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SV650s only running on one cylinder above 5000rpm


Matthew Duncan
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so, not a yamaha, but its still worth asking as all you people are extremely heplfull!

basically, the SV i bought is running fine, up untill about 4500-5000rpm, and the one of the cylinders cut out.

there was a heap of water in the tank, but thats been drained/cleaned along with all the lines and the carbs,

anyone got any ideas as to what to check next?

was planning using it this week but since its nae got the same reliability as my yamaha, i decided to take my *caugh* trusty xj *cough* instead.

Cheers.

Matt

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Well Matt it sound electrical,so go over the basics first check for loose dirty connections,figuer out wich cyl is going down,swap coils, plug caps and see if it switches cyl's. easy to check with a non contact temp gun if you have 1 or access to 1

If not then check the pick up coil's againts each other,I belive the sv has 1 per cyl.

O on second thought do a comperssion test as well might have a weak valve spring from sitting compressed for so long and your getting valve float at 5k rpm.

The Sv also uses a fuel pump so you need to check the fuel volume availble,not pressure VOLUME ie 1 liter per x time,the pump might not be able to supply enough fuel at 5 k and both cylinders are running lean. I have seen lots of pumps make good pressure but fail on volume so run the pump for at least 5 min and watch the flow.And be careful no sparks or smoking around open container of gas

I know this wasn't a exact answer but you don't know if thats why the bike got parked in the first place,so by process of elimination you will find the problem.And if the members can help with a car then I'm sure they will help with a SV if they can.

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The Curvy does not a fuel pump. Vacuum air fed.

My mistake only the 1000s does a fuel pump.

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No worries DT, I just didn't want him to start looking for a pump somewhere. If it was in the workshop section I would have thrown in a few ideas.

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No worries DT, I just didn't want him to start looking for a pump somewhere. If it was in the workshop section I would have thrown in a few ideas.

Appologies, i thought it would be a bit cheeky to put i question about a suzuki in the yamaha clubs technical section - is there a way i can move it?

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No worries. There and an increasing number of techie questions being started in the bar and new members areas. I am at work at the moment but if no one else moves it I will move it later. Have you determined which cylinder is cutting out? The front one is a barsteward to mess with as it is so close to the rad. Things I would do are; Check both plugs and plug caps - tightness, gap and loose ht leads Check the fuel and vacuum hoses under the tank for pinching and splits Check the choke cables to each carb to make sure one isn't seized Check the air filter box in on the carbs correctly and check the air filter is clean Then check the coils as previously mentioned The sv's are prone to running on one cylinder even in light rain unless you have a fenda extenda. Check you have no water or oil leaks that are only apparent at temperature and this isn't shorting out the plug. I have had mine 3 years and apart from a speedo sensor and a holed oil filter all I have done is service it and the usual consumables like tyres and batteries. They are reliable bikes and fun to throw around.

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No worries. There and an increasing number of techie questions being started in the bar and new members areas. I am at work at the moment but if no one else moves it I will move it later. Have you determined which cylinder is cutting out? The front one is a barsteward to mess with as it is so close to the rad. Things I would do are; Check both plugs and plug caps - tightness, gap and loose ht leads Check the fuel and vacuum hoses under the tank for pinching and splits Check the choke cables to each carb to make sure one isn't seized Check the air filter box in on the carbs correctly and check the air filter is clean Then check the coils as previously mentioned The sv's are prone to running on one cylinder even in light rain unless you have a fenda extenda. Check you have no water or oil leaks that are only apparent at temperature and this isn't shorting out the plug. I have had mine 3 years and apart from a speedo sensor and a holed oil filter all I have done is service it and the usual consumables like tyres and batteries. They are reliable bikes and fun to throw around.

Cheers! i thought it was the rear one, but the more and more i read itno it it sounds like its the front thats more prone, i will check these things later on tonight. someone at my work mentioned to me that they had one that was running like shit, and as soon as they took the foam padding off the underside of the tank it ran a treat? apparently its a usual thing for this to be sucked into the top of the filter

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If you have had foam sucked into the carbs then you are in trouble. Never heard of that to be honest. Let me know when you have checked my previous list and which cylinder it is.

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yeah thats what i thought! they later clairified that they meant pulled in as in to cover the hole, not actually liittle bits coming off and getting sucked into the block

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