Ceiling Unlimited Build performance details With Puch head review (Pic heavy)

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Tohri

New Member
Aug 28, 2010
159
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People's Republik of Massachusetts
I've probably got about 72 or so hours of research for this build alone, and things are going to get exciting when I decide to go the Foureasy route with my next motor (Puch massive port kit and 70CC hi hi head on a happytime bottom end). But just to document what I've done so far:



Gently Ported stock jug with port matched intake and exhaust
Puch 50CC hi compression head
Chopped and kludged pocket bike exhaust pipe with kludged heat shield
Hookworm 26x2.5 tires
36 tooth sprocket
Reamed stock carb
Billet throttle, 2-into1 brake lever, toggle kill switch, and cushy springer seat.
Damp pro sound dampeners
Lots of little fidgets and upgrades over the last 4 years.

So how does it run?
Like a bat out of H3ll, I'm almost afraid what a spedometer will tell me. Torque still needs improvement, it Still doesn't like hills. For flat land and gentle inclines however, I'm finding myself looking seriously at picking up a set of riding goggles. Between the dry eyes/Drippy nose at full throttle to getting hit by a june bug in the face that felt more like a paintball impact, flat out top end performance is something I'm proud of. Let's look at how it happened.







Yep, the piston comes about 1.5MM from the top of the cylinder deck. And yes, that's a squish band on the Puch head. Quite an improvment over the stock head, and to give you an idea of scale:



Yes, it's a good three times bigger overall than the HT head. Same spark plug and everything, same bolt pattern, I'm amazed SBP isn't selling them as we speak. Treatland has them over here Puch 50cc Hi compression head And even if you don't want the extra compression, the huge amount of extra cooling will be more than appriciated on the long rides. I rode 30 miles Wide open throttle the other day with no overheating what so ever.

The pocket bike exhaust was from a failed project (That got me an A for my Associates degree final. No complaints) But you know how it is, Reduce, Reuse, Reconfigure. So, after the purchase of some silicone tubing from SBP and a trip to Sears for hose clamps and copper fittings, the pipe is mounted, and somewhat smelly. This may have to do with the Nomex heater blanket keeping my legs burn free, or the gorilla tape used to wrap it. This pipe is still undergoing testing, and will probably get some real welds soon instead of the Rube Goldberg assortment of pipe fittings and tubing it has now.
But I like the lines, and the pipe has made a difference in the power profile of the motor, although I haven't noticed the 'Coming on the pipe' feeling people mention when the exhaust is in line with the motor's RPMs. It could be the silicone tubing is absorbing and flattening the pressure waves. More testing needs be done.

But next on the list for mods is swapping out the clutch lever for a 3speed trigger shifter, swapping out the 2-into-1 back to the long brake levers the bike had in the first place, replacing the carb with a dellorto replica, and replacing the freewheel with a shimano megarange 34-14 7 speed. I'll post performance and pics this weekend!
 

DaveC

Member
Jul 14, 2010
969
1
18
Boise, ID
I don't know how your getting away with the stock plug or even a NGK BR6HS. I was useing a BR9HIX Iridium plug. Raise the compression on a two stroke you generally have to run a colder plug. What kind of color are you getting?
 

Tohri

New Member
Aug 28, 2010
159
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People's Republik of Massachusetts
I was getting a nice toasty golden brown to dark brown after a long cruise at wide open throttle. Went to start it up yesterday though, it wouldn't start easy and my chain jumped and locked the rear wheel, bent the frame. I wanted a new frame anyways.
 

DanielMaia

New Member
Jun 24, 2009
309
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Portugal
DaveC, the engine has just arrived, cat wait to put this beast on the road.

Treatland is the only seller of the hi compression puch head?
 

ToxicAz520

New Member
Mar 11, 2011
288
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0
Tucson,Arizona
I just ordered my punch head tonight. thank for the review should go good with my new cdi and kx80 coil and the extra cooling will help on the slow parts of mt bike trails I ride.
 

flatblack

New Member
May 22, 2011
374
1
0
Fairfax, VA
Just a heads up. The Puch head is not a direct bolt-on. The head has smaller bolt channels than the stock head. I was able to bore mine out to fit, however you will need to either run a shorter head bolt or have a way to shim the stock set.
 

flatblack

New Member
May 22, 2011
374
1
0
Fairfax, VA
Most likely. The holes have probably worn in a bit. I was able to get the head down to the jug, but the stock head bolts/nuts left a good 1/2" before making contact with the head. My head bolts are only threaded on the ends and smooth in the center, not allowing me to tighten the nut snug to head without shims of some sort.
 

flatblack

New Member
May 22, 2011
374
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0
Fairfax, VA
Here's some pics to clarify:

Stock head stud with nut:


Stock head stud with stock head clearance


Puch head with stock head stud clearance:
 

flatblack

New Member
May 22, 2011
374
1
0
Fairfax, VA
Yup. Was just down in the garage rethinking things. I'll grab some more hardware this Monday. Wouldn't it be wise to just replace it all, though? Or is this size of thread gonna be hard to find?

What have you done as far as tuning with this head? Right now, I have the CNS V2 carb, exhaust/intake port matched, SBP xchamber on a Jet 66cc. Nothing has been ran or tuned. I have a RT carb from Dax on it's way. Seems to me that it'll be wanting more to drink with these mods. The Dax carb comes with a jet kit. Maybe I'll just leave the CNS on for a day or two and see what happens.
 

Tohri

New Member
Aug 28, 2010
159
0
0
People's Republik of Massachusetts
The only thing I adjusted was squish band clearance, but I think it put the compression in the danger zone. I'm going to have to tear down this motor fully and put it on a new bike anyways, I'll take pics and document it fully when I do, probably going to try and balance the crank while it's apart.
 

DaveC

Member
Jul 14, 2010
969
1
18
Boise, ID
One of the problems with the Puch head is you need the smaller 13mm nuts and not the standard 14mm. You can't get a 14mm socket into the space between the fins. This is on the 66cc motors not the 49's and their smaller M6 1.00 studs.

2 ways around the stack of washers thing, tap the holes to the bottom. Many times that is not done, I think to cut costs. 2nd is to get the sick bike parts head stud kit. It has a stud of hi-grade steel all-thread. Plus the M8 kit comes with the 13mm nuts. You do have to enlarge the holes a bit more that 8mm because they don't exactly line up. The Euro bolt pattern is slightly smaller than the Chinese.