My CB200 Build - AKA "Incognito" - UPDATE MARCH 21 - VIDEO PROOF THAT IT LIVES

Re: My CB200 Build - AKA "Incognito" - UPDATE MARCH 20 - MORE PHOTOS

Also, milling it off the head increased the compression even more so, because it reduced the volume more than off the block would, because it flares out where the piston is supposed to recess. We milled it to the point where it was just about the the valve seats. If that gives you any ideas. I can't speak for milling off the block.

However, teazer generally knows what he is talking about, so if you want specifics and scientific data.... go to him. I am just speaking from personal experience from my cb200 project. I did not heed all the words of caution, and decided to just go for it. I made sure I had plenty of clearance by doing the "Playdoh" clearance test. I don't know my specific numbers, b/c neither I nor the machinist knew quite what the typical changes should be. We just kind of did the milling based off of assumptions and guess work. It ended up working out quite well. But I do know he took of 1mm from the head. Hope that helps!
 
Re: My CB200 Build - AKA "Incognito" - UPDATE MARCH 20 - MORE PHOTOS

alec.korver said:
No I did not have to make room for valve clearance. Its hard for me to get a compression reading b/c it is so high, I would have to put the compression tester in the bike and push it down a hill in first gear.... Maybe I will do that. But before I had the engine in the bike, my cold compression was 190 post milling. So my hot compression is probably around 200+.

I had 1mm taken off of my head. It was not milled off of my block. So far, no clearance issues or anything. Everything is working SPECTACULAR. Don't take off too much.
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you are making me laugh I have a spectacular picture in my head with you doing a compression check going down hill...video please! Are you using copper gaskets?
 
Re: My CB200 Build - AKA "Incognito" - UPDATE MARCH 20 - MORE PHOTOS

Texasstar said:
you are making me laugh I have a spectacular picture in my head with you doing a compression check going down hill...video please! Are you using copper gaskets?
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ok how fast does you cb go with a mad scientist that is 6'5" and have you considered Kevlar undergarment...oh never we can tell you have major titanium balls :)
 
Re: My CB200 Build - AKA "Incognito" - UPDATE MARCH 20 - MORE PHOTOS

http://youtu.be/GiqIB4NBCGM this is the way we started our twostroke gokart after my dad notched the pully and almost broke his hand trying to start it with a pull rope
 
Re: My CB200 Build - AKA "Incognito" - UPDATE MARCH 20 - MORE PHOTOS

Haha, No I am running new stock gaskets. I'll try n take a vid of the bike running today. Probably not going to be shooting a video of my compression testing methods... Seeing as I haven't tried it yet! All I can say is that you will be very happy that you milled your head down. My bike has no problem getting up to 60 in 4th gear. Pre rebuild 60 was my max, 65 in 5th gear on a slight down hill. I would assume that My new top end is somewhere around 85. I still have yet to test that out... I haven't really put on my speedometer or tachometer yet... Can really only judge my speed by the traffic around me. I'll try not to let them ride over my titanium balls when I lay it down on the pavement though.
 
Re: My CB200 Build - AKA "Incognito" - UPDATE MARCH 20 - MORE PHOTOS

http://youtu.be/tHDfDL-BoZA


Sorry I couldn't have a full run by, My street if very short, and by the time I get to my house, I need to let off the accelerator and hit the brake.
 
alec.korver said:
Also, milling it off the head increased the compression even more so, because it reduced the volume more than off the block would, because it flares out where the piston is supposed to recess. We milled it to the point where it was just about the the valve seats. If that gives you any ideas. I can't speak for milling off the block.
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I agree with your try and see approach. In the final analysis that's what you have to do. Try it.

In reality taking 1mm off the bore will reduce the clearance volume by more than machining it off the head. The difference is small while you are machining the squish band though. I prefer to match the squish band to the piston and carefully manage the squish gap but that's another refinement that isn't always 100% necessary. It does generate better turbulence in the combustion chamber and more torque, but it's not a big thing and it takes a lot of work.

On one motor the head was machined into the valve seats and then we cut a squish band and recessed the valves and machined the block and the pistons. On a race motor that helps us to keep up with the big bore cheaters, but on the street that's a lot of bucks for not a huge extra bang.

In the final analysis, it's about having fun and enjoying the ride, not about bragging rights from a dyno pull. That bikes sounds nice and if you are enjoying it, case closed.
 
Thanks teazer, you have been a big help along my build. I have spent a lot of time reading your posts. However, I do not think that it will ever be case closed.... It is just too much fun to wrench on these bikes.

Question for you:

The popping you hear from the down shift, engine braking, whatever you wish to call it. What is that from? Is that bad? Is it fine as is?

Thanks man.
 
Popping in the exhaust on overrun is usually caused by an air leak in the exhaust. It might be at the header to head gaskets or where pipes meet mufflers. It can also happen if the low speed ie pilot jets are too lean.
 
Is it damaging anything by riding my bike like that? Ideally I will probably isolate the leak and fix it, but I don't want to damage my engine by having fun with my bike.
 
A run to end of the street and back is unlikely to do much damage but if it's lean it's running hot and one day will be a problem.
 
Re: My CB200 Build - AKA "Incognito" - UPDATE MARCH 20 - MORE PHOTOS

alec.korver said:
http://youtu.be/tHDfDL-BoZA


Sorry I couldn't have a full run by, My street if very short, and by the time I get to my house, I need to let off the accelerator and hit the brake.
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sounding sweet and looking good!
 
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