Misfiring on front cylinder?

[G - renamed]

I've recently got an early Curvey with 20k miles, seems to have a reasonable history.

Battery was fairly dead when I got it, but I've stuck in one of my minitwin ones for the mo.

(I knew about this when I got it by the way, but it was a decent price for a 20k miler)... It seems to be misfiring on the front cylinder from what I can tell.

I did try and get the spark plug out to have a look, but that was /before/ I bothered to read the manual to find out how to do it. (And my hands aren't quite as small as the average Japanese persons', so was having a bit of trouble.) It turned out I was doing it right anyway, just gave up too quickly! So ended up not checking it and haven't had a chance to do much since.

It only seems to be a problem at low revs, haven't noticed it at high revs.
It seems pretty similar to what my TRX did when it got a bit of water under one plugcap. The bike hadn't been ridden for a while, so I was hoping it might be this.
Took for a half decent (well, 25 miles or so) ride and it did get a little better I think, but not totally sorted. Ride was in the dry, so should have a good chance to evaporate any moisture left around.

A friend mentioned that the coil is a likely suspect, also.
Any suggestions? Any common problems around this area?
Bit busy for me to to start to strip it to try and find the problem at the moment - with all the preparations for the first race weekend this year (my first championship minitwin race and loads to do still)



While I'm here, anyone know a good (cheap) place to get decent brake pads for the SV (Performance Friction or Carbone Loraine SBK ideally).

Cheers,
G

[jambo]

Use the search feature, if it's happening in the wet it's rather common and a fender-extender or similar will sort it, if it's happening in the dry then check the coil.

[Fuzz]

Take the lead off and check for corrosion. If the plug is corroded (as mine was) it might mean the plug drain is blocked up. Stick a pipe cleaner up there to get out any crud that might prevent water from draining away.

My front plug also had moisture on the electrode. I cleaned this up and drained a little fuel from the carbs to release any water that was sitting at the bottom.

[G - renamed]

Sorry, it's only happening in the dry.

I did try searching for 'misfire', but didn't come up with anything relating to my specific problem.

Will trying searching for coil stuff.

Cheers,
G

[mysteryjimbo]

Carb icing happens at low revs more.

Also, could be water in the front carb (havent bothered to check which you have :wink: ) or tank

[embee]

Like they said.

If it hasn't been used much I'd definitely drain the carbs out, preferably removing them and cleaning out the float bowls properly. Maybe even the tank too. Check the filler cap recess drain pipe is clear and isn't rusted through to the tank.

Two other things. First, the standard choke sticking issue, usually down to corrosion build up where the cables meet the plungers. Clean up and lube generously.

Second check for the usual wiring chafing points behind both rider's seat bolts and where the harness wraps round the edge of a frame bracket on the left side of the cubby under the pillion seat.

I like iridium plugs especially with carbs, though not everyone finds any benefit.

[G - renamed]

Cheers for the thoughts.
Haven't realy got the time to play for a bit, but plenty to keep me going.

I did spray some water-displacement down toward the plug when I had the lead off. Didn't help.

From riding today it seems to mostly happen between 2k-3k when not engaged to the rear wheel (ie fairly constantly happening like this.)

Gotta get the carbs of my race bikes and give 'em a good clean, so I'll be in good practice for my road bike ones when I get a chance :).

I don't think it was carb icing. When I've had water in carbs before it's acted differently, but I'll take it into consideration.

Cheers.
G