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Discussion Starter · #1 ·
Hey guys so i finally decided to start building a "high" performance engine for my cateye frame that has been needing a motor for months now. I plan on putting a big bore head, fcc, wt-813 carb, along with alot of other things to make this engine far better than stock.
As of now i have lightened the flywheel, currently lightening the HD clutch, blueprinted the case, blueprinted and cut the cylinder head, and i also have a tranny for the bike.

Here are some pics of the mods. Im not sure if i did a good job blueprinting. I also wasn't sure how much your suppose to open up the intake and exhaust holes so i just ground down the edge of each hole.
 

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Discussion Starter · #2 ·
So here come the questions.
1. Is this the right start pawl cup?
2. What types of bolts will i need for the cup and flywheel when running the fcc?
3. Is there some type of solution i can soak the case and the cylinder heads that will get the gunk off or will i just have to get it with a rag in all the nooks n crannies?
4. What would happen if you only blueprinted the opposite side of the case and cylinder head?
5. What do i need in order to polish the inside of the case?

I have more questions, but they will come later in the build when i have the parts.
 

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If your following sniperkills thread youll notice he ran into a problem in the end...This is because he didnt map the cylinder and piston to the smaller stroke before he ported and sized the cylinder........

You need to put the 49cc non-windowd cag piston on the FCC rod without any rings and roll the engine down to BDC to mark the top of the piston ...This is going to be your guide as to how high you could port the intake roof less 1/8" to ensure a descent seal.....Make sure its a non-windowed reed inducted engine piston too!!.

Then you roll the piston to TDC and make a mark..You want to add .010-.015" to bring the engine into the squish range of .035"minimum with a .025" thick copper ring...This way you can use juiced-up pump gas with 104+ octane booster........

Once you make TDC calculations I suggest you have the top lip professionally deck milled to calculated height to ensure theres a good tight seal........

Use the piston pins less 1/8" on each side to gauge how wide you go on the exhaust and intake ports...Its best to match the two in sizes......
 

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So here come the questions.
1. Is this the right start pawl cup?
2. What types of bolts will i need for the cup and flywheel when running the fcc?
3. Is there some type of solution i can soak the case and the cylinder heads that will get the gunk off or will i just have to get it with a rag in all the nooks n crannies?
4. What would happen if you only blueprinted the opposite side of the case and cylinder head?
5. What do i need in order to polish the inside of the case?

I have more questions, but they will come later in the build when i have the parts.
1./2. Yes..Look at ebay and scooterparts4less for the pawl bolt...You want the longest bolt......Theres 3....1 for non electric starter and 2 for e-starter.

3. Brake parts cleaner works good

4..When you blueprint the head to cylinder you only blueprint 1 side..The flow side...This is the side the crank rotates the mix towards the transfer ports.....Removing any more just removes material vital for keeping crankcase volume down to maximize velocity flow.......

5..I Use mothers Billet/Nev-R-Dull and Miracle Metal Polish,,emery paper aswell as scotchbrite pads..
 

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Discussion Starter · #5 · (Edited)
Whats BDC and TDC? Ok so ill just used one of the pistons i currently have. So since i don't have the fcc yet i can't do all the stuff yet.
Ok so i need to drill two holes on each side of the piston and reshape the side skirt.
Porting the intake and exhaust holes will increase performance, but only if they are not too large. But this isn't a necessity to do, correct?
I also decided to just use the metal manifold i have, but ill also need an adapter plate if using the walbro 813 carb.
So how much more should i take off of the intake lip or is it fine as is?
Anything else i can do without the crank?
Just realized my piston is different so im going to have to buy the correct one.
 

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Whats BDC and TDC? Ok so ill just used one of the pistons i currently have. So since i don't have the fcc yet i can't do all the stuff yet.
Ok so i need to drill two holes on each side of the piston and reshape the side skirt.
Porting the intake and exhaust holes will increase performance, but only if they are not too large. But this isn't a necessity to do, correct?
I also decided to just use the metal manifold i have, but ill also need an adapter plate if using the walbro 813 carb.
So how much more should i take off of the intake lip or is it fine as is?
Anything else i can do without the crank?
BDC = Bottom Dead Center.............. TDC = Top Dead Center..........

Only things you can do is get the rest of the parts ready for reassembly like lightening the flywheel and modding/blueprinting the clutch

For the aluminum intake you can JB Weld in the intakes teardrop then after the JB cures take a 1/8" drillbit and fron the fromnt face drill straight through.......Then the pulseports will line up and there will be no intake leakage.......
 

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Discussion Starter · #7 ·
sounds good ill check my local stores hopefully they have some jb weld.
I also looked for pull start bolts and the longest one i can find is 2.5 inches.
 

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Discussion Starter · #10 ·
Ok so i finally finished the clutch mod.
I also just finished sanding the case with the emery paper, is it good enough to start polishing it?
Is a rocket key suggested for a fcc?

Cam i don't know how i didn't understand what you were saying about the head porting. It finally clicked last night. Thanks for the help.
 

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Yes on the rocket key, I don't polish the inside off the cases, the mixture will want to stick to it. You only need smooth flow, no sharp edges or anything that blocks the flow.
 

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The cases look good, alot like the cases in my 5 port, 3rd Stage avatar Lucky 7 semi chopper. It will jump on the lower end, when I crank the throttle on my redwood deck the rear wheel starts spining and smoking, the engine is screaming, the neighbors Love it,lol. I had a 7/55 gear on it and changed to 7/68, much more fun on the start,lol.
On your ports, the exhaust should go up to a hump or football shaped, on the intake you would use the same shape but go down alittle. It's a very fine line, you go .020" to far and you have a boat anchor. If your doing heavy mods you need to put a degree wheel on the crank, so you know where your at.
 

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Discussion Starter · #14 ·
thanks epr im glad i did that right. Porting the head will probably be after the bike engine gets started up since i need to big a bigger more powerful rotary tool. Next up is the jb weld mod in the manifold, engine bearing mod, slim down the head lip for the bb head. Whats the best way to slim down the lip? By hand files or could i use the sanding wheel on a belt sander?
 

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I did the ruff stuff on my 8" bench grinder to get it close to fitting inside the alloy head lip. I finished w/ a little dremel work and jewelers files and wet dry sandpaper. At the end I put a slight taper on the cylinder lip, & put the .020" round copper head gasket in an hand fit them till the lip off the head was hitting the taper, nice tight fit. Only the very top of the lip has to be very flat where the copper gasket sits. I use Permatex copper head gasket spray, it seals good. I don't use a base gasket on the stock cylinders to get the piston higher in the cylinder I spread a thin layer of Yamabond on the cases, put it together finger tight, and torqued it the next day. I have a 1 1/2" thick slab of alum I surfaced on a Brigdeport Mill, I use 3M poster tape ( double sided ), on the block edge to edge and the wet/dry sand paper and hand mill the top of the lip. Glass will work too.
 

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Discussion Starter · #16 · (Edited)
sounds good, thanks. I just ordered 2 copper gaskets and large rocket key from scooter parts. I also just ordered from amazon the silcon oil 350, variety sandpaper 600-2000 grit, and permatex spray. Ill also order the motor bearings from ebay next week and hopefully hp fcc, gaskets, piston kit, motor seals, and maybe a few things to get $100 order from pbp in 2 weeks.
Do i want the 10mm or 12mm wrist pin crank/piston?
Will the rear hydro brake conversion kit work for a cateye?
Thanks
 

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The 12mm crank is much stronger than the 10mm and there the same price, hkmotos has both for $25 shipped. Even the 49cc stock Cag has a 12mm bearing.
 

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Not sure about if the brakes will fit, but PB Parts in Florida has an info order phone, I ask them when I am not sure.
 

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Discussion Starter · #20 · (Edited)
Sounds good ill have to ask. Should work, but i think they don't suggest it because of the lack of slack on the line, maybe? I measured and the line would have to be 34 inches and the line that is on the hydro brake is 35 in so basically no slack. Which would not allow you to turn right. I was considering buying the front hydro brake conversion and possibly making it to fit inside of the left foot peg as a foot brake. Would definitely have to be careful, but would be something you don't see very often.
Heres another question, when doing the 4 port piston do you start the drill from inside of the piston or outside?
Just went to home depot to buy some more stuff. One thing they didn't have are m5 bolts long enough for the bb head. Any places were i can get those bolts from?
 
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