K6 with no power , after repairs

I had i crash a year ago , and the SV was almost a year on the garage waiting for all the spares .

I haven't ride the sv , or any other bike this year , but i remember her like a angry little beast , twist the throttle, blink and see 120kmh on the clocks , btw thats how i crashed

My problem now is that the sv , fells like she has less power than my 1.0 Toyota yaris , she seems to have lost all mid range power , struggling to get over 5000 revs , lower revs also seems a little lazy to develop.

the crash smashed the air box , witch i have repaired , i also have a new(used) fuel tank , and I'm back to stock exhaust.

Now sure whats went wrong assembling the bike back , or if the the smashed tank and air box damage anything on the engine , but im hoping someone can guide on where to look first


I also had a erratic idle problem , revs jumping up and down , and strange bang noise coming from the engine as if it missed a beat (bike shakes and makes a sound like if someone hit the engine with a metal hammer)
this problem seems to be gone on its own now .. but maybe it can help to isolate the low power problem.


ps: excuse me for the poor English :/

Originally Posted by dotted

ps: excuse me for the poor English :/

I've just been talking on the phone to a guy talking Spanish at me (support environment). Can you go teach him for me please? Anyway...

OK, you have a loss of torque... is this accompanied by the engine not revving properly?

Have you put the bike into "dealer mode" to see errors on the LCD panel? To do this, you'll need a little wire, and search the forum for posts to do with TPS adjustment. You don't need to do the adjustment, but that'll tell you where to put the wire (with pictures). Then once the wire is in place, turn the ignition on, fire her up, and rev. Hell, take her on a run in that condition.

Any diagnosable error will show a Cxx code where the temp gauge normally is. From that, you can find out exactly where the fault is (if the error code shows).

It depends how it was put back together, but I'd start with the basics first (stale fuel, water in fuel, oil/filter change, TPS adjustment, throttle body balance etc).

Dealer mode doesn't show any error codes.

the engine revs good in neutral , its just when im riding the bike that she gets to lazy , and struggles to get over 5000 revs .



I will try to drain the fuel system tomorrow , maybe theres some crap from the new(used) fuel tank that clogging the fuel system ... no idea on how to do throttle body's balance , so thats a last resort for me

thanks for the reply

Could also be crap in the front plug, check that out whilst you're working on it. (search for water in front plug, running on one cylinder etc etc).

Can't harm it to try it.

Ok, i have followed the SV650 manual to check the fuel system and throttle bodies.


- I have drained the fuel system , and filled the bike with 95 oct. fresh fuel.
Fuel pump had lots of pressure , even more than the minimum of 170ml / 10 sec.

- Took the throttle bodies off , and look for crash damage , found that the strap that connects the TB to the from cylinder was smashed , did my best to make it strait and put it back again.

- check TPS - good
- STV (secondary throttle valves) synchronization - good
- STP sensor (secondary throttle position) voltage - good
- Fast Idle Adjstent - good
-couldn't inspect and clean the injectors , because couldn't make the injectors bolts move...
- haven't sync the TB , don't know how , and don't have the tools..

Bike runs a little better now (or im geting used to it) , but i still have a bad idle , hunting +-400rpm , runs a little rough , but the bottom line is that i don't fell happy with the engine response... im sure the bike was a lot smother and powerfully before the crash

I believe the key to find out whats wrong with the bike , is to find was causing the hunting idle .
Any help is welcome

Originally Posted by dotted

I had i crash a year ago , and the SV was almost a year on the garage waiting for all the spares .

I haven't ride the sv , or any other bike this year , but i remember her like a angry little beast , twist the throttle, blink and see 120kmh on the clocks , btw thats how i crashed

My problem now is that the sv , fells like she has less power than my 1.0 Toyota yaris , she seems to have lost all mid range power , struggling to get over 5000 revs , lower revs also seems a little lazy to develop.

the crash smashed the air box , witch i have repaired , i also have a new(used) fuel tank , and I'm back to stock exhaust.

Now sure whats went wrong assembling the bike back , or if the the smashed tank and air box damage anything on the engine , but im hoping someone can guide on where to look first


I also had a erratic idle problem , revs jumping up and down , and strange bang noise coming from the engine as if it missed a beat (bike shakes and makes a sound like if someone hit the engine with a metal hammer)
this problem seems to be gone on its own now .. but maybe it can help to isolate the low power problem.


ps: excuse me for the poor English :/

You sure you've got that airbox right? If it was smashed as you say it's probably leaking or summit, or at least a leak somewhere on the inlet side

My K6's rev's seem to hunt when the Throttle Bodies are out of sync, by roughly the amount you've said (400rpm give or take when at idle). It also sounds rougher.

To balance them, you'll need a carb sync tool. I have a Carbtune II (or Carbtune Pro - can't remember).

From the left side of the bike (rider perspective), find the idle adjust screw. There's a small hole between the frame (only just big enough to fit my hand through) a little forward, and up from the idle screw. In that hole, you'll find 2 bleed nipples (covered with rubber boots). Take the boots off, put the cab sync tool on the nipples.

Seats off, fuel tank up, engine on. It doesn't matter what values the tool shows, only that they are equal. Look vertically down behind the airbox, and there's a screw (screwdriver will be very close to the air box whilst adjusting). Turn this screw slowly, stop, rev the engine, check the gauges on the tool. Continue until the mercury is level in both tubes.

Once balanced, check your idle speed. You should be able to set the idle speed ~1600rpm, but it'll sound a lot slower, as it's in sync.

Personally, I don't think that will sort out your power issues, and perhaps the best way to investigate that would be to get the bike on a dyno run?

finally got the injectors off just needed a XXL screw driver !
There was a some very thin rust residue on the front injector , will clean them at work tomorrow with a air compressor .

I know , shouldnt try to balance the Throttle bodies whitout the right tools , but even so i tried to fiddle a little with the screw , and it made a difference
Still jumps a little +-100 rpms , but is a improvement , with the carb sync tool i should be able to make it better

About, the airbox... she was badly smashed ,even the rear hole that goes into the TB got cracked , i used sicaflex to seal all the cracks , but i will double check the airbox for leaks , i remenber when i removed the airbox snorkel it made the bike lose a lot o mid power , maybe the lower power is just a problem on the airbox.

Thanks o lot for all the advices guys , will keep you updated

I know im a bit slow updating the news on the bike repair , thats because the bike stays at my parents garage , and its hard to find time to go there and fix it...

Originally Posted by dotted

I know , shouldnt try to balance the Throttle bodies whitout the right tools , but even so i tried to fiddle a little with the screw , and it made a difference

Why not? I've got to the stage where I can balance my SV without the tool, but then, I've done it with the tool every time I've gone near the bike with spanners/screwdrivers for the last 30k miles.

So now, whenever the fuel tank is up, I have alittle fiddle with the screw as well. So long as you don't massively change it, you can't really go that far wrong.

Anyways, good luck hunting for the cause, but I reckon that injector rust has to be at least some of the issue.

ITS FIXED , i have my angry little beast back
I think the bike was running on only 1 cylinder ...

went for my first big ride to test the TB balance , and after 10 min riding, the bike starts surging and backfiring a lot , i look back and notice lots of white smoke coming from the exhaust , was a scary moment , crossed my mind the the engine was going to finally die...
But no after a few seconds , theres was no backfire , and no surging on power , only lots and lots of Power , had to learn again how to be smooth on the throttle.


When i got back home , i had to adjust the idle from +3000rpms to 1500rmps , and balance the TB because idle was very erratic again.
And the bike been running great for the last weak , 200miles .

Dont know what caused the loss of power, or what made the bike fix her self just by riding , but my SV is perfect again , and im happy