Running Rich

[rez]

I seem to be noticing a rich running issue recently. It appears to me it is at idle conditions. Fuel mileage seems ok...similar to what i always get. Around 40 mpg. At idle i notice a strong fuel/rich mixture smell...if it idles for any length of time....some 'smoke' from right pipe (fuel?)...accompanied by strong fuel/rich mixture odour. I pulled and checked plugs. Right front cyl. seems to 'foul' badly...wet with fuel. If i pull vacuum barb cap on that cyl...notice some raw fuel...but no external fuel leakage otherwise. Right rear plug looks somewhat rich too.... but better than front cyl plug. Left side plugs look perfect. If i try to adjust mixture.... left side carbs will lean out and stall out engine...right side makes very little difference as screws are adjusted. Bike runs decent starts well...no issues otherwise. Bike hasn't been sitting. Have changed plugs several times. Brand new set right now. Have run seafoam in the past...late last year....just as a 'maintenance' thing. Just changed diaphragms(only because of age...was running ok)...seems problem surfaced or more noticeable then...or coincidental??? 3 of 4 diaphragms had a small pinhole each. Synched carbs several times. Any thoughts/suggestions?

Edited July 15, 2009 by rez
clairfy subject title

[GeorgeS]

What are your idle mix jets set at?? About 2 1/8 CCW from bottom ?

 

I'm thinking Float valve sticking open, or float level way off in that carb.

Open the drain on that carb, run fuel pump, compare to the others as to

fuel draining from the drain hose on each carb.

 

Maby the ignition coil , for that cylinder is getting sick.??

 

Also, clean the Electric Plug Pins, on the TCI.

 

Check the Red, -- Run Stop -- Switch, make sure no excess resistance across

the contacts of that switch. That can lower the supply voltage to the TCI unit.

 

Sounds like you will be on a witch hunt on this one.

[safetyguy]

Have you checked for spark for the cylinders on that side? I'm kind of with GeorgeS thinking it may be spark related -- the one that is fouling isn't firing.

 

Last fall, you were thinking about replacing your plug wires -- did you ever? You can check the resistance in the old ones with a VOA meter. Your problem could be something as simple as getting some new wires and caps.

 

[rez]

Thanks so far. My mixture screws are out about 2 1/4 turns. Just checked spark tonight....very good spark. If i pull wire on the right front cyl. while running at idle makes no difference. Will check for compression tommorrow. If thats good will probably look for a carb problem??? Haven't changed wires yet...seems the Ebay company selling the set most here recommend won't ship to Canada at a reasonable cost. Will just pick up wire and meter check the caps and make my own. Doesn't look like a spark problem anyway. I did check plug cap resistance on right front cyl cap...measures out at 10k ohms. Thanks again for your suggestions and help.

[GeorgeS]

Worth doing if you have not allready:

 

Screw the Spark Plug wire OUT of the Plug Cap, and the Ignition Coil for the sick cylinder.

 

Inspect copper wires in center of plug wire ( 7MM solid copper plug wire ) The ends of that section of 7MM wire might be Fried, burnt etc etc.

 

Nip off about 1/4 inch each end of the wire, and re-Install. ( The wire is standard 7MM stock ignition wire ) ( avialable most auto parts stores in bulk )

 

Also, Check the Resistance of the Plug Cap, compare it to the others. Should all be about the same.

 

Another thing, while your in there, buy some new 7MM plug wire, and replace all 4 of them. ( hint hint )

Also, NGK, has a nice replacement for the Plug caps. ( much cheaper then yamaha ) I been useing them for 10 years, work just fine.

[RedRocket]

Thanks so far. My mixture screws are out about 2 1/4 turns. Just checked spark tonight....very good spark. If i pull wire on the right front cyl. while running at idle makes no difference. Will check for compression tommorrow. If thats good will probably look for a carb problem??? Haven't changed wires yet...seems the Ebay company selling the set most here recommend won't ship to Canada at a reasonable cost. Will just pick up wire and meter check the caps and make my own. Doesn't look like a spark problem anyway. I did check plug cap resistance on right front cyl cap...measures out at 10k ohms. Thanks again for your suggestions and help.

 

 

I'm sure a member on this side of the fence that lives in your general direction would re-ship from his house to you.

[rez]

Still dealing with a problem. Have checked spark and it's good. Finally got around to checking float levels today...did all 4 carbs and they look/test very close to spec. I'm thinking now after some more observation and diagnosis that the right front cylinder is fouling with oil. If it sits and idles for a few minutes and then i accelerate (in neutral on stand) i get a good puff of smoke which is looking more blue than black...if i accelerate a few times it clears. I let the bike idle...shut it down and pulled the plug...it was very wet...hard to tell if fuel or oil....I suspect both. No smoke if idling just when i accelerate...and then clears. Friends have been following me...and notice only occassional puff (looking more black than blue). I'm thinking it could be a valve seal/guide problem??? Any thoughts....suggestions? I never hear anyone talking about those as being a problem?? I noticed the other day on cold start up same thing...good puff of smoke when it fired. But the next time it was fine??? My fuel mileage is still the same as prior to me noticing problems developing. No noticeable oil consumption. Seems to run good....and strong. Idles ok but not as smooth as it use to. Thinking dead cyl.(s) at idle. Noticeable fuel/rich odour at idle...if fouling by oil is occurring then plug won't fire and therefore will run rich too i guess....cuz fuel isn't burning. Right rear cyl is suspect too....plug colour indicates rich. Left cylinders seem good. Also..as before...right cyls. mixture adjustment makes no noticeable change to engine running speed or smoothness...even if turned in and 'closed'. Thanks for your help and suggestions.

[Condor]

Sync'd your carbs lately?

[rez]

Can a bad sync give me the issues I'm dealing with?? I have sync'd and checked several times since I've noticed this problem....although with a homemade type sync tool (vinyl tubing and oil). I may not be dead on but think I am pretty close.

[GeorgeS]

Sounds like compression check is the obvious thing to do.

 

Also, pull the valve cover, and check the valve settings.

 

Starting to sound like a Piston Ring, is not sealing, allowing oil to pass by.

[Yammer Dan]

No Sea-foam since last year? Time for a little stronger dose. But could be a ring? Or weak plug wire? Wire will fail at times and check fine.

[rez]

I have just run seafoam thru it my last tank of gas. Made no difference. Should I run it in the oil? I am meticulous about maintenance and have done numerous oil and filter changes. Running 15w40 dino oil. This bike has not been sitting....have put on 22,000 km since Sept. '07. Have intentions to check compression but had to make an adapter to suit. Will check this week. Poor compression could suggest a tight valve and/or ring problems.

[safetyguy]

Another idea --

 

How much oil is showing in the sight glass? If you have anything more than half way, you will pull oil into the air filter box. Are you seeing oil on your air filter. It could be part of your problem.

[mbrood]

As Mike said (Safetyguy), you REALLY want to make sure the sight glass is ONLY half full... anything more loads the engine and frothing tosses some up into the air filter.

 

From a cold engine, fire it up, choke if needed, but reduce the choke as soon as able and let it run just 1 minute... then shut her down. Put a hand on each cylinder and feel for even temp on all cylinders. An overly hot one talks about a carb sync issue, a cold one talks about a firing/fuel/compression issue.

[TexasFlyer]

Did I miss the post that suggested replacing the plugs? I have seen more than one bad plug show up with those symptoms - even in my airplane. Replace the plugs, and start testing again.

[TexasFlyer]

Yep - it was there and I missed it. Still, symptom sounds like a bad plug.

[rez]

I have tried 3 different spark plugs in that cylinder...2 new ones...one good used one. All NGK brand. Same results..no improvement.

[rez]

My oil level is between the marks but to the high side...almost to the top mark. I will drain it back a bit. Could this cause a problem in just one cylinder..wouldn't it be noticeable in all cylinders? My air filter is clean and dry...no oil contamination. I will do a compression check and cylinder leakage check next. Thanks for all the help and suggestions.

[rez]

Still dealing with mysterious problem here. Did carb. float checks and all carbs are on spec. and giving same levels. I put bike on center stand....sitting level. Used method described in manual.....clear tubing ...opened float bowl drain while running...etc. Results within spec. Visual check on spark at all cyls....very good. Did compression check....all cylinders identical but getting 90-100 PSI...could be my guage. Seems randomly I'll get good puff of blue smoke from right exhaust pipe. Suspect right front cyl. fouling with oil but randomly. Pulled air filter and checked...NO oil in or on filter....only minor amount of oil residue in filter box...what I would say is normal. Last night out for a good ride...idling at light...pulled away...good puff of smoke from right side...could see it in my mirror. Otherwise didn't notice anything while out riding. Previous cold start up...maybe a week or two ago...good puff of smoke on cold start up.....subsequent start ups no notice of smoke???? Bike runs very decent....pulls strong.....starts good.......maybe a little sputtering when letting off throttle and then back on it again. Bit of 'popping' at around 2200 RPM...if running under little or no load conditions. Any more thoughs out there? Thanks.

[GeorgeS]

Maby we should start thinking about a valve stem guide---

 

I'm thinking maby some oil getting past one of the valve stems ?? But I never

had head off one of these, so not sure if this could happen. but worth considering.

 

Oil must be getting into the combustion chamber some how.

 

Try dropping the oil level down to near the lower mark. ( might prove or disprove something ?? )

 

Did you check the Anti freez, for any sign of oil ?? ( wild card ) Drain the anti freez fluid at plug under the water pump, into a clean container, and check for any sign of oil in the coolant mixture.

 

Conversly, drain the oil into a clean container, and check for any sign of Anti freez i the oil.

[rhncue]

Sounds like intake valve seal to me. Valve guide/seals show most smoke during higher vacuum periods (idle and deceleration).

 

Dick

[TEW47]

I have black sut at the end of each exhaust pipe. The dealer says it is because it is running to lean, what do you think? It hardly ever pops and I am getting about 44 mpg.

 

tew47

[Venturous Randy]

And you are checking the oil level with the bike on the center stand?

RandyA

[rez]

I checked coolant and engine oil no contamination visible what so ever. I still have to drain back oil some. I have been leaning towards valve stem seal issue with this. Although have never heard of anyone dealing with or talking about valve seal problems on this motor. If in the end I determine that could be the cause does anyone know if you can do valve stem seals with engine in frame??? Thanks again for all the help and suggestions.