I thought the same thing when I saw the first line of post # 132... but he DID start it and has a certain amount of ownership, right? J /K man, I don't want or need any flames.....just some good natured ribbing....
I have been playing with w/c motors and built cag's for a few now. I got most of the hard parts but, need to get in and tune it now.
I have the whole package now.
14/14 rep and real
fc and fc stroked cranks
two peice heads, one 40mm and two 44mm
4 pedal reeds glass
2 pedal carbons
2 pedal glass
lighten fly wheels
and two diffrent pipes.
ada race pipe and a jet pro high rev.
Not sure where this head came from but, looks very similar to the one that ddm sells. Also have one of those but, have not checked the timming yet.
Two peice head, 44mm, small boost port (8mm) no window in piston.
Stoked crank with just gasket under cylinder.
Squish .58mm
ex opens 97 duration 166 port aera 262
trans opens 120 duration 120 port aera (total trans and boost) 202
Blow down 25 deg
With jet pro pipe power starts at 6,000 and pulls to about 10,000 then over revs to 11,000. Strong enough to pull the front up with a 7/74 from 6 to 8,000 rpm !!!!
Ada race pipe, power starts a 7,000 and rips at 9,000 and pulls to 11,000 rpm. wheelies at 9,000 with same gear.
I just put the ddm head on with a fc crank. I dont have the specs on it yet but, jet pro pipe power starts at 6,000 and rips in the 8,000 range but, only winds up to 10,3 or 10,500 rpm. This one has the same size boost port but it has a window in the piston. And the squish is at 1.1mm.I am sure the ada pipe will raise the rpms that the power comes on at but, testing say's it wont effect the total rpm.
I was thinking about cutting the cylinder to get the squish to .6 but.......I cant keep the other motor together (stroked crank and .5mm squish), it keeps ripping the head bolts out !!!! Two sets of case's now and just way too much compression for these little cases. Just need to heli coil it and that should hold.
yea i got a new engine for my bike. one is at my house, because the guy that i bought it from didnt put packing in the box, and it was a little busted up. broken cylinder head fin, crushed air filter, ect. so he's giving me another one free. itll be here wed. so im happy. just orded a light flywheel, fg reeds, a plug, a billet starter pawl, clutch springs, and might do a stock pipe mod.
Alright so since boost ports relate to port timing and area. Where would I carve a boost port in, how wide, how deep, how long etc. and where from the stock transfer ports?
(Stock cag)
Edit: Ok opposite the exhaust, same size as transfers. Same place as transfers too?
This is the kinda thread i've had wet dreams about, I just found it and read it religiously from page one.
I've been porting a few engines over the past few years and was just about to get stuck into a 44mm (RevUnlimited) Boost ported (looks like it was made with a cordless drill) headkit.
I am currently/going to increase the boost port to 20mm wide and make it approx 4.5mm deep, angle the roof to aim at the plug, correctly angle the piston window to feed the boost port, index the piston SKIRT to feed the transfers, run a single ring, check and modify squish to around .5mm. Depending on what Mr. Degree Wheel says will determine if I change the exhaust port timing, I will be widening it.
I have so far inverted the reeds, which means the crank swirl aids in drawing fuel/air through the reed, unlike the stock reed configuration which causes the incoming fuel/air and crank swirl to collide. I have also taken the lump in the top of the case near the reed out to assist the new inverted reed setup.
I've matched the cases to the topend to help create a straighter path for the fuel/air. And i've matched the carb to manifold and manifold to reed block.
I have a fatboy pipe kit, and it needs some attention, the manifold needs to be matched to the exhaust port, the manifold pipe needs to be modified because it has a 22mm pipe going straight into a 36mm pipe on the expansion chamber, the stinger also protrudes into the expansion chamber by about 40mm. This will need some attention.
Sounds great. The only tips i have is to do one change at a time. This way you can see what works,what does not and what changes are not worth the time or effort.
Get your pipe sorted out before anything. I have beated built motors with stock pipes with a stock motor and good pipe!! There worth there weight in gold on two strokes. Plus it makes it a lot easyier to feel the changes and what they did for performance.
Also, try the port a calc program posted here in the thread. It works awsome and will really help get the last bit out of your combo.
So you noticed the air/fuel flows backwards in these motors too? Hehehe....i went to a 4 pedal reed and didnt notice a diffrents !!! My finding's are, it really doesnt matter that much. Maybe you will find out diffrently.
Sounds great. The only tips i have is to do one change at a time. This way you can see what works,what does not and what changes are not worth the time or effort.
Get your pipe sorted out before anything. I have beated built motors with stock pipes with a stock motor and good pipe!! There worth there weight in gold on two strokes. Plus it makes it a lot easyier to feel the changes and what they did for performance.
Also, try the port a calc program posted here in the thread. It works awsome and will really help get the last bit out of your combo.
So you noticed the air/fuel flows backwards in these motors too? Hehehe....i went to a 4 pedal reed and didnt notice a diffrents !!! My finding's are, it really doesnt matter that much. Maybe you will find out diffrently.
Keep us posted on how it goes.
dk
Thanks for the tip, I have this horrible disorder where if I know i can improve something, i'll go to almost any lenght to do so, and IMO 'stock' is the dirtiest word in the dictionary...
I agree, the biggest improvements are always in the pipe, but i've often wondered if thermal wrap on the manifold would help keep heat in the pipe and possibly stop exhaust gases from cooling and condensing.
I've always been a fan of the longer "fatter" pipes for their very wide powerband, as opposed to the shorter thinner peaky pipes.
With the 4 petal reed setup, I'm not sure exactly what they are like because I have never owned one, but they look like they add more volume to the crankcase which might be why you didn't see an improvement.
I've been reading and re-reading the 2 stroke tuners handbook the last few months, and I just can't believe some of the stuff in there that you wouldn't think of in a million years!
Oh, does anybody know what kind of hp ceiling these cag engines have? Anywhere near the 10hp at the shaft?
the best cag engine for horsepower is our new 6 port design which is simular to the pbu scorpion but is also fitted with an ada type 15.5 to 1 comp head, full circle balanced race crank, free role high speed case bearings, case work, bw tripple stage 4 petal reed unit, 16/16 dellorto , mds ignition unit. output is around the 6.2 to 6 .7 h.p.
Hi guys! I haven't been on here in months! Thought i'd pop back to see whats going on and this thread is on the first page! Its cool to see it has popped back up! d.king, looks like you have been busy since you started modding you cag! Keep up the great work & info and its really interesting to see your results. jkulhanek - i think if you put everything together (like you say) you should be getting way over stock HP, i'd have thought you should be at 6+ HP. I agree RD Racings engine deosn't make me wet myself given its spec. keep it up guys!
yep, have been spending a little money on these things. Gotta tell ya, a little cash and a lot of attention and you can get these little china bikes to run GREAT !! Fires up every time, throttle response is perfect and i dont really see any problem with finishing a season or two with out needing any attention.
Did get to find out how drastic a storker crank effects port timing. They will take a 7,000 rpm motor and turn it into a 10,000 rpm monster. Just silly.
As far as your first post of durtaions that might work, i think the only thing that you can go by with the durations are the blow down numbers. If you have that then it does not matter where there at, just have to get the port timing correct. All heads are different, thus need different port timings to get them to work correctly. I have ported about 8 heads since last winter. All worked way better than the stock and the last one i did, i used a mill and i gotta tell ya, that is the only way to go !!!! Super clean ports and runs awsome !!! Still have not gotten the roof of the boost port perfect but, from what i have seen it does not matter that much. Still need more testing.
And i know you dont like other stuff in here but port timing but, the pipe IS very critical to power delivery!! I have two pipes to play with and one starts at 5500 rpm and pulls to 10,500 and the other starts at 8,000 and pulls to 10,500 !! same motor just swapped pipes to get the power where i want it. All so, its REALLY hard to feel the deferents in port timing with the stock pipe. The aftermarket pipes tell you right away what you did.
One last note and i will stop rambling.......Tork motors are WAY better than rpm motors from some recent testing. They get out of the corner way harder and can pull bigger gears for more top end. I can wheelie out of a tight turn with a 7/68 and pull past every body on the strait. This bike really does feel like a euro bike.
Is this an accurate way to get timings (in degrees) if for example the one on the left is the height of my exhaust and the one on the right is the height of my transfers.
As you can see it measures from the bottom of exhaust, to bottom of transfer, then across to get one of the angles.
Is this an accurate way to get timings (in degrees) if for example the one on the left is the height of my exhaust and the one on the right is the height of my transfers.
As you can see it measures from the bottom of exhaust, to bottom of transfer, then across to get one of the angles.
Affraid not my friend, that is totally wrong. Have a read of this site http://www.macdizzy.com/cylinder_map4.htm. There is all the info you need and huges amounts more.
Affraid not my friend, that is totally wrong. Have a read of this site http://www.macdizzy.com/cylinder_map4.htm. There is all the info you need and huges amounts more.
Man, where do you find this stuff!?!?!?!
Nice find, looks like i got some reading to do.
J /K man, I don't want or need any flames.....just some good natured ribbing....
