Crazy Enrichment Circuit

A couple of days ago, I start the bike with the enrichment and it revs up to 4,000rpm. I turn down the enrichment and it goes to 1400rpm. The bike was warming up and running beautifully. But the next day, I start the bike in the morning with the enrichment on. Hard to start and it runs at 700rpm. Yeah, only 700rpm. What could have happened overnight? Also, it takes a while now to get the bike warm enough that it will not bog at takeoff. Once warm, the bike runs decent, but not like it did before this happened.

I drained and replaced fuel from another gas station. Still happening.

I took carbs off and cleaned (the proper way because I read "Church of Clean"). Still happening.

Sprayed around carbs with no leak found. All new rubber parts from last summer.

Valves in spec 2800 miles ago.

Please help. I "think" I have tried everything. Any suggestions will be much appreciated.

 

I think the seal on the end of one of the enrichment plungers hath snuffed it.

Or has a hunk o'crud lodged. Inline fuel filter?

 

I have an inline fuel filter. Would never run the bike without it. I just can't trust the filter in the tank.

That would be horrible if that is the case. But could possibly be.

The funny thing is, I removed the spark plugs after running the bike on idle and on the enrichment in my driveway for about 5 minutes and all of the plugs were black like the circuit was working. Would that still happen if one of the plungers is clogged?

The plugs are brown if I ride without enrichment. I just tested it with a plug chop today, just to make sure.

 

The seal that Fitz mentioned is on the outside of the carb, and keeps air from being drawn in through the enrichment plunger bore. If one or more of the seals has failed you'll get a not-rich-enough condition when the enrichment circuit is open, and a very low initial idle speed when starting from cold.

 

I believe that seal is more for keeping rain out......When the enricher is off, the plungers are down, and the springs keep them closed tight, so there's no air going through there anyway. Correct me if I'm wrong.

Dave f

 

Do you mean the ones that are put on after the plunger bolt is tightened? I thought those were just dust seals. I sprayed carb cleaner at those points but it didn't change anything. I will take them off in the morning and inspect them.

 

Well, I checked all four of those seals and there is nothing wrong with them. They are still soft and pliable with no cracks. I will be removing the carbs to do another clean.

Since this is a problem that I just cannot figure out, I will be going through the whole cleaning process again. That's a bummer that all it takes is something small to cause such a ruckus.

I did change the inline filter after it happened, but I wonder if my old inline filter failed, which could cause something to get inside the carbs. The filter was the same from last summer. I know, that was very stupid of me. I need to make sure that I change it out every year.

Thanks for the help guys. After my "Church of Clean" is finished, I will let you all know if it worked.

 

Buzz,

Do get disenchanted with the carbs. I had mine off 6 times before they were perfect. Yamaha and Hitachi designed some great carbs, but the have a very narrow line of out of adjustment. I followed the advice given here, but I guess I had to develope my own sense of "pure perfection" in the work performed on the carbs. I guess it would be easier if they had plug and play parts, but they don't for the most part. Check and double check, clean and re clean, polish and re polish. Set all items to spec, re check and check one more time. That one thought "that it should be good enough" is the stinking thinking that made me a professional carb remover and installer. You will be rewarded in the end for all the effort with a fantastic running machine.

hang in there, hope this helps

 

Sounds more like either some of your enricher tube/wells/jets are clogged
And/or some idle jets are getting clogged...

Dave f

 

Gonna tear it apart once I get home from work. Guess I won't be riding for a couple of days. But at least I know it will be fully cleaned without any question. Thank you all for the help and encouragement.

 

Well, unfortunately my bike will need to wait until this weekend to be worked on. My brake booster in my car went out, so now I am replacing that first. I should be done with that tonight and will remove my bike's carbs when I'm done with the car.

Never fails. When one thing goes wrong, it seems as though a lot of things go wrong.

 

I decided since the carbs were off, I would check the valve clearances, even though it has only been less than 3000 miles on them.

I had to change out my #4 Exhaust. It was loose. I didn't want that to prevent me from being able to tune the bike properly.

Also, I found some junk in the carbs. I inspected the old filter and there was a rip in it. Stupid filter. For now in, I will change the filter every riding season.

 

Alright. I finally finished the job. Been busy with work that I had no time when I got home. Anyway, carbs are great. Bike runs like a dream. Other than not having a colortune, bike is in good tuning. Can't wait for the money to get one of those. I have just been plug chopping it. Rode it yesterday and I loved it.

 

Glad to hear!

dave