Bike running great - I don't know why?

[Simonr501]

Many of you will know that I rode my rebuilt Jota 120 from Keith's place for nearly 500 miles in March.
The bike ran very well. Keith had picked up a rich-shift at low throttle-opening but did not have the slightly smaller pilot jets required at the time.

Keith sent them down, I fitted them and retuned the pilot screws - bike ran even better and much smoother.

This situation persisted for a while until I took the bike through Central London. She ran rougher and rougher and was strangely reluctant to rev and vibrated quite a bit. This did not go away afterwards as the weeks went by even after a few fast runs, I thought that the carbs had gone out of sync or something.

In frustration the other day I gave the engine the beans to the red line a couple of times (warmed her up properly first), as I parked the bike up I thought she was a bit better.

Fast forward to this evening, I switched her on and cor blimey guv she's a flyer again, nice and smooth and feels a lot more powerful.
Trouble is I DON'T KNOW WHY?

My best guess is that one of the plugs fouled in London and didn't clear properly until she was given what for.
I've never fouled a plug in my life, so is that what happened?

Whatcha reckon?

Simon.

 

[Grant]

My 120 used to eat plugs all the time.

 

[padlock]

When things like this happen i think it best not to worry about it. Just enjoy

 

[Reggie3cl]

There's a moral in there:  Thrash the tits off it and be happy!

 

[Simonr501]

A pocket full of plugs and she's good to go then.
The girl has seen London once - think that is enough.

I will give her a good hard run every now and then.

 

[a14rgs]

There's a moral in there:  Thrash the tits off it and be happy!

+1

 

[noodels]

always good to clean fuel taps filters/and carb bowls !!thrash on lean fuel could result lean mix over heat and deternation result holed piston

 

[Simonr501]

That's a comforting thought!
I cleaned the float bowls out when I changed the pilot jets - some small amount of crap.
Next opportunity I will remove the fuel taps for cleaning.

Doesn't feel lean at all - plenty of punch, hardly surprising as Mr Nairn tuned it up lovely.

 

[noodels]

just love the simple things in life delortos

 

[Reggie3cl]

Doesn't sound like leanness- more like rich fouling.  My 180 would foul the plugs dead easy if I didn't knock off the choke pronto.  Never did find the reason- RGS will chunter away happily on the choke no probs.  Go figure...

 

[noodels]

forgot never used choke on 900ss twist and go squirt ha!ha!or get it wrong would launch me over handlebars

 

[nick7]

Keith binned the air filter and it partially then fully  swallowed a leaf?
Nick7

 

[Simonr501]

If mine swallowed a leaf then it looks like it's been spat out the other end now.
So it looks like you have gone green Nick and you are burning Biomass Fuel now - you are supposed to let the leaf decompose first though.

SimonR.

 

[veravista]

Sounds like it's knackered Simon.  Tell you what I'll take it off your hands for ?500....

 

[CLEMTOG]

COLD FOULING
well thats what I think anyway, it happens much more on (gay) 120's espcially Jota 120's I have  no idea why, but cold fouling occurs if you start the engine, but fail to warm it thoroughly, then kill it and go back indoors, eg, your mate comes round and you start it up, we all do it, dont you just love the sound? well it causes cold fouling, something to do with the modern fuel shit that we get sold, sometimes the only cure is new plugs, a good thrashing also works, in the main.
CLEM

 

[3patC]

My Audi A8 Does that Clem. If you turn it off before it gets properly warm it can be a bugger to start on all 8 cylinders next day. Otherwise it behaves impeccably.