Access to the pilot screws?

Discussion in 'Mechanics Garage' started by seano, Apr 5, 2014.

  1. seano

    seano New Member

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    While I had the carbs apart for cleaning, I cut a notch into the pilot screws so I could just use a screwdriver to make adjustments. I have the fuel tank removed for access - doesn't seem to make a whole lot of difference- and have a lawnmower fuel tank rigged up.
    How in the hell do you access the pilot screws for carbs #3 and 4? Can't fit my hand in there from the right side (don't even have large hands), I could probably reach them from the left side by getting myself into some crazy contorted position, but then I wouldn't be able to see the screwdriver to accurately count 1/2 turn, 1/4 turn, etc. Any secrets to this or special 90 degree screwdriver to recommend?
     
  2. seano

    seano New Member

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    Anyone know if that $25 Motion Pro 90 degree pilot adjusting tool will work on a gen4?
     
  3. rangemaster

    rangemaster New Member

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    Anyone know if that $25 Motion Pro 90 degree pilot adjusting tool will work on a gen4?
    Yup. Only because you cut the slots in the stupid "D" shaped pilot screws. That tool has a fixed screwdriver end that won't take hex bits/sockets.
     
  4. seano

    seano New Member

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    Yes, I understand that it has a fixed screwdriver end, and so do my modified screws, but in reading customer reviews on it, it does not work on all bikes that have the appropriate screw head because it cannot reach the screw for a variety of reasons. So while I understand that theoretically it can work, I would like to know specifically if it does work on a 4th Gen before I throw $25 out the window. Thanks!
     
  5. squirrelman

    squirrelman Member

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    I believe you can buy a 90 degree tool similar to the MotionPro with 1/4" replacable sockets, including a D-shaped head for your 4th gen, but don't ask me where.....
     
    Last edited: Apr 5, 2014
  6. ridervfr

    ridervfr Member

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    25 dollars is a cheap gamble on a tool in my opinion. I happen to have aboot three of those tools you mentined, The Snap On one has assorted slotted bits that were used for carbs on cars, worthless on the viffer. An old Mac Tools one with a built in slot, the one that works the best is one I got when I was around Triumph. It has a small flat blade that is fixed and has a circular cup of plastic that gets you into the ball park when zeroing in on those screws your talking aboot. Helps to use a good inspection mirror and get used to burned hands and cursing honda engineers. Helps if you can get the bike high up on a lift too. Once they are close, its pretty spot on. Bench synchronizing will get you very very close btw...Cheers and good luck.
     
  7. seano

    seano New Member

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    You're right. $25 is no big deal. Don't have a lift, but it seems like the best way I've found so far is when I'm laying on my back.
    I carefully bench synched them, and then synched them successfully with my new Carbtune.
     
  8. seano

    seano New Member

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    Well, I got the Motion-Pro one and it does work on #3 cyl. and I think it will with #4 cyl. with some fiddling about.
    I don't feel that my tach is accurate enough to register the 50 rpm fluctuations of the idle-drop procedure, and it takes me so long to do the 4 adjustments that I can't maintain the focus needed to detect the 50 rpm increase, so I picked up an old handheld tachometer at a garage sale. It has a black lead and a green lead. I'm assuming the black lead will go to ground. Can anyone tell me where on one of the coils I would attach the green lead?
    Also, how critical is the idle-drop procedure? I'm spending a butt-load of time monkeying around with this.
     
  9. kennybobby

    kennybobby New Member

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    The exactitudeness of the 50 rpm is not critical. All you are doing is turning the mixture screw in until it has reached a point of 'going lean' which causes the idle to start dropping slightly, and then you back the screw out 1 turn (2nd gen), 1/8 turn (3rd gen) or 1/4 turn (4th gen). If you had an exhaust gas analyzer you could dial it in much closer, but this procedure is a quick and dirty way to get it running with a slightly rich mixture.

    Not sure why there is so much variation on the back off turn amounts, but i would ride it for a couple of tankfuls and measure your fuel mileage, then turn the screws in 1/8 and run it and check mileage again, etc. Your mileage can vary from 30 to 50 mpg depending upon those screws and the size of your pilot jets.
     
  10. ridervfr

    ridervfr Member

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    I usually go with 2.5 turns oot. Funny thing, I was working on a turd of a yamaha virago 250 bike, alot of fingers had been "in-her" and she was compromised :wacko: Well, this particular bike, would refuse to run worth a chit without those fuel mixture screws turned oot 3.5 or so. Real PIMA pain in my arse, but it was a happy ending.

    I go by how the bike fires up and idles, and how much choke you have to use or not use and how quick it will take throttle. Some pigs are cold blooded beasts, some are honey pies. Same theory can be applied to people too :thumbsup:
     
  11. seano

    seano New Member

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    I set the pilots at 2.5 turns out and then synched the carbs. Runs much better than before at 1-5/8 turns out and no synch, so for now I'll leave it and monitor the gas mileage. Kennybobby, what ballpark mileage am I shooting for with "average" riding habits? I take it that mileage will improve as pilots are turned in 1/8 at a time?
    Also- ridervfr, I'll take note of "how the bike fires up and idles, and how much choke you have to use or not use and how quick it will take throttle". What signs am I looking for that in that regard that would indicate correct / very close pilot setting? I do notice what I think is a rich smell to the exhaust when I'm at traffic lights, etc.
    Thanks again for all of the help and patience. This bike hauls ass!!
     
  12. kennybobby

    kennybobby New Member

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    Ride it awhile--see how the fuel mileage works out and then you can decide. But if it smells rich then it probably is and the mileage will show it too. A 750cc bike could deliver 50mpg with the right tune and driving habits. If you get in the low 30's its either too rich or a stuck open thermostat, etc. and something needs to be done.

    Go for a ride and notice just how little you have to crack the throttle open to maintain speed at 70mph--when cruising you spend most of your time riding on the pilot jets and the mixture port, and they will determine your mileage. Most of the time a bike is running under choked-flow conditions which is not efficient in usage and conversion of fuel energy.

    The carburator and the engine run most efficiently when flowing high velocities and volumes of air, so when you need to accelerate go wide-open and let that bad boy breathe and burn the fuel at highest efficiency.

    BTW if you don't need to use the choke to start a cold engine then your mixture screw setting is too rich.
     
    Colddevil and dgp like this.
  13. ridervfr

    ridervfr Member

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    I love oatmeal with raisins, I just had to get that oot of the way! That being sed, my viffer I must start with a choke always, I let it run with it for aboot 20 seconds gently feeding in some throttle, then I flick the choke off and give it a couple more seconds of gentle throttle, to 4000 to 5000 RPMs. Back it oot of the driveway, snick that sucker into gear and off I go. It takes throttle like a little honey and this is wear your fuel mixture screws come into play, low speed rideability and throttle response. This bike sees aboot 50-75 miles a week, the ride is always the same pretty much and its over 100mph the entire time, the other day we saw 140mph for a tick or two, otherwise its around 115mph. I get consistent 32-36 mpg. I EX500 gets 42mpg and its always WOT on the highway/biways. If I was not so ham-fisted cruising, I read that I could get 60mpg. The Kawi I can start with a CH of throttle when its cold, sometimes it wont start that way (mostly after it sat for more than a week and if its cold here) then I give it a little choke and it comes alive fast.

    Funny, I picked up another gen3 bike that I am working on, and the fuel mixture screws look different than my 1991 bike, it may be my burned oot, cosmic memory failing, but I do have a photogenic memory, never forget a pretty face, :hippie:
     
  14. seano

    seano New Member

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    Thanks again for all your input guys. I'll keep a close eye on the fuel mileage.
    Ridervfr - you must have a nice collection of speeding tickets?
     
  15. ridervfr

    ridervfr Member

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    :wave: When I lived in good old nj, I had a rap sheet the length of your arm (shoulder-to-wrist,or maybe pinkie?) Down here in beautiful South FL, the traffic runs pretty fast, I am usually at 90mph regardless of what I am riding. I used to run a valentine radar detector with an earphone jack in NJ and when I first moved here 20 years ago, tried it. The type of riding/driving we do here its basically not needed. When I do a big road trip, I will hook it up though.

    I am flying up north in May and plan using it as I dont want a going away gift from nj/ny like I got when I decided to relocate here. Bastages! :flip: my dL is point free knock on wood, dont jinx me Man! btw, last night I passed a nice Ducati 1098 on my little EX500. Its all good in the hood...:thumbsup: Ride safe
     
  16. VFR750F3

    VFR750F3 New Member

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    I know this is an old thread. I found it in a search, and so might somebody else. I also know the OP didn't say what generation VFR he has. For future reference,

    On an RC36, there's a hole in the frame spars that gives access to the rear pilot screws. I don't have my RC24 handy but it kind of looks like the screws may be more easily accessible.
     
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