Chinese Scooter Club

hagur

Hi,

I just received my big-bore kit Smile

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=330238359707&ssPageName=ADME:X:AAQ:MOTORS:1123

Higly recommended seller by the way, only took 6 working days to ship this from Taipei to Iceland Shocked

Anyway, he sent me a "high-performance" camshaft also as a gift, like he said. Just wondering how that camshaft is different from the stock one? Should I stick with the stock camshaft or use the new one? Anything special I must do if I use the new camshaft?

P.S anyone got that kit and would like to share their experience with it? I was going for the Naraku 85cc kit but I could not find any seller which had it in stock so I started checking out E-bay for alternatives. Ended up with this one.

Any pointers for me before I install it? I know I'm going to have to upjet, and I've already ordered new jets in various sizes from 80-98. Just waiting for them to arrive Wink

Fox · Posted: Fri Jun 13, 2008 10:44 pm Post subject:

It's probably got taller lobes on it so the valves open a little further to allow a little more fuel air mixture to enter the combustion chamber and conversely allow more flow from the exhaust side.

Compare it to your stock cam upon disassembly. Wink

jpmacd733 · Posted: Sat Jun 14, 2008 12:41 pm Post subject:

With the larger cylinder and performance cam, that engine is going to want a lot of air and a lot of exhaust to get rid of. Hope you got a plan to open the intake and exhaust for more flow. Smile

Also, though not confirmed by me, I think the CDI has a rev limit at 8000 rpm which will be the speed restriction no matter how big the bore kit. Without a no-limit CDI, you should see good acceleration but not much speed increase, is my guess. I here a lot about up gearing the final drive to gain speed but have yet not seen the gears available for a 50 cc China scoot, would be nice way to go.

If you do get the no-limit CDI, that is even more need to allow more air and exhaust flow for the higher rpm's.

Interesting project. Please keep posting with your results.

Joe
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Yellow Scooter · Posted: Sat Jun 14, 2008 1:27 pm Post subject:

Fox · Posted: Sat Jun 14, 2008 1:40 pm Post subject:

I would think that with the increased torque, the roller weight and clutch springs will be key in the final tweaking for max performance.

You may also look at porting out the cylinder head, and a bigger carb/intake and a straight pipe.

Read this page:
http://www.rc-trucks.org/gy6-engine-performance.htm

hagur · Posted: Sat Jun 14, 2008 6:16 pm Post subject:

Thanks guys, I'll definitely keep you posted and probably also gonna ask some question about installing it. Although I'm quite familiar with the inner workings of four-stroke motors, this is my first attempt of actually "rebuilding" one, if this can be called a rebuild.

I'm not really after a huge gain in top speed, what I'm looking for is good acceleration and enough torque to climb relatively steep hills without slowing down to a crawl.

I've already ordered new main jets and I'm planning on sticking with the original air-box if possible, but I will drill additional holes to allow for more air. I'm also going to get a new CDI. I will see about the exhaust, but if it's completely necessary, I will try to upgrade it.

I'm not really looking for a race machine Wink

Just want to make my 50cc scooter a little bit better for keeping up with traffic, be it on the flat or uphill Cool

I'm probably not going to install this until when I'm back home from my vacation, which won't be until early July. Will keep you posted.

95talontsi · Posted: Sat Jun 21, 2008 9:59 pm Post subject:

I just picked myself up a 88cc kit also, mine didnt come with a head or cam though, mine ran me 110 bucks.

I'm also just looking for some more acceleration and hill climbing power. I got the roller weights and am happy with the results but now I want more Twisted Evil

Dont know when I Will have time to install mine either, I will need transportation everyday for the next month and half so I wont start till after that.

Maybe you will get yours done first and post some info about the swap SO I know what to look for when I tear into mine. Good luck!

Stanislavs1 · Posted: Sat Jun 21, 2008 10:45 pm Post subject:

Did anybody know that 125cc engines have 52,4 mm bore? That's kind of odd because a 52mm upgrade for 50cc counts only as 88cc.
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TJ · Posted: Sat Jun 21, 2008 11:04 pm Post subject:

Alexis050891 · Posted: Sat Jun 21, 2008 11:20 pm Post subject:

Yeah, which is good because all you do with increasing the bore is increase revs, conversely a longer stroke gives more torque which in my eyes is better.

(correct me if I'm wrong)
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hagur · Posted: Sat Jul 19, 2008 9:34 pm Post subject:

Well, the plan is to install this kit tomorrow.

Just wondering if 4.4gr rollers are still a good idea, or should I go heavier? I've got a 5.1gr set and a 6.7gr set.

What about jetting? I reckon I'm gonna need atleast a #90.

Will keep you posted ......

jpmacd733 · Posted: Sat Jul 19, 2008 10:02 pm Post subject:

hagur · Posted: Sun Jul 20, 2008 7:10 pm Post subject:

Well, started installing the kit today. I began with taking some body panels off to get better access. Once I had most of the panels off I decided that I would be far better off by just removing the engine/drive assembly from the scooter, and so I did. Only 3 bolts which mount it to the rest of the chassis, so it was easy.

I then put the engine assembly up on a table I had in my garage so I had everything in a really good working height. I disassembled the engine and installed the new piston, cylinder and head. I installed the new camshaft and then decided I had done enough for the day. At that point I had spent about 4 hours.

I'm going to need a feeler-gauge to measure the valve clearances and I will also need to remove the exhaust bolts from the old head and install them into the new head. I reckon I'll be able to do that using my trusty clamping plier, but I must be careful not to damage the threads. Any tips for me to remove it?

After I'm done with that, I just have attach the engine assembly to the scooter, hook up the rear brake wire, the electrics to the engine and re-attach the body panels. Then it's start-up time Cool

jpmacd733 · Posted: Sun Jul 20, 2008 10:10 pm Post subject:

hagur · Posted: Sun Jul 20, 2008 10:20 pm Post subject: