My First Motorbike Project

gera229 said:
Lowracer, that's what I read. More RPMs is good too. I plan on finishing my bike on thanksgiving break. Possibly by Monday.

5-7 Heaven, I know, but I was saying at 8,000 RPM engagement for an engine that can only do 10-11k RPM just does not seem to do. Especially that for cruising it will be loud.
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The 8000rpm engagement clutch can be modified with lighter springs to engage just off idle, @ 3000,3500 or 4000rpm.

If your pb clutch doesn't hold up, this is an option.
 
I'm only putting on a race clutch if my 3 shoe clutch starts wearing out or snapping springs on me. But 3 shoe clutch is my priority.
 
Simple question: Does you pb engine have a tapered crankshaft nose?

Next simple question: Does that 3 shoe clutch have a tapered center?
 
Well, if the race clutch mounts correctly on your engine, my questions are moot ones.

What are you using for a fuel tank?
 
I'm using the metal gas tank that comes with the China Girl kits.

My next step is taking out that paper gasket which is stuck to the engine. I am afraid to scratch the engine.
 
gera229 said:
I'm only putting on a race clutch if my 3 shoe clutch starts wearing out or snapping springs on me. But 3 shoe clutch is my priority.
Click to expand...

hi !

my only option was the Race Clutch to get rid of Snapping springs (some lasted only 100km and some regulary 20km)

but as its obvious that Race Clutch has super Stiffy springs, i instantly modded it and im using super soft "Duocore" springs (smaller diam spring inside bigger diam spring) and i still have the Adjustability option on the Preload tension.

my "DuoCore" springs i bought from universal spring assortment from gas station, Zinked springs.


the Race Clutch i weight measured when new ,as i did also for std 3-shoe clutch. i just cant remember the weights atm. Anyway no weight problems meaning Vibrations due the Clutch weight.

the Aluminium alloy on the Friction arm will wear out around the Steel metal Pivot bolt BEFORE the Friction material will/would worn out. the classical problem with friction issue between Aluminium alloy and steel, "like a butter and knive".


Now i have offically started to build my 2nd MB, with Cag engine etc same simular parts as Current1.

bye:)
m
 
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gera229 said:
I'm using the metal gas tank that comes with the China Girl kits.

My next step is taking out that paper gasket which is stuck to the engine. I am afraid to scratch the engine.
Click to expand...

Make a scraper from a flattened out piece of hard copper pipe, sharpened with a flat file.
The copper is softer than aluminum' No matter how aggressive you scrape, you can't harm the aluminum. I used this method when rebuilding a Subaru auto engine.
Works great. Scraper dulls quickly, just keep touching it up with the file.
 
So I completed my project today. Runs great, but stalls in the very beginning I am unsure why. Started good after warming it up.

Looks like the spring that holds the exhaust pipe to the engine adapter causes that spot to leak.

Another thing I notice is that the fuel does not go and fill up the fuel line completely. The gas does not run through it, but I figured out why. It is because when the float bowl is all the way up it blocks air. I have the Dellorto carb clone (Does it happen to you?)
What size are the stock jets for the RT carb?
I used 87 octane gasoline for the first half a gallon for break in, but will switch to 91 octane after.

Another thing is that I revved the engine with the clutch housing off and guess what? The clutch smeared on the engine, a spring flew it, and it stalled (thank goodness). But the pad seemed to be ok although a little bit worn.

I fixed the springs and they hold good.
But, I cannot set the idle screw so that the engine does not turn off as well as so that the rear wheel does not spin. (The rear wheel spins if I pick it up, but if I put it down it stops spinning.)


Finally, the engine vibrates pretty hard, even at idle lol. (Maybe because I do not have shocks I can feel it so hard?)
 

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gera229 said:
So I completed my project today. Runs great, but stalls in the very beginning I am unsure why. Started good after warming it up.

Looks like the spring that holds the exhaust pipe to the engine adapter causes that spot to leak.

Another thing I notice is that the fuel does not go and fill up the fuel line completely. The gas does not run through it, but I figured out why. It is because when the float bowl is all the way up it blocks air. I have the Dellorto carb clone (Does it happen to you?)
What size are the stock jets for the RT carb?
I used 87 octane gasoline for the first half a gallon for break in, but will switch to 91 octane after.

Another thing is that I revved the engine with the clutch housing off and guess what? The clutch smeared on the engine, a spring flew it, and it stalled (thank goodness). But the pad seemed to be ok although a little bit worn.

I fixed the springs and they hold good.
But, I cannot set the idle screw so that the engine does not turn off as well as so that the rear wheel does not spin. (The rear wheel spins if I pick it up, but if I put it down it stops spinning.)


Finally, the engine vibrates pretty hard, even at idle lol. (Maybe because I do not have shocks I can feel it so hard?)
Click to expand...

Gera,
1st thing to do is fix your jetting before you fry the engine running it too lean. Not sure what the stock jet size is since it isn't labeled, but the stock RT carb has the perfect size already in there. I went smaller jet playing with it & cooked a piston & cylinder for a $50 lesson...
When I cold start my PB engines, I only need to choke them for about 5-10 seconds, then they run fine off choke w/ no stalling. The engine rpm's shouldn't cause your clutch to engage when idling, maybe you got it too high. Make sure your gas tank is breathing cause if it isnt, the engine will bog out & wont get fuel through the line (I made a gas cap modification to accept a fuel line breather tube & capped it with a dirtbike breather). To solve the exhaust leak, buy a small muffler clamp (got mine from McMaster Carr to clamp the pipe to the fitting). I also use 1/2" thick rubber skateboard riser pads & cut them to make engine mounts & exhaust hanger mounts to greatly reduce vibration into the bike frame. I got them on eBay & they work great. My full suspension bike gets very little vibration, but my no-suspension bike still gets some but not bad. Once I ran it with the exhaust solidly mounted & the vibration was horrible. Then went home & rubber mounted the exhaust hangers & solved that problem.
Your throttle cable could be a bit short or need adjusting if the idle screw isnt lowering your idle below the clutch engagement point.
-Lowracer-
 
Lowracer,
My point is not the throttle, it is that the clutch engages and if I turn the idle screw out, the engine does not even start. So yeah, might be loose springs (because on the first start I forgot to put the clutch housing on and the pull the throttle and the clutch went wayyy spread out and 1 spring flew out and the others probably loosened.

I do not know what jet size was stock so I am unsure and worried right now because I do not know how to measure them and I mixed the jets up. Thank goodness I only opened up the 75 jet and not the others. So I would know 1 is 75 and the other is stock.

I opened the gas tank cap and the fuel still did not go. (It is the float boal that stop it, when it is all the way up I noticed the air is blocked. When it goes down the fuel runs down the line just enough to fill the float boal.)
 
I hope I can get answers quicker because I am trying to complete this thing very quickly.

Oh to mention, my engine won't even start with choke on.

Lowracer you did not understand about the idle screw. It is lowering it, BUT if I unscrew it to the point where the sprocket does not spin, the engine will turn off.

Can you link me to the skateboard riser pads? I can't seem to find any that say rubber.
 
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The choke works ok.

So when I get the pads, I place them right under each engine mount hole?
 
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Use some big washers to sandwich the rubber pad & mount under each hole. Might need slightly longer bolts...
-lowracer-
 
Lowracer,
I don't understand why my engine isn't idling correctly without my clutch engaging, but my spark plug is black at the tip. What color is your plug?

You have never snapped a clutch spring? I snapped 2 already lol.

Using 87 octane.
 
Gera,
Not sure whats wrong with your setup?
My plugs are brownish (not black) running 40:1
I have never snapped a clutch spring & run 3 of these Cags many miles between the 3.
Now I will tell you this, the best running, most powerful cag of my 3 is on 'The Beast'.
These are all Stage 2 cags, but this one engine is just better than the other 2 (why I dont know)...It will do higher rpm's under load & just runs better & sounds better (all running premium no ethanol).
Not all cags are created equal?
-Lowracer-
 
Maybe because I'm running too rich? I'm running 25:1 for break in.

It runs higher RPMs? By how much? Lol. There's a guy that sells head kits on Pocketbikeplanet and he custom ported them. The price is very competitive compared to the ones that are Chinese-ported.
He says he lacks low range, but once it hits like 20 mph it FLIES in acceleration so good mid and top power. He has both single and 2 piece cylinder with 3 ports.
 
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