new bonanza project.

joshua. c.

Well-Known Member
#21
I was hoping to have the bike ready for a race this weekend but that's just not happening at this point. I have a project on the house that takes priority this week so not enough time to work on the bike and the walburo pz22 carburetor I ordered should have arrived at the beginning of last week and still hasn't so something has gone wrong. I contacted the seller and he's looking into it.
I did take a little time off from the house project to get a little work done this week. I just found out the front wheel at the bearings is to wide for the forks. I had to pull the forks apart to put the wheel back in and they are spread so wide it binds the outer sleeves and wont let the shocks move freely. now I know why it was so hard to get the axle out when I took them apart. I either have to modify the forks or the wheel to make this set up work or I need to buy another front wheel. I'm defiantly not messing with the built in spacers on the forks in case I find an original wheel. so that leave only modify the wheel or buy another wheel.
 

joshua. c.

Well-Known Member
#22
I just found out about what happend to my carb. the shipping label had the wrong address on it and it went to the wrong house, sellers fault. the post office is attempting to contact the person who received it to get the package back but there's no guarantees that I'll get it back.
 

joshua. c.

Well-Known Member
#23
The post office contacted the person who received my crab and they brought it back to the post office. and I'll be picking it up this week. I owe the person a thank you for bringing it back. now I'll be able to start on the engine modifications.
 

joshua. c.

Well-Known Member
#24
sorry for the long time with no updates I've been very busy. and up till recently I've been very short on cash. I am still tight on cash but its not as bad. I just picked up my dream mini bike engine for cheep. its a 206cc briggs and straton fire breathing monster that puts out 9hp out of the box. I've wanted one for years but the price was never right . I got this one for cheep and I'm very exited. even if its smoking and dead its worth the money payed. (if so I'll just re build it.) it feels like its got grate compression. if you haven't figured it out its a briggs animal. (a purpose built kart racing engine) .I was going to build another engine for this project to be set up very close to the way this one is but this is ready to go and is made with better stronger parts. It might be a while before I do another update I don't have time to work on this right now.

hears a picture, the pipe and carburetor didn't come with it. it had no carb and a pipe that wouldn't fit in the mini bike frame. and theses a bit more work to do to it before its ready to fire up. (installing a pull start for instance. )

bonanza animal.JPG

animal.JPG
 

joshua. c.

Well-Known Member
#25
I finally have some updates ,so far I got ahold of an original animal pull start. and Ive ordered the correct starter cup and nut. so i can now make the engine usable in a mini bike. I also cut the make shift foot pegs off and ground the remainder of them off the frame. I have a set of motyorcycle foot pegs that im going to mount where the originals would have been. I tracked down an original front wheel and I have made up the wheel spacers front and rear the bike is realy coming together. but I ran into an issue with the rear sprocket. something is warped, at first I wasn't certain if it was sprocket or wheel hub but after switching the front and rear wheels and re mounting the sprocket nothing changed so I'm fairly certain its the sprocket. unless both wheel hubs are warped the same way. (not impossible) the when I spin the wheel the sprocket wobbles side to side while spinning and integrated the brake drum wobbles rubbing on the brake in a few spots. just for reference the wheel and sprocket/brake drum assembly are originals and the bearings and rear axle and brake are brand new. the sprocket is a very rare part an would be hard to replace and the only company I could find that is producing a sprocet that woold work now called American racer overhauled the sprocket design so it would never look original. ( I went looking for a better reproduction but couldn't find one) I woold prefer to either buy an exact reproduction or find some way to fix what I have. Has anyone else encountered this? and is there any easy fix? (picture's to come soon.)
 

joshua. c.

Well-Known Member
#27
Most of the parts I need for this bike I already have or are on order so progress is moving quickly. It's kind of ironic I'll have at least 3 new bikes running this year and with whats been going on I'll have no events to bring them to.

I don't have a dial indicator but I can strap a screw driver to the frame facing the wheel to act similarly to the tool bike shops use to tel if a wheel is strait. When I held the screw driver on the frame the sprocket wobbled about 1/4 an inch side to side. the question is what to use to bend the sprocket ? its thick hard material not meant to bend, it won't be an easy task.
 
#28
Most of the parts I need for this bike I already have or are on order so progress is moving quickly. It's kind of ironic I'll have at least 3 new bikes running this year and with whats been going on I'll have no events to bring them to.

I don't have a dial indicator but I can strap a screw driver to the frame facing the wheel to act similarly to the tool bike shops use to tel if a wheel is strait. When I held the screw driver on the frame the sprocket wobbled about 1/4 an inch side to side. the question is what to use to bend the sprocket ? its thick hard material not meant to bend, it won't be an easy task.
I would try shimming the back of the sprocket a bit and look at the results. 1/4” is a lot, maybe a shim or two could bring it to 1/16” or so.
If the results are poor, I would pull the sprocket, clean it real good and lay it on a flat surface, like a table saw deck or a piece of floor tile. Then poke it a bit. It could be mounted wonky and a bit warped.
I would think a carefully set-up shop press could split the difference if it’s warped.
 

joshua. c.

Well-Known Member
#29
I had considered shimming the sprocket it might be the easiest solution. and using a press might be an option but only if shimming it fails.
 

joshua. c.

Well-Known Member
#30
I tried shimming the sprocket today and it may work. I found out where the high spot was and shimmed the other side with a washer but it was to thick and it only shifted the high spot to the other side so I'm going to get some thin strips of sheet metal and try that next. if this works I'll be able to mount the wheel and move on to getting the chain attached. after I get the sprocket true I'll also need to check that the brake drum in the center is also true or that could give me some braking issues.
 

joshua. c.

Well-Known Member
#31
Its been a while but I finally have some updates on the bonanza. recently I just received the briggs animal back from the dyno cams engine shop after deciding it kneaded a refresh. the block is freshly board the head now has big valves and is shaved and ported. it's also getting a bigger carb and 315 lift cam. this motor is going to be crazy powerful. as for as the frame, I have the front brake drum mounted to the wheel and have made a weld on bracket to attach hub to the fork tube. I also made up a bracket to replace the missing foot peg mount on the left side of the bike. and as far as shimming the brake drum I've shimmed it enough to completely eliminate the sprocket wobble. the brake drum may still be a bit off but its good enough for now. sorry no pictures yet I'm getting my broken pc replaced and I'm using a loaner for now. I don't want to download anything un necessary onto a pc that's not mine.

I have a temporary motor stuffed into the MTD so I could get it running but I had some carb issues and haven't had more time to work on it so its not running yet.
 

joshua. c.

Well-Known Member
#32
new pc up and running pictures to come soon.

My mtd is running and I've been to 2 events with it so far as my back up bike. It lacks power but that's to be expected when comparing a stock tecumseh hs50 powerd bike to my modified briggs raptor powered mini bike. its running quite well and now it just needs better more aggressive knobby tires and a kick stand. the side kick type not the original useless display stand. the display stands need level ground or your bike falls over.
 

joshua. c.

Well-Known Member
#33
DSCN0331.JPG DSCN0328.JPG DSCN0330.JPG




the first picture is of the bracket I fabricated to replace the missing foot peg mount and the second picture is the MTD in running condition. The motor is temporary until I can find a 20 over piston to rebuild the original. the third picture shows how I ground down the built in spacer on the forks to make room for the front brake. sorry that its a bit blurry but it dose show what it needs to.
 
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mustangfrank

Well-Known Member
#34
View attachment 280927 View attachment 280926 View attachment 280928




the first picture is of the bracket I fabricated to replace the missing foot peg mount and the second picture is the MTD in running condition. The motor is temporary until I can find a 20 over piston to rebuild the original. the third picture shows how I ground down the built in spacer on the forks to make room for the front brake. sorry that its a bit blurry but it dose show what it needs to.
Last place you would expect it but blackwidowmotorsports.com sells a repro MTD center stand in zinc, nice piece, I just got one for my Flite.
 

joshua. c.

Well-Known Member
#35
DSCN0329.JPG DSCN0332.JPG


I have been very busy with a number of projects recently and my finished ones are usually always slowly evolving I keep modifying and tweaking them as I find new ways to improve them. the first picture is to show the new knobby tires I just got for my fastest bike. they are quite grippy and look cool. and the second picture is a preview of a future project I just picked it up I really like the cool look of these older Colemans. what you see is what I currently have for it. I'm thinking of dropping a modified over head valve briggs in the frame. except unlike the bonanza it will be an inteck instead of an animal, not built to be quite as powerful and with a torque converter instead of a centrifugal clutch.

I never buy or hold on to more than one of each bike model as I feel having so many bikes already makes it useless having more than one of each. I already have quite the backlog of projects but there are one or two more bikes on my must have list that I'll need to really feel my collection is complete. once I find them thats it done! no more new bikes! at that point its all about the tweaks and improvements.
 
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joshua. c.

Well-Known Member
#36
on a side note I've taken the MTD to Windber and to Goma's as a back up bike and after some seat time I've discovered several major issues. the first being the foot pegs are slightly worn out, they point a little downward and my feet keep slipping off. easy enough fix with a welder. and the second is these tires are crap. they slip and slide to much, time for some knobbys like my fastest bike. also the seat is overly stiff. it could be the way its made or it might be an age issue or the fact that its been sitting for who knows how long but I'll have to solve it if I want to ride it regularly.
 

joshua. c.

Well-Known Member
#37
Last place you would expect it but blackwidowmotorsports.com sells a repro MTD center stand in zinc, nice piece, I just got one for my Flite.
thank you for the info but I don't like the center stands they are unstable on anything other than flat level ground and even then they are tipsy. I'm going to find a way to mount a side mounted kick stand at some point. I just wish someone made a weld on one to for bikes like this so I wouldn't haver to fabricate one.
 

joshua. c.

Well-Known Member
#38
Update on bonanza project, I just got the head back from dyno cams I had a valve that wouldn't fit into the valve guide so I sent it back to dyno cams to get some answers, turns out it was just a faulty valve with an oversized stem. and I now have all the parts to put this engine together except the carburetor. I was considering making this engine a stroker but now I'm thinking that won't be necessary in order to keep up with the local crowd, only time will tell. I can always make it a stroker later. I'm currently looking into foot peg options the ones I have right now aren't great for this purpose. I also have a bicycle kick stand that I may be able to fit onto this bike to replace the missing one.

I was also researching tire options. From what I've been seeing fat tire bikes have a real traction advantage at most of the mini bike events I go to so I need to find that widest knobbiest tire that will fit on my rims. It's not an immediate issue, the tires I have will work for now but I'm not finding to many options. go karts usa seems to have a knobbier version of what I have but it's just not aggressive enough to make it worth making the switch in my opinion. I'm looking for a verry aggressive knobby dirt bike like tire that's as wide as I can fit in this frame and on these rims. If anyone has any options I would appreciate the help. ( I did see a bonanza build on this website for the gambler mini bike event that had a big set but it's not the type I'm looking for, think rupp motocross tread like I just put on my blue bike pictured above but wider and fatter)
 

joshua. c.

Well-Known Member
#39
I just cut off my Bonanzas rear fender, it was made by one of the previous owners and it did look ok but it's extremely thick and it's much heavier than the fenders I plan on putting on this bike. Go Karts USA has some reproduction fenders for this bike and I'll be picking up a set soon. I'm just waiting to hear back from them on whether they can get a few other parts I need for this project. As far as I can tell the company American Racer took over the Bonanza product line and they sell threw Go Karts USA, unfortunately a few of the parts I need aren't listed and I can't find any info to contact American racer directly.

I also just bought the carb I need for the Bonanzas motor. It's a 28mm flat slide Mikuni, it's a big carb to match a set of oversized valves.
I will be starting the motor re assembly soon possibly later this week.

One of the next issues I need to figure out is whether a standard centrifugal clutch would hold up to this much power or whether I should switch to a racing clutch. I have a standard clutch on the shelf so maybe I'll try that first and if it wears out quickly I'll look into other options.

I'm charging my camera so pictures to come soon.
 

joshua. c.

Well-Known Member
#40
28mm carb.JPG bike with fender removed.JPG
close look at fender brackets.JPG
The first picture is the new carb setup roughly mocked up, the second is the Bonanza after the rear fender was removed and the third picture is looking closer at the mounting brackets after they were cleaned up.
The front fender not staying, I mounted it to see how it looked but it doesn't look the way I want so I'm taking it off.
The rear fender was 1/8th thick and was welded to both the frame and the original mounting brackets. Whoever made that fender really didn't want it to move lol. After cutting the fender free It took quite a bit of work to clean it up the brackets, it's not perfect but I think it came out good enough.
I would like to have this bike assembled and running by spring but we will see how far I get.
once I'm done replacing the missing frame parts I'll take this bike apart for paint and it's going to be several coats of red spray paint.
 
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