Bonanza BC1100 Resurrection

#1
This was my first mini bike I got years ago when I was a young kid. Originally it was just thrown together with a stock 5hp Briggs with the governor removed. It has the original go power wheels and it was pretty darn fast. I lost interest in it over time and it sat for while. My dad robbed about every good part off it to build other bikes and now all I have left of it is the frame and the engine block. So the plan is to build it back up again. It’s going to be a resto-mod the frame is going to be pretty much restored to original including some go power wheels, chain guard, maybe some other original bonanza parts. However powering this bike is going to be a dual bearing Briggs 5hp I/C block that I plan on hot roding with a 107ss cam 22mm Mikuni custom exhaust port and polish work etc...



The engine that was on it is actually in good shape however it is just a bushing block so I’ll save it for another project that I’m going to run a more stock engine on. It does appear to have a shaved head on it.






After tear down and inspection of the original engine I put it back together and prepped it for storage



Started working on the frame next. The fork springs were stuck as most usually are but a little heat and they pulled right out




The springs look like they’ve seen better days and I will be on the lookout for some new ones.

So the frame is pretty much stripped right now. I’m going to go out and pull the I/C engine I have off the rototiller that it’s attached to. It appears to be in really good shape and is a ‘94 model if I remember right. I’ll tear it apart to inspect and report back later today. Kinda excited for this one I’ve had the itch to build something for awhile just been so dang busy with other things lately it’s hard to do what you really want to do. Anyways comments and tips/suggestions are always welcome. Thanks!
 
#3
It should be a fun project no doubt. Well I just tore down the other engine turns out it’s only a single bearing block. So now the question is do I look for another dual bearing block or just run what I have? It’s in really good shape seems to have low hours
 
#6
Well frames stripped doesn’t really need much other than filling in the extra holes in the engine plate and I’ll most likely weld a kickstand onto it.



I got my engine torn down that I want to build however it ends up only being a single bearing block which I’m kinda bummed about. The cam I want to run pulls to 8000 rpm not sure if a single bearing block will be sufficent for my setup any thoughts?

 
#7
Well frames stripped doesn’t really need much other than filling in the extra holes in the engine plate and I’ll most likely weld a kickstand onto it.



I got my engine torn down that I want to build however it ends up only being a single bearing block which I’m kinda bummed about. The cam I want to run pulls to 8000 rpm not sure if a single bearing block will be sufficent for my setup any thoughts?

That's going to be a great project. And the backstory is fabulous. Glad to see you bringing her back to life. I wouldn't weld the kickstand on it though, I saw re pops right here on OMB somewhere recently. Keep up the good work looking forward to seeing your project completed. The hot rod motor will be fun. Screenshot_2018-10-06-21-39-55.png Mark
 
#8
Well I put in my deposit with Karen (manchester1) for a seat so I should have that sometime around February sounds like. Now I just got to start ordering all the other parts but with it being the holidays I might not really be getting much until after the first of the year. Unless I get a good Christmas bonus this year. Stay tuned...
 

delray

Well-Known Member
#9
I got my engine torn down that I want to build however it ends up only being a single bearing block which I’m kinda bummed about. The cam I want to run pulls to 8000 rpm not sure if a single bearing block will be sufficent for my setup any thoughts?
that kind of sucks, I am no means a expert on the I/C blocks. I really thought all I/C's had dual bearing setups. I think you will be ok spinning the motor at 8000 rpm's if they are just quick burst up to 8000 and off the throttle. now if it was in a gokart on a race track. that might be a different story. I have run a Tecumseh in the pass with only pto bearing and it pulled 8200 rpm's at 125ft when drag racing it on clay surface and no damage at all on the bushing side. so in my opinion you will be safe. maybe make the engine the last thing you want to build and another I/C motor will pop up with a dual bearing? there is a way you might be able to make that a needle roller bearing setup. but that would be a lot of work involved if your not a machinist or don't have access to one.(free)
see it's a cast iron sleeve too. that's a plus for sure.
 
#10
that kind of sucks, I am no means a expert on the I/C blocks. I really thought all I/C's had dual bearing setups. I think you will be ok spinning the motor at 8000 rpm's if they are just quick burst up to 8000 and off the throttle. now if it was in a gokart on a race track. that might be a different story. I have run a Tecumseh in the pass with only pto bearing and it pulled 8200 rpm's at 125ft when drag racing it on clay surface and no damage at all on the bushing side. so in my opinion you will be safe. maybe make the engine the last thing you want to build and another I/C motor will pop up with a dual bearing? there is a way you might be able to make that a needle roller bearing setup. but that would be a lot of work involved if your not a machinist or don't have access to one.(free)
see it's a cast iron sleeve too. that's a plus for sure.
I might see if a good block pops up on eBay or maybe I’ll get lucky and see if I can get a complete engine for a good deal. If not I’m just going to build this block.
 
#11
For what it's worth Bryan, I built a Raptor I which was a single bearing block at the PTO, canted valves, etc. with hot rod FH components. No problems with it, and two plus years later it's still running great on a heavy Tote Gote. I also bought a hot rod IC based engine from a member here with a single PTO bearing. I ran that engine hard, and still no issues.

Unless you are going to hard core race it and spend most of it's life with the throttle wide open, I don't see a problem. Just my opinion. Two bearings are almost better, but certainly not necessary for a hot engine sitting in an adult-ridden mini bike.
 
#12
For what it's worth Bryan, I built a Raptor I which was a single bearing block at the PTO, canted valves, etc. with hot rod FH components. No problems with it, and two plus years later it's still running great on a heavy Tote Gote. I also bought a hot rod IC based engine from a member here with a single PTO bearing. I ran that engine hard, and still no issues.

Unless you are going to hard core race it and spend most of it's life with the throttle wide open, I don't see a problem. Just my opinion. Two bearings are almost better, but certainly not necessary for a hot engine sitting in an adult-ridden mini bike.
Then I might just run it this is just going to be a fun rider don’t plan on racing it or beating the piss out of it
 
#16
Went digging through some parts and found a set of go power wheels and a 60 tooth rear sprocket. Not sure if I am going sandblast and paint the wheels or get them burnished? And the rear sprocket looks to be in good shape but I was thinking of getting a new one if I can? I know the go power sprockets are hard to come by and I don’t know of anyone that makes new ones currently? It does appear that the sprocket is welded to the drum brake hub so theoretically I could grind off the old welds and remove the old sprocket and have a new sprocket made for it and welded back on. Or maybe leave the existing sprocket and drill it to be used for a newer style split sprocket? Any ideas what I should do?

 

delray

Well-Known Member
#17
that would work bryan. just cut the old welds off and weld a new one on. if you can get your hands on a lathe that will help true up everything better. it would be nice too if you had a plating service near you that could nickel-plate or zinc it for cheap. some places just won't take in one small piece? or paint? that too will keep the welds from rusting.
one thing I really like on my bc1100 bike was the factory brake setup. it works and works good.
 
#18
that would work bryan. just cut the old welds off and weld a new one on. if you can get your hands on a lathe that will help true up everything better. it would be nice too if you had a plating service near you that could nickel-plate or zinc it for cheap. some places just won't take in one small piece? or paint? that too will keep the welds from rusting.
one thing I really like on my bc1100 bike was the factory brake setup. it works and works good.
I’ve really been wanting to buy a lathe for myself. I did quite a bit of manual machining during my high school days and a little Cnc programming. It would defiantly help in this situation as the inside bore of the sprocket needs to be 5.250 for a nice tight fit on the brake hub. I’m most likely going to have to buy some steel sprockets and have a machine shop bore the holes in them to fit the brake hub. If i go that route I’ll probably have them do half a dozen of them so I have a bunch for future projects. As far as finish goes I don’t know of anyone in the area that does plating. With all the BS enviromental laws and regs here I think the state of California has pretty much run all the old plating shops out of business. So I’m either looking at paint or shipping it out for plating.
 
#19
Not a huge update but got the holes in the engine plate plugged up. Thinking of buying tires and tubes this week and get the wheels painted and all assembled.


Also thinking of making some foot pegs for it. Something that matches the original ones but slightly longer as I have big feet that don’t fit on the stock pegs
 

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