help with this

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rod · 23-08-2008, 09:25 PM

Iron plugs need replacing more regularly as the electrodes erode. The CR9EIX are iridium so should last at least 10,000km. Probably put the original plugs (RA4HC?) in and see how it goes. I think the lower the number the hotter the plug?

DJ749s · 23-08-2008, 10:32 PM

Yea lower the number the hotter the plug from the ngk book anyway.Italian tune up? if it involves smoking rear tyre no dice

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Cheers for the help

DJ

Nero Diablo · 24-08-2008, 06:39 AM

No smoking rear tyre just taking out for a ride and waiting for the valves to start bouncing off the pistons before changing gear.

Evolution · 24-08-2008, 07:41 AM

Desmodromic valve train = no valve bounce = peak RPM tough love on the open road to clean those snotty plugs. The italian tune i believe was being referred to. Shift by feewl grasshopper!!

DJ749s · 24-08-2008, 07:51 AM

Ah got it, time for an out of town run.......