To Rich - How lean can I go.

[gfiandy]

Hi,

I replaced the air filter on my 94 Daytona with a K+N one then because the general wisdom seemed to be that this would make it lean, I raised the needles in the carbs by a notch an wound the idle out by a further 1 turn to 2.5 , 3 , 2.5 turns.

It is quite definately now far to rich. Smells rich boggs down when the throghtle is opend fast.

Since I am planning to go on a long tour I would like to get the best economy I can I intend to drop the needles again and go back to 1.5 , 2 , 1.5 wich were the settings it had before.

What symptoms should I look for for it being too lean.

What risk is there to going even leaner and dropping the needles 2 notches. I know if you lean out the idle any more it is a bugger to start when the temperature is anything but hot.

Regards,
Andrew

[trypcil]

It's a good idea generally to make one change at a time, keeping a log of settings and comments is also a prudent past time. Probably resonable to go back to stock with the needles and see what can be done with the fuel screws - not sure if the pilots are 38's or 40's. It's possible that raising the needle with a washer, splitting the clip position, would extrude a little better response but chances are all that'll be needed is the fuel screws to be tweaked to smooth 'off' idle to taste. Remember that carb circuits are purely relative to throttle position, nothing else. With tape about the throttle at the switch block side, plus an index - you can divide the twist into Full, 3/4, 1/2,1/4,1/8 th's. Scroll down this :- http://www.geocities.com/MotorCity/S...476/basics.htm and one of these or the such like! http://www.daytona-sensors.com/WEGO4.html

[Droz900]

I'd be very surprised if a K&N air filter required rejetting. I'd set it back to stock and leave well enough alone.

In my opinion, it takes some serious engine modifications to require rejetting. And since improvements in airflow would only become apparent at maximum airflow, I would think it would be your top end jetting that would need to be bumped up. But again, I suspect it would take alot more than a new air cleaner to require that.

[gfiandy]

Ok so I tried leaning out the mix a bit. Set needle hight back to stock and set pilot screws to 1.5 turns out.

The bike would barerly run with this setting. If this is the stock setting in the US it must be a bugger to get the bike to idle properly.

Couldn't face taking carbs out again to reset no 2 cylinder (you can just about reach the others) so ordered a 90 degree head screw driver for £36 from Morgan Carbtune. Once this had arrived I reset carbs to stock 2 turns on 1 and 3 and 2.5 on 2. Bike ran as before idle OK but a bit lumpy and smelt a bit rich. So after fully warming up I tried adjusting them. Anything below 1 turn on 1 and 3 and the bike stalled but I could turn 2 down to nothing and it kept running.

So suspecting that 2 wasn't firing properly I tried turning it up, at around 3.5 turns bike started to run much better by 4 turns it was running smoothly. So I guess 2 wasn't firing all the time and that was why it smelt rich. Not quite sure what is going on as to why my bike wants to run so rich on number 2 but it is quite clear that is the case.

Maybe the spark is weak on 2 and it needs to be rich to fire. Any ideas anyone?

Anyway bike now seems to be running well and I have a 90 degree screw driver if it ever needs adjusting again. I will check balance again but the pilot jet didn't seem to make any difference to this last time I change it.

Andy.

[aje]

Just a thought,
have you synchronized them?

[gfiandy]

Yes I tryied balancing them when they were in the lean setting made no difference as far as I coudl tell. This also seems to be consistant with what the tuning guides say that idel and balance are not greatly related.

Andy.

[LaneSplitter]

Andy,
Have you had the carbs out to clean them at all? It sounds like the pilot jet is plugged in the #2 carb, if so you will need to remove the carbs :-) and clean the pilot out with a spray cleaner or small wire. I had the same thing happen on another bike and that is what the problem was. You shouldn't need to have the pilot screw turned out so far (usually just about 2 to 2.5 turns on each carb should do it).

Glenn

[gfiandy]

Thanks Lanesplitter.

Not what I wanted to hear but a good plausible possibility. I have had the carbs apart to clean them but I didn't do the pilot jets. Bugger I hate taking the carbs out and now I am going to have to do it again just to be sure.

Amdy.

[LaneSplitter]

I feel for ya Andy, I have a set of Keihin carbs that I'm going to put on in place of the mikunis and have been putting it of for awhile now.
Good luck and let us know how it goes.

Glenn

[gfiandy]

Just got back from a days riding and worked out MPG, my Daytona 900 got 49MPG (UK gallons). So whilst I will still probably strip the carbs at some point I don't plan to rush it, Ill probably leave it till the end of the season.

Andy