Flat spot

[Trojan]

Evening Gents, just been out on a rideout and after running in still, noticed the engine was failing a few times,uphill and starting was very sluggish then suddenly kicked in and pulled like a train, I had jetted the carb from the original settings as they were way out....set up is ...Rapido 225 race, Fran speed supertourer. 30 mm Dell PHBH...AV266 (NOW) PILOT..55 SLIDE 40...NEEDLE X7 Second clip from top FLOAT VALVE 300 all these adjusted from the original settings,just wondered if I ve overlooked anything ...how ever, I noticed the exhaust seems to run on if that makes sense when I ve opened up and the closed down say downhill as if it was free wheeling and not corresponding to the throttle action.....cheers again gents for any advice

[Morgan]

"I noticed the exhaust seems to run on"

Sounds like an air leak, possibly an intermittent one, this would also explain a sudden surge when the air leak kicks in. maybe do some plug chops at different throttle positions.

[ktmh5]

What's your main Jet?

[Trojan]

Hi Ktmh5...the main jet is 130, ...Morgan, leak down has been done,really should have phrased it better, when full chat and leave the throttle to close it seems to run on and not in sequence as if its missing, if that makes sense, I will be checking the flow from the tank as that may also be the cause, like its running out of fuel, process of elimination...cheers Gents

[camel]

Hi N....riding behind you for a few miles i did notice your scoot would go like the clappers then fail to cruise,to me it seemed something to do with your gearing,you seemed to rev well into your power band but couldnt cruise in it,either the porting is too revvy to stay in the power or you may need to check the gearing to adjust it to stay in the power better,it certainly sounded good when you wound it up.

[Trojan]

Hi Camel, yes you did mention that,and I ve taken on board, but what concerns me is when I opened it up there was a flat spot .close the carb and re open then it goes, when we went up hills it was flying as you saw...So gearing Yes...but I also think theres something un balanced between Carb , maybe fuel flow ??? and then its enough in the float bowl, and the Exhaust seems to run on when after revving and coming down from speed, as if its not on sequence to the engine revs ???? of that makes sense...cheers for the input,as im trying to eliminate as many faults as poss.....

[Trojan]

Evening Gents....so far, I have drained some fuel from the tank to check the flow....disappointingly 380ml in 60 secs, I think its safe to say that may be the reason why im getting a miss from the Exhaust after full chat, also sluggish then literally kicks in like a mule....fingers crossed this may be the answer....Fast flow tap I think.....

[holty]

fuel starvation can give the same symptoms as an air leak as was suggested earlier, ive always been told a pint in a min on a tuned engine is whats needed, like you say a fast flow tap is the way forward.

[Trojan]

Cheers Holty and yes it seems that's one of the reasons why the Lammy was acting the way it was, Camel s comment is taken on board also, as he was with me in the ride out whilst it was acting up....Thanks for the comments Gent, it all adds up to an answer