SV not running right
 

Hello


SV has been laid up for few years, dug it out and MOT'd a few weeks ago but it was running like crap, erratic idle, was slow returning to idle when revved and would briefly drop a cylinder occasionally when idling cold. I've stripped the carbs and done the following;

Replaced choke plunger o-rings
Needle's clear
Float chambers fine
Diaphragms fine
carbs balanced
No split pipes
Sliders nice and free
It looks to be fuelling nicely

Now the bike is running like a sewing machine, starts on the button, revs nicely, idles nice and steadily (when hot, its too hot today to get it cold again) but it's popping like mad which makes me think there is an air leak? but I can't find one. The popping isn't effecting the running of the engine so it's over fuelling into the exhaust. Valves possibly? its driving me nuts! I've included a link to a video of it running.


https://youtu.be/W7umLSSGqvE

Re: SV not running right
 

You haven't mentioned the Spark plugs.Try a new set maybe and also with a Multimeter check the resistance of both plug caps.They start off @ 5k ohms but once they get north of 8K ohms they can cause similar problems to the sounds in your video.

The OEM caps are way too expensive in my IMHO so I replaced mine with NGK Straight racing ones,

SD05FMR Red ones

https://www.ebay.co.uk/itm/Suzuki-SV...~fq:rk:13:pf:0

or,

SD05FMB Black.

I made around debris protector out of some old inner tube to replace the OEM rubber one as it didn't fit right on the Straight Caps.If I were going to use the bike commuting I would make a 2nd slightly larger piece to go over the circle as added moisture/debris protection.


https://i.imgur.com/Vnstao6.jpg

Re: SV not running right
 

Hard to be sure from remote diagnostics, but I would suspect an air leak at some point. If you have balanced the carbs are you sure that you've blanked off the balance connectors fully and there are no splits or leaks there? Next I'd be looking towards the exhaust, are all the joins solid, if you are still on the original down pipes the front to mid section likes to corrode. Also what is the condition of the end can, I had some popping where the exhaust packing had burned through?

Whats it like while riding?

Re: SV not running right
 

Good point/s.My old Honda CX500s didn't like even the smallest leak in the exhaust system.

This stuff is the Dog's Danglies for sealing joints on exhausts and dead cheap too,

https://www.ebay.co.uk/itm/GRANVILLE...IAAOSwuxFY2Sme

Re: SV not running right
 

right an update.

I stripped and cleaned the carbs for third time, still no difference. There's definitely no splits pipes. Inlet rubbers are in good condition. There doesn't seem to be an exhaust leak that I can feel. It pops with both the standard can and stubby can on. Riding wise it accelerates nicely as it should and cruising its nice and smooth but when the throttle is shut and slowing to a stop, the throttle seems to run high and it pops on deceleration.



I've put a second set of carbs on and it still pops and runs the practically the same. Coughs abit when throttling up past 6k but those carbs have been sat for ages so I need to ride up and down the road to clear them.



Oddly my speedo move's occasionally even though the bike is stationery and my speedo is on magnets due to the gsxr front end, not sure what thats about but maybe I have some sort of ignition issue which might explain the occasional dropping of a cylinder? Only thing I've touched electrical wise is remove the heated grips and I put a new lithium battery in because the old PB was dead, but off the top head the voltage and amps were the same.

I haven't checked the plugs of leads yet.

Re: SV not running right
 

Seem to remember my Speedo went a bit weird just before the RR gave up the ghost.

Re: SV not running right
 

I've had my RR pack up before and it never caused a running issue.

Re: SV not running right
 

When mine went it ran really badly.

mines been popping and banging because the choke cable needs replacing, as the cable to the rear carb is sticking