The Ultimate Off-Road Bonanza Gambler 100 Project

Bonanza Bryan

Well-Known Member
#1
Well Ive had a few posts giving a few sneak peeks of this build and I guess it’s time for a thread dedicated to the build. I am building this bike for the Gambler 100 mini bike race. It is a 100 mile enduro race in central Oregon this May.
Now the bike started life as a solid rear suspension bonanza frame with a dozen holes drilled in it and a bunch of random crap welded to it. So I stripped it down and plugged all the holes and got the frame prepped for the modifications I’ll be making. The first noticeable thing I did was fab up some triple trees and I used some pit bike fork tubes I got off eBay for a good price.



Next was a custom extended swing arm to somewhat resemble an original bonanza swing arm. I think this ended up being 6 inches longer than stock and I made it out is thicker 3/16 material and gusseted it for extra strength. Now I am kicking around the idea of remaking it to utilize bearings at the pivot point but I’m not sure where to start so any suggestions would be great.




Engine wise it will be getting a predator 212 with the usual billet goodies and a 265 CM dyno cam with a 22mm Chikuni and 27/25 stainless valves and some mild work done to the head. I have all the engine parts I am going to drop my head off tomorrow to get milled and hopefully get the engine built this weekend however I am waiting on my champion rockers still so at least hopefully put the bottom end together. This will be a great bike once it’s finished I’m hoping to be riding it come early-mid April to get all the bugs worked out and fix anything before the race in May
 
#6
I am really digging this ( I am partial to a badd ass Bonanza) , my build a few years ago was similar, I stretched swingarm 4.5" . Went with 8" spinners and Shinkos too , I did keep the stock front end as I wanted to maintain the vintage appeal .Good work , I'll be anxious to see the finished project . Also you may want to consider an OKO carb ! 20180512_130455.jpg
 
#7
I am really digging this ( I am partial to a badd ass Bonanza) , my build a few years ago was similar, I stretched swingarm 4.5" . Went with 8" spinners and Shinkos too , I did keep the stock front end as I wanted to maintain the vintage appeal .Good work , I'll be anxious to see the finished project . Also you may want to consider an OKO carb ! View attachment 241226
That is soooo nice. Do you still have it?
 

Bonanza Bryan

Well-Known Member
#8
I am really digging this ( I am partial to a badd ass Bonanza) , my build a few years ago was similar, I stretched swingarm 4.5" . Went with 8" spinners and Shinkos too , I did keep the stock front end as I wanted to maintain the vintage appeal .Good work , I'll be anxious to see the finished project . Also you may want to consider an OKO carb ! View attachment 241226
Thanks I went through your build on that bike it came out great. I already have the Mikuni so I’m gonna run that and see how I like it
 

Bonanza Bryan

Well-Known Member
#11
Well I dropped off my head to get milled .050 ream the guides out and get a 3 angle valve job done. I will be picking it up Friday. Hopefully my rockers show up so I can build the engine this weekend
 

Bonanza Bryan

Well-Known Member
#12
Here’s a little update. I’ve been working long days at work and saturdays so I haven’t had much time to work on this but I got some time today. I welded up the swingarm pivot holes and reloacated them slightly to give me more clearance. Before in the original location the chain would hit the swingarm tube because of the much steeper swingarm angle but now it is perfect. Also tacked up some shock mounts and an test fitting everything at the moment. I’m waiting on a order from OMB that has most of the little pieces I need to get this thing together but I still have a lot of work to do.



 

Bonanza Bryan

Well-Known Member
#13
Picked up my RTC-6 head up from the machine shop. .050 off reamed guides to 5.5mm for stainless valves and a valve job. Hopeing I can get the motor built this weekend but I’m working tomorrow so we will see if I have the time
 

Bonanza Bryan

Well-Known Member
#14
Well I got my parts. Almost have a roller have a few other mods I need to do to the frame and I’m hoping to build my engine this week. Handlebars are mounted and front end is almost complete. I’m going to make a new steering neck with tapered roller bearings and give it a little more rake. Rear shocks are too stiff so I will be looking for some softer ones here’s some pics let me know what you think


 

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