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weird feeling coming on and off power

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geewhizz
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weird feeling coming on and off power

Post by geewhizz on Thu 24 Mar 2016, 10:42 pm

I’ve been trying to figure out the cause of what id describe as a ‘lag and snatch’ feeling when I come on and off the power. As if there is some tension to be taken up when coming on the power and a loosening of tension when coming off. Its hard to properly describe the feeling to be honest. I’ve checked the chain for tight and slack spots (I have non), checked the coosh drive rubbers (all good), the bearings seem tight, as does the swing arm. I’m considering the possibility that it may just be a consequence of fitting the r6 throttle, which I already described as a little snatchy. I need to replace one of my rear suspension units as the dampener is leaking but I doubt that would be it. It’s the sort of feeling I could get used to, but at the moment it’s stopping me just riding the bike and enjoying it!  Any ideas anyone??


Last edited by geewhizz on Fri 25 Mar 2016, 1:01 am; edited 1 time in total
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Jameshambleton
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Re: weird feeling coming on and off power

Post by Jameshambleton on Thu 24 Mar 2016, 11:20 pm

Have you checked that the hand grip isn't catching on the bar end of the switchgear
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geewhizz
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Re: weird feeling coming on and off power

Post by geewhizz on Thu 24 Mar 2016, 11:34 pm

new grips, bars, bar end weights and cables... they're all functioning better than ever
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jchesshyre
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Re: weird feeling coming on and off power

Post by jchesshyre on Fri 25 Mar 2016, 12:53 am

Not 100% sure but I think I've more than once had this as a result of needing to sync the carbs, as well as (on other occasions) loose chain or worn cush rubbers.
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geewhizz
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Re: weird feeling coming on and off power

Post by geewhizz on Fri 25 Mar 2016, 1:08 am

its due a carb sync after changing the downpipes and putting a sealant on the rocker cover, will be happy to do that and rule it out...but if that was the remedy, what would the cause be?...altered fuelling?
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Tricky.
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Re: weird feeling coming on and off power

Post by Tricky. on Fri 25 Mar 2016, 8:35 am

is the R6 throttle a quick action? single/twin cable? what sort of mileage have you done since changing it? could you not swap it back to rule out if this or not?
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geewhizz
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Re: weird feeling coming on and off power

Post by geewhizz on Fri 25 Mar 2016, 8:55 am

The throttle tube is a quick action,  twin cable.  Done a couple of hundred miles since getting it back on the road after fitting a new swing arm too. I think I've already chucked the old throttle tube unfortunately.
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jchesshyre
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Re: weird feeling coming on and off power

Post by jchesshyre on Fri 25 Mar 2016, 11:20 am

The carb sync being out means each cylinder is getting a slightly different air-fuel mixture, mostly at smaller throttle openings and lower revs, which can cause the symptoms you're talking about. 

Can you remember if it's done it ever since you changed the throttle tube? I know sometimes it's hard to pin down exactly when something like this started.
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ANDYC
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Re: weird feeling coming on and off power

Post by ANDYC on Fri 25 Mar 2016, 1:09 pm

As we're running CV carbs on these, unless of course you've changed them then the throttle should have no effect on the lag you're experiencing.
The R6 throttle may open the butterflies quicker but the airflow is controlled by the slide and vacuum that moves it. Do they move freely? are the rubber diaphragms in good condition? is the vacuum chamber full of bits of old sponge from the small air filter?
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eternally_troubled
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Re: weird feeling coming on and off power

Post by eternally_troubled on Tue 29 Mar 2016, 12:26 pm

I know this sounds dumb, but have you fiddled with the amount of slack in your opening/closing throttle cables?  Could it just be that you have a little too much slack?

All the MOT man will do is turn the bars lock to lock with the engine running and check that the revs don't increase - so as long as you've got a little bit more slack than that it's up to you...
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geewhizz
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Re: weird feeling coming on and off power

Post by geewhizz on Sun 03 Apr 2016, 5:50 pm

All cables are set up perfect. I balanced the carbs - it was definitely needing done as it has significantly reduced overall vibrations but this slack feeing is still there. I've never had the disintegrating sub air filter problem but i cant say what condition the carbs are in overall - I expect they are fine. The issue feels mechanical to me and not a fuelling issue. I can't get my head around why i feel it coming off the power - super annoying!! If my chain is too tight it would only be by a tiny fraction - I doubt its this but who knows - maybe
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Beresford
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Re: weird feeling coming on and off power

Post by Beresford on Sun 03 Apr 2016, 10:30 pm

Loose drive sprocket ?
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geewhizz
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Re: weird feeling coming on and off power

Post by geewhizz on Sun 03 Apr 2016, 10:43 pm

I don't think so as I took the sprocket carrier off to look at the Cush drive rubbers and all seemed fine there, sprocket seemed solid too. I guess I'm going to have to recheck everything and maybe consider replacing the wheel bearings again
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jchesshyre
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Re: weird feeling coming on and off power

Post by jchesshyre on Mon 04 Apr 2016, 10:11 am

Have you checked the sprocket carrier bearing? In 100k miles on my last CB I never had to change the rear wheel bearings but had to change the sprocket carrier bearing twice in that time. I was alerted to it by weird grinding noises from the back end, but it could possibly cause your symptom.
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Beresford
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Re: weird feeling coming on and off power

Post by Beresford on Mon 04 Apr 2016, 12:35 pm

@geewhizz wrote:I don't think so as I took the sprocket carrier off to look at the Cush drive rubbers and all seemed fine there, sprocket seemed solid too.

I was thinking of the front sprocket and bolt, as I'd assumed that you had already checked the rear one.
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geewhizz
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Re: weird feeling coming on and off power

Post by geewhizz on Tue 05 Apr 2016, 9:01 pm

I checked that too, the front sprocket seems fine. It got me thinking however...could it be the chain on the way out - stretched links? The reason I didn't think this before is because the wear indicator isn't anywhere near the position where i changed it last time. In fact I've rarely adjusted it. I was pretty good with the lubeman auto oiler but for a little while i kept forgetting to top it up and I was therefor running it dry for a while. More importantly I didn't take note of the milage when i changed it over but that was likely sometime may -july 2013 ( i remember the sun burn well ) - there is a little play when i pull the chain either out or downwards at the rear of the sprocket, i don't recall if this is normal...
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Beresford
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Re: weird feeling coming on and off power

Post by Beresford on Wed 06 Apr 2016, 12:18 am

As DelBoy says, a chain should be good for at least 25K miles if you change the front sprocket at the half way mark. How many miles has yours done?
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geewhizz
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Re: weird feeling coming on and off power

Post by geewhizz on Wed 06 Apr 2016, 10:02 pm

In total 45k, I've done 20k in my ownership since October-2012. Do you have a link to that particular delboy vid? I'm curious to hear about changing the front sprocket mid way - I've not heard that before. 

I think it may have improved a little since I've heavily oiled the chain. I spoke to a mechanic today who suggested thinking about the clutch.
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jchesshyre
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Re: weird feeling coming on and off power

Post by jchesshyre on Wed 06 Apr 2016, 10:15 pm

45k on one chain? Congratulations! Methinks a new chain may solve the problem though...
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geewhizz
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Re: weird feeling coming on and off power

Post by geewhizz on Wed 06 Apr 2016, 10:29 pm

hah I wish. It's likely to be more in the region of 15k on this chain.
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Beresford
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Re: weird feeling coming on and off power

Post by Beresford on Wed 06 Apr 2016, 11:12 pm

https://www.youtube.com/watch?v=UxD3qdD7LhE
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geewhizz
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Re: weird feeling coming on and off power

Post by geewhizz on Thu 07 Apr 2016, 12:12 am

thank for that B, thats a perfect excuse to try out a 14t front sprocket too Smile
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geewhizz
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Re: weird feeling coming on and off power

Post by geewhizz on Fri 29 Apr 2016, 12:02 pm

Ok Beresford I think I owe you a pint!! Great shout about changing the front sprocket. I just put in a 14t renthal sprocket, a quick ride round the block and the feeling seems to have gone. pictures of sprockets to follow...


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Beresford
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Re: weird feeling coming on and off power

Post by Beresford on Fri 29 Apr 2016, 8:51 pm

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skyrider
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Re: weird feeling coming on and off power

Post by skyrider on Sat 30 Apr 2016, 8:25 pm

looks like someone is a bit chuffed Smile

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Re: weird feeling coming on and off power

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