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DIY Home Built Motorized Bicycle (non kit) Post all about your home built rides here. Weedwacker motors, lawn mower engines ect. This area is for non kit builds

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  #31  
Old 01-04-2017, 03:41 AM
MEASURE TWICE MEASURE TWICE is offline
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Default Re: Adapting Briggs Build to accept bigger engine

Put everything back together, but want to test out the engine with the carb it was never run with yet. I'll not have any of the tranny connected up when doing so. Also will yet see how it runs before threading the recoil starter pull cord through the hole in the cover on the right side of the engine / carb.

Along with the centering drill set I bought a HF that was a good deal, I tried out the allen wrench set that is both short and long handle for both Metric and Standard. The did not snap right away, I'm hoping they are also a good deal! Another of the free flash lights with hook and magnet attach point was nice. Three leds on or Twenty Five for real bright.
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  #32  
Old 01-04-2017, 03:51 AM
MEASURE TWICE MEASURE TWICE is offline
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Default Re: Adapting Briggs Build to accept bigger engine

Another good thing happened. I wanted the tapped bolt on the end of the jack shaft to have a flat washer that made it so that it would compress just a small amount along with a split lock washer at the end of the shaft. The washers that I got that have an inner bore equal to the jack shaft diameter, shimmed it just right before. Now I needed a thinner washer or I would have to shave down possibly a spacer.

When I could not find what would work. I bought a few washers same package as before. When I got home I saw they were a bit thicker even though the same part number on the package.

I removed a few of the originals and add two of the newer thicker ones, mixed an matched for a perfect shim.

Without opening up stuff in the store, you don't realize there is not really a set standard on some of the hardware dimensions.
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  #33  
Old 01-07-2017, 04:30 AM
MEASURE TWICE MEASURE TWICE is offline
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Default Re: Adapting Briggs Build to accept bigger engine

https://vimeo.com/198453385

I ran the newer used Briggs with the same carb/tank setup that was used before on the older used Briggs and it ran good. The engine had not yet warmed up in this video.

When it warmed up a little more I have another video, but it was not for long I ran the engine with the fuel line attached. The gas shut off valve started to leak. Four years old and I need a new one. I ran the fuel in the bowl till empty and noticed it idled a bit better. I do not have the governor hooked up due to the elbow intake manifold.

I realized I could adjust the minimum butterfly throttle position to go a bit slower and will try another time.

Not sure I ever saw that same fuel valve available on Amazon anymore, so I might need to use a different one and find possibly needing to figure how a different type could be mounted.

I also had just one chain hooked up and with the cover on for safety, I notice the top jack shaft run smooth and no chain noise. After the cover removed I saw the sprocket and chain looking the same so it seems good.

Would have done more but hot engine and a leaking shut off valve is no way to test, another day I get back to it!
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  #34  
Old 01-07-2017, 06:42 PM
MEASURE TWICE MEASURE TWICE is offline
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Default Re: Adapting Briggs Build to accept bigger engine

http://www.ebay.com/itm/321903405337

Ebay has the part and is less than any place I checked, so soon I replace the gas valve.
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  #35  
Old 01-09-2017, 06:55 PM
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scratchbuilder scratchbuilder is offline
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Default Re: Adapting Briggs Build to accept bigger engine

Het MT, I swapped cranks..the 3hp 5/8 shaft with the 3.5 3/4 shaft. I put the 3hp 5/8 crank into the 3.5 engine. Used the micrometer on the cranks, the same. Rods, the same. So when I get a new head & side gasket I'll fire it up and hope for the best.
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Last edited by scratchbuilder; 01-09-2017 at 06:58 PM. Reason: add pic
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  #36  
Old 01-16-2017, 01:03 AM
MEASURE TWICE MEASURE TWICE is offline
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Default Re: Adapting Briggs Build to accept bigger engine

I have some cranks now I will get a chance and see about swapping them in also. For the pillow bearing holders, what I got from the AGK kit for jackshaft, I never realized that it would have been best to make my own holders or get a kit that has holder for the bearing that have more surface contact with the outer bearing sealed race. Also they brake press cut the hole in the bearing holder for the outer bearing and it leaves a rough edge. Most of the cut hole is too wide a diameter and the bearing is loose in the holder.

I already have used them like this, but am going to try and shim the bearing in the holder with aluminum or copper thin sheet material. Also the spring clip that is on the holder I have made a corresponding weld dot (and shape with Dremel). This is to keep the outer bearing surface from moving and wearing out the holder and the outer bearing surface.

I know the spring clip only has some much grabbing force. But it is OK, I just want to be sure the bearings are turning not the outside of the bearing in the holder. The shaft on the inside of the bearing surface is tight enough and a special Locktite kinda stuff made special for bearings I may use some there.

I will inspect and just replace the bearings after a while, but when I hear the tell tale noise of the bearings grinding, I would like it to be just the bearings that take the wear and nothing else to replace.

I got the new fuel valve and am ready to reassemble the bike and test out 13 or 14:1 ratio. If it is not good enough I have the two engines and 4 crankshafts I can all mix and match. Maybe back to belt clutch with the 5/8 long shaft or 3/4 long shaft from the ones I can clean up I got from Tony01. I have the 3/4 clutch that uses 35 chain. With that I can be back at 20:1 or even higher which I don't think I do, but nice to know I can if it comes up.

The regular aluminum foil is so thin it rips. Still enough stays in place I could go with that, but I have some copper foil that is thicker by a small margin and I fill give it a try.
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Last edited by MEASURE TWICE; 01-16-2017 at 01:10 AM.
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  #37  
Old 01-16-2017, 09:16 AM
curtisfox curtisfox is online now
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Default Re: Adapting Briggs Build to accept bigger engine

Do you have a picture of the bearing you got from them, sounds like you are talking about self aligning bearings?................Curt
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  #38  
Old 01-16-2017, 02:30 PM
MEASURE TWICE MEASURE TWICE is offline
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Default Re: Adapting Briggs Build to accept bigger engine

These are standard roller bearings with snap ring. They are fixed not self aligning. They are not set in a big pillow block, like some with oiling port.

Shown in picture the height of the bearing is such that it sticks out the back of the holder a small amount. You can see the break edge from the stamping cut.

I made sure where I bolted the holder that the bearing sticking out the back did not contact anything. A bracket that the holder bolts to was shaped so that it does not contact.

Special bearing I know are made that are self aligning and they are not these.

Even if they were self aligning bearings, you would not want to mount them loosely.

The bearings were OK to a degree, but the mounts were really not ideal. The replacement bearings I bought recently do not spin as easy. I thought that was not good. I now realize that is the grease inside. This is normal and is better in the life span of the bearings. When you feel a grinding that is when they are tossed in the trash.

They are called Bearing Hangers the flat stamp cut parts:

https://www.affordablegokarts.com/mm...egory_Code=PCJ

The snap ring bearings:

https://www.affordablegokarts.com/mm...egory_Code=PCJ

The kit I bought local, same as on Ebay:

http://www.ebay.com/itm/VINTAGE-MINI...3D121661858488

Last edited by MEASURE TWICE; 01-16-2017 at 02:57 PM.
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  #39  
Old 01-17-2017, 02:02 AM
MEASURE TWICE MEASURE TWICE is offline
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Default Re: Adapting Briggs Build to accept bigger engine

Got the bearing hangers modified and seeing how they will work on the brackets.

The use of copper foil to shim them more firmly in the hanger yet to decide if it can work to make it any better to fix the loose fit.

I looked at some bearings that come in nice hangers that have oiling ports, but it is a large pipe thread that is used to mount the bearings. Totally different than how I have it now. Least expensive I've seen some around $25 for each on Amazon. I'd need 4.

Self aligning bearings are still probably more. Also there seems to be a lot of different shaft sizes that are metric, but I am using 5/8 inch standard. I don't want to sink more money into just replacing what is only around $10 for 4 bearings the way I have it set up now. Just like to make it as best I can with simple means.

I think maybe I will get some kind of hour meter for running time to decide when to just change the bearings, not waiting for that screeching sound.

Will try to have it done before next rain to see about the ratio at 13 or 14:1 and the newer used Briggs 3.5!
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Last edited by MEASURE TWICE; 01-17-2017 at 02:07 AM.
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  #40  
Old 01-17-2017, 07:14 AM
curtisfox curtisfox is online now
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Default Re: Adapting Briggs Build to accept bigger engine

Just take a chisel or punch and hit the retainers in one or two spots and they will fit tighter......Curt

Also they make a small pointed needle for grease gun, take a small point pick lift the seal to get the needle in and grease the bearings later down the road.

Last edited by curtisfox; 01-17-2017 at 07:18 AM.
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