Taida 203cc kitted CygnusX
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Author:  Speedpro [ Sat Oct 27, 2012 11:04 pm ]
Post subject:  Taida 203cc kitted CygnusX

About time I started my own thread.

I've now got all the bits from Taida that makes up their 203cc kit fitted to the scooter. This includes a +3.5mm crankshaft, 65mm cylinder with forged piston, their cylinder head with 24mm intake and 22mm exhaust valves, strengthened rockers, and their T6 camshaft. I've also fitted one of their gruntier starter motors.

The motor has been put together with the thinner base gasket as I can't get the cam chain & sprocket fitted with a thicker one and therefore the compression is reasonably high. I also got a OKO 30mm PWK carb kit and manifold from Jiangwayne with the cable and everything. The pod filter is the only thing I'm not completely satisfied with and then only because the intake is pretty noisy.

I still have the stock exhaust pipe on it. I have a new stepped header pipe and flange all welded up but need to machine a recess for the o-ring where the flange fits into the head for sealing. I bought a muffler from TradeMe, the New Zealand version of ebay, for $80 and need to machine a flange to connect the pipe to it.

This has been a step by step process building up to the complete engine. The end result is pretty impressive even with the stock exhaust and it's catalytic converter. It was very nice to ride and got away from lights in a big hurry, or so I thought. I put it on the dyno today to find it was only making 11.?hp although it was making it at any speed with the CVT transmission. We went down a jet or two in the carb and ended up with 15.?hp. Now it really does get away from the lights in a hurry. It has up gears fitted and was hitting the limiter at about 130Km/H on the dyno. The rest of the transmission is completely stock but has been freshened up. On the dyno it's strange having the motor go straight to certain revs and stay there as the speed climbs and only over the last 15K or so having the engine revs rise. It seems about right as at about the point where the revs start rising the horsepower tails off a little so it looks like the engine is being held to about it's maximum torque. I do intend to try heavier rollers though.

To think, I bought a 4-stroke scooter so I wouldn't be tempted to modify it :doh:

Author:  Speedpro [ Sat Oct 27, 2012 11:08 pm ]
Post subject:  Re: Taida 203cc kitted CygnusX

About the exhaust. If anyone has suggestions about diameters and lengths I'd be interested to hear. The port is 29mm diameter and the mandrel bent first section is also 29mm ID. I've run that for about 200mm and then stepped up to 32mm ID for the remainder back to the muffler.

I can always make another pipe and I'll be checking outcomes on the dyno anyway.

Author:  ZUMIKE [ Sat Oct 27, 2012 11:21 pm ]
Post subject:  Re: Taida 203cc kitted CygnusX

those 200cc+ dont hang around here much, most go back to smaller or just get rid of the bike

Author:  ZUMIKE [ Sat Oct 27, 2012 11:26 pm ]
Post subject:  Re: Taida 203cc kitted CygnusX

one guy I remember tried so many exhausts they kept breaking on him
and oil temps were very hot

Author:  Speedpro [ Sun Oct 28, 2012 1:57 am ]
Post subject:  Re: Taida 203cc kitted CygnusX

The exhaust problem I see is making it long enough. I've been looking at where I could put a loop in it and even considered running it toward the rear of the scooter to get the length and then turning it forward and into the muffler, or even into the side of the muffler. It would be easy enough to have the exit from the muffler at the front but have a tight bend down and back.

Another thing I want to check and alter is the cam timing. The chance of the cam timing being exactly right is remote. Somebody must make a vernier sprocket for these surely but I have never seen them advertised. With so many teams racing them somebody must be making the sprockets.

It does run hot. I haven't given it a prolonged thrash like on a motorway. I did take it up in the hills a bit and was on and off the throttle a fair bit. Towards the end it was being a bit odd with the throttle possibly from heat. I've got Mobil1 in it at the moment which I have every confidence with having run it in a turbo Z1 engined bike I have which runs super hot on the track.

Can you shed some light on why people revert to a smaller engine or get rid of the bikes. It's been a bit expensive so far and I think I need to get a variator kit from Chris yet as well, though the transmission "feels" good right now. It's so much fun with the extra power I can't think why I'd get rid of it.

Author:  johnysmokes [ Sun Oct 28, 2012 7:23 am ]
Post subject:  Re: Taida 203cc kitted CygnusX

Speedpro wrote:
Can you shed some light on why people revert to a smaller engine or get rid of the bikes.

With one recent and notable exception, I can't recall any members that have reverted to a smaller engine. However, most will draw the line at going over any size that requires machining/boring the cases. I think all our REALLY big bore guys have just moved on. Not everyone has the time or desire to twitter away thousands and thousands of posts on a scooter fourm. :rolleyes:

I've never seen a vernier cam sprocket used, but I have seen at least one slotted sproket on RC Scooters's facebook page. I guess you use it in conjunction with a camshaft degree wheel. OBTW, I always thought those exhaust headers with the loop were just for looks. Shows how much I know about exhaust tuning.

Anyway, don't mind the haters, keep us posted on your build, and remember we really like pictures! :D

Author:  ZUMIKE [ Sun Oct 28, 2012 8:08 am ]
Post subject:  Re: Taida 203cc kitted CygnusX

The guy who took his to the beach went back to smaller engine.he was working out of a hanger i think. I believe Dan also did too but you have to search back to 2009-2010. You can find the threads.
Then some disappear like mnscoot. So we have no idea how that was in the long run.
There was the dohc that was started but no updates.

A lot of issues with other parts going bad not able to handle the power. Mpg also gets way to low
If its just to mess around on and not transportation probably won't be a big deal if things break down

Author:  Speedpro [ Sun Oct 28, 2012 11:17 pm ]
Post subject:  Re: Taida 203cc kitted CygnusX

I've noticed that a tank of fuel doesn't last anywhere near as long as it used to. Mind you, I have been exploring the new-found performance, all 15hp of it. I'm expecting to have to upgrade the transmission, after all the motor is 60% larger now so not unreasonable. I'm also seriously looking at how to fit an oil cooler using the sump plug. My thoughts are to make an adaptor that feeds the oil pump input tube from one line to the cooler and the other line just connects to the cavity on the perimeter of the sump plug. The oil will be sucked up from the sump plug area, through the cooler and back to the sump plug area and connect to the oil pump input. May even plumb in a proper oil filter. My other idea is to locate the oil cooler under the seat over where the air filter/box used to be and have a thermostatically controlled fan to move the air through it.

I'm trying to keep it discrete to surprise other riders at the lights. The new muffler may put paid to that though, it has a 50mm hole through the middle.

Author:  Race Concept [ Mon Oct 29, 2012 1:32 am ]
Post subject:  Re: Taida 203cc kitted CygnusX

i sold several 200 cc kits and never hear back. all too busy enjoying riding the little monsters.

reason why shane stepped down was due to MPG.
dan has two scooters and his wife's one was the 162cc project while his was still the 290 something cc.
MNscoot still has his just no longer on the internet and concentrate more on family.

if it's built right with all the right parts and no half butt. it has been reliable to the point i never heard about belt snapping except for MNscoot he snapped it 1x. however people who did build it half butt or with cheap parts did blow it up or run into problems. yes a good exhaust is important. takes a beating from the big bore. simple header in stainless steel nice and thick with as less welds as possible. something fancy like wirus win and fancy sections with many welds just couldn't hack it.

the step up on the header needs to be sooner and best if stepped up 2x minimum.

also would get a oil cooler kit for it. they do get hot especially if your choking it with a stock exhaust.

with the correct exhaust and more tunning you should be able to hit 18hp or more.

cvt has to be upgraded. the clutch and bell especially.

Author:  Speedpro [ Mon Oct 29, 2012 2:59 am ]
Post subject:  Re: Taida 203cc kitted CygnusX

It should be all good as all the parts came from one place and are part of the same kit they sell.

Couple of photos below (hopefully). All parts are from Taida who seem to make very nice stuff and have great customer service with very quick shipping.

File comment: 30mm Carb kit from Jiangwayne showing old carb for comparison
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File comment: The new bits from Taida. New rocker arms as the valves are spaced out and new starter motor as the original struggled, badly
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File comment: Exhaust port, 29mm ID
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File comment: Cylinder head, 24mm intake valves and 22mm exhaust valves
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Author:  Speedpro [ Wed Oct 31, 2012 2:16 am ]
Post subject:  Re: Taida 203cc kitted CygnusX

Working on the exhaust system as I'm too tight to just buy one. I've spun up a spigot that the 32mm tube can be pushed into. I need to machine a little recess into the end of the spigot for the o-ring to go in. This will form the seal between the head and pipe. Once that's done I will weld the spigot to the pipe. The flange is high tensile stainless. I torched a mates drill bit drilling one hole. The steel hardens if you get the cuts wrong, and the second hole when drilled ended up taking the edge off the drill bit but with the meaty 3 phase drill press it went through anyway. It literally burned through - very embarrassing. Once I get the flange for the pipe-muffler connection I'll dummy it all up to make sure it lines up and then weld away. The second piece of tube just slips over the first. Once I know exactly the angle I'll weld it in place. It should be good and strong with about 10mm overlap. I'll make the flange so the the end of the pipe fits into it, again for strength. To support the muffler I'm tossing up whether to go for a tubular bracket of maybe a flat alloy plate with a standoff out to a clamp. A tubular bracket would be cool. I like to roll my own tube from .8mm panel and seam weld. It's real light but pretty strong and I can make it any size I want.

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Author:  X7rocks [ Wed Oct 31, 2012 1:01 pm ]
Post subject:  Re: Taida 203cc kitted CygnusX

15 hp out of a 200 ? .... somethings not right, what ratio is your piston and are there better pics of the ports of the valves? even the valve size sounds small to me.

Author:  johnysmokes [ Wed Oct 31, 2012 3:23 pm ]
Post subject:  Re: Taida 203cc kitted CygnusX


Author:  X7rocks [ Wed Oct 31, 2012 8:06 pm ]
Post subject:  Re: Taida 203cc kitted CygnusX

johnysmokes wrote:

When we made honda style 50 engines up to 18 hp being only 124cc the valve size from a two valve motor would be 28mm intake. even the 4 valve heads from takagawa are larger then those motors.

But you already know this right..

Author:  Speedpro [ Thu Nov 01, 2012 2:23 am ]
Post subject:  Re: Taida 203cc kitted CygnusX

The hp is something to think about. 15hp from 200cc is pretty modest in my book as well. Supposing the exhaust pipe frees up a few more I'm still only looking at say 18hp. Currently it's making 15.?hp on the dyno and in comparison a stock FXR150 makes 14hp on the same dyno, at quite a few more revs. The best FXR150 race bike here in NZ is poking out 27hp on the dyno but that is an exceptional engine. 22hp is more easily achievable, and reliable. I think the low numbers are due to restricted revs. Stock they only go to 9000rpm I think and since the ECU is original that hasn't changed. The other thing is that even with the bits I have it's still a pretty relaxed state of tune.
I've built a few bikes and currently run a Honda MB100 which has dynoed at 30hp and a few bigger bikes at LOTS more. All were at a significantly higher state of tune. Considering the amount of fuel it uses I was wondering about transmission losses. My sons CB125T makes 19hp on the same dyno and I'm pretty sure it uses less fuel even when being thrashed on the track.

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