Briggs and stratton air vane handle bar throttle conversion

TheSignGuy

TheSignGuy

Member
So I've been debating on adding a throttle grip assembly on this upcoming month but there is a few things that stand in my way,

I have a older flat head with an air vane as represented by this image illustration.

TM-5-4240-501-14P_142_1.jpg


To the left of the segment shows the engine at idle and to the right represents when driving.

The underlying issue is if I install a common throttle found on mopeds, scooters, and motorcycles I would need to develop an opposite leverage that draws the vane close via spring to pull the throttle back to its closed position without fully effecting then vane.

I would also need to develop a bracket that comes up to the top of the motor as the specs are reversed accelerating the speed of the motor.


In the current position pushing the factory lawn cable "in" accelerates the engine which pushes "up" the butterfly & vane.

The object of this post is where or what spring can I attach from the cable holder plate to the linkage which operates the butterfly and vane without applying full tension but will allow the engine to idle up when needed.

Once that is set up I can properly attach a cable under light tension which allows throttle cable play enough to not effect the vane at idle.

Looking for ideas cannot be too weak but not too strong.....

I will take measurement of the distance from the linkage opening slot to the control cable factory mount area sometime tomorrow.
 
If you are using this engine for a motorized bicycle, why would you even need to use the air vane. My understanding of the purpose of the air vane is to govern the engine to a constant speed to run a piece of equipment like a lawn mower, water pump, generator, etc... When a load is placed on the engine or removed from the engine the air blade would move one direction or another to keep the speed constant. If you are going to control the engine with a twist throttle the air vane is no longer needed. You would just need a return spring with the proper tension to return the throttle back to idle when released. The air vane can be completely removed as it is no longer needed.
 
malatious said:
If you are using this engine for a motorized bicycle, why would you even need to use the air vane. My understanding of the purpose of the air vane is to govern the engine to a constant speed to run a piece of equipment like a lawn mower, water pump, generator, etc... When a load is placed on the engine or removed from the engine the air blade would move one direction or another to keep the speed constant. If you are going to control the engine with a twist throttle the air vane is no longer needed. You would just need a return spring with the proper tension to return the throttle back to idle when released. The air vane can be completely removed as it is no longer needed.
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My thoughts also, if you really want the right spring. Take the model, type, and serial numbers off the flywheel cover to a small engine repair shop. Like a John Deer place, get a new for a $1 or about that..............Curt
 
curtisfox said:
My thoughts also, if you really want the right spring. Take the model, type, and serial numbers off the flywheel cover to a small engine repair shop. Like a John Deer place, get a new for a $1 or about that..............Curt
Click to expand...



Problem with that it's a single spring that goes to the vane which means that spring would be then moved to the side that pulls the engine out of idle and the cable would have to go to the opposite side where the spring currently sits.

That way when the throttle is twisted it pulls down the linkage which in turn accelerates the engine.

I can either leave the spring where it is but then the cable would be pulled overhead.
 
That spring is not strong enough to pull a cable back to idle, you will have to get a stronger one. And yes you will have to make a bracket to clamp cable from over head, you could use one of the carb manifold bolts or head bolt. ..........Curt
 
curtisfox said:
That spring is not strong enough to pull a cable back to idle, you will have to get a stronger one. And yes you will have to make a bracket to clamp cable from over head, you could use one of the carb manifold bolts or head bolt. ..........Curt
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Well looks like someone's going to Tacoma screw I refuse to pay more then 5 for just a spring.

WA is a piece of ###### when IT comes to prices at parts stores.
 
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curtisfox said:
Have you tried a hard where store? Home depot?.........Curt
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One thing about those typical box stores..

"no offense half of my bike is home depot grade."

is that they have a poor spring selection plus that's a drive to delridge or sodo district.

If I'm making that type of commitment of rather have throttle on hand so I cannot drive it until the repairs complete on the spot.

That's how my car got a perfect time up on a 37 mile drive 8 miles in with the engine hot I pulled to the side cause I got tired of idle traffic stalls.

I like being stranded to feel like I fixed a car lol

I also enjoy distracting road traffic cause they nosy as **** they stare so hard they forget the lights green and get beeped at.
 
TheSignGuy said:
One thing about those typical box stores..

"no offense half of my bike is home depot grade."

is that they have a poor spring selection plus that's a drive to delridge or sodo district.

If I'm making that type of commitment of rather have throttle on hand so I cannot drive it until the repairs complete on the spot.

That's how my car got a perfect time up on a 37 mile drive 8 miles in with the engine hot I pulled to the side cause I got tired of idle traffic stalls.

I like being stranded to feel like I fixed a car lol

I also enjoy distracting road traffic cause they nosy as **** they stare so hard they forget the lights green and get beeped at.
Click to expand...

ACE Hardware
 
curtisfox said:
ACE Hardware
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Ace is OK don't know if there is one in my area...


Closest hardware stores like Lowe's less then 3 miles to and from included.

I hate Lowe's though, the difference is Lowe's charges for they fancy layout.

Home depots for the hard grinders next time you walk in both look at the difference one is rough looking the others a suit and tie store.

Home Depot has bike racks Lowe's don't have nothing..... no rack means no cyclist business.
 
Harbor Freight has a variety box of springs. Many more than you need but I bought that and the assortment of keys for crankshafts. Flywheel keys (weaker type of aluminum) are expensive, but I bought a box of like 3 so in case something jams. Flywheel keys I went to Yardbirds and they can be expensive, so I know what you mean.
 
MEASURE TWICE said:
Harbor Freight has a variety box of springs. Many more than you need but I bought that and the assortment of keys for crankshafts. Flywheel keys (weaker type of aluminum) are expensive, but I bought a box of like 3 so in case something jams. Flywheel keys I went to Yardbirds and they can be expensive, so I know what you mean.
Click to expand...


Yeah my rigs OK but could use a lot of improvement by time I'm done I know she'll weigh in at 120 lbs to 145lbs flat.


Now harbor freight I can do I also need the rest of my flywheel key installed I'm using the factory key made on the clutch.


Good thing about belt it won't over torque it's self.

Eventually I will do a tear down and build a custom rack welded to cut back on weight.


Admiring the idea of hard backed old school Schwinn 60s cruiser rack styles. Sturdy as ****.
 
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