212 non hemi build help.

[MMB 954]

Hi everyone I'm new to mini bikes and want to build a 60 mph motovox to race vs dirtbikes 85cc to 250cc. I own many dirtbikes and do all my own mechanical work, so building isn't an issue. Here's my plan so far.. Let me know how realalistic or unrealalistic it is.
•billet rod / fly wheel
•hemi head milled and heavy porting ( ncrracing ) or w.e its call
•26lb springs
•cam .....????
•alky carb with filter
•custom header
•clutches .....?????
Any after market high comp Pistons, etc any other parts that will help to reach my 60mph goal. Money wise I'd like to stay in the 700-1000 range. Thanks in advanced guys.

 

[DBMonster85]

i would start with the hemi because it already has a flat top. unless you already have your motor then just buy a hemi flat top piston for like 25 bucks. yes on the billet goods but you need to measure your deck height before you buy the rod, so you know wich one to get, like 20 over or the 10 over, and so on. usually with the flat top the 40 over rod will work but you MUST measure first. cam I would go with the black mamba for the simple fact of it being cheap and very powerfull. I don't run alky so I cant say much on that note I just run 110. carb you either want a tilly or mikuni. I run the 24mm flatslide and my head is a Honda 18cc head with 28 and 25mm stainless valves. if your going for a power build I would not cheap out on the valve train. your going to want chromoly pushrods stainless valves and aluminum locks and retainers and billet or welded rockers. 26# springs will be fine. and as far as a clutch since you are racing you will need a race clutch. cheapest entry level disk clutch is the noram cheetah its 180 bucks. never tried it I run bully clutches because well they are the best in my eyes but they are a bit more. and really 60 mph is not that hard to reach gearing will do that but to do it safe now that cost. and if your doing 60+ on a mini bike I would be looking that frame over and be welding some reinforcement on there. also speed rated tires and bearings. I have almost 2 grand in one bike to safely go those speeds. just some food for thought. good luck and be safe!!

 

[Prowler08]

Yes on the Mamba cam... With a bigger carb on Alky it is a mean little cam... Especially with ratio rockers... But you will have to run 37lbs springs or duals with ratio rockers...
Are you looking for low end grunt or high rpms and hp? The NR307 cam is just plan nasty in the upper rpms...

Have not played with my Hemi heads yet still running the Honda heads with either 28/25 valves or 32/28 valves...

In my Hemi I run a .060 stroker crank with a .020 rod and I am at 0 deck.with a .028 gasket
The non Hemi I run a .040 rod, stock crank and .020 in the hole with a stock .009 gasket...

 

[MMB 954]

Thanks for the help guys, I've been looking around for a week so far and this is what I've came up with for 510$ even. Not to bad here in Miami.. Haven't had much time to break down the "hemi" motor but will keep you guys updated.

 

[MMB 954]

 

[Txpowdercoater]

get the "mongrel" clutch, its the best of the centrifugal world for the $100.
Its a max torque base and shoes, it has Bully roller bearings, Hillard machined drum and engages in the 3,800 rpm range. best 100 you can spend as far as clutches go, period

 

[DBMonster85]

yea I was going to try that mongrel before I bought my bully clutch. it seemed like it was a pretty bad a$$ clutch for the money. I still might buy one for my cruiser I'm building because it will have a built motor on it but I will cruise and drag while I'm on the ubly 50 mile run here in Mi.

 

[David wulf]

View attachment 71427

I see two predators in the pic , one hemi and one reg . If that non hemi sitting there is a 69730 model , then look to see if it is a RTC6 head . If it is put it on the hemi , it has big valves 27 in and 25 ex , also has big ports . You can also mill the shit out of it for stupid compression . You can't really get much compression out of the hemi head .

 

[MMB 954]

No longer have the non hemi sold 90$.. I'm starting the break down this week. Also chopping a frame and adding 8inches no wheel bar for me.