Curvy sv650 down on power

Originally Posted by punyXpress

Did you use the choke lever?
If so, did the choke fully close when you returned it?
You DID return it, didn't you?

I used it first thing in the morning when the bike was cold. Yea it was returned but somebody at work mentioned that it may be worth investigating that its functioning properly. Gonna get the tank up tomorrow and start by having a clean of the filter and go through from there. Hope its nothing to serious.

So tonight we had a good look around the accessible areas:
1) Spark plugs - Front was finger loose when taking it out, sooty looking too on the spark end. We swapped it for a spare and got it tightened up, no cross threading either.
Rear seemed fine and was tight.
2) Air box, again no restrictions obvious, filter looks good, the box itself has a little oil in it.



3) The fuel filter was clean, we tested the petcock off the bike using a syringe to open the vacuum valve and fuel flowed freely out of the tank.



4) All vacuum pipes and fuel lines are in good condition and the bike was tested with the tank raised to make sure nothing was kinked with it down.
5) The battery terminals were cleaned as they looked a little crusty.
6) The choke was fully pushed back but we didn't look into the carbs themselves to see what the choke was doing at the end of the cables.

After which the engine was sounding like this, question to you guys is, does it seem right or do we still have a lot of hesitation, we seem to think it may have improved but we're not sure if we are imagining things!!

Thanks for the input so far, all help gratefully received.

[Sid Squid]

A loose plug won't fire correctly, carbon builds up on the gasket face and stops it connecting to the engine case completely.

Originally Posted by Sid Squid

A loose plug won't fire correctly, carbon builds up on the gasket face and stops it connecting to the engine case completely.

do we need to go back and remove the carbon build up somehow?

[punyXpress]

When you started it, was there a strong smell of petrol and black smoke.
Recheck stage 6 & make sure the choke plungers return fully when the choke is closed.

Should have shown this too, its the front spark hole:

Originally Posted by punyXpress

When you started it, was there a strong smell of petrol and black smoke.
Recheck stage 6 & make sure the choke plungers return fully when the choke is closed.

No black smoke, some funny smells but not like petrol.
Are the choke plungers easy to see properly?

[Sid Squid]

Originally Posted by Redmist

do we need to go back and remove the carbon build up somehow?

Unlikely, unless it's been doing it for a very long time, the action of screwing the plug in will have wiped it away and now there will be metal to metal contact. Won't hurt to pull the plugs and clean them anyway, the plug condition might provide some info too.

Originally Posted by Sid Squid

Unlikely, unless it's been doing it for a very long time, the action of screwing the plug in will have wiped it away and now there will be metal to metal contact. Won't hurt to pull the plugs and clean them anyway, the plug condition might provide some info too.

The front spark plug came out dry but sooty, has been replaced by a good looking spare.

This will be the choke plunger then and we should be able to get those out and take a look: (Image from another thread)

[punyXpress]

Look at it on a parts list - Robinson have one to look at / download.
You'll see it has a splitter just inside the left hand top frame rail. It's notorious for sticking.
Best way to check is probably by 'feel' - when you close the choke lever you SHOULD be able to feel the cable is a fraction slack at each carb, just like the clutch cable should.