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?:confused:

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

Re: lack of power in mid range revs sv650 1999
 

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

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?

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.

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 :-)

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.

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?

Re: lack of power in mid range revs sv650 1999
 

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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Re: lack of power in mid range revs sv650 1999
 

Sorry forgot to say starts and idles with no problems


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