best budget build ideas for 70cc

[asadad00]

I would like to hear your ideas on building a 70cc engine for mx racing on a budget(about 1200$) what is the most bang for the buck ? I am starting with a 2010 drr 50 very good shape has good shocks and suspension and axle. engine is a stock 50 that has been ported, stock pipe ign etc. I know what a full blown national 70 cost (i got one for the older son) but money is tight and little brother has outgrown 50cc. Want to get as close to performance to my national r/t as possible.

[Logan #34's Dad]

I'd put a Malossi team cylinder with a long rod crank and the Hetrick pipe up against any R/T out there. Everyone got caught up in the R/T push so I'd bet you could find a Malossi kit on the cheap.
Buying used is the only way to save money. If you are able to gather up the parts you want it is not hard to split cases and put one of these engines together...

[nordic quad]

We built a Apex Polini Evo 2 for fun a cuopple of years ago using stock crank 24mm pwk carb and a custombuilt KX 65 pipe,still hauls the mail to this day,only thing holding it back is the stock ignition and cdi.I think you can use the stock crank with the evo 3 but not with the evo 4 ?One a sidenote we ran 10-12 min motos with it.
Stein A

[don bassani]

Polini evo 3 with stock crank,Hetrick gen 3 pipe.This combo will run with anything when clutched properly.Should cost you under $900

[nastynotchback1]

You could just buy my stage 6 motor for 1000 and ride.

[hotquads1]

I agree for the budjet using the stock crank and Polini-3 is perfect however I am partial to the Mach-1 Evo-3 exhaust and might add an adjustable clutch , this would be less than 1200 and as said by others it will run very well. The weak links for reliability would be the belt and crank and stock ignition, you could upgrade those in the future.

[asadad00]

I never had much luck with used stuff so rather buy new , sounds like the polini is a good choice won't even have to open the cases.
So you think the 21mm carb and stock ignition will run well . I would gladly pay a few dollars more for the mach1 pipe I know how well they work. this set-up will work without an overange?

[Hetrick Racing]

The adjustable clutch is not needed for the 70 Bassani won last year with a Yamasida.
If you skip the adj.clutch and spend your money on the ignition,way better performance.

1.EVO CYL
2.A.M IGN.
3.GEN 3 PIPE
4.OVER RANGE CLUTCH
5.MAINS AND SEALS(OR CRANK KIT STOCK)
Without the crank(but with mains and seals) this set up a bit above but your getting what works.
Will work fine with the 21carb
not much above though.
Give me a call

[kfx450]

Pm sent to nastynotchback

[asadad00]

UPDATE;
Got all the parts in , installed myself in 2.5 hours and its scary fast. My younger boy is 30lbs less so that helps too but in A 200FT DRAG RACE its all over the R/T bike less than one length. Thanks to everyone for the advice we built a bike that is very close to my R/T for way less than 1/2 price. Went over budjet a couple hundred but I sold a couple of used pipes and recoverd that and then some. Here is what I did...
Polini evo 10mm
stock 21mm carb and intake
Mach-1 70 pipe
Stage 6 pvl
Stage 6 clutch
stock yamasida variator and 787x16 belt
new spark plug
total cost including shipping = 1490$ my boy and I are both very happy.
thanks for the help.

[desratt]

Originally posted by Hetrick Racing
The adjustable clutch is not needed for the 70 Bassani won last year with a Yamasida.
If you skip the adj.clutch and spend your money on the ignition,way better performance.

1.EVO CYL
2.A.M IGN.
3.GEN 3 PIPE
4.OVER RANGE CLUTCH
5.MAINS AND SEALS(OR CRANK KIT STOCK)
Without the crank(but with mains and seals) this set up a bit above but your getting what works.
Will work fine with the 21carb
not much above though.
Give me a call

hey on your web site it says the gen 3 is for 90's only..I too am building a 70.

[don bassani]

Hetrick has gen 3 for both 70 and 90. The gen 3 pipe for 70 is also good for 50.

[desratt]

Didn't see it on web site