SV650 not starting

[Damon]

Hi all,

It's been a long time since I last visted BCF but it's always my turn to when the going gets tough!

I have a 1999 SV650 in the workshop at the moment that broke down and had to be recovered. The symptoms were that the bike would idle but die with any throttle at all. (Bike wouldnt start at all when I received it)

First thing to do is rebuild the carbs... Full of silt. Cleaned the jets etc and put them back together. Cleaned the tank and replaced the fuel with fresh also. Nothing - no starting whatsoever. Confirmed that fuel is getting to the float bowl and wetting the plugs on both cylinders.

Both plugs are firing with a bright blue spark. New plugs

Both cylinders have just over 200PSI compression (cold).

Substituted ignition control module for a known running bike and the module is fine.

I have sprayed easy start into the rear cylinder inlet and I can get it to fire for around 0.5 seconds on about the 4th attempt with the spray. The front cylinder seems to fire again for a very short time with easy start directly into the cylinder via the spark plug hole.

Once fired once however it doesn't seem to respond afterwards to any cylinder charging for at least 20 mins.

Coolant seems fine with no oil mix and engine oil is at the right level and not contaminated at all.

Once thing I have noticed is that there is alot of crankcase pressure venting out of the crankcase-airbox vent tubes. Is this normal on a twin such as the SV? My thoughts would be that there would be a low compression readings from the cylinders if there was blowby due to worn piston rings??

Anyway, I'm hoping someone could shed some light on the situation as it's driving be bonkers

Thanks all,

Damon

[Taught2BCauti...]

Excessive crankcase pressure doesn't make any sense if the engine isn't running - normally, the fact that the pistons are moving in opposite directions, should more-or-less equalise the pressure.

If the engine was running, crankcase pressure might be a symptom of blown rings and would be more noticeable.

Might be worth taking off the cam covers to see if the valves are operating correctly.

If you have good compression, a good spark, and fuel is getting through, you just need to check that the ignition timing is correct - e.g. you're not getting the spark at the top of the exhaust stroke.
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[Supermoto_Fan]

Unplug the carb heaters and try it. They should be 2 plugs on each carb on UK spec models. They have no use in the UK climates and after 3 weeks of trouble solving why my bike wouldn't start I just happened to unplug them and it ran first time.

Just try it
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