lack of power in mid range revs sv650 1999 - SV650.org

31-05-17, 04:49 PM

Hi
all of a sudden I have lost power in mid range revs.
also when cruising at 70mph at 5,000 revs , twist throttle and nothing happens , no increase in revs. engine generally sounds lumpy.
I have checked both spark plugs ( that's a job in itself) and both are ok and not wet, put a brand new battery in ( made no difference), bike charges battery at correct amp-age, emptied fuel tank and put in new clean fuel, made sure filter was clean and vacuum system was working ok. Took out air filter and cleaned it .
Am now at a loss what to do next, as nothing I have done has made any difference
anyone any idea's?

R1ffR4ff · 31-05-17, 05:25 PM

Try some RedX fuel treatment(Asda).

See this thread,2nd page,

http://forums.sv650.org/showthread.php?t=226910

maviczap · 31-05-17, 08:50 PM

Stuck choke plungers, take them out and give them a clean

R1ffR4ff · 31-05-17, 09:02 PM

Mavs. I've not looked at my manual but I assume my curvy has choke plungers and just so I know in case I hit this problem where are they and how Would I clean/service them?

maviczap · 31-05-17, 09:11 PM

Lift tank, take off air box, follow choke cables to each carb and you'll see the screw holding the plunger in place. These screws are made of cheese, so be careful in removing them. A proper JIS screwdriver is the best thing to use. These screws can snap, so go easy.

Take out plungers clean and lube, with a light grease. Replace everything. I changed my choke plunger screws for little Allen bolts.

R1ffR4ff · 31-05-17, 09:16 PM

Thanks for that. As soon as I saw Cheese and screws my head says replace

That's a service job on the list

Red ones · 31-05-17, 10:05 PM

"took out air filter and cleaned it"
How many miles has it done? Is it an OEM or after market? I've found they are worlds apart and now only use OEM and replace but never clean. They seriously affect the performance from about 6000 rpm when dirty.

johnnyrod · 02-06-17, 08:57 AM

Sounds more like the carbs need a clean. Bit of a main jet blockage. Does it start and idle fine?

02-06-17, 09:08 AM

Quote:

Originally Posted by johnnyrod

Sounds more like the carbs need a clean. Bit of a main jet blockage. Does it start and idle fine?

Hi, i have now put in new spark plugs and air filter and added redx, tested all electrics as per haynes manual and all within specs.Bo difference

So guess it can only be fuel. So will now need to remove carbs and do full clean.

One other strange thing is did a temp reading on exhaust at inlet to rear exhaust it is around 60c and manifold is at 140c - do you think their could be a blockage in exhaust?

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02-06-17, 09:09 AM

Quote:

Originally Posted by jon-northampton

Hi, i have now put in new spark plugs and air filter and added redx, tested all electrics as per haynes manual and all within specs.Bo difference

So guess it can only be fuel. So will now need to remove carbs and do full clean.

One other strange thing is did a temp reading on exhaust at inlet to rear exhaust it is around 60c and manifold is at 140c - do you think their could be a blockage in exhaust?

Sent from my iPhone using Tapatalk

Sorry forgot to say starts and idles with no problems

Sent from my iPhone using Tapatalk

31-05-17, 04:49 PM	#1
jon-northampton Guest Posts: n/a	lack of power in mid range revs sv650 1999 Hi all of a sudden I have lost power in mid range revs. also when cruising at 70mph at 5,000 revs , twist throttle and nothing happens , no increase in revs. engine generally sounds lumpy. I have checked both spark plugs ( that's a job in itself) and both are ok and not wet, put a brand new battery in ( made no difference), bike charges battery at correct amp-age, emptied fuel tank and put in new clean fuel, made sure filter was clean and vacuum system was working ok. Took out air filter and cleaned it . Am now at a loss what to do next, as nothing I have done has made any difference anyone any idea's?

31-05-17, 05:25 PM	#2
R1ffR4ff Member Mega Poster Join Date: Feb 2017 Location: JAMOADR(1999 Curvy) 39,000 miles Posts: 1,487	Re: lack of power in mid range revs sv650 1999 Try some RedX fuel treatment(Asda). See this thread,2nd page, http://forums.sv650.org/showthread.php?t=226910 __________________ "Stultus est sicut stultus facit"

31-05-17, 08:50 PM	#3
maviczap Member Mega Poster Join Date: Mar 2007 Posts: 9,097	Re: lack of power in mid range revs sv650 1999 Stuck choke plungers, take them out and give them a clean __________________ We're riding out tonight to case the promised land Make everyday count RIP Reeder - Jolly Green Giant and comedy genius

31-05-17, 09:02 PM	#4
R1ffR4ff Member Mega Poster Join Date: Feb 2017 Location: JAMOADR(1999 Curvy) 39,000 miles Posts: 1,487	Re: lack of power in mid range revs sv650 1999 Mavs. I've not looked at my manual but I assume my curvy has choke plungers and just so I know in case I hit this problem where are they and how Would I clean/service them? __________________ "Stultus est sicut stultus facit" Last edited by R1ffR4ff; 31-05-17 at 09:04 PM.

31-05-17, 09:11 PM	#5
maviczap Member Mega Poster Join Date: Mar 2007 Posts: 9,097	Re: lack of power in mid range revs sv650 1999 Lift tank, take off air box, follow choke cables to each carb and you'll see the screw holding the plunger in place. These screws are made of cheese, so be careful in removing them. A proper JIS screwdriver is the best thing to use. These screws can snap, so go easy. Take out plungers clean and lube, with a light grease. Replace everything. I changed my choke plunger screws for little Allen bolts. __________________ We're riding out tonight to case the promised land Make everyday count RIP Reeder - Jolly Green Giant and comedy genius

31-05-17, 09:16 PM	#6
R1ffR4ff Member Mega Poster Join Date: Feb 2017 Location: JAMOADR(1999 Curvy) 39,000 miles Posts: 1,487	Re: lack of power in mid range revs sv650 1999 Thanks for that. As soon as I saw Cheese and screws my head says replace That's a service job on the list __________________ "Stultus est sicut stultus facit" Last edited by R1ffR4ff; 31-05-17 at 09:18 PM.

31-05-17, 10:05 PM	#7
Red ones Member Mega Poster Join Date: Jul 2003 Location: Hertfordshire Posts: 1,422	Re: lack of power in mid range revs sv650 1999 "took out air filter and cleaned it" How many miles has it done? Is it an OEM or after market? I've found they are worlds apart and now only use OEM and replace but never clean. They seriously affect the performance from about 6000 rpm when dirty.

02-06-17, 08:57 AM	#8
johnnyrod Member Mega Poster Join Date: Jul 2003 Location: Doncaster, oop norf Posts: 2,128	Re: lack of power in mid range revs sv650 1999 Sounds more like the carbs need a clean. Bit of a main jet blockage. Does it start and idle fine?

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