Very poor running, help!

Thank you for all the responses, I'm going to try the Redex at the weekend but I have a question: If one cylinder is playing up what is the easiest way to identify which one it is? I tried touching the headers as they warmed up but as it is only an intermittent misfire they warmed fairly evenly, up until now I've had single and twin cylinder 2 stroke Yams and with a separate pipe for each cylinder it's easy to fault find. Short of taking a plug lead off and seeing if the bike will run on one I'm not sure what to try?

[R1ffR4ff]

Originally Posted by volvoboy73

Thank you for all the responses, I'm going to try the Redex at the weekend but I have a question: If one cylinder is playing up what is the easiest way to identify which one it is? I tried touching the headers as they warmed up but as it is only an intermittent misfire they warmed fairly evenly, up until now I've had single and twin cylinder 2 stroke Yams and with a separate pipe for each cylinder it's easy to fault find. Short of taking a plug lead off and seeing if the bike will run on one I'm not sure what to try?

I would still go for new Plug caps,

Do a forum search as I posted some cheaper NGK alternatives recently.


Glad you brought this up.I too am used to twin exhaust twins so troubleshooting a cylinder was easier.I could do with an easy way to check for problems in the future.

I have an Infra-red temp gun so could check cylinder temps but that may not be enough for diagnostics.I suppose I could also check exhaust down-pipes and if a cylinder is cutting out enough one should be cooler than the other.

They don't cost a lot and are a useful addition to the toolkit,

http://www.ebay.co.uk/itm/UK-Digital...kAAOSw9N1VlLp1

Just,"Spit-ballin'" here as our colonial cousins say

[Blapper]

Or even:

http://www.ebay.co.uk/itm/Nice-Non-C...wAAOSwU~FWERrd

[R1ffR4ff]

I needed the temp gun when I set about getting rid of the Mechanical fans on my CX500s.I came up with a system using 2nd hand Ducati electric fans and cheap temperature thermostats.

However I now know the temperatures of my Walls,my fridge and next door's cat<BFG>

Boy's toys

Well, replaced the HT leads between the coils and plug caps today......... still running rough. Just the Redex to try now and then I've had enough! If anyone can recommend a good bike shop in the Fareham / Southampton area I might have to try that, although the thought of leaving it in the corner of the garage to rot is quite appealing at the moment! So far with this bike I've changed front wheel bearings, speedo rotor twice, rebuilt the front calipers, replaced the headlight loom, clutch lever switch, front brake light switch, float bowl seals, rear shock, rewired the starter solenoid switch, replaced the indicators, clutch actuator, rebuilt the rear caliper, changed rear wheel bearings. And now with this poor running issue I'm reaching the end of my tether I've always had Yams up until this point and am wondering if all SVs are this unreliable?

[R1ffR4ff]

Don't give up.Many of us have been through what you are going through with older 2nd hand motorcycles of all makes.It's usually down to previous owner's neglect and not a specific brand.

As you say you have done some work on the Carbs I've found that CV carbs have to be refitted very carefully so as not to introduce air-leaks and that may be an added cause of the problems.On the old CX500s there are joints at the air-box and carbs ends to be wary of.Less of a problem with the SV inasmuch as the Air-box goes right onto the carbs.

A quick way to check for air-leaks is @ idle spray some WD40 or Carb/Brake cleaner around the carb joints areas and if the speed increases there's air getting in.

I have a feeling that a good carb clean and setting up and solid refit should go a long way to help with the problems.

[SV650rules]

RiffR4ff is correct, if the previous owners have ridden it in all weathers and not kept the bike up to scratch (or done some shoddy work on it) you cannot really blame the bike manufacturer, IMHO SV's seem to be some of the more reliable bikes around.

Personally I would have tried the Redex first as it is the easiest thing to do, just pop a 'shock and awe' overdose (at least twice the normal amount - but putting more in will not hurt).

[R1ffR4ff]

RedX or STP fuel treatment are two of my,"Unsung Heroes" over the years.I never get stale fuel by using them as well as keeping the carbs good and lowering the carbon build up in the cylinders.RedX used to originally be advertised as,"UCL"(Upper Cylinder Lubricant) IIRC but then was realized as a great liquid service tool for the whole fuel/combustion system.

Sidenote:

Some years ago I was on a ride-out with a load of newer Bikes than one of my old Honda CX500s.By the time we got to Hawes from Hull several of the very new bikes were coughing and spluttering like mad.
Turned out all the ones suffering had tanked up at the same supermarket petrol pumps and had got some crappy fuel!!!

If there is suspect fuel in the tank drain it and keep it for cleaning stuff and get some known good fuel in there and there may even be some water in the bottom of the tank and some may even have got into the float bowls?

On my old CV carbs any little water droplets in the float bowls caused no end of rough running but the carbs had nice easy to get to Float Drain screws.

I'm just redoing my old CX500 webpages but some of this info is still useful in general terms,

http://sheppola.comeze.com/Carbs2.html

[Blapper]

That isn't rare. I once was the first customer into a petrol station as it opened. I filled my brand new car with petrol and drove off. Ten minutes later the thing was running like a pig. I got out and sniffed the exhaust to find I had got a dose of diesel in with my petrol. It turned out that the tankers fill the garages diesel tanks then switch the hose over to the petrol compartments so the petrol tanks in the garage get a build up of diesel in with the petrol which normally doesn't show up as the agitators in the tanks keep it moving but I was first in and they switched it all on while I waited so it had settled into the bottom of the tank and was over the suction pipe...

I got my money back and a complete tank of fuel as compensation.

[Bibio]

if you have stripped the carbs and sorted the choke plungers and you are getting fuel then its electrical.

spark plugs, what colour are they and are any of them wet. have you checked how healthy the spark is. remember a wet sooty plug will look like oil but it could be unburnt fuel and misfiring. plugs with this condition will break down so pretty much fubar, get a new plug or swap the plugs over to check that the plug is still working.

ECU, its a not so common problem but it does happen. when this happens it gives the same symptoms as you are describing. there are a few people on the forum who have gone bald trying everything and a swap out of the ECU has worked when nothing else has.

if you say you have tried and replaced most things, getting healthy voltages, new plugs and serviced carbs then its looking like the ECU.

another thing is the oil level, ALWAYS keep it topped up above the min or the motor is toast. sv's do not like low oil levels.