Difference between revisions of "K-Star 70cc Kit Compendium"

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To those less knowledgeable - read up before even looking funny at your engine. Search the site. Minimal reading is the link below.
 
To those less knowledgeable - read up before even looking funny at your engine. Search the site. Minimal reading is the link below.
  
[[Rebuild_a_Puch_E50_Engine]]
+
[[Rebuild a Puch E50 Engine]]
  
 
'''Rebuild your bottom end.'''
 
'''Rebuild your bottom end.'''
  
The stock crank’s bushing WILL NOT like going 9500 rpm with a larger piston displacement than stock. The K-Star apparently likes higher crank case volume, so a new unstuffed crank will work just fine. (Others words, not mine. I used a stuffed crank and stayed shallow to keep low rpm air velocity for my SHA and bottom end.) Also, that means the transfer ports can be brought back pretty deep. Case match! And clean up the oil port for bearing lubrication while you’re at it. There is a chance that you’ll need to add some JB or epoxy in the upper right hand corner of the case to avoid blowing your base gasket. Up to you. Pictures below.
+
The stock crank’s bushing WILL NOT like going 9500 rpm with a larger piston displacement than stock. The K-Star apparently likes higher crank case volume, so a new unstuffed crank will work just fine. (Others words, not mine. I used a stuffed crank and stayed shallow to keep low rpm air velocity for my SHA and bottom end.) Also, that means the transfer ports can be brought back pretty deep. Case match! And clean up the oil port for bearing lubrication while you’re at it. There is a chance that you’ll need to add some JB or epoxy in the upper right hand corner of the case to avoid blowing your base gasket. Up to you. Pictures below. For crazy modders, here is a link to a [[DIY reed-valve kit|DIY reed valve setup]].
  
 
[[Image:45_is_bad.JPG|thumb|left|The stock crank dislikes going over 9500 rpm. A lot.]]
 
[[Image:45_is_bad.JPG|thumb|left|The stock crank dislikes going over 9500 rpm. A lot.]]
[[Image:Case_port_material.jpg|thumb|left|It was recommended by some to add case material. I didn't. Your call. Pardon the unfinished porting job.]]For crazy modders, here is a link to a DIY reed valve setup.
+
[[Image:Case_port_material.jpg|thumb|left|It was recommended by some to add case material. I didn't. Your call. Pardon the unfinished porting job.]]
  
[[DIY_reed-valve_kit]]
+
{{clr}}
  
 
'''Get a pipe and carb.'''
 
'''Get a pipe and carb.'''
  
 
Maybe work with clutches. Pipes are variable – if you want top end buy a top end pipe. Biturbo perhaps? For low-mid end, I like the Tecno Estoril. A 19mm+ Dellorto PHBG is recommended for carburetion. Hi flow air filters rock stock sucks. Also, I like angled intakes instead of the 90 degree suckers that come with most parties. They have better flow characteristics and look badass sticking off the front of your ped.
 
Maybe work with clutches. Pipes are variable – if you want top end buy a top end pipe. Biturbo perhaps? For low-mid end, I like the Tecno Estoril. A 19mm+ Dellorto PHBG is recommended for carburetion. Hi flow air filters rock stock sucks. Also, I like angled intakes instead of the 90 degree suckers that come with most parties. They have better flow characteristics and look badass sticking off the front of your ped.
 
  
 
The Wiki article on clutches is nearby. I’m still running the stock 2 shoe.  
 
The Wiki article on clutches is nearby. I’m still running the stock 2 shoe.  
  
[[Clutch_tuning]]
+
[[Clutch tuning]]
  
 
If you're feeling like an artistic welder, you can make your pipe a side bleed for a bit of extra kick.
 
If you're feeling like an artistic welder, you can make your pipe a side bleed for a bit of extra kick.
  
''Sidebleed'' | http://www.mopedarmy.com/forums/read.php?7,2110313,2110487
+
[http://www.mopedarmy.com/forums/read.php?7,2110313,2110487 Sidebleed ]
  
 
'''Gap your ring.'''
 
'''Gap your ring.'''
  
You'll want to gap your ring to make sure that it doesn't expand into a port and cause great ugliness.
+
You'll want to [[Ring gap|gap your ring]] to make sure that it doesn't expand into a port and cause great ugliness.
 
 
[[Ring_gap]]
 
  
 
'''Okay – porting.'''
 
'''Okay – porting.'''
  
We’ll start with the cylinder. I only chamfered so my terrible dremel skills and lack of mathemagical knowledge wouldn’t ruin loop scavenging or make timings worse. I’ve also heard of people bridging the boost ports, but I haven’t been able to substantiate anything. Gurus and daredevils may want to reference the threads below for better porting (piston & cylinder) information and other stuff. A nice story too. Take your time and read through all of the threads. Some good stuff can be found if you dig. Plus a wiki article!
+
We’ll start with the cylinder. I only chamfered so my terrible dremel skills and lack of mathemagical knowledge wouldn’t ruin loop scavenging or make [[Port timing|timings]] worse. I’ve also heard of people bridging the boost ports, but I haven’t been able to substantiate anything. Gurus and daredevils may want to reference the threads below for better porting (piston & cylinder) information and other stuff. A nice story too. Take your time and read through all of the threads. Some good stuff can be found if you dig. Plus a wiki article!
 
 
[[Puch_cylinder_kit_summary#K-star_70cc_.2845mm.29]]
 
 
 
''Long E50 Story'' | http://www.mopedarmy.com/forums/read.php?7,2118067,2733010
 
 
 
''Porting a 70cc K-Star'' | http://www.mopedarmy.com/forums/read.php?7,2107879,2107879
 
 
 
''K-Star Porting'' | http://www.mopedarmy.com/forums/read.php?7,2010370,2010370
 
 
 
''70cc K-Star'' | http://www.mopedarmy.com/forums/read.php?7,1981781
 
  
''Piston Port Intake Timing - K-Star 70'' | http://www.mopedarmy.com/forums/read.php?7,2065260,2065264
+
:[[Puch_cylinder_kit_summary#K-star_70cc_.2845mm.29|Puch Cylinder Kit Summary]]
 +
:[http://www.mopedarmy.com/forums/read.php?7,2118067,2733010 Long E50 Story ]
 +
:[http://www.mopedarmy.com/forums/read.php?7,2107879,2107879 Porting a 70cc K-Star]
 +
:[http://www.mopedarmy.com/forums/read.php?7,2010370,2010370 K-Star Porting]
 +
:[http://www.mopedarmy.com/forums/read.php?7,1981781 70cc K-Star]
 +
:[http://www.mopedarmy.com/forums/read.php?7,2065260,2065264 Piston Port Intake Timing - K-Star 70]
 +
:[http://www.mopedarmy.com/forums/read.php?7,2118425,2119000#msg-2119000 13 Port K-Star/DMP]
  
''13 Port K-Star/DMP'' | http://www.mopedarmy.com/forums/read.php?7,2118425,2119000#msg-2119000
 
  
 
'''Next – the piston.'''
 
'''Next – the piston.'''
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[[Image:Piston_port_kstar_70.jpg|thumb|left|Rough cross section of the piston porting scheme I used. NOT to scale.]]
 
[[Image:Piston_port_kstar_70.jpg|thumb|left|Rough cross section of the piston porting scheme I used. NOT to scale.]]
 +
{{clr}}
  
 
'''Re-squish.'''
 
'''Re-squish.'''
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If you buy the kit from Treatland, they give you their 70cc hi compression head. It’s not so good for high rpms. You’ll want to read the thread below if you’re planning on creating a new squish. Crazy Wayne isn't "compromising" per se, but he knows his stuff.
 
If you buy the kit from Treatland, they give you their 70cc hi compression head. It’s not so good for high rpms. You’ll want to read the thread below if you’re planning on creating a new squish. Crazy Wayne isn't "compromising" per se, but he knows his stuff.
  
''How to Untap Squish Band Power'' | http://www.mopedarmy.com/forums/read.php?7,2067883
+
[http://www.mopedarmy.com/forums/read.php?7,2067883 How to Untap Squish Band Power]
  
 
I went the lazy way and did a bit of dremeling/sanding to make it more of a hemi. Using bouncy balls and golf balls wrapped in sandpaper is the other route. Or using machine shop tools. But not all of us are that awesome.
 
I went the lazy way and did a bit of dremeling/sanding to make it more of a hemi. Using bouncy balls and golf balls wrapped in sandpaper is the other route. Or using machine shop tools. But not all of us are that awesome.
  
Time it right and put a good plug in (BR8HIX, BU8H). Etc.
+
[[Ignition timing|Time]] it right and put a good plug in (BR8HIX, BU8H). Etc.
  
 
At that point, it’s just a matter of fine tuning. Check out the category link at the bottom of the page for more information on tuning.
 
At that point, it’s just a matter of fine tuning. Check out the category link at the bottom of the page for more information on tuning.

Revision as of 23:25, 4 March 2012

A lot of people buy the 70cc K-Star a la Treats. For many, it is a first kit. There is a ton of info on getting more speed out of it, but no one has bothered to collect it in one place. I'll do the legwork for others and post what I did, with links to more extreme threads on MA. They have port pics n’ such. One is from a German, so it must be good stuff, ja? Some of this will be redundant for gurus, sorry. But for the less knowledgeable this should be good.

To those less knowledgeable - read up before even looking funny at your engine. Search the site. Minimal reading is the link below.

Rebuild a Puch E50 Engine

Rebuild your bottom end.

The stock crank’s bushing WILL NOT like going 9500 rpm with a larger piston displacement than stock. The K-Star apparently likes higher crank case volume, so a new unstuffed crank will work just fine. (Others words, not mine. I used a stuffed crank and stayed shallow to keep low rpm air velocity for my SHA and bottom end.) Also, that means the transfer ports can be brought back pretty deep. Case match! And clean up the oil port for bearing lubrication while you’re at it. There is a chance that you’ll need to add some JB or epoxy in the upper right hand corner of the case to avoid blowing your base gasket. Up to you. Pictures below. For crazy modders, here is a link to a DIY reed valve setup.

The stock crank dislikes going over 9500 rpm. A lot.
It was recommended by some to add case material. I didn't. Your call. Pardon the unfinished porting job.

Get a pipe and carb.

Maybe work with clutches. Pipes are variable – if you want top end buy a top end pipe. Biturbo perhaps? For low-mid end, I like the Tecno Estoril. A 19mm+ Dellorto PHBG is recommended for carburetion. Hi flow air filters rock stock sucks. Also, I like angled intakes instead of the 90 degree suckers that come with most parties. They have better flow characteristics and look badass sticking off the front of your ped.

The Wiki article on clutches is nearby. I’m still running the stock 2 shoe.

Clutch tuning

If you're feeling like an artistic welder, you can make your pipe a side bleed for a bit of extra kick.

Sidebleed

Gap your ring.

You'll want to gap your ring to make sure that it doesn't expand into a port and cause great ugliness.

Okay – porting.

We’ll start with the cylinder. I only chamfered so my terrible dremel skills and lack of mathemagical knowledge wouldn’t ruin loop scavenging or make timings worse. I’ve also heard of people bridging the boost ports, but I haven’t been able to substantiate anything. Gurus and daredevils may want to reference the threads below for better porting (piston & cylinder) information and other stuff. A nice story too. Take your time and read through all of the threads. Some good stuff can be found if you dig. Plus a wiki article!

Puch Cylinder Kit Summary
Long E50 Story
Porting a 70cc K-Star
K-Star Porting
70cc K-Star
Piston Port Intake Timing - K-Star 70
13 Port K-Star/DMP


Next – the piston.

I bridged the boost ports and angled them, making them slightly larger in the process. The angling is something I hadn't found on anywhere before. (If you bridge the cylinder ports, I would try connecting both ports on the piston as well. The pistons are cheapish.) On top of that I ground the top edge of the piston skirt back to increase intake duration. The cutout is as wide as the intake, not wider, and rectangular. I cleaned up the sharp edges with a few strips of high grit sandpaper. Consider balancing the piston to minimize slap wear. More can be found in the links above. I sketched a cross section approximation – look below.

Rough cross section of the piston porting scheme I used. NOT to scale.

Re-squish.

If you buy the kit from Treatland, they give you their 70cc hi compression head. It’s not so good for high rpms. You’ll want to read the thread below if you’re planning on creating a new squish. Crazy Wayne isn't "compromising" per se, but he knows his stuff.

How to Untap Squish Band Power

I went the lazy way and did a bit of dremeling/sanding to make it more of a hemi. Using bouncy balls and golf balls wrapped in sandpaper is the other route. Or using machine shop tools. But not all of us are that awesome.

Time it right and put a good plug in (BR8HIX, BU8H). Etc.

At that point, it’s just a matter of fine tuning. Check out the category link at the bottom of the page for more information on tuning.

Don't forget luck. Good luck. Pray ye to the moped gods.