Curvy backfiring under load.

[muddydude]

Hi having a problem today with bike backfiring when under load..ie when putting a bit of throttle to pull away...its just been in the shop to get cct and valve clearences checked and were fine..it was fine going to work this morning and the only thing different I did was give it a wash at work befor the problem started..any ideas thanks in advanve :-(

[rictus01]

water under the plugcap perhaps ?, have you checked the plug drain ?

[muddydude]

Plug drain??? enlighten me lol thanks..

[rictus01]

clearly if you don't know what it is, you have never checked or cleaned it...

It is in the service manual for the bike, by the way.

the well the sparkplug sits in has a drain from it's base, on the fron cylinder this exits on the righthand side on the head just below the level of the plug itself, if this is blocked then the well fills with water and can interupt the spark.

[muddydude]

Thanks will check it ;-)

[muddydude]

Wasnt water took sv to the bike shop where cct were done mechanic thinks chain slipped gave me a vfr800 to use nice but not a patch on the sv ;-)..willupdate when i get it back

[yorkie_chris]

Doesn't sound like that at all to me given what you've said above.

[hm-89]

I had a similar problem when sitting in rain not long ago, had to limp home because it was misfiring, turned out it was the front spark plug, supposedly a common problem, easily sorted though. If u change it and find out this is the problem, be sure to seal it, or spray a bit of wd-40 for a bit of water resistance, hope this helps.

[muddydude]

Got my bike back today yeay!! turns out I had quite a bit of water contaminating my petrol !!! now its fixed Ill have to try and find out how it got in..Thanks for your help and comments guys ;-)

[yorkie_chris]

Drain hole to left of fuel filler is usual culprit. Otherwise condensation can occur over years.