5000 rpm flat spot

[Rasta-ninja]

Hey all, recently fitted my bike with new plugs(flooded the engine.... ) and got a new battery cos the old one was, well, old. After putting it back together and taking it for a spin i found that i have a flat spot around 4500-5k revs which wasn't there before. It also makes a weird sound. The only thing i can say it sounds like is when you've got a paintball gun and hold the cock lever whilst pressing the trigger, really quick firing but high pitched. Its fine once you get past it though.

Its got an aftermarket can, but i doubt that has anything to do with it as it was fine before.

Ive looked at other similar posts, and it mentions cleaning the carbs, i stripped em down about 2 months ago and gave em a good clean so theres nothing blocking it......any ideas?

[Tirpitz]

If it wasn't there before then it must be something to do with what you have interfered with, or disturbed while doing it. Process of elimination to find out which it is. Don'y go chasing after things which were never touched / disturbed like the carbs, that's illogical.

Presumably you gapped the plugs before fitting?

Airbox on properly, no leaks?

No trapped fuel hoses?

Plug leads secure, not trapped?

etc.

[Rasta-ninja]

thats what i thought at first, so i took the plugs out and checked the gaps and they were fine, .075. The only thing i can really see is that the one of the boots the carbs sits into appears to have a little crack in it but it doesn't look like a hole, or like anything would be leaking, il check to see that none of the hoses are being squished by the fairings or something silly....

One other thing i was possibly thinking is maybe i need to re-balance the carbs. Ive never actually done it whilst oning the bike(6 months) and i'm not sure when they were last balanced. Is it possible to out-sync then whilst taking them apart and cleaning..?

[richr]

did you do the carb strip just before the flooding/battery or was it ok when you flooded it

sounds like a possible air leak or fuel starvation

as said before check anything you moved/changed prior to delving deeper

h t h rich

[Rasta-ninja]

It was the same time, my bike wouldnt start up and i was trying to find the cause and it seemed like fuel starvation cos it just wasn't firing, so i stripped the carbs then. But turned out i flooded the engine. The only other thing i can think is maybe when replacing the sparks i put them in too tight. I dont have a torque wrench so just put them in as tight as they could...would that have an effect? Thanks for all the advice btw, i just can't do anything right now cos i dont have a garage -.-

[Tirpitz]

No it will be nothing to do with the tightness of the plugs but FFS don't do them up really tight and strip the threads. You really need a torque wrench. These http://www.ebay.co.uk/itm/Draper-3-8-Dr ... 2318b781ce really are very good and are as cheap as chips. I've bought from that company too and can recommend.

If you've stripped the carbs then yes, you will have knocked the balance right out. Even left alone these bikes get out of balance inside 3k miles. Deffo needs doing, could easily be the problem but either way it needs to be eliminated.

[Rasta-ninja]

Thanks so much for linking me with that!!! Ive seen so many that are worth ridiculous amounts of money. As for the balancing i'll get on top of that and let you all know how it goes.

[banner001]

i have a sealey torque wrench 2-24NM and a teng 19-110NM, i can recommend both.