Last cry for help, Misfire...

[stevie16v]

>:(As you'll know from my posts. Ive been working on a xj 600s, L reg which had been sitting for a while. Done most things, But it will only fire on cylinders 1 and 2. I've checked everything i can, New plugs, Plug caps, Checked resistances on coil packs, compression seems ok.
3 and 4 do have a spark, But it doesnt seem to be doing much. The coil packs are split into 1 and 4, 2 and 3. So really doesn't appear to be that. I have checked most things that I can, The only common factor i can see between cylinders 3 and 4 is the red and orange wire which comes out of the back. I thought if that was faulty then i wouldn't get a spark at all, Maybe you can tell me otherwise. I'm really just looking for one last pointer before i throw the towl in and scrap it to try and get some of the silly amounts of money i've thrown at it back. Any suggestions?

[palmydays]

Steve,
Did you get any response at all from this post & did you sort out the misfire at all?
I am experiencing a similar problem but cannot pin it down, I was going to post but if folk don't respond it's not much cop! :\
Hope you didn't scrap it, would have been a shame!!
Cheers,
Dave.

[bobh]

I like to think that the folks on here are about as helpful, and knowledgeable, a group as you're likely to find. But unfortunately if no-one else has encountered a similar problem, and found the solution, they probably won't be able to offer much in the way of advice. So please don't take the lack of responses as a lack of willingness to help where possible.

Obviously I can't do a proper diagnosis on the information available, and not having a D6 any more I can't check the relevance of the red and orange wire mentioned. But it looks like there is a spark on all cylinders, since both coils are operational. I assume that the OP has done the obvious check of switching the HT leads from 1&4 and from 2&3 to see if the problem goes with the lead (might be necessary to de-mount the coils if the leads aren't quite long enough).

If it's still the same cylinders that won't fire up, I'd turn my attention to fuel, particularly as the bike has been standing for some time and could have blocked jets or other orifices - just squirting some carb cleaner in doesn't necessarily do the job. The pilot jets in particular have very tiny holes which can block up with petrol residue, and have to be blown clean. Also the floats or float needles can stick. Or the choke plungers could be stuck open and cause an over-rich mixture. In fact there are mnay things that can go wrong with carbs that haven't been used for a while.