blue smoke out of a carbed raptor 650!

i've got a little problem guys, here goes:

- it's a carbed cagiva raptor 650 from 2001, 22kms on the clock

- the last few times i rode her, she's beginning to have some issues: i'm losing power quite irregularly, it feels as if i'm running on 1 cylinder sometimes, and when i open the throttle fully, it picks up with a few 'thud thud thud' 's and from about 6k rpm, she comes to life, and has full power.

- steady throttle, and after a few seconds i can feel her losing power again. I open up the gaz and off she goes again (with a serious hesitation).

- i thought: rainy days, front plug is getting soaked or something, but i have changed the plugs today, together with a valve job (all within spec), and i was going to synchronise the carbs, but i can't get her to run properly! it's got me puzzled i start her up with some choke, and she runs ok for a few seconds (both pipes are hot, so i've got spark on both cylinders), but from the moment i touch the throttle, she sortof misfires, and starts running badly (with a gigantic cloud of blue smoke out of the pipes)

any ideas? bad power from coils or something? could it be something electrical? could it be bad fuel?

she's bone stock, except for a K&N airfilter which i mounted two weeks ago (can't imagine that's the problem).

thanks for your suggestions!
W.

the engine should be identical to the curvy sv650's by the way, but i guess most of you knew that already

here are the plugs, maybe it helps:

both the plugs have black (charcoal sortof :O) edge and pin, and one of the two (rear cyl.) has a normal white core, the other one (front cylinder) has a black charcoaled core. see pics . plugs are dry.

[fizzwheel]

I thought blue smoke signified burning oil.. surely if it was bad fuel it would effect both cylnders not just one.

Coupled with the black plug, I reckon its oil your are burning

Sorry I cant help anymore

I own a 650 Raptor and have had similar symptoms. Turned out to be
Water in the fuel.

Drain the carb float bowls into a jar and see what you get.
its easier to get to the drain screws if you dismount the fuel pump.
If theres water then drain the whole fuel system, pump lines and tank, chuck the lot away.

On my bike the drain from the filler area had got blocked, it appears as a black rubber tube beside / lower than the brake pedal, its one of the two, blow through both to check they are clear.


Hope thats all it is ,
my raps done 23K miles and still runs great.
Cheers
pod

hi pod, thanks for your reply.

i'm gonna check out the carbs tomorrow. how can you tell there's water in the carb float bowls?

cant see it being oil getting into the cylinders if the plugs are dry, but if they are sooty it would indicate running rich, so i would check that your chokes not jamming

Hi


At the base of the carb float bowls are drain spigot pipes , attach a length of hose to the spigot and put the other end in a jar, undo the allen head drain screw a couple of turns and the bowl will drain into the jar, water will be obvious as a more viscous blob slithering around in the petrol.
A ball ended long allen key will help get in there.

i had problems with one of the drain screws seizing in the threads, its a good plan to remove them and put some anti seize copper goo on the threads to save future hassle.

To drain the tank, if it needs it, pull the fuel delivery hose at the pump inlet and then pull off the vac hose which fits on the inlet manifold, suck on the end of this hose to open the fuel tap, pinch this to keep the fuel tap open , and drain the fuel.

To drain the fuel pump, disconnect the fuel and vac lines then shake to get the fuel out.

i mistakenly let the contaminated fuel settle and put the fuel back in minus the water , big mistake, had to redo the whole thing and chuck the bad stuff away.

Water seems to gather in one carb more than the other, cant remember which, this gives the running on one pot symptoms you describe.

Halfords type places sell a Silkolene fuel additive in a wee purple bottle that keeps the fuel dry, this will help a lot since you can still get condensation problems even if all the drains are working OK. Helps stop carb icing as well.

While you are at it change the plugs for iridium types , they last a lot longer .
Cheers
pod

hi pod,

i went a little further than you described, and i have taken off the carbs completely (gotta learn carbs sometime ) , and i have started to disassemble them.

rear diafram out, all good.
front diafram out: i see a spring and needle holder and washer just lying in the diafram! must have shaken loose or something?? (or maybe it shook loose when i took off the cap, but not very likely...
Could a stuck diafram/needle have caused my symptoms?

anyway, i took off the float bowl caps too, and they're spic and span mate, also i checked out the little fuel filters in there, and not a spot of dirt.

a few pics because i can





and now i'm waiting on some little washers, and some bigger jets before reassembling the carbs again, will give me a bit more power combined with the new race exhausts i'm gonna put on

thanks for the helping thoughts so far,
i will keep you updated on how she runs when i get her all back together!

Yep, that would have caused those symptoms. The holes in my FZX carb diaphragms caused similar symptoms but it's fixed now. The joy of keeping old carbs in the shed - I just robbed the non-holey diaphragms out of those and it works now

Just make sure there's no bits left over when you put it all back together



PS. got those lovely pipes fitted yet?