Magician Performance Improvement Project

[China Rider 27]

Got another run in yesterday at 41 degree ambient temp minus the baffle. Amazing sound deep and loud with that lack of restriction blah trail off after throttle. Idled and ran excellent with good strong acceleration all through the range thru WOT. I am kinda surprised that it takes that much jet and the plug looks good. (attached from day 1) Nothing to do but increase jet size and ride to rich.

[China Rider 27]

PZ 30 tuning continues. Last week I put a 130 main (amazon generic) and took it out for testing. Idled just as well with excellent acceleration. At WOT seemed fine but as you roll off WOT there was surge for just a second which repeated itself over several attempts. No change in plug appearance. Top speed over my WOT test area 61 mph. Temperature 41 degrees.

I put in a 127.5 Jets R Us Mikuni OEM) and again I could tell no difference in idle or acceleration it was good. At WOT it exhibited the same momentary surge rolling off WOT. Top speed 61 mph, no change in the plug appearance.

Today, just for fun I put in a 135 (amazon generic). Idle unchanged and good but upon acceleration it was a little different sounding muffled maybe slightly less forceful but somehow smoother. No issues up to WOT but after a few seconds it would hiccup or spit for just a second and confirmed on second attempt. The plug looked pretty much the same and might, I say hard to tell, be a darker brown spot on the base of the center electrode. The tail pipe seemed to have a little black residue on it with a finger swipe. Top speed 60 mph. Temperature 46 degrees.

Put the 125 main (amazon generic) back in. Idle and acceleration good. No issues at WOT. Top speed 62 mph.

Thoughts…. It appears you can run a wide range of mains with little affect on idle up through ¾ throttle. Confirming the ideal Main jet probably takes a plug chop. Wish I had some means to measure these jets to confirm their size. Why does a carburetor surge during throttle roll off?

[China Rider 27]

How bout a PWK 30 on a Magician? Yaa, let’s do it!

Over several months I gathered the pieces to make it happen unsure if in the end it would work. It required cutting a new path in the airbox as the carburetor sets lower and to the side some. Used a hack saw blade. I only altered the original O ring airbox entrance with what was needed so I could put back the PZ30 intake hose system if desired. Requires a new piece of 1 ½ inch PVC. A silicone hose 2 inch to 1 ½ inch reducer. An intake manifold from Tao Bao PE28 30. A PWK 30 off of Amazon.

To finish up from the last post. I settled on the PZ30 tuning of a 42 pilot, about 2 turns out on the pilot screw, and a 120 main. The 120 seemed to make the most power and I got GPS speed of 64 mph I think it was backward on the WOT course though and aided by a little dip at the end. I took the 120 main out of the PZ30 and put it in the PWK 30.

I put it all together and tried to tune it. No dice. Idled erratic with no idle speed and limited idle mixture adjustment. Hmm. Leaking carburetor? Next day went after it anew. Déjà vu, back to my first PZ30 carb tuning experience. The throttle cable is very short on the Magician and tight under the gas tank where it makes the 90 degree into the carb and it was holding open the throttle slide! It worked fine without the gas tank but the added downward pressure applied with the gas tank caused it to slip out of the slot on top of the carb putting tension on the slide with very little difference in the feel of the throttle. CARB Tuning 101. Note to self. Confirm before tuning that the throttle absolutely works as intended and the slide is closing completely or it will not tune!

Got it running and I tuned that idle mixture from the side with a smile on my face and I fiddled with it twice as long as I needed too because I could. I had changed the pilot to a 41, main jet 120, mixture screw 1 ¾ out. The PWK uses an air mixture screw so turning it in richens the mixture and out leans it.

Got one ride in and one run on my WOT course with a top speed of 61 mph GPS. Right at ¾ throttle it has a miss or bog for a second then pulls strong up to and through to WOT. It needs some tuning.

Thoughts….with just one ride I might be off the mark in commenting but I will. Very interesting this PWK 30. It runs differently than the PZ30. I mean the transitions are different. I think the increased airflow and slide has an effect on how the engine reacts to throttle manipulations such as transitions at throttle let off and acceleration. The acceleration is outstanding and it feels good to put on the throttle and it responds quickly! Better than a PZ30? Maybe. A PZ30b? I can’t say it is right now. Testing will continue.

[China Rider 27]

Update. Spent the whole day trying to dial in this PWK30 and no deal. It seemed to get progressively worse as the day went on with a hanging idle and throttle response going away. I am 1 out of 3 for these $30.00 carbs. Testing will have to wait until I get a functioning PWK30 but I am stoked that the intake system works.

[China Rider 27]

Thought I would add this post for all the struggling carb tuners out there as knowledge and experience is tuning power! It is the struggles that take you to school, so yesterday I went to school with this PWK30 carb again. It just looks too good to not work. It uses a jet block which is to say a piece screwed to the center of the carb holding the pilot jet, main jet, jet needle tube. A rubber gasket is used to seal off the passages where it mounts to the carburetor. Air or fuel must be leaking into the carburetor throttle bore from somewhere and after disassembly it looked like this gasket may not have sealed well. It is known to be a problem area with this carb. I ordered a new gasket off of amazon which came in Friday and it is twice the thickness of the stock gasket.

The float adjustment looks perfect, and the needle seats with no gas leaking at the overflow.

I put in a 38 pilot and started it up and it will run. Set at 1 ¾ out no adjustment will adequately stabilize. It will rev and sometimes bogs and occasionally will die.

Put in a 35 pilot and again it runs at 1 ¾ out on the adjustment. Upon removal gas was observed pooling in the bottom of rubber intake boot where the carburetor mounts and observed collected in the carburetor bore surrounding the pilot jet exit hole.

Tried a 32 pilot and it runs 1 ¾ out same as before with gas collecting.

Appears there is no way to reduce the idle gas flow to a manageable level. Persistence is a necessary carb tuning mentality and I will continue to apply that to the PWK30!

[JerryHawk250]

Check the float height that it's nor set too high. I just went through the same thing with my pe30. I lowered the float level a little and solved the problem.

[China Rider 27]

Thanks Jerry you got me back on it! Float looked perfect to me but upon closer inspection it might be a little high so I reset it a lot lower. Put the 38 pilot in it, replaced it, started it. A lot of the same issues idle mixture turned out 3+ turns, throttle response not real good, idle funky. Took it off and again gas pooling in the rubber groove of the intake manifold and some in the carburetor. Went over everything again, took off the jet block to check the gasket, checked the choke passage for leakage, blew out pilot air intake Bottom line is the only way it gets gas at idle is through that pilot jet. Put the 32 pilot in it and reinstalled. Starts right up and fiddled with idle a bit sounds pretty good at 1 1/2 turns. Turn it in 1/2 turn and it will drop rpm. It will take some throttle revving, restarts immediately. Need to road test it, but the weather not good today. Time will tell. Pix of the float setting before adjustment and pooling.

[China Rider 27]

Yaa……so, this carburetor I never could get to work. But I got another one for $26.00 with great machining an extra needle and two hexagonal style Keihin main jets. Spent a whole day trying to get that PKW China clone to work. No go. The pilot circuit just leaked too much fuel somehow. I tried all the pilot jets from 40 down to 32. The inexpensive clone carburetors may work in many situations but I have to say BEWARE the PWK clones coming out of mainland China based upon my experience. Something about this carb design is not well replicated.

I am determined to get a PWK to work and it must also have a 50mm inlet carburetor bell to work with my intake system so options are limited.
I ordered a PWK 30 from OKO (the original OKO) which is a PWK clone made out of Taiwan for $90.00. A significant price but you know when you think about it, you spend $100 on an exhaust no problem and skimp on the carburetion? When I look back at the cost of my time, spent thinking I could “tune” my way out of a nicely machined piece of aluminum I cringe. The cost compared to time is cheap!

You can specify the jetting. I guesstimated it based upon my extensive recent experience at 38 pilot and 120 main.

The carb came in last Monday. Cleaned it out. Put it on. Started right up. Turned it this way and then that way and settled on 1 ¾ turns out. Took it for a short drive, and made one pass on the road with some WOT grabs with no immediate significant issues done in 30 minutes. Some work yet, but it Idles very, very well. And it looks SICK in black oxide! Shame to cover it up with a side panel.

[Megadan]

Originally Posted by China Rider 27

The pilot circuit just leaked too much fuel somehow. I tried all the pilot jets from 40 down to 32. The inexpensive clone carburetors may work in many situations but I have to say BEWARE the PWK clones coming out of mainland China based upon my experience. Something about this carb design is not well replicated.

\ A significant price but you know when you think about it, you spend $100 on an exhaust no problem and skimp on the carburetion? When I look back at the cost of my time, spent thinking I could “tune” my way out of a nicely machined piece of aluminum I cringe. The cost compared to time is cheap!

You can specify the jetting. I guesstimated it based upon my extensive recent experience at 38 pilot and 120 main.

You had the same problem myself and a few others have fought with the cheap PWK carbs. Something about them is poorly replicated and they just draw fuel at idle. Literally word for word the issue I had on my own thread.

I also agree on spending more for a better carb. That is why I dropped the money on the Nibbi PE30 over the cheaper clones. Worked out well.

Your jetting numbers are pretty close to what the starting point for a lot of people is. The PWK30 carbs like the larger 38 and the PE30 likes a 35, but main jet wise they basically the same, with the PWK30 being a size smaller if the power jet is left in place.

[China Rider 27]

I took the day off as going to be close to 79 degrees today and I had to ride. Been long cold spring. Put in a 130 main to start out richer and it will pull it no hiccups up through WOT but only got 60 mph on my WOT course. Seems just mushy somehow like just doesn't have enough energy. I am going to let cool off and pull the plug look. Oh man does it idle nice. You can let the clutch out with no throttle and it will pull away from a stop sign and just put, put, put. I think that is a sign you have the low speed figured out.

[China Rider 27]

The Magician gas tank sits down on the carburetor creating a pinched throttle cable. It had caused problems hanging up the throttle. On the OKO PKW I requested it with a 45-degree elbow to cure this issue. The problem is a 45-degree elbow requires a little more cable to make the turn. The stock cable had no length for this mod.

I could find no cable of length that would fit in the stock throttle threading size. A switch to a ¼ turn throttle is a good upgrade in my book, but the starter and kill switch are built into the Magician stock grip. So often with a mod, to get where you want to be you are going to have to go round about to get there. I got a starter and kill switch for about $8 looks similar to HAWK kill switch. I cut off the stock wiring about 3 inch above the plug in and soldered the new switch ends to it and then shrink wrapped. I found a ¼ throttle came with a longer cable I think it was about $14.

The ¼ throttle was working slick, no more binding, and plenty of cable. Made some runs with it, then I figured out it was not opening the slide all the way at WOT and had 1/8 slide hanging down in the bore. The new cable was not adjusted correctly. From now on, when I install a carburetor, I will connect the cable to the carburetor off the bike and make sure the throttle is retracting the slide fully as it should. It is especially important with this carburetor design.

Note: You can adjust a ¼ throttle until it has NO slack in it. When you turn it, the carburetor and thus the bike reacts. Takes a little getting used to and can create some drive ability issues until you are familiar with it, but it puts performance in the throttle application.

[China Rider 27]

I shook down the OKO PKW 30 over the past few weeks with two runs today. The following are the results. No adjustments were made to either the idle speed or idle mixture, idle speed 1500 avg, with 1 ¾ mixture. Approximately 200 feet elevation give or take some feet due to terrain changes. Speed GPS confirmed.

5/9/20 130 main, 38 pilot top speed 60 mph

5/10/20 125 main, 38 pilot top speed 61 mph for sure (62 maybe but potential error) temp 85 degrees

5/17/20 125 main, 38 pilot top speed 60 mph

At this point, I identified that the throttle slide was not completely retracting and that issue was resolved. Of course, I had to go back and retest to see if there was a difference.

5/18/20 120 main, 38 pilot – lean condition indicated by cutting at WOT and with 1/8 roll off engine power came up.

5/18/20 125 main, 38 pilot top speed 61 mph, temp 60 degrees

5/23/20 125 Main, 38 pilot top speed 61 mph, temp 47 degrees

5/23/20 130 main, 38 pilot top speed 62 mph, temp 56 degrees

Thoughts: I almost skipped running the 130 main today because of its poor performance in its initial run. Was I mistaken! Hands down it provided the best tuning for this carburetor and equaled the top speed. Smooth running with a quieter note, it accelerated well, with a smooth steady deceleration absent any popping or rumbling. It goes to show you cannot speculate on what you may think. You need to test it. It is somewhat odd that a 130 main would tune as it is outside what I have seen for the PKW 30 given this motor and my modifications. That makes me wonder about these generic jets and one day I will spring for some OEM replacements to see if that holds. I cannot rule out that there is some more to be had and one day I may go up to a 135 main to see. Given the temperature today, I would expect needing a 127.5 as summer progresses but there I go speculating again.

The OKO PKW 30 has proven to me to be an excellent carburetor that will work with exhaust modifications in an otherwise stock CG 250 engine. The idle is nothing short of outstanding, the best I have experienced. The throttle response likewise exceptional in its crispness and the acceleration excellent. Well worth its cost!

[China Rider 27]

If you have read my previous posts, you know how much I like a CCC (cheap cloned carburetor) which are really CCCC (Chinese cheap cloned carburetor.) They are similar to knives, flashlights, and guns…...in that there is always another one that looks good. Depending on the design, some appear to be relatively free of issues and others not so much.

I have been curious about the PE30 so I bought one for $26.00 off of Ebay and I have been tuning it the past few weeks. It is advertised as 30mm but measurements show the bore inlet diameter to be 28.66 mm. There is a 28mm version looks identical I suspect it measures the same. Just to note, the other carbs reviewed in this project do not spec at a full 30 mm bore either but fall at 29mm plus.

Per Megadan’s tuning specs, I started with a 35 pilot and given my previous work with the PWK30 a 130 main. Fired right up and a sweet idling carburetor it is. Might be close to or at least as good as the PWK30.

5/24
Pilot 35
1 1/8 turns on idle mixture
Main 130
WOT 61 mph
Some hesitation, cutting just off idle.

5/31
Pilot 38
1 2/3 idle mixture
Main 130
WOT 62 mph
temp 58 degrees
Hesitation off idle continues. Little weak on top. Some popping on deceleration. Plug looked good at the insulator, the tip a little blistered.

6/2
Pilot 38
1 2/3 on idle mixture
Main 135
WOT 62 mph
Temp 55 degrees
After run added 1 thick washer to needle but hesitation continued.

6/8
Pilot 40
1 7/8 on idle mixture
Main 135
temp 50 degrees
WOT to be determined. Removed the shim when I installed the 40 pilot. In town driving showed the off idle hesitation to be gone.

Thoughts: Idle stands out immediately with this carb and good it is. Seemed hard starting and required the choke to even fire but that could just be the adjustments as I worked out the tuning. It came with a throttle cable choke but luckily, I had some spare carburetors for parts (CCC grave yard) and I took a manual choke off a PWK30. Surprisingly the great idle was consistent across all pilot jets between 1 and 2 turns. The throttle response and acceleration were excellent and similar to the PWK30. The throttle cable inlet is cast into the screw housing so no 45 or 90-degree throttle guide can be used. I had to install the stock Magician cable and this set up resulted in a hanging high rpm throttle incident during a ride when the cable slipped out and caught the lip of the inlet. As far as tuning idle and speed on the Magician you need to move some wires out of the way, but otherwise no issues and it is closer on the right side than the PWK 30 from the left. Excellent carburetor design sake for the throttle cable inlet.

[China Rider 27]

To continue with positive movement on performance, I knew one day I would have to open up the breathing of this CG motor. I studied the accomplished China Rider porters and you all know who you and they are, and if not, you can find them on this link:

http://www.chinariders.net/showthrea...t=head+porting

I also found this video helpful.



I completed this job in January past but have been too busy up until now to finish it up. I have never ported a head. My goal was to complete a good basic port job. I also wanted to make a record that might help give others confidence in trying it. The head is a Peace Sports piece for the Brozz and you can see the air injection port in the exhaust. This head appears to me to be fairly maximized for performance with a minimum of material in key areas, especially sloping up to and around the valve guide that assessment made in comparison to pictures I have seen of the HAWK head. You can actually stick your finger into the casting in spots and feel for the thickness which seemed to be about 3/8 inch or a slight bit more. I thought about heat and that gave me pause for cutting to aggressively in the valve guide area or beyond about 3/8-inch port wall thickness anywhere.

The plan was to open up the port some at the port roof valve guide pinch point, smooth all the transitions, and polish the exhaust port. My mission was to increase flow but not enlarge the port and damage through velocity.

Pictures show before and after, sorry about focus on some.

The intake bowl showed a valve seat and bowl machining deformity with an edge protruding some ¼ inch out from the edge of the seat in a malformed circle off center shortening the port. Makes me wonder what my HAWK head looks like inside? I reshaped the bowl to line up with the valve seat with the ball and oblong rounded cutting bit and it shaped up nicely. I was not concerned about the intake so much aside from the bowl deformity and took off here and there protrusions and squared up areas.

The intake manifold is made of rubber and aluminum and I port matched it to the head. It required taking off a lot of the rubber with a flap sanding disc to enlarge to 30mm and the aluminum to match the port. I polished the combustion chamber to take off the sharp edges.

Thoughts: Thinking air flowing. Thinking minimal removal. Visualize the flow through the port and see the obstructions that when removed provide some velocity to the air. I shaped the port with the cutting tools always moving, smooth it, and polish. Triple tape the valve seat with duct tape all around leaving no area uncovered! Five or six times trying to get a spot at an angle back in I scrapped the seat with the backward part of the spinning cutting bit or chuck and luckily never broke through. Can’t wait to get it mounted and fired up! Performance remains to be IM……… proved.

[China Rider 27]

Exhaust PIX