Running rough

[tex]

   Not sure what this one is any help suggestions appreciated, bike was running great then filled it up with super unleaded  on the way home started running rough spluttered home like pulling away in third. Got home had some tea then went back out and it was fine again used it for 3 days no problems,  went out yesterday and it was bad again, so drained the fuel and put fresh in but no difference, starts up fine revs high but back fires, only thing I did notice when I turn the ignition on it doesn't make that clicking noise so maybe the fuel pump is on the way out , does this sound like the fuel pump ? I don't think it's blocked jets as I use sea foam and it hasn't been laid up for more than a few weeks.

[Trebus]

Had a similar issue on a Honda that appeared straight after fuelling up in France. Turned out to be high resistance plug cap

[celticbiker]

Plug, plug cap/lead  or coil I'd say.
Was it raining around the time it started?

[tex]

Yes celtic it was pissing down   thanks 

[tex]

Had a similar issue on a Honda that appeared straight after fuelling up in France. Turned out to be high resistance plug cap




 Thanks I'll have a look

[celticbiker]

Knowing Yamaha I wouldn't be surprised if it's a coil then but first off I'd clean the low tension connectors and SA tape the leads and blow out the plug tunnels.
If your drain holes are blocked you'll have water sitting around your plugs causing trouble.

[ogri48]

spray brake cleaner on your downpies mate, suss out which one aint running right first. then swap coil leads to further isolate the problem ( four and one the same, ditto 2 and three) sorry if thats saying what you already know mate, and hope you get it sorted

[Trebus]

Knowing Yamaha I wouldn't be surprised if it's a coil then but first off I'd clean the low tension connectors and SA tape the leads and blow out the plug tunnels.
If your drain holes are blocked you'll have water sitting around your plugs causing trouble.

I can vouch for the self-amalgamating tape tip. Had a XJ600 divvy at one point, complete piece of shit to be honest. When it rained it ran like a dog, tape stopped the HT leads arcing. When it was cold the carbs iced and ran like a dog. When the weather was fine it vibrates and buzzed like crazy despite having done essentially no miles and in good mechanical order. Compared to the old XJ600 it was an awful bike.

Thread hijack over 😀

[celticbiker]

I had a love affair with the xj series too.
I had the 600, 900 and an xj650 turbo. Loved them all.

[Trebus]

Had a couple of older XJ600 and an early XJ900 until quite recently. Very capable bikes even by modern standards. Would have either again. Just the 600 Divvy I didn’t like, vibes and poor brakes.

[tex]

spray brake cleaner on your downpies mate, suss out which one aint running right first. then swap coil leads to further isolate the problem ( four and one the same, ditto 2 and three) sorry if thats saying what you already know mate, and hope you get it sorted

   Thanks ogri ill go through the lot at the weekend

[tex]

Finally  sussed it , as you sit on the bike the far left header pipe was cold, took the plug out but it still sparked when earthed to the frame , so checked the airbox that was clear, bit of head scratching later I put a new plug in and that cured it so must have been bracking down in the head, I'll do all 4 while I'm there and paint the headers .

[ogri48]

excellent result mate

[Trebus]

👍🏻👍🏻