new bonanza project.

joshua. c.

Well-Known Member
#42
This is the carb recommended to me by dyno cams for my build. It's using a big valve head on an animal block, a 315 lift cam and the head is ported. the stock size briggs and straton world formula head uses a 26mm carb so I think it will be ok. If it doesn't work I can always buy s world formula carb or a 24mm and save this carb for a 305cc OHV build for a go kart later.

I think by the measurements I got that these are 32mm intake and 28mm exhaust and dyno cams did the port work. My goal is to make this bike so powerful that my skill becomes the bottleneck. I have been verry frustrated recently losing all the time due to my bike at full throttle not being able to keep up. I'm fixing that with this build and if it's still not enough I might go stroker later.

Also isn't a model 15 a flathead? I'm using a Briggs and Straton Animal over head valve.

DSCN0348.JPG
 

delray

Well-Known Member
#43
model 15 block is kind like a intek or animal block with a big bore that can handle a 3 or bigger piston with a steel sleeve in it and still use animal parts on it.. thumb1.PNG
315 cam set up right will easily handle 9000+ rpm's very good cam if it is use right/setup correct.
what type of racing are doing?
 

joshua. c.

Well-Known Member
#44
that model 15 sounds like a verry strong platform but I think it might be braking or at least bending the rules of most of the events I go to. the rule at most of them is 6-7hp block size or under and no other rules. (do whatever you want to the motor.) I don't think a 3 inch boar would really be fair to the competition considering that's close to the size of an 8hp block.

I'm doing whatever type of racing comes my way, sometimes small circle tracks sometimes large tracks. There are lots of local mini bike events within reach and competition is getting fierce. check out youtube videos about Gomas mini bike massacre, it's the most fun event all year, just be warned someone posted one this year with added in nudity (not from the event, the event is family friendly).

(Neat fact) The cam I bought was a new design from arc racing with a mechanical compression release that can handle high rpms. From what they have told me the compression release is only made for the Briggs and Straton animal for the time being. I'd love to have one for my older briggs raptor, it hurts when that thing kicks back. I have to start it with the throttle closed to prevent injury.
 

delray

Well-Known Member
#45
well don't the competition fool joshua. there is always someone trying to out do you. still kind left the window open for what you want to do with that engine. a truly built motor that can handle a 315 dyno cam will have very strong power range on the high end and will hold it strong. on a small bull ring track that engine would suck if you tried to gear it to the track(9000+ rpm's). it would be out of control and would wheelie and spin the bike in a circle. on a big track it pull hard if it was gear to that track and crazy hard if you ran it through a good clutch. torque converter it will eat up the belt eventually or break the driver. i run a crazy built clone motor for flat track races and it will run pass model 15 block with a ded billet head., when it's running. not saying you can't build a briggs and all. just that this guy keeps breaking the crankshaft....lol more then likely it's not balance correct with his 3inch piston. what's this new design cam from arc racing? last time i look arc wasn't making cams? 315 cam should be a dyno cam.
 

joshua. c.

Well-Known Member
#46
my mistake, I meant to say dyno cams, it was a typo.

I also have a motor I'm building for another bike that's a bit less crazy based off a Briggs Inteck 6.5hp with stock valves and a Walburo pz22 carb so I'm going to have some choices as far as what bike I can ride. Haven't chosen whether that one is getting a clutch or torque converter yet. it does use the same cam but won't be as powerful. and it's going in a 1970s coalman mini bike frame. (I got some rare bikes). I still need some parts for that project so I haven't started in on that one yet.

The bike in my avatar started smoking recently so it needs a rebuild and might be getting oversized valves and a 24mm carb while I'm at it. that bike is running a Briggs Raptor and a torque converter but that setup might not be ideal. I was wondering would it be faster with a centrifugal clutch? Raptors are good for high rpms and torque converters are known to limit that.

I could control any excess power by gearing the bike higher couldn't I? with a motor this strong even geared high it should still be enough to keep up on a smaller track as long as its geared just shy of wheeling correct? I keep getting outrun by faster bikes at every event THAT WILL END!
 

delray

Well-Known Member
#47
joshua if your just talking about racing in a oval track only. in my opinion a clutch will out run a torque converter all day. when a clutch locks up it becomes direct drive to the rear tire. on a torque converter there is always belt slippages. never 100 percent drive to the rear tires. well not with a 30series design...lol breaking affect to me works a lot better with engine break when also using a clutch.
here is a picture one of the guys that uses a model 15 briggs with ded head on a coleman bike you might like to see.
race head 2 sm.jpg

and we have a new guy building one... race this summer.
brad.PNG
 

joshua. c.

Well-Known Member
#48
That's cool, although I think my bike will be a bit slower than his. I find that the Briggs and Straton looks really good in that frame. My bike is missing the wheels, handlebars, seat and motor but has everything else. The guy who runs Windber was supposed to get me some wheels and has my contact info but hasn't gotten back to me. I'm going as original as I can except for the motor.
 
#50
The original wheels are Azusa spinner wheels and are readily available every where. I agree with delray with the saftey concerns. If your going to put a built up motor into that stock frame you need to think about upgrading some other components, mainly brakes. The stock brakes had a hard time stopping the stock bike let alone a bike with more hp then originally designed for. I’d look into at least disc brakes in the back better yet would be hydraulic disc brakes front and rear.
 

delray

Well-Known Member
#51
some of our tracks we race on are big and AMA district 16 has clock use going close 60 mph....crazy fast. you really can't safely go that speed on a stock bike let alone 40+. need good suspension,rims,tires,good wheel bearings,brakes...etc.. i have seen guys show up on complete stock suspensions with a built motors. not a pretty site to see when they think they can go fast into a corner.
 

joshua. c.

Well-Known Member
#52
The original wheels are Azusa spinner wheels and are readily available every where. I agree with delray with the saftey concerns. If your going to put a built up motor into that stock frame you need to think about upgrading some other components, mainly brakes. The stock brakes had a hard time stopping the stock bike let alone a bike with more hp then originally designed for. I’d look into at least disc brakes in the back better yet would be hydraulic disc brakes front and rear.
Not a Bonanza frame. The Bonanza may be the main topic but we were speaking of a 1970s Coalman at the time with a mild motor so Azusa spinners aren't correct for this bike and I was only racing off road on mostly grass and loose dirt on tracks not made for the purpose. also use these bikes just to have fun. I also think the stock brakes work just fine as long as you have both front and back, verry few people in my area ever mess with them but I would consider better rear shocks if there's a set that would fit in the frame as is. The Coalman shocks aren't even hydraulic but I'm not sure on the Bonanza. I got the shocks that are on the Bonanza at a motorcycle swap meet so they could be hydraulic but I won't know until I try them, they do appear to have the right spring strength for a bike this size. also I found some knobby rupp tires that will work well for the coalman. but I'm still searching for a better set for the Bonanza. I found a set but they are smaller in diameter and considering they aren't that much knobbier than the stock ones the size difference will loose grip instead of gain it. Also the bonanza doesn't come with a front brake stock so I'm adding one.

on the tracks I'm racing at I highly doubt anyone is getting up to 60 except for maybe at Gomas in the straits, most of the tracks are just to short and rough. and Gomas is known for braking bikes (rims, forks, frames, extra) that type of damage is usually due to operator error.
 
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#53
I was confused. Maybe you should start a new thread for the Coleman bike your working on. Regardless It takes a lot to build a nice reliable bike that can hold up to the extra power of a good modified engine and you should take into consideration some things delray and myself have mentioned (we have both built some pretty cool machines that can take a beating) I’m looking forward to seeing one of these projects get finished racing mini bikes is alot of fun. Good luck :scooter:
 

joshua. c.

Well-Known Member
#54
I just got my 6hp briggs less aggressive engine built. It's still up in the air what bike this motor is its going in but I'm leaning towards the coalman. Now that I've built one engine I've got a better idea how to put these back together and I'll be building the bonanzas monster engine soon. I also just mostly finished the front brake mount for the bonanza. It just needs a throttle handle type adjustment screw installed. Its made differently than I originally planned. I wasn't sure if it would be a good idea to weld a mount to the thin fork tube so instead I made it a separate pace out of angle iron also I just bought a rear fender bracket off ebay so now I can order the rear fender and get it installed. I'll get a picture once I finish the brake mount.
 

joshua. c.

Well-Known Member
#56
I just noticed how close it's getting to Gomas mini bike massacre, the biggest race of the summer in my area. I cant make it to Windber this year due to a family event the same weekend but I can make this race. I'm going to try to have the bonanza at least running by this event but no grantees. If push comes top shove I still have the bike in my avatar (now with better tires.) Its not fast enough to win but I may still make the finals If I get a good start. I may try to squeak more power out the bike in my avatar at a later time, I can still go bigger valves and bigger carb if needed and possibly go stroker If I can find a cheep used crank. I also just ordered a juggernaut clutch for this bike to see if it make a difference. I just ordered the parts to finish my front break setup and a few parts for another bike build that's not so important. I have a powerdyne frame that I'm slapping together with a bunch of parts I have lying around and its pretty close to running already due to its simplicity, no power mods, correct part hunting or heavy repairs like some of my other builds. I still have some parts to order for the bonanza that I'll be ordering next week (motor parts and fenders.) more updates to come soon.
 

joshua. c.

Well-Known Member
#58
I just receved the brake ajuster bolts so soon I'll be able to finish the brakes but It turns out they are m10-1.25 A metric thread pitch that I dont yet have a tap for and nither home depot or lows carrys one. I have one more place to check tomorro and if thay dont have it I'll have to wait untill monday to buy one at work (anoying but not that big a deal.)

On a different topic I tried to place an online order for the plastic replica fenders sold by Go Karts Usa just to have them cansle my order stating they don't have any right now due to supply chain issues. Its utterly unexcusable to leave a product in a state where it can still be orderd when you dont have any! I dont have any other options for getting Bonanza fenders so I'll have to look into incorect generic options.

I may start the motor build this weekend. The head is mostly assembled so all I have to do is assemble the block and piston assembly and bolt it all together.

side note: the built in spell checker isn't working for some reason so sory if this is spelled horibly.
 

joshua. c.

Well-Known Member
#59
DSCN0352.JPG DSCN0350.JPG DSCN0349.JPG

I posted an image of my front break setup because the tap is taking longer to arive than I expected, It's a M10-1.0, An uncomon size.

I also posted a picture of a set of footpegs I have that I think would work well on this bike. Finding an origenal set seems imposible so im going this rout.

The last picture is of the parts after cleaning. On a related topic, my motor build gave me a new surprize today, the bearings are shot. When I was washing everything before final assembly I noticed that the bearings were grinding when I spun them by hand. Its not alot but I'm not risking my build on them. I'll have to send the crank and side cover out to get new bearings pressed in, I'll also have them check the crank tollerences while they have it.

This motor was full of grime I had to use carburator cleaner just to break it up, it was a thin layer of black stuff, I should have taken pictures of it. Now I know why I got this motor so cheep lol. Even with the grime and needing a rebuild this motor is still worth the money, Id buy 3 or 4 more just like it if I could.
 
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joshua. c.

Well-Known Member
#60
Quick update: new bearings are installed and ready to go so the motor build is coming soon. and the tap arived so the breaks are complete

I just need a couple afternoons to work on the project ( im very busy right now so thats a tall order.) I'm working a full time job pluss part time handyman/manual labor job after my main job as needed by my employer and working on a fixer uper house and helping my dad set up a new farm so im very busy, so that explanes the delay, more updates as soon as I have time to work on the bike.

If anyone has an origenal tank or fenders for this bike that they would sell I'd be interested, I'm willing to offer around 200$ an origenal tank and around 100$ for a set of fenders with mounting brackets, thay can be beat up or rusty as well (I can fix that).

ebay mini bike parts are getting stupidly expensive. word of advice to the entire comunity IF YOU DONT PAY THE STUPIDLY HIGH PRICES THEY WILL BE FORCED TO DROP! a part is only worth what somone is willing to pay for it. If you all stop paying whatever they ask untill the price resumes a resonable level it will be better for everyone. (exept the seller). as a rule of thumb: when prices are higher for a single part than what you can buy a running bike for the price is to high (so don't buy)!
 
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