Engine revs

Technical stuff specific to the Raptor 650
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Dave Vee
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Engine revs

Post by Dave Vee »

Hi all.

Having a problem when the engine is warm or hot,the motor revs rise and fall at tick over and some times when coming to a halt the motor cuts out completely,I've checked for air leaks in the induction system but not found anything obvious :? any ideas guys???
Dave.
pod
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Re: Engine revs

Post by pod »

Water in the fuel,
Stay calm.
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Miz
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Re: Engine revs

Post by Miz »

You could run a dose of "dry fuel" through it to rule out water. How long since its last service, throttle bodies balanced etc?
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norrie
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Re: Engine revs

Post by norrie »

Carbed or injected? Defo try draining the tank and trying fresh fuel as suggested but.
Norrie.

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Dave Vee
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Re: Engine revs

Post by Dave Vee »

It's a carbed model,did the syncranisation a couple of weeks ago,can also feel some hunting at moderate revs suggesting a weak mixture,I did set the idle screws also to 3.5 turns out,I may need to check the settings are correct for these caarbs.
Dave.
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Miz
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Re: Engine revs

Post by Miz »

OK, did the problems start after the synch or before?

Have you tried the wd40 trick to check for leaks?
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Spyke
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Re: Engine revs

Post by Spyke »

The fuel tank breathers seem to get easily clogged, which in turn means it's easier for water to get into the tank in rain or at bathtime. As an alternative to the dry fuel you can chuck in a cup of meths which should then sink to the bottom of the fuel, absorb any water, and burn away when she starts up.
Road racing's where it's at - going round in circles all day is for hamsters.
Dave Vee
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Re: Engine revs

Post by Dave Vee »

I'll have to do a thougher check next weekend and report back.
Dave.
pod
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Re: Engine revs

Post by pod »

I bet the fuel tank breather has an insect in it, every time I check mine a fly has wedged itself in the top.You can blow the blockage out by finding the other end of the breather which is tucked into the frame loop beside the RHS riders footrest, one pipe is for the cooling expansion tank, the other is the fuel tank cap area drain, do this with the fuel lid open.

I have had very bad water contamination before, to the point no amount of magic potions make any difference, its much easier to dump the fuel and start again with fresh. Do you know where the carb float bowl drains are?, I find it easiest to access them with the fuel pump removed and tucked up out of the way, (no deed to disconnect pipes just the two mounting screws.

Link to carb drain thread
http://www.raptorchapter.org.uk/viewtop ... =15&t=1548
Stay calm.
Dave Vee
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Re: Engine revs

Post by Dave Vee »

Hi all.
Sorry I've taken time to report back.Well I've increased the idle jet screws turn out to 4.5 turns which stopped the hunting,re-balanced the carbs which seems to have improved the problem a little,and also blown out the breather pipe,I've still got some occasional stailling when coming to a stop,so better but not perfect!
Aussiejoe
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Re: Engine revs

Post by Aussiejoe »

Service manual for SV650 carby model available here https://www.dropbox.com/s/r9qgbwqz4wbva ... Manual.zip. Pilot screws should be 2 and 1/2 turns out according to the manual, also check/adjust the TPS(Throttle Position Sensor). Check the springs on the choke plunger, I gave the ones on my bike a bit of a stretch to make sure they were seating the plunger properly. Also check the drain holes on the spark plugs, there is one on the left hand side of the rear cylinder and the right hand side of the front cylinder. I found the front one blocked up after riding in heavy rain and had water sitting in around the spark plug. I've taken the the fuel tank drain out of the bottom of the tank for the breather, going to get a plastic one with a bigger hole and use larger diameter rubber tube.
pod
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Re: Engine revs

Post by pod »

again on the choke plunger and the TPS, dont mess with the carbs
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