What did you do to your bike today?

The only time I've come across something like this was when I knackered the crank/crank bearings in the SV when it got too low on oil. It would get to a certain point in the rev range and then bog down and splutter.
 
Oh gawd MowyTone don't say that ! lol that's proper in the bowels of the engine, I don't think I'm mentally ready for that kind of job haha
 
you'll find 9 times out of 10 its something daft

I hate these type of problems though,one's you cant pin down

sounds like coil or ht lead related to me,esp high ish revs and it spluttering/not revving higher but idk
 
Just had a search and a super blackbird had a similar problem to what you describe, but it was injected. It turned out to be a fuel line clip/kink in the feed to the injectors.

It also mentioned that if the butterfly value in the exhaust doesnt open you can get the same issue.

Here is the link in case it's any help
 
With the cut off so high in the rev range then fuel starvation... possibly cylinder 3.... maybe even far too much fuel in cylinder 3.. this points at carbs. Check main jets are in correct order.. i believe the inner two should be larger than the outer two. Then check needle heights. The only other possibility i can see is coils. You start to notice coils breaking up first of only in the higher end of the rev range... again check the coil pack cylinder 3 is attached too.. firing order is 1-2-4-3 so coil pack on the left of the bike should have leads 1 and 4 so the right hand coil and lead 3 is where i would look for an issue....
 
I'll pick up a multimeter on my way home from work tomorrow and see what the leads and coils have to say. From the videos I have just watched it's really simple.

As for carb work ... I need to read more about them first before I start poking around. I'll also need to have a good look and see if the fuel line is kinked.

Whats that lead coming from the tank on the right hand side leading to nowhere ? is that overflow ?
 
SPARC said:
I'll pick up a multimeter on my way home from work tomorrow and see what the leads and coils have to say. From the videos I have just watched it's really simple.

As for carb work ... I need to read more about them first before I start poking around. I'll also need to have a good look and see if the fuel line is kinked.

Whats that lead coming from the tank on the right hand side leading to nowhere ? is that overflow ?
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If theres 3 pipes coming from the underside it will be one from the fuel petcock and the other two are drainage hoses. One from the lip of the tank to stop water getting into the tank
 
Put a cheeky 80 miles down after work yesterday. Went from Southampton to Romsey then country roads to Andover...Took a wrong turn somewhere by Thruxton and ended up on the M3 to Baisingstoke, so turned round and came back down M3 to home.

The seat is not so comfy after that kinda time (2 hours) and arms were tired. Wrists were fine though
 
SPARC I had something similar to what MowyTone linked to, mine was a kink in the fuel line, might be worth checking that, and all coils, spark plugs etc.
 
SPARC said:
Ah ok I see thanks.

Yes. Perfectly to the actual red line.
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I'm 90% convinced it's fuel related then.

In my experience, if it were coils you'd likely see the issue revving at a standstill, and the bike wouldn't always splutter at the exact same revs. Also it would tend to get better as the bike warms up.

I doubt it's the ECU as again you'd see the problem at a standstill.

It could also be a split carb rubber or vacuum hose somewhere- that can cause all sorts of odd issues. Can be tough to track down though.

But before investigating all that, I'd be checking the obvious stuff. Pull the tank off, pull the fuel lines off and poke something through them. Try it without the fuel and air filters on the bike. If the problem gets better/worse that'll help you home in on the issue.

It's definitely not your crank, you'd have all sorts of other noises, vibrations and stuff going on. Investigate the easy obvious stuff first.
 
A word of caution on removing all the hoses. Depending on the age of the hoses they could break or split so keep in mind you might have to replace some.
 
Fireskull said:
SPARC I had something similar to what MowyTone linked to, mine was a kink in the fuel line, might be worth checking that, and all coils, spark plugs etc.
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CGrieves said:
I'm 90% convinced it's fuel related then.

In my experience, if it were coils you'd likely see the issue revving at a standstill, and the bike wouldn't always splutter at the exact same revs. Also it would tend to get better as the bike warms up.

I doubt it's the ECU as again you'd see the problem at a standstill.

It could also be a split carb rubber or vacuum hose somewhere- that can cause all sorts of odd issues. Can be tough to track down though.

But before investigating all that, I'd be checking the obvious stuff. Pull the tank off, pull the fuel lines off and poke something through them. Try it without the fuel and air filters on the bike. If the problem gets better/worse that'll help you home in on the issue.

It's definitely not your crank, you'd have all sorts of other noises, vibrations and stuff going on. Investigate the easy obvious stuff first.
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MowyTone said:
A word of caution on removing all the hoses. Depending on the age of the hoses they could break or split so keep in mind you might have to replace some.
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Thanks lads. I'll be having a good look at the lines at the weekend. I think I'm going to take the carbs off as well and clean them out. Watched a few videos last night regarding this and it looks super simple just as long as I take my time. That will give me plenty of space to get in and look around at the boots. I'll keep and eye out for any lines which are starting to split at the ends and just replace them. Fuel line off ebay seems cheap enough.

This is actually really good. I'm learning a lot here :) If I manage to get this sorted I owe a few folk here a pint :D
 
Make sure you use tools that fit perfectly when removing jets.... They're brass and pretty soft, and after years in a carb the threads will be completely dry. Nothing more frustrating than having to drill a jet out... I know this from painful experience!
 
So the bike I bought has it's MOT next month and the only advisory it had last time was due to noise, but it passed.

Should this be something which worries me? I could buy a baffle for £30 online but I guess if it passed before it should pass again
 
JunglistE said:
So the bike I bought has it's MOT next month and the only advisory it had last time was due to noise, but it passed.

Should this be something which worries me? I could buy a baffle for £30 online but I guess if it passed before it should pass again
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If you don't get an advisory for noise, it means your bike is too quiet :p

Mine didn't get one :( they obviously didn't rev it to 14,000 rpm :D
 
As long as it's not got a "Not for road use" stamp on then I don't think they will ever fail it on noise as the only guidance is that it shouldn't be louder than the OEM part but they don't actually bother to test that in depth so you just get a "it's a bit loud" advisory.
 
ah awesome!

I know this fresh out of the womb period is probably the most dangerous period of riding but it's seriously addictive. I've never had this feeling with driving. On my way home from work yesterday I ended up going right past my house at 16:40 but not actually getting of the bike until about 6pm.

Does this feeling of wanting to take longer routes ever go? lol.
 
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