Author Topic: Running rich at high revs? (Read 3334 times)

onearmedbandit · « **on:** February 01, 2007, 06:06:33 AM »

Hi all, this is my first post but have been getting alot of valuable info off the site for a while now.

Was just on my way back to the office from a meeting and my bandit 400 vv started to loose power and eventually cut out. This was on the highway at about 130kph. I have recently stripped the carbs and replaced the O-rings (not the plugs as my dealer was waiting for stock, got them now) set float heights, synched etc.

After about 5 minutes it started again and ran on 3 cylinders and intermittantly 4. This happened before but I thought it was the coil wires coming loose so they have been cleaned and tightened.

The mechanic at my local Suzi dealer told me that it was prob running rich and fouled the plugs (will have a look at them tonight) is this possible when doing 130? I would have thought that it is running on the main jets by this stage and the little pilot jet plugs would have no effect. Jets are 102.5 on the outer two and 105 on the inner two.

Sorry for the long post has anyone got any suggestions?

Cheers
Joe

PitterB4 · « **Reply #1 on:** February 01, 2007, 08:57:10 AM »

If that is in fact the problem, it could be crappy plugs (I'm understanding that you have them but haven't put them in) or maybe it's not getting enough air. I had that exact problem one day when I forgot to put the little plastic side covers back on. I got in my tuck on a long highway stretch at WFO and without the covers, my knees blocked all air getting to the airbox. TOTALLY fouled the plugs in just a few miles. So, I'd look at anything weird blocking air getting to the box and also check the air filter. Just a couple thoughts.

If you've been looking around here, you probably know to check the plug leads, too. The stockers are crap and can loose the connection to the cap.

pmackie · « **Reply #2 on:** February 01, 2007, 02:40:43 PM »

I'd be looking at the fuel supply side. Make sure you haven't pinched a fuel line, or tank vent line. (Not familiar with the 400, does it have a tank vent line?).

You could be slowly starving the carbs for fuel. Check the plugs, are they fouled or do they look baked hot? If you are starving for fuel at high revs, you will be lean and running hot. A look at plugs should give you some additional clue as to what is going on.

onearmedbandit · « **Reply #3 on:** February 02, 2007, 02:58:10 AM »

Guys, firstly thanks for the replies.

Right after stripping the bike at the side of the road on my way home last night I got to the root of the main problem.

Pmackie, you were right it was indeed fuel, as it turns out there is an intermittant vacuum leak on no.1 I think on the petcock line so obviously bike was getting starved (I got home sucking on a length of pipe and a drill bit in the vacuum hose!

Plugs are a bit sooty but delivering a good spark (at approx $15 a piece I don't want to replace them for no reason - anyone ever tried cleaning them with oven cleaner?) I know the bike is runing rich at low revs but how do you check the richness at high revs?

PitterB4 the air filter looks OK and the snorkel(now removed) was not blocked.

I am hoping that the little blanking plugs sort out my low end richness.

Any advice on setting up these little carbs much appreciated as most of my experience is with fuel injected cars.

Thanks
Joe

pmackie · « **Reply #4 on:** February 02, 2007, 12:56:57 PM »

I'm not sure I would use oven cleaner. I've used Ether (starting fluid) and a soft, stiff brush. You can use a point file or emery cloth to lightly touch up the centre electrode, etc., but if they are too fouled, you need new plugs.

$15 each sounds high. Maybe look for different source.

stormi · « **Reply #5 on:** February 02, 2007, 02:51:06 PM »

Plugs can usually be ordered from the local autoparts store. Way cheaper. Even -I- don't pay $15 a plug, and I'm in canada.

The autoparts stores may not have them in stock, but it shouldn't take them more than a day or two to get them in.

interfuse · « **Reply #6 on:** February 02, 2007, 04:01:38 PM »

I'm a sucker. I pay $15 a shot for the NGK dual prong plugs. But I only change them once a year which is probably overkill for the amount of KMs I put on...

stormi · « **Reply #7 on:** February 02, 2007, 04:34:59 PM »

Quote from: "interfuse"

I'm a sucker. I pay $15 a shot for the NGK dual prong plugs. But I only change them once a year which is probably overkill for the amount of KMs I put on...

Do you guys have Napa there? I think you do...

I get plugs there for Dita for around $10 each, and they're the iridium ones.

gsxr400 racer · « **Reply #8 on:** February 03, 2007, 03:37:30 AM »

just run cr8e's not ek's unless your sure you got carb fixed saves yo some money when tunning!

onearmedbandit · « **Reply #9 on:** February 05, 2007, 02:50:00 AM »

I tried one of the autoparts stores and after looking at me blankly for about 5 minutes said they couldn't get'em. Customer Service is not a requirement in South Africa (Oh and $15 was with a 15% discount as a buddy of mine works at the bike shop!)

Anyway an update on the bike.

I replaced the PJ blanking plugs and cleaned the carbs again! TBH I wasn't expecting there to be much difference but boy was I suprised

My idle is back throttle response is crisp and bike goes like stink. It's even a bit quiter as I took the cam chain tensioner off, cleaned it in thinners and oiled it. This made a big difference to the smoothness of it's operation so that saved me a few bucks as well.

Went for ride put feet up nad had a

Cheers
Joe

gsxr400 racer · « **Reply #10 on:** February 05, 2007, 11:46:47 AM »

cool