NErd trys a HF212 (on the cheap)

T

Thud

New Member
Hey guy's,
I dont think Ive ever started a "build" thread on this forum.....here is my big bore gasser bike to haul out to cali for the 15th at Bairdco's event (my summer vacation)

Engine starts as a typicle preditor 212 6.5 hp (on sale for $100)
mods:
remove governor
Add a decent flywheel to take the new rpm limits (bmi steel unit $60)
upgrade the con-rod for the same reason (standard billet ARC $65)
upgrade the valve springs ($10)
upgraded parts are more $ than the motor...go figure LOL
future mods:
Add a fire breathing cam & a big ol' carb to get some air flowing thrugh the engine.

I dug into my pile of salvage frames to chop up & brazed it up today. looks a little like this:
P8190085.jpg


I did roll the top tube & downtube into a more pleasing shape.
the geometry is 23deg steer angle & i'll shoot for 3ish inches of trail
wheel base is dead on 48"

Things to do this week:
get the chain lines situated & weld on corrected front drop-outs for the trail #s (the front wheel is not mounted in the above photo) & add disc brake mouting points front & rear.
fab up a carb adapter to use the stock carb.

I'll be running a Hilliard clutch & a little mojo to the rear wheel #35 final drive chain.
I'll post more as I have it....I find it doubles my work time taking decent photo's & frankly I forget to snap pictures at the best times.

I have a cam & some race springs for it...but the preditor has a little larger journals on it than a typicle clone...Later,I'll bore the journals & insert bronze bearings to the standard sizes so I can try any clone cam I desire.
any questions for the supposed e-bike nerd?
 
good thing i don't have a tech inspection at my races.

just kidding... :) looks like a beast.

aren't you're bringing a china bike too?
 
Looks good so far & I cant wait to see it when its finished. Ya know my 212 is all stock except the flywheel. I'll see you on the 15th if the dr gives me the go ahead.
 
Last edited:
Looks good Todd, I only read one prob so far and that is the ARC rod will not the predators crank journal, you have to get one that is specifically made for the Pred as I don't think they have a bearing yet that will convert that particular ARC rod. The Pred rod is a bit more expensive also and they come in 2 different lengths 3.308" and 3.707" and have Predator cnc'd on them with machine date and the length. One is ARC #6255 and the other I can't quite remember. AGK and NR both carry them.....pretty sure BMI doesn't.

Just thought I'd let ya know so ya don't screw up a perfectly good engine. Look forward to seeing you again next month, take care.

scotto-

dnut

Thud said:
Hey guy's,
I dont think Ive ever started a "build" thread on this forum.....here is my big bore gasser bike to haul out to cali for the 15th at Bairdco's event (my summer vacation)

Engine starts as a typicle preditor 212 6.5 hp (on sale for $100)
mods:
remove governor
Add a decent flywheel to take the new rpm limits (bmi steel unit $60)
upgrade the con-rod for the same reason (standard billet ARC $65)
upgrade the valve springs ($10)
upgraded parts are more $ than the motor...go figure LOL
future mods:
Add a fire breathing cam & a big ol' carb to get some air flowing thrugh the engine.

I dug into my pile of salvage frames to chop up & brazed it up today. looks a little like this:
P8190085.jpg


I did roll the top tube & downtube into a more pleasing shape.
the geometry is 23deg steer angle & i'll shoot for 3ish inches of trail
wheel base is dead on 48"

Things to do this week:
get the chain lines situated & weld on corrected front drop-outs for the trail #s (the front wheel is not mounted in the above photo) & add disc brake mouting points front & rear.
fab up a carb adapter to use the stock carb.

I'll be running a Hilliard clutch & a little mojo to the rear wheel #35 final drive chain.
I'll post more as I have it....I find it doubles my work time taking decent photo's & frankly I forget to snap pictures at the best times.

I have a cam & some race springs for it...but the preditor has a little larger journals on it than a typicle clone...Later,I'll bore the journals & insert bronze bearings to the standard sizes so I can try any clone cam I desire.
any questions for the supposed e-bike nerd?
Click to expand...
 
Hey Scotto,
Thanks for the concern.
I measured the stock rod at 3.305" & the stock crank journal measures 1.187(& is dead concentric I was pleased to find) the ARC 6270 is 3.303 & good for 1.180 +/- .005 on the journal.

I will lap the big end to proper oil clearance you can be sure,(the length is well within chinees tollerance i bet LOL) I am just debating weather to put the energy into re-sizing the cam bearings & adding that heat to it right now that the motor is on the bench & in pcs.

Baird, Definatly bringing the china girl....need to fine tune the chamber a little & I need a few other little details. But she's a scream'r & looking for action.
 
Thud said:
Hey Scotto,
Thanks for the concern.
I measured the stock rod at 3.305" & the stock crank journal measures 1.187(& is dead concentric I was pleased to find) the ARC 6270 is 3.303 & good for 1.180 +/- .005 on the journal.

I will lap the big end to proper oil clearance you can be sure,(the length is well within chinees tollerance i bet LOL) I am just debating weather to put the energy into re-sizing the cam bearings & adding that heat to it right now that the motor is on the bench & in pcs.

Baird, Definatly bringing the china girl....need to fine tune the chamber a little & I need a few other little details. But she's a scream'r & looking for action.
Click to expand...

Was just letting you know because I bought the same ARC rod from BMI and ended up putting it on the brand new GX 160 e/start because the tolerances wern't right on the Pred.

The Pred has the same size main journals but a different sized rod journal. Be sure and use plastigage like they suggest for your oil clearance. And it's good you know about the cam bearing journals.....I did a bearing enlargement w/sleave for the awesome billet side cover......turned out slick!
 
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