good idle, runs lean

I'm in the process of fine tuning my bike. I have it set so that when it's at idle, the plugs are tan. This was achieved by adjusting the mixture on cylinder 3 and 4. 1 and 2 were already "bunsen burner blue" and that color remained, no matter how much I twisted the mixture screw in or out.

After running the bike ( anywhere between 4k and 8k RPM) all of my plugs turn WHITE around the insulator. Now, I have the UNI air filter in place and from what I gathered I would not need to re-jet my carbs. Can the air filter make such a huge difference at normal operating RPMs that it will lean my mixture out? I had the colortune in place and revved the engine up t about 4 -5k and it still showed bunsen burner blue. If it helps, my bike starts right up with a quick blip of the throttle and stays running, however, given almost any choke it will stall out.

Any ideas?
Also, how safe (for the engine) would it be to take this bike on a 250 mile trip? I noticed that today after running for a bit the engine was hotter than normal (this is also the first day I ran the bike in 65+ weather), water would boil off instantly when it touched the engine it self. Is this normal?

 

Are you using the YICS tool when you adjust the mixtures, if required ??
I believe the colortue plug only sets the IDLE mixture. When you rev the
engine the carbs are on a different circuit. I could be wrong on this.
Running the engine lean could burn the valves. I would not go anywhere untill you fix this problem.

 

if you have it set right at idle you shouldn't have to touch the mixture screws. 4k to 8k seams like it would be in the needle in your slides. If your needle has adjustable clip positions moving the clip down will richen the mixture in your 4 to 8k range.
I had to buy a jet kit for mine the needle didn't have a clip. You may try finding small washers thin ones and placing them under the plastic head of the needle. The washers will have to be EXACTLY the same thickness though.
You may want to see what some the other guys have to say about it. In theory I think it would work with out spending $120 for a jet kit

 

Make sure your float levels are set. Low level means lean. Use clear tube method and let us know.

MN

 

MN-Maxims - I set the floats to be 3mm below the lip, all verified with a clear tube.

lowlifexj - which needle do you mean?

Foxman - I did use YICS tool for my original synch, then did further syncs without it as it seemed to give me the same results.

I just swapped in my old stock paper filter to see what happens. When I turned her on, she ran just fine and responded to the choke without dying. I'm going to go on a few quick rides and check the plugs. I would really like this bike to be ready by Wednesday evening for a trip I had planned. Everything's set right, except the mixture at normal operating revs.

 

did you oil the filter? if not you could be getting not enough pull for the fuel.
another quick thought is the intake boot gaskets.... as long as the boots have no leaks. but while in there check the crush washers on the YICS ports. .... anytime you run lean across all cyl like that you pretty much have an air leak or in other words too much air.

 

midnightblu - I did the propane leak test with the bike at idle, the rev's maintained at 1100. Should I do this while revving her a bit? The filter has been oiled as per the instructions. While it's out right now I'm going to try re-oiling it. I see you have the UNI filter in your ride, too, how much oil did you use? I have the spraycan and applied a liberal coating of blue oil all over it and let it drip out while I had dinner and then reinstalled.

The thing that stumps me is I'm getting about 36 mpg with a lean condition. I always assumed that I should be getting phenomenal mileage if my mix is too lean.

 

http://www.babbittsonline.com/pages/par ... fault.aspx
check this out the needle is #7 good luck

 

+1 on oil the filter
I run a uni on my shadow and it can be tricky to get the right ammount of oil in it. If you don't have enough, you pull too much air and will run lean.

cheers
k

 

I just swapped in my old (and somewhat dirty) stock filter and the problem seems to have gone away (except cylinder 3 is a TAD bit lean). I guess I just need to oil the filter real well... and figure out what to do about cylinder 3. I'm going to fiddle with it and attempt my 250 mile ride tomorrow. I did 45 miles today in one go after swapping the filters and she felt much better.

Jedininja - how much do you saturate your filter? Should I spray mine until it's completely blue and then go over it again?

 

lowlifexj - Where can I see a picture of how this needle can be shimmed? I looked it up on google for how it's done on the SV650, but would like to take a look at something more model specific.

 

I usually load it up and then squeeze out the excess. Nasty job if you use the blue stuff. it's sticky. Works great in the filter though.
Squeeze carefully to avoid tearing the foam.
Here is a little q and a on foam filters. Pretty simple, but covers the basics.

http://www.all-offroad.com/DirtBikes/Tr ... Oct98.html

Keep in mind that foam filters flow better than paper so you will run a bit lean even if you get it oiled right.

cheers
k

 

Holy crap this jsut gave me a lot of info. I'm running lean in my Maxim too and its probably cause of my oil filter. Thanks guys. I'm gonna clean her up and oil her again
-SLK