front not firing

running fine thurs / friday, took her in for shock swap/fork seals rear bleed..all non engine stuff. but now Im only running on the up right? I know carb icing etc buth the pro fst is in there, there is a juicy fat spark at the front, the battery is a new full yuasa, I pointed a heat gun at the front carb for a few minutes even tried the carb a little richer/leaner (1/4 turn each way) the mechanic is off today so anything else I could try before taking her in tomorrow for more £xpenditure?!
cheers.
Alex.
"get an injected 900" yes, I had thought off that already! so no smarty pants replies along those lines please...............(bertie)

ignition timing is off ? (you get a fat spark, but at the wrong time)
I'll see how long it takes for someone in the kown to tell me this cant be.

It cant be! as the upright timing is ok, they cant be changed independantly of one another (I hope)

pretty quick..
then it's a tough one. if you have a good spark at the right time, it can only be fuelling..but that, you knew already.
what happens if you make a sacrificial offering ? a chicken ? neighbours pet ?
i'd try that.

there are some sheep at the bottom of the garden.....

think ur getting confused with the poddington peas. I for one would not like to cast aspurtions that the aforementioned are co-habbiting with a collection of hopefuls destined to become part of arfurs next jacket. shame on you.

[Pedro]

Yerbs

you may find that the plug is breaking down under compression and not sparking. Try swapping front and rear over and see if the prob moves.

If not, it sounds like it's broken.....

Ped

muchas gracias! its always the obvious things we overlook! after a few hearty pops as 5 miles of gumpf in the cylinder burnt off all is well untill the next time! looks like icing and then fouling-note to self: carry spare plug and rag, and try a bit of optimax...one thing I didnt mention was that whilst tidying I took the carb warmers off! hmmmmmm I'm going to run a couple of lines up to the front carb I think as that seems to be the problem area. has anyone tried the electrical heaters or know of a good supplier? being an aesthetic ponce I cant be doing with miiles of dangly bike guts.

one more thing, plug gap? o.6 mm?

see.. i told you a sacrifice would make it go again.. so did you go for the sheep ?

I used to go for sheep but then the rspca stepped in.............idiot that I am swapped plugs over quick up and down the road "hmm now its the upright-doh" is this an occasional problem with iffy plugs this one was nearly new? why do they spark but then not under pressure? anyway put a couple of denso s in and all seems fine bar the occasional characterfull "pop"

If a spark plug is getting tired, it will, as you have found out, spark OK when out of the cylinder but when you put it back in - it wont! As the piston rises on the compression stroke, it literally "blows" the spark out if the plug is crook! Even a nice fat blue spark is no guarantee of how a plug will perform once in situ. Glad you sussed it out, Garry. :burnout:

the thing is it was only a week or so old and I had (hardly) been anywhere on it, oh well nothing is perfect.
ps a monster limping on one pot is a pitiful sight....

[Pedro]

Yerbs

I bought some new NGKs a while ago and they lasted about 150 miles before I had to chuck em out. Didn't look too bad but bad miss fire.....

Pays to check the simple things eh?

Ped

it also pays to have someone point out the simple things once in a while! cheers again.