66cc Flying Horse Tear Down

Fast Shag

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So I torn my top end apart last night to test out my new dremel tool on it....The stock jug looked amazing compared to most of the pics I've seen on here! There were no casting burrs on the ports or transfers! The transfer ports were lined up(mapped out on paper), had a good forward angle and the piston opened completely on intake and exhaust ports. All i did was blueprint, or round off all corners, matched header flange and intake tube. The SBP expansion flange was horrible! I roughened up the intake and tube for better atomizing, and sanded jug for a little more compression. I ran it good and hard today, finding little performance increase but low end throttle response was quicker. I worked on the head when I first got the motor. Going over to bro's house tomorrow to use his compression gauge. Hoping for 120-130psi. I'm very pleased with the quality of this motor! Looks like I got a good one!:whistle:
, PB070022.jpgPA300008.jpg
66cc Flying Horse
Cranbrook
SBP expansion chamber
41 tooth sprocket
blueprinted
33.4 mph on flats, climbs steep hills with ease
 
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The newer engines coming out seem to have corrected port matching, plus the transfer ports are angled much better, so we don't have to do Jaguars JB Weld fix any more. Nice job on the chain tensioner! If you haven't done it already, you'll want to remove the clutch shaft housing and clearance the inside, you'll see where the chain rubs on it. This mod greatly reduces those annoying pinging noises that sound like problems, but are just the cover echoing when the chain rubs on it.
 
That chain tensioner set me back about $4 at ace hardware! Thanks for the tip on the clutch housing. When I cold start it sometimes the rear wheel will lock up on me. Just a little backward push fixes it... But it did happen to me at an intersection once that really messed up my game. I'm using a #41 tractor chain and I think it's hanging up inside the housing when starting. Just another fun project with my new $10 Dremel!

I tested my compression today and it came out to 126 psi. Not too bad and still not a pain in the butt to start.
 
Purple, Explain " clearance the inside". I don't have a full gallon run through my 66 flying horse yet,so break in is still in process, but I hear all kinds of noices . As this is my first bike, i'm not sure what is normal ( in the typical sound perimeters ) for them. I understand that they may have some piston lateral movement sound, and the normal chain noise, so if I can eliminate any noices, that would be nice. Also if I could isolate "outside the engine" sounds, I could hear whats going on inside a bit better. Thanks for your input .
 
Million dollar question is how are you guys getting 40mph and up on these?!

lots of time and money for some, miscalibrated speedometers for others

for me it's lots of compression (172 PSI), lots of port work, a 19mm carb, ram air, cold intake, a 5 digit redline, and a very strong ignition with an aggressive timing curve
 
A good CDI is next for me but $80 for one is outrageous compared to the same price for a brand new motor! I'm trying to make this Ducati cdi work I got off my Piaggio Grande, but can't seem to get it going...
 
A good CDI is next for me but $80 for one is outrageous compared to the same price for a brand new motor! I'm trying to make this Ducati cdi work I got off my Piaggio Grande, but can't seem to get it going...

You are wasting your time, because the Jaguar CDI gives you the option of using 4 different ignition curves, as well as ambient temperature compensation.
The Jaguar CDI is well worth it's money. If it wasn't it wouldn't be fitted to my bike.
 
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