Author Topic: Hoses, clamps and fuel pumps  (Read 2159 times)

Rikugun

  • Visionary Grand Master
  • *****
  • Posts: 3216
Re: Hoses, clamps and fuel pumps
« Reply #20 on: October 27, 2017, 11:05:37 AM »
Quote
However- it now seems very automatic- that when the temp (gauge) reaches its norm- the idle climbs to about 3500. As you said- the ride is great
up to that point and then becomes uncomfortable, especially sitting at light in traffic with this roaring motor.
That sounds very annoying at best and potentially dangerous. That could be vacuum leaks. Did you try directing spray chemicals at the throttle shaft ends and manifold sealing surfaces to check for leaks? Depending on the chemical used the idle will either go up or down. No matter though, you are simply looking for a change. Oh, and do this when the engine is heat soaked, not on initial fire-up.

Another possibility is the carb low speed circuits are still clogged. Insufficient fuel flow makes for a lean condition. A cold engine won't idle like that so one turns the idle speed screw in until the motor "idles". However, the throttle plates are now open so much the engine is "idling" on the next circuit up the food chain. Even if that circuit is clear, a cold engine still doesn't like it and runs slower there than when hot. So, when the engine is thoroughly hot (including the carb bodies, not just coolant temp) the engine will happily run on that transition circuit/throttle plate setting. With no load, the engine will run quite fast with the throttle plates open only very little beyond where they should be for a normal idle.
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

RBFD415

  • ROV Full Member
  • ***
  • Posts: 94
  • I love YaBB 1G - SP1!
Re: Hoses, clamps and fuel pumps
« Reply #21 on: October 27, 2017, 04:23:48 PM »
Rikugun:

I find your second paragraph rather intriguing! I'll have to reread it several times and let it soak in completely.

As I said, it is a very repeatable process, like clockwork- runs fine cold, when fully warmed up it takes on a different character and starts revving. If you drop it in gear and load it against the front brake the revs drop to normal, however applying the clutch and removing the load and it takes off to 3500 rpm again (no pause). There does not seem to be a transition rise in the rpm's as it warms, its more like a toggle switch is thrown when the engine is fully warmed.

Walt_M.

  • Contributing Member
  • Visionary Expert
  • ****
  • Posts: 2339
  • Hold my beer and watch this!
Re: Hoses, clamps and fuel pumps
« Reply #22 on: October 27, 2017, 07:10:47 PM »
Try setting your idle speed when fully warm. You will then find it unrideable before it is up to temp. Or, check that your richening(choke) circuit is staying open, it acts the same way.
Whale oil beef hooked!

RBFD415

  • ROV Full Member
  • ***
  • Posts: 94
  • I love YaBB 1G - SP1!
Re: Hoses, clamps and fuel pumps
« Reply #23 on: October 27, 2017, 09:23:05 PM »
Activating the choke (enrichment) when fully warmed up and racing (high rpm's) causes the idle to drop, for about 15- 30 seconds and then returns to 3500 rpm. Otherwise I believe, for starting purposes- it seems to be working as normal.

QBS

  • Contributing Member
  • Visionary Grand Master
  • ****
  • Posts: 3282
Re: Hoses, clamps and fuel pumps
« Reply #24 on: October 27, 2017, 11:55:13 PM »
I just did a quick review of this thread and didn't see any mention of the carbs being verified as being in synchronization.  Maybe I missed it in my scan, but if the carbs aren't well synchronized you'll be chasing ghosts for a long time.  If they are in synch, possibly the enrichner cable is improperly routed or attached.

Prophet Of Doom

  • Contributing Member
  • Visionary Expert
  • ****
  • Posts: 2587
  • The really perverted one amongst us
Re: Hoses, clamps and fuel pumps
« Reply #25 on: October 28, 2017, 12:32:22 AM »
+1 QBS, I was just typing an almost identical post.




RBFD415

  • ROV Full Member
  • ***
  • Posts: 94
  • I love YaBB 1G - SP1!
Re: Hoses, clamps and fuel pumps
« Reply #26 on: October 28, 2017, 12:55:57 AM »
I did sync the carbs, but I did not balance them. As I noted prior, based on observation the enrichment circuit would appear to be functioning, also by visual check of the operation of the plungers. I would not take any option out of the mix and welcome any comments. I look forward to your thoughts!

QBS

  • Contributing Member
  • Visionary Grand Master
  • ****
  • Posts: 3282
Re: Hoses, clamps and fuel pumps
« Reply #27 on: October 28, 2017, 01:45:30 AM »
What do you mean by "balance"?

Rikugun

  • Visionary Grand Master
  • *****
  • Posts: 3216
Re: Hoses, clamps and fuel pumps
« Reply #28 on: October 29, 2017, 10:05:11 AM »
I often neglect to caveat engine tuning suggestions with the phrase: First bring your bike to stock specs i.e. adjust the valves, sync & adjust the carbs, verify adequate compression ...

Having said that, if there are vacuum leaks, carb cleanliness issues etc. the carb sync is a band-aid remedy at best. That process will only have the engine running smooth given there are no other issues. As you work through and repair issues you should go back and readjust sync and idle mixture settings.

I'd try Walt's suggestion first - after all, adjusting the idle should be done on a warmed engine. And yes, that will make it such that care will be required to keep it running when cold. Every bike is different. Some can idle on a particular choke/enrichener setting when cold and some require the throttle opened a bit as well. An inexpensive throttle lock helps in this regard.

You may have actual carb issues or it may be you are expecting too much of an 80's carbureted engine? I'm not sure if this is your first bike or not but worth mentioning. This isn't like a fuel injected car  where you get to turn the key and drive away! Carbureted engines (bikes in particular) need some babysitting until warm.
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

RBFD415

  • ROV Full Member
  • ***
  • Posts: 94
  • I love YaBB 1G - SP1!
Re: Hoses, clamps and fuel pumps
« Reply #29 on: October 30, 2017, 02:23:59 PM »
Hummmmmmmm!? Where do I go with that last paragraph? First Bike? For the record, Iíve owned this Vision since 1983. I bought it from the first owner; it was essentially in new condition. Iíve also owned an old BSA single and a 70ís Honda twin. So Iíve had the bike long enough to know- how it should run. Itís obvious the bike had layers of problems that Iíve been picking away at. Making adjustments along the way, with various items is all part of the big picture- thatís a given. I know Iíll be revisiting various adjustments as problems are cleared up.
As far as balancing and sync goes, these were 2 terms that Iíve heard for years. I think that I, like maybe others- conflated the 2 terms into one item. After fully investigating it, my understanding was if you sync the carbs, you are adjusting the mechanical link front to rear that adjusts the position of the throttle plates to one another. After making this adjustment (they were off), I noticed an immediate improvement.
Balancing- I thought was attaching something along the lines of a commercial manometer, or more likely a homemade device with hoses to the vacuum ports and using this to balance the adjustment of the idle screws front and rear. This I have not done. I did do a basic idle screw adjustment using the tach.
In the event that Iím using the 2 terms incorrectly, then please correct me.
Thanks for your help, everyone!

fret not

  • Contributing Member
  • Visionary Expert
  • ****
  • Posts: 2109
  • Mike Lewis - Grass Valley CA
    • Michael Lewis Instruments
Re: Hoses, clamps and fuel pumps
« Reply #30 on: October 30, 2017, 02:56:28 PM »
The terms do get conflated and are often used interchangeably.  You seem to have a good understanding of the mechanical adjustments and vacuum equality required.  All of that is involved and necessary to synchronize the carbs (to make them work together as evenly as possible).

To me it still sounds like an air leak somewhere, though it could be some small passage(s) slightly obstructed.  These carburetors seem to require scrupulous cleaning.  You are close, don't give up.
Retired, on the downhill slide. . . . . . . . still feels like going uphill!

QBS

  • Contributing Member
  • Visionary Grand Master
  • ****
  • Posts: 3282
Re: Hoses, clamps and fuel pumps
« Reply #31 on: October 30, 2017, 03:17:21 PM »
Your idle adjustment procedure sounds right.  Even if that adjustment is off, it wouldn't yield the drivability problems you have.  Rather, it would show up in a difficult hot starting scenario.

fiat-doctor

  • ROV Full Member
  • ***
  • Posts: 133
  • Compared to my Fiat, the Vision is VERY reliable!
Re: Hoses, clamps and fuel pumps
« Reply #32 on: October 30, 2017, 10:03:47 PM »
a couple of thoughts on this.

I'm not sure how you synchronized the carbs without a vacuum gauge of some type.
I think it's important to do that and after you get them equal and then you adjust the idle speed and mixture you will have to go back and forth a couple of times.
I would do this with it warmed up.

I have had a couple of TCI's that would only fire one cylinder when warm but I have one that will only fire one cylinder when cold then it comes to life like it was switched on after a few minutes of riding.  Since it runs fine cold and warm (except for the idle) I don't think this is the problem.

Can't remember all of the thread....  valve adjustment has been checked as ok?

Good luck,
                   Steve