SV feels rough, when rolling off the throttle - SV650.org

07-02-17, 04:34 PM

Hi guys,

I need some help! I ride my SV650S Sport K8 every week day to work. It does over 250+ miles a week, and has 23000 miles on the clock. It has a scorpion shorty exhaust and and steel braided brake lines, they are the only mods!

Recently when rolling off the throttle it feels very coarse and rough, it's more noticable in 2nd and 3rd, and it feels more coarse when it gets under 5K revs and there is a lot of vibration feedback coming through the pegs, more than usual.

This has been followed with a change of feel when the bike get below 2.5K revs, where it use to jolt slightly when coming to an almost stall, now it just wants to stall straight away believe 2.5K. The engine itself sounds and runs fine, and there is no issue when accelerating!

Nothing has been replaced on the bike other than the mods.

I've had all the bolts and nuts checked and tightened, but I can't have a diagnosis without leaving the bike at the garage for a day or two. So I wanted some expierienced SV owners to help!

I appreciate any help and advice given!

Sent from my SM-G925F using Tapatalk

tom_e · 07-02-17, 04:53 PM

Worn chain and sprockets? Wheel bearings?

A badly worn chain with lots of seized links (back when I knew no better) made my old 125 feel very rough and clunky when rolling off the throttle so I'd probably check there first.

07-02-17, 05:33 PM

Nope, new sprockets and chain! Not even done 600 miles on them!

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Blapper · 07-02-17, 05:37 PM

Maybe a choke cable issue.

How about getting it dyno'd again to see what the mixture is like when it happens?

07-02-17, 05:44 PM

Never had it Dynoed...Previo
us owner installed the shorty end can. And a dyno will cost a fair bit of £££.

But I'll take on board about the choke cable! Thanks.

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Biker Biggles · 07-02-17, 05:54 PM

When was it last serviced?Throttle balance,plugs,air filter and have the valve clearances ever been checked?

07-02-17, 06:09 PM

Last serviced at 20,000 miles. Throttle balance, and the air filter get checked during the service. The valves are due to be checked at 24,000 miles.

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Sir Trev · 07-02-17, 06:12 PM

A K8 will be injected so will not have a cable choke.

Are you sure the chain is tensioned right? If it is as new as you say it could have stretched when bedding in. Also, need to check if the wheels are in alignment. If a shop fitted the c&s for you don't assume they did it right, especially if something does not feel right - it will serve you well to learn how to check things like this.

Craig380 · 07-02-17, 06:19 PM

As mentioned above, I'd look at chain & sprockets and the wheel alignment.

Out of curiosity, what's the idle speed when the engine is fully warmed up? Can't remember if you can easily adjust the idle on a K8

07-02-17, 06:34 PM

Cheers for the info guys. I regularly go to these guys for my motorbike. The chain is tensioned accordingly, I don't think the wheels being out of alignment would cause this for the simple reason that it has only occured very suddenly.

And I completely agree, it would serve me well if I was more mechanically minded! Lol.

The bike idles at 1100 revs.

Sent from my SM-G925F using Tapatalk

07-02-17, 04:34 PM	#1
Sam_Le_Rouse Guest Posts: n/a	SV feels rough, when rolling off the throttle Hi guys, I need some help! I ride my SV650S Sport K8 every week day to work. It does over 250+ miles a week, and has 23000 miles on the clock. It has a scorpion shorty exhaust and and steel braided brake lines, they are the only mods! Recently when rolling off the throttle it feels very coarse and rough, it's more noticable in 2nd and 3rd, and it feels more coarse when it gets under 5K revs and there is a lot of vibration feedback coming through the pegs, more than usual. This has been followed with a change of feel when the bike get below 2.5K revs, where it use to jolt slightly when coming to an almost stall, now it just wants to stall straight away believe 2.5K. The engine itself sounds and runs fine, and there is no issue when accelerating! Nothing has been replaced on the bike other than the mods. I've had all the bolts and nuts checked and tightened, but I can't have a diagnosis without leaving the bike at the garage for a day or two. So I wanted some expierienced SV owners to help! I appreciate any help and advice given! Sent from my SM-G925F using Tapatalk

07-02-17, 04:53 PM	#2
tom_e Member Join Date: Jun 2015 Posts: 438	Re: SV feels rough, when rolling off the throttle Worn chain and sprockets? Wheel bearings? A badly worn chain with lots of seized links (back when I knew no better) made my old 125 feel very rough and clunky when rolling off the throttle so I'd probably check there first.

07-02-17, 05:33 PM	#3
Sam_Le_Rouse Guest Posts: n/a	Re: SV feels rough, when rolling off the throttle Nope, new sprockets and chain! Not even done 600 miles on them! Sent from my SM-G925F using Tapatalk

07-02-17, 05:37 PM	#4
Blapper Member Join Date: Jun 2016 Location: Rochester,Kent. Posts: 824	Re: SV feels rough, when rolling off the throttle Maybe a choke cable issue. How about getting it dyno'd again to see what the mixture is like when it happens?

07-02-17, 05:44 PM	#5
Sam_Le_Rouse Guest Posts: n/a	Re: SV feels rough, when rolling off the throttle Never had it Dynoed...Previo us owner installed the shorty end can. And a dyno will cost a fair bit of £££. But I'll take on board about the choke cable! Thanks. Sent from my SM-G925F using Tapatalk

07-02-17, 05:54 PM	#6
Biker Biggles Member Mega Poster Join Date: Jan 2005 Location: Barnet Herts Posts: 5,068	Re: SV feels rough, when rolling off the throttle When was it last serviced?Throttle balance,plugs,air filter and have the valve clearances ever been checked? __________________ On a clear day we stand there and look further than the ordinary eye can see.

07-02-17, 06:09 PM	#7
Sam_Le_Rouse Guest Posts: n/a	Re: SV feels rough, when rolling off the throttle Last serviced at 20,000 miles. Throttle balance, and the air filter get checked during the service. The valves are due to be checked at 24,000 miles. Sent from my SM-G925F using Tapatalk

07-02-17, 06:12 PM	#8
Sir Trev Member Mega Poster Join Date: Jun 2005 Location: High Wycombe, where the chair factories used to be Posts: 1,440	Re: SV feels rough, when rolling off the throttle A K8 will be injected so will not have a cable choke. Are you sure the chain is tensioned right? If it is as new as you say it could have stretched when bedding in. Also, need to check if the wheels are in alignment. If a shop fitted the c&s for you don't assume they did it right, especially if something does not feel right - it will serve you well to learn how to check things like this. __________________ We are the Goon Squad and we're coming to town, BEEP BEEP!

07-02-17, 06:19 PM	#9
Craig380 Member Mega Poster Join Date: May 2015 Posts: 1,238	Re: SV feels rough, when rolling off the throttle As mentioned above, I'd look at chain & sprockets and the wheel alignment. Out of curiosity, what's the idle speed when the engine is fully warmed up? Can't remember if you can easily adjust the idle on a K8

07-02-17, 06:34 PM	#10
Sam_Le_Rouse Guest Posts: n/a	Re: SV feels rough, when rolling off the throttle Cheers for the info guys. I regularly go to these guys for my motorbike. The chain is tensioned accordingly, I don't think the wheels being out of alignment would cause this for the simple reason that it has only occured very suddenly. And I completely agree, it would serve me well if I was more mechanically minded! Lol. The bike idles at 1100 revs. Sent from my SM-G925F using Tapatalk

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