Huffy Alpha Raider

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Loki

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Dec 25, 2015
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A winter project.
Here's my new /old idea - take a Huffy Cranny frame convert it to a 6-7 Speed.

Add one new torquey PK-80 motor, plus a pitbike 47cc carb.
Stir in a front brake, Acera click shifter and freewheel rear.
Mix a fat rear tire, 2nd brake (cause it's gonna need it!).
Blend in new Voodoo exhaust, KMC chain, wide crank, 41T sprocket.

Soon to be: add an SBP shift kit and RSE Reed Valve.
The goal is multo-torque with +reliability.

Still breaking in th' motor, haven't gone over 20 mph so far, lots of torque,
pulls out of corners with ease.
Acera click shifter's hard to get to - its crowded up dere!
Going to the ever-popular ATV thumb throttle to ease shifting.

Did a non-power test ride last night.
Wowzer the ability to click to next higher gear is just what wuz needed.
This thing's gonna be a blast to ride with a trusty SBP Shift Kit.

The rear rim you see is a strong old school Huffy Blades MTB unit.
Bigger tire gets mounted today.
Oem coaster brake heading fer th' spare parts bin.

Still working on the basics - carb & intake fine tuning / jetting is next.
 

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Dec 11, 2014
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Very very nice. I have built 20+ Cranbrook s and love to motorize them. Keep the pics coming with the shift kit. And please brace or remove that fender, they have seriously hurt some people.
 

Loki

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Dec 25, 2015
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Thanks LSR
Good idea:

I have narrow heavy braced trike fenders and a pair of superlight aluminum fenders.
Bit dinged up by shipper; Now where'd that plastic body mallet get to?
Either set could work with stainless 3/16" rivets on alloy brackets.
Depending on how involved engine tuning & testing is the frame may have 'fend for itself'.
With distracted cage drivers and potholes I gotta avoid hurts.

Added 6mm axle nut on left to get clearance for drive chain until
the shift kit arrives.
 

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Dec 11, 2014
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Bummer on the shipping damage, you could get all that out with body mallets I'm sure. It looks like it would be tough not to damage the paint though. I'm anxious to see the shift kit on your Cranbrook and see the chain angles. Keep the pics coming you have an awesome bike coming together.
 

curtisfox

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Dec 29, 2008
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Could make a mold out of bondo,coat the fender with vaseline, or wrap with saran wrap. Build it up with bondo, let dry and them take it off use it to beat the dents on................Curt
 
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Loki

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Dec 25, 2015
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PK-80 stocker, NT Carb +Voodoo pipe, 41T rear >

With right at 22 miles on it I took the Raider out for a quick cruise;

First Ride 19-20 mph: 3.5 miles
Turns out the oem Z4C spark plug (sooty) wasn't helping things, plus there's
waaay too much oil at a very greasy 16:1.
Hiccuping & stumbling with NT carb on its middle needle setting.

Second Ride 21mph: 4-5 miles
Changed to 32:1 mix and installed a new NGK BP7HS plug = What a difference.
New plug is now tannish brown, motor still skips a beat getting to 6K revs.
Over 6K it definitely needs a tad more fuel to 'get on th' pipe'.
Gonna try the all-out needle / raised slot for a plug chop.

Suspect the stock CDI is also holding it back.
Every ride gets a full warm-up and rest before checking th plug state.
Not heading for 9K - just a smoother transition to 'on the Pipe.'

Or are these 'dolls' like an Ernst Degner 50cc class GP racer with a 'light switch throttle' sudden revs?
 

Loki

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Dec 25, 2015
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Alpha PK-80 is evolving into a beast.

Third Test Ride to 18 mph: 3 miles
NT Carb needle raised to full rich - throttle response below 10 mph muddy.
Between 12-15 mph th' PK-80 gets on th' Voodoo pipe very strong; no hesitation, wants to rev.
Had to throttle it back a bit.
Apparently the #70 Main Jet is just a hair too large for parking lot, trolling speed.
Tomorrow / Time for 'nother plug chop.
Old racers trick; enlarge #61 jet with a letter size drill using vernier calipers
- get diameter equal to #67-68 main.

May have to raid the piggy bank $ for a real carb; Dellorto or Mikuni?
I favor the Mikuni tho it takes plus mounting space.
Considering an RSE reed valve.
.....
All controls & chassis set. Waiting on Dual Brake Lever.
The Acera Click Shifter now works 100% better situated upside down.
Reversed it has great access to the spring-loaded shift paddle.
Dual brakes slow the bike down like running into a sand bank.
Bye bye to obstructing fenders.

A satisfying day's work = big grin
 

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Dec 11, 2014
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Bike is looking awesome!!! The stock CDI is as good or better than all the aftermarket, look at all the racers and what they use. The stock boot and wire are pretty bad and need to be replaced with good parts though. The factory ignition timing is too advanced and not adjustable, there is power to be had in filing the notch in the magnet to retard the ignition there. Your bike just flat out looks great, truly one of my favorites. The dual brake lever will be amazing with your set up also, I was against them and had to try one and have to eat my words they work great in this application. Do a lot of reading on here for power, every bolt on made won't make half the power as a motor with all stock parts and a ported cylinder and ramped piston. I hit 43mph on the GPS with all stock parts and port and piston work on that identical Cranbrook with a 44 tooth sprocket. If you decide to do it yourself there are a few good write UPS on here and I'll be glad to help.
 
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Loki

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Dec 25, 2015
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Bike is looking awesome!!! The stock CDI is as good or better than all the aftermarket, look at all the racers and what they use. The stock boot and wire are pretty bad and need to be replaced with good parts though. The factory ignition timing is too advanced and not adjustable, there is power to be had in filing the notch in the magnet to retard the ignition there. Your bike just flat out looks great, truly one of my favorites. (^)
... every bolt on made won't make half the power as a motor with all stock parts and a ported cylinder and ramped piston. I hit 43mph on the GPS with all stock parts and port and piston work on that identical Cranbrook with a 44 tooth sprocket. If you decide to do it yourself there are a few good write UPS on here and I'll be glad to help.
Lee -
thinking I've seen a couple of your bikes buzzing 'round town.

That's the plan;
Do the magnet, finishing NT re-jet today,
will get the piston / port work done e.g. Phase 2.

Any pics of magnet notch-ing?
Reference on where to get decent copper plug wire & spark plug boot parts?

Carb No Go :oops:
Turns out the Dellorto-looking Pit Bike carb's a pita.
It has no lower fuel circuits, just a cheap knock-off = waste

What do you think of the SHA carb?
With the Voodoo pipe go with 14mm size, or larger?

Thanks agin'
RJ
 
Dec 11, 2014
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Do you have pics of the carbs? The member on here with the username Davezilla has found about the only aftermarket carb that will out perform a stock one on these motors. If you can, find him on here and read thru some of his posts and it should be easy to find. If you look in my pics of my old green Caraci that clone carb is the only one that works ok but not great. The reason I worked with it so much is I was able to flow enough thru it to make the nitro/methanol system work with the Briggs fuel pump. I did start to fight it leaking around the bowl with the pump feeding though. I am pulling it out of retirement to use as the secondary carb on my dual carb set up though since it is already set for nitro. I am hoping that in the secondary position as a power adder it won't need to be fed by the pump and the manifold design will pull enough thru to work.
It would be a good idea to pick up an extra magnet if you want to file one. The direction to retard the timing would be filing the notch further to the left as your looking at it with the cover off on the left side of the bike. Picture the magnet being behind where the factory set the notch in the rotation of the motor. Just a tiny bit at a time because in this spot just a tenth of a millimeter is a lot of rotation and we only want around a degree to be safe. You could potentially take a spare magnet and keep filing and testing, you will feel it get better, then worse and then you know how far to take the second magnet for the sweet spot on your motor. I realize this is far less than good science but if we line up ten of the best of these motors they will react differently so it's a bit of trial and error to get the absolute most from them.
I am curios if you really need to re jet the N/T carb, usually they seem quite rich out of the box but once you have some break in and the needle set lower it should be actually close and combined with the VooDoo pipe you should be able to get rid of most of the 4 stroking especially mixing at 32 to 1.
I am shopping for good copper core 7mm wire by the foor and have not found anything I like. Don's hot rod shop and many online vendors have boots that will work well. I have actually been making the most power with the 3 prong kit spark plug and now have at least one or two NGK's that I am not sure what I will do with.
Last thoughts on carbs for now, try to find that carb Davezilla recommends and remember the smaller the bore the better the velocity. Think, small carb= throttle responce and seat of the pants power, larger carb= more flow capacity at high revs but less velocity and less fuel atomization.
Lee
 

Loki

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Dec 25, 2015
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Bought the 47 - 49cc Pocket Performance Carb on Ebay.
Item # 131560386081
Throttle slide is the square / gate style.
Pics to follow... in a sec.

Yes - an NT carb should work better in the middle slot.
At any rate; PK-80 +Voodoo runs smoother; but with less power and less jerky transition / stumbling,
with the stock NT carb set in the middle.
NT: Full rich setting gives a lot of revs / power but its like having a 'light switch' for a throttle.

The voodoo pipe seems to be tuned to develop best power @ 5500+ rpm.
One thing - the end stinger has a small outlet ... wondering if it's part of the tuning picture?
Fred at CR says its a "restrictive type exhaust".
Its some dba's quieter than a stock exh. pipe.

May try out the Pocket Bike carb this afternoon - and find out fer sure
if it'll work. Maybe I'm selling it short ...

Will get a magnet to file soon.
 

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Loki

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Yessir that's a useful carby breakdown; pics - all a guy could want.
Reaching fer my screwdriver right now.
Float may be set wrong.

Thanks Curt! (^)
 
Dec 11, 2014
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This bike pulls hard from off the line all the way to a top speed of just over 45mph on a 44 tooth sprocket I built it for a 270lb physical trainer. It has the stock NT carb with the filter housing opened up a bit and a port matched but un modified VooDoo pipe just like yours. It does have an extensively ported cylinder and ramped and drilled piston. I don't think the carb/pipe combo is a problem on your motor, one thing is they need miles put on them before they can really be tuned in a lot of cases. You will really be casing your tail swapping carbs and parts around for the first few hundred miles. I have that same aftermarket carb and it can make a touch more top speed but at the cost of throttle response in a lot of cases. It's not a bad little carb at all just a bit more tricky to tune, the moped guys really have that one figured out and is where I learned to tune it.



Very similar set up to yours and the NT carb is great on it.
 

Loki

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Dec 25, 2015
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LSR - good tech info ... that's a big effort.

Finally found it ... this Carb & Pipe combo's 'Sweet Spot' :)

Put another 8 miles testing just a while ago; running medium fast.
NT carb is very clean inside, no crud.
#.65mm MAIN Jet:
Needle in #3 Slot – (one slot left to be full Lean).

Idles, crackles a bit, engine pulls hard, no stumbles, gets on the pipe real smooth.
Does trolling speeds much better. Got to 22 mph - cruised it home.
Now I'll have to use smaller rear sprockets for cruisin' N keepin' things easy.
 

2door

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Sep 15, 2008
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This bike pulls hard from off the line all the way to a top speed of just over 45mph on a 44 tooth sprocket I built it for a 270lb physical trainer. It has the stock NT carb with the filter housing opened up a bit and a port matched but un modified VooDoo pipe just like yours. It does have an extensively ported cylinder and ramped and drilled piston. I don't think the carb/pipe combo is a problem on your motor, one thing is they need miles put on them before they can really be tuned in a lot of cases. You will really be casing your tail swapping carbs and parts around for the first few hundred miles. I have that same aftermarket carb and it can make a touch more top speed but at the cost of throttle response in a lot of cases. It's not a bad little carb at all just a bit more tricky to tune, the moped guys really have that one figured out and is where I learned to tune it.


Very similar set up to yours and the NT carb is great on it.
I concur. Quit worrying about performance until you get some miles on that engine. Too many mods and seeking high speed and performance is "chasing your tail" until you have 200 to 300 miles on the rings and cylinder.

Tom
 

Loki

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The 'worry' or 'how fast' was not the topic of the jet tests or my immediate concern.
The desire is that these lo-po parts work in harmony.

Having three carbs laying around ...
1 used oem NT,
1 new Speed / NT nib,
1 new Pocketbike 47cc nib
... means being spoilt for choice.
These carbs lack mixture screws for secondary adjustment circuits; that's when I expressed the desire for a Dellorto or Mikuni - for tune-ability.
Others have been bringing up WOT tuning characteristics.

My focus on carburation has been dealing with a rough transition from low speed / part throttle to 70% throttle;
not on top speed - WOT.
I mentioned 'throttle acts like a light switch'.
If the bike ran too fast 'I backed off' on the throttle.
Our roads are too durn'd rough for all-out riding.

It takes test time to reveal items needing correction:
It turns out the used NT carb had a #.75mm main jet lurking inside;
that's why the spark plug was sooty black.
Once th' NT carb was rejetted things worked - as designed.

The Voodoo & NT carb now function together as a team, which was always the primary goal.
I'm happy with that result, +torque. dance1
If posting carb tests is 'worrying' or 'chasing' then I guess I'm guilty.

A water-cooled Morini on a GT-LTS looks way more inviting if one wants a go-fast,
go-anywhere MB but that's 'nuther story involving $$$.

http://motorbicycling.com/showthread.php?t=53782
 
Dec 11, 2014
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Sorry we got too complex in our answers. These motors have to get a few hundred miles on them to be consistent and it's tough to describe and get thru to a lot of people new to these motors. It's actually worse if your new to this but are an otherwise experienced mechanic because some of the things with these bike kit motors are very counter intuitive. See here I go again ha ha. Awesome to hear that you got it running good! Now go have fun!
 

Loki

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Dec 25, 2015
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Thumb throttle works 100% easier/better than the old rotating grip style.
Installed & tested - bike's running great. :)

Big plus: this type throttle allows more space to set right bar controls;
All functions's are now within easy reach.
Levers do not interfere with each other.
 

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