Pto twist and lock throttle?

Discussion in 'Motorized Bicycle General Discussion' started by TheSignGuy, Sep 26, 2017.

  1. TheSignGuy

    TheSignGuy Member

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    IMAG0152.jpg
    Hey anyone here using a PTO TWIST & LOCK THROTTLE?


    If so what's your experience with this type of system?


    Drive line is complete, don't want any fancy brackets or tensioners.


    Keeping it vintage mopar style, slippage occurs replace the belt.
     
  2. 2door

    2door Moderator
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    Don't do it! Any device that interferes with the throttle returning to idle when released is dangerous. In an emergency situation you do not want to be fumbling to release any type of friction or locking device that keeps the throttle open.

    If you are having trouble holding the throttle with your hand start looking for weaker springs or more friction free linkage. Yes, some big road bikes,cars and trucks have cruise control but that system is complex and sophisticated. It can be canceled by touching the brake pedal or tapping a button on the steering wheel.

    Tom
     
  3. KCvale

    KCvale Active Member

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    I have to agree with Tom, you don't want anything that locks you throttle.

    If it is vibration that is getting to you, replace the hard plastic grips. Heck I do that to every build.
     
  4. TheSignGuy

    TheSignGuy Member

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    Let me further, expand in order to add a non push pull throttle the linkage needs to be "drilled out" I am currently using a throttle cable that's a choke cable found at part stores it is push and pull type as that's what's available but I didn't go for the locking one I've been riding it though successfully


    There is no slip in end small enough to fit without drilling or converting rod type cable to braided cable.

    Update: 10:27pm OCT 2, 2017


    So I've devised an idea which involves installing a proper "Clevis" with the addition since some older Briggs & Stratton have a non pull type throttle on older flat heads.


    What if I take and move the governor tension spring in front and put the throttle cable behind it as most throttles don't allow acceptance of a throttle cable on flat heads...


    My only other option if that doesn't work is remove the PUSH PULL CABLE add in a single light weight spring and put in a L bracket in the cover which will allow me to pull up the throttle thus giving proper acceleration without removing the spring as shown in the previous post earlier.
    Up is down and down is up.
     
    #4 TheSignGuy, Oct 2, 2017
    Last edited: Oct 3, 2017
  5. MEASURE TWICE

    MEASURE TWICE Active Member

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    Before you drill anything out, please show some close up clear pictures of the carb throttle assy.

    I have a similar Briggs 8000 and 9000 series engines and have changed the carb that came with them as they were not used from gravity feed gas tank. The bowl with float valves in the carb kind of carb I am talking about.

    I had modified the carb but only slightly to get it to have a twist grip throttle. I also am off roading so I use gloves and the additional grip that is on the handle I know is tough on bare hands, but splash with mud and you have a better chance with this type.

    Back to the point, I have many documentations on my motorbike carb throttle setup in the threads I have started.

    I did not like the plastic part of my carb that the connection would be made to, in fear that it would soon break. I also did not have any easy way to continue to have a governor on my engine. The reason is that I had to use and elbow manifold to clear the frame. I added a spring, separate from the throttle cable return spring. The spring is just connected to the butterfly valve plastic part outside of the carb. It is connected to the twist grip throttle assy by means of a pin on the assembly that connects to the spring.

    With this modification when I am at idle or at full throttle, the spring bends. This way there is only very small force that can be applied to that crummy plastic part on the carb.

    When I had another carb temporarily being used it had it 180 degrees the opposite side I needed to have the cable going to the carb. I reused without changing any existing parts, just added some new parts and removed others. The end result was the carb had other issues I did not like and returned it for warranty refund. I still had the parts saved and reverted back to what I originally had.

    All in all you I know are creative and have something going that I like in that bike build.

    A twist grip throttle not using any lock is a good way to go. There are those that use other means by small levers and the like to have a throttle, but they I have most notice have a return spring and do not lock.


    https://motorbicycling.com/attachments/img07605-20120329-1804-jpg.46483/

    Above link to picture shows where the pin connects to inside the vertical spring. That vertical spring is connected under a block of aluminum on a pivot point. The pivot point is actually from a door hinge. I added a place to connect a twist grip throttle cable and return spring. Also adjustment stops limiting both idle and full throttle.

    Just figured I'd also mention that there is a block of aluminum I drilled and made to put between the manifold elbow and the carb since the engine is on a tilt and this levels out the carb bowl and float to be at its best.
     
    #5 MEASURE TWICE, Oct 3, 2017
    Last edited: Oct 3, 2017
  6. TheSignGuy

    TheSignGuy Member

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    Recoil cover state 80302 model 1507043854607394840322.jpg 15070438993991308384814.jpg 1507043964182539303749.jpg


    First slide governor second slide carb face
    Last slide see where the bolt is? That add throttle to the spring via tension.

    Update: On my ride to the doctors office I have made adjustments to the carb, it holds its idle better re dialed in the main jet and idle mixture still needs further tunning how ever I did not tune it based on half throttle the settings where set to where it's manageable not running lean or rich..

    Pleasant exhaust but not burn your eyes over bearing with fuel will take some additional time to mess with the over all idle to get the perfect low idle. It's off only by a hair due to the cable and governor work against each other.


    Overall still take a look at those photos and see what we can tally up.
     
    #6 TheSignGuy, Oct 3, 2017
    Last edited: Oct 3, 2017
  7. MEASURE TWICE

    MEASURE TWICE Active Member

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    I guess this is an engine that has a centrifugal force weights inside the crankcase to operate the governor through a linkage outside the case. Not a fly wheel fins and and air vane type.

    Also the connections seem to be hidden behind the carb picture where the idle screw with spring is shown.

    It would seem then that the butterfly valve has a connection to an armature on two sides. The one side showing with the idle screw and the other side where it is connected to the governor and of course the cable that you adjust the throttle..

    If you know the model number and make of the carb that would help, this given I do not know what this carb looks like hooked up in entirety. Even better if you know where a link for a pdf file for the carb exist, but I could try looking it up my self knowing make and model carb.

    I do have a generator that uses a mechanical crankcase fly weight governor. It does not have a idle adjustment as it is meant to operate at a single speed only.

    I don't know what the engine model you have. That would also be necessary as the linkage connection and a pictorial view of how it operates. I would hope the engine with that carb and governor was meant for operating at a range of speed.

    Since you got it hooked up some how to run the bike from start to speed, I would think that it may have been used with that same stiff lawn mower adjustable speed throttle.

    Maybe some one else already has done this kind of hook up on that same engine and carb. See what you can come up with on the specs so I can better help.

    I don't think you should take apart the carb from the engine to get pictures as a lot of stuff is shown on save information on the internet. A good one I use is Smokstak.com

    MT
     
  8. TheSignGuy

    TheSignGuy Member

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    80302 I know it, manuals don't do nothing but I already found a tuning procedure long time ago, it's the cosmetics which are a considered.

    Racks to light! In the legs one sides wake due to offset motor.

    Plus it's an Amsterdam default defect.

    Debated welding on thicker legs or bolting new legs on with a bigger drilled bolt at the axle while welding on some different parts...


    If I could have coil overs I could mount on open hole shocks for a car.

    Modify to fit most likely parts for a Honda junk yard dawg.

    Listen to Post Malone feat. 21 Savage - rockstar/Nickelback - Rockstar (drewdonnelly edit) by NathanBlaney #np on #SoundCloud
    https://soundcloud.com/nathanblaney...rockstarnickelback-rockstar-drewdonnelly-edit
     
    #8 TheSignGuy, Oct 3, 2017
    Last edited: Oct 3, 2017
  9. MEASURE TWICE

    MEASURE TWICE Active Member

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    https://www.ereplacementparts.com/briggs-stratton-80300-series-engine-parts-c-16758_17347_22194.html

    Above for detail pictorial diagrams shown of the 80300 series. It is air vane type governor.

    https://www.smokstak.com/forum/attachment.php?attachmentid=179411&d=1384280116

    Above check out this round throttle linkage. Not sure how it was attached, maybe press fit?

    It could be used with some bracket attached some where on the engine to have it connect up. Not sure where the idle adjust went to since I thought it was mounted the same place on the carb.
     
  10. TheSignGuy

    TheSignGuy Member

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    Correct it is a air vane type although not sure how this reflects the carb by adding a throttle due to what is illustrated here:
    TM-5-4240-501-14P_142_1.jpg

    In theory, I believe by replacing the control style cable at low idle the throttle is simulating a choke if the specs are pushed out far enough it will not no longer stall I normally have to currently press the throttle controller to keep idle at bay if it isn't pushed a tiny bit every now and then it stalls by its self very very slowly although it has an external choke at the end of the car toward the air filter.

    After a carb adjustment 8 miles in of 34 mile ride including from and back I pulled the plug only to find its not running too hot and is not ashy white anymore the tip looked fairly clean kind of a titanium color the grove how ever in between was fouled from the initial carb retune in theory.

    I think I should install another new plug at this point.

    How will this vane effect installing a throttle cable at this point
    I know I will have to install a spring to make it return to low idle where the control cable is.
     
  11. MEASURE TWICE

    MEASURE TWICE Active Member

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    Maybe the carb in conjuction with the governor on that engine was set up not to have a very slow idle. I guess I never used one of those types. The vacu-jet Briggs carb with air-vane governor I have had almost sound like a hit an miss idle without stalling very slow speed

    I wonder if all the parts of the carb linkages with the governor are present.

    What I remember is that the throttle cable is not hooked up to the butterfly valve directly.

    The butter fly valve does have that idle adjust screw, but the throttle cable I remember going to another hinge plate of metal that connects to the air vane through a stiff wire linkage. That hinge plate is not the same as the butterfly valve.

    When connected this way there is no struggling between a throttle cable and the governor.

    The way it reacts as I remember on a lawn mower is that at idle it is kept from stalling.

    Secondly when at say half full throttle going through a lawn of medium high growth, and then say you come upon much taller lawn the engine will slow temporarily.

    Very soon afterwards the governor reacts since the fins on the slowing flywheel don't push the air-vane as much, the spring the becomes shorter. The shorter spring then move this hinge plate which is connected to the butterfly and thus compensates and speed the engine back up.

    It will usually over compensate by a bit and speeds up too much just for a second.

    Then it quivers a bit slowing and speeding up and slowing a few times and settles in at very close at the same speed of half full throttle as prior to encountering a thicker lawn to deal with.

    You might become a member on that Smokstak.com and post the question there.

    Maybe also find on this site some other place to ask the question rather than general discussion area.

    https://motorbicycling.com/forums/intake-exhaust.51/

    Maybe try this area. Search first and maybe find an answer. Maybe also include Briggs in the search. Post question there if nothing help, but maybe that more defined area could turn up something.

    MT
     
    #11 MEASURE TWICE, Oct 5, 2017
    Last edited: Oct 5, 2017
  12. TheSignGuy

    TheSignGuy Member

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    You've helped enough and exactly as you have explained the setup is how I feel the vane is attached to the carb and is tensioned through the round nut located between the intake and air filter housing.

    I however will not be able to tech said issue dealing with stalling at low idle, this can only be cured by throttle flicks once installed.

    The arm that sits between the butterfly which is attached to carb as well as the vane the cable is set up to be installed there so there is no missing parts.

    When I low idle via control cable or throttle assembly based cable this model only provides control on idle at less then a few mm's if I tap the throttle in just a hair (it wants to go then and right there) more reason to upgrade to a lighter weight flywheel which in return will generate more air to the vane.

    In the 2t world of mopeding slot of people upgrade their fans to promote better cooling also others install air scoops as well.

    So in theory by this being a 4 stroke motor this should bring better flow to the vane with less struggle.

    Old Briggs has poorly designed flywheels they are bulky heavy cast iron so I'm thinking a thin steel flywheel would help cut-down on issues with the vane while providing ability to stimulate the vane better.
     
  13. MEASURE TWICE

    MEASURE TWICE Active Member

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    If the spring is deformed it will impact how well it can idle since the governor is not operating as it should. Since I swapped to a carb that did not have a low and high speed fuel mixture screw, it has nothing adjustable, I do pulse the throttle a little to idle. The elbow manifold makes it that I had to do away with the governor.

    One thing though is if the idle gets going too fast and you have to be not moving, you have to be quick with the kill switch button. Some times I have just held the brake, but the clutch shoes and drum can heat up adversely.

    Have you come up with or gotten to what you were mentioning about making stronger or more rigid engine mount? Also maybe also adding an idler or back idler pulley for adjusting belt tension as it wears. Used a back idler pulley I made from some kind of nylon plastic with metal mount and bearings. Now that I just have one belt and two chains, the single belt is adjusted with an adjustable diameter pulley.
     
  14. TheSignGuy

    TheSignGuy Member

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    No I have not yet, when I can I will but I was considering drilling hole in which I can mount rods from the frame to the rack with good body work and precision anything can happen.

    Just got two old mirror racks pretty thick but my wife gave me an idea, instead of drilling the frame use the two bendable racks and make rod tensioners for both sides imagine like rebuilding a wheel. Can accept about 3 or 4 rods per side which can increase durability with adjustment to counteract the vibration engine offset strength.

    This idea stems from Looking at the coaster brake arm holder....
    As only tools required would be:

    1) A Rod wooden dowel...
    2) A mallet,
    3 Two 2x4 blocks...

    An angle cutter wheel and a drill bit.


    Without damaging the metal as a 2x4 absorbs damage...

    I also found a cheap aluminium thick welded name brand rack that's post mounted that may be modified.

    It's a Schwinn made rack, I went to Walmart and tried crushing the base by hand was very strong says only withstands 20 lbs but can be notified to accept a bit more weight problem I feel is the aluminium.
     
    #14 TheSignGuy, Oct 6, 2017
    Last edited: Oct 6, 2017
  15. TheSignGuy

    TheSignGuy Member

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    Update: October 6,2017 9:40PM
    Just pickup some supplies at Lowe's.

    (1) 48 inch 3/8 square tube steel, (8) 5/16 -18 rods, (42) 5/16th stop nuts with the nylon inserts to prevent vibration, (1) drill bit set, (3) 5/16 short bolts.

    (It's about.... to go.....DOUWN.)(p)(p).fly.shft..mbcsb
     

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