Bike loses power sporadically

[koba]

for someone whos hands on it can be a money saver too. Ive been to mechanic before who wouldnt have a clue what they are doing but charge you to go through all the options that i can do myself.

Ok then, your best off looking for a service manual, it will tell you how to test all the specific components.

[CookMySock]

ok the last internet diagnosis isn't anywhere near this gem....I've been a mechanic for the last 20 odd years and never heard of this one....maybe you should stick to what ever the fuck you do during the day....

Shoot filthy mouth off? much? Stick to talking to your women like that ay? Jerk.

Steve

[crazyhorse]

Too technical for me - I'd take it to a bike shop

[stify]

Shoot filthy mouth off? much? Stick to talking to your women like that ay? Jerk.

Steve

oh no I've got hurt feelings....and I stand by awaiting more usless information from you...dick

[YellowDog]

Hey Skinny, I did have something like this happen on my XF650. It would just lose power jerking on and off at around 100kph.

The solution turned out to be the battery terminal screw being a bit loose. I tightened it and all was sweet for a week or so and then it did it again. I stripped and cleaned both terminals and then did them both up tightly. The problem was completely cured.

Hope you problem is something as simple as this.

[FROSTY:Me]

Skinny given your description I'd be STARTING to look at the carbs,fuel pump fuel tap area.
Look at it this way if I'm right you're ahappy camper if I"m wrong you've given the carbs a good huck out which on an older bike is never a bad thing.
From thereI'd have a look at the plug leads and caps,--seeeing as the tanks off anyway.

[SS90]

oh no I've got hurt feelings....and I stand by awaiting more usless information from you...dick

Dangerous Bastard just chose his words wrong.
By "vaccuming down" (sic), I took it to mean that he was suggesting that the breather on the fuel cap could be blocked, so, when the fuel level decreases, the fuel tank cannot equalise with the ambient air pressure, creating a negative pressure in the fuel tank, essentially stopping the flow of fuel to the carb (the carb cannot equalise this pressure, because of the float valve, so you have air pressure (thereabouts) in the float bowl, and a negative pressure above the float needle.

Positive pressure will always try to equalise negative pressure, not the other way round, so in effect, there is more chance of fuel going upwards (except for the float valve stopping it) to the tank than from the tank to the carb in this situation, like when you pour petrol from a 20l plastic container, you have to undo the little "breather cap" on the top to allow the fuel to flow faster the little piddle that comes out

That's what I took from his statement.

It is a possibilty (but these engines are well known for problems with the emulsion tubes wearing out, and flooding the airbox,giving similar faults).......and, quite common.

[CookMySock]

[....] That's what I took from his statement.

He's just taking a (small) opportunity to abuse a person because it makes him look big.(sic)

Steve

[GOONR]

Skinny given your description I'd be STARTING to look at the carbs,fuel pump fuel tap area.
Look at it this way if I'm right you're ahappy camper if I"m wrong you've given the carbs a good huck out which on an older bike is never a bad thing.
From thereI'd have a look at the plug leads and caps,--seeeing as the tanks off anyway.

+1 for looking at the carbs my bike would start to run on 3 cylinders when it was hot, my emulsion tubes are buggered but George from Motorcycle Doctors sorted them out and the bike runs sweet now.

[blossomsowner]

tend to agree with frosty on this one. check carbs, plugs and leads.
Can you tell which cylinder is dropping out by header temp or plug condition?