Peek inside 7hp HF Predator......

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LifeSeemsDead

New Member
Jul 21, 2011
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SoTX
In the exploded parts diagram for the 212cc version, it shows that the head is a tradition configuration divorced from the jug. Looking at your pictures, it seems like the head is integral to the jug, though. I was planning on polishing the chamber and surfacing to raise from 8.5:1 to 12-13:1 for methanol use, but if this head isn't conventional where chamber work is easily done, I need to look at something different than the 212-420cc Harbor Freights. How exactly is the head/jug arranged on it?
 

scotto-

Custom 4-Stroke Bike Builder
Jun 3, 2010
6,505
25
38
Ridin' inSane Diego, CA.
Hey LSD, It's conventional type with a separate cylinder head and barrel......so mill and port away! The exploded diagram is correct.

In this pic you can see the cyl. head bolts...
URL=http://imageshack.us/photo/my-images/546/img0543xo.jpg/]
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And if you look hard, you can see the cyl. head gasket in this pic....




dnut

In the exploded parts diagram for the 212cc version, it shows that the head is a tradition configuration divorced from the jug. Looking at your pictures, it seems like the head is integral to the jug, though. I was planning on polishing the chamber and surfacing to raise from 8.5:1 to 12-13:1 for methanol use, but if this head isn't conventional where chamber work is easily done, I need to look at something different than the 212-420cc Harbor Freights. How exactly is the head/jug arranged on it?
 
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LifeSeemsDead

New Member
Jul 21, 2011
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SoTX
Cool to know, thanks for confirmation on that. I knew the 420cc had a separate head, but couldn't really tell from pictures of the 212cc.
 

scotto-

Custom 4-Stroke Bike Builder
Jun 3, 2010
6,505
25
38
Ridin' inSane Diego, CA.
Cool to know, thanks for confirmation on that. I knew the 420cc had a separate head, but couldn't really tell from pictures of the 212cc.
No prob. I'm seriously looking at the 420cc for the tandem....love that electric start, even tho on the description it says not to motorize a vehicle with it......yeah, right!

dnut
 

LifeSeemsDead

New Member
Jul 21, 2011
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SoTX
Strong dropouts, chain and seat stay reinforcement, gussets on the gooseneck and seat post to backbone, stays, and down tube should be fine. The automotive experience in me says build the vehicle to support the power going through it. If you approach it from the standpoint of you are making a 1930's or 1940's era motorcycle with pedals vs a bicycle, you should be fine.

If I decide on a 420cc for my build, I won't be worried about my frame being strong enough to handle it. My biggest worry would be that it has got an 87lb shipping weight and having to pedal a bike with it in the frame. Not that at ~13-14hp it wouldn't be more than capable of moving itself, just that it is still a bicycle at its heart.
 

MotoMagz

Well-Known Member
Aug 2, 2010
1,817
1,154
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Michigan
Hey Scotto Really nice job on your bike!Was wondering if you thought of adding a shift kit?Shoot your almost there.