Starting again!

Spring time rides had me questioning the engines strength on my personal/race bike,It was still running well but lost some pull after over 1k of hard miles. So I figured time to rebuild again and since I had to pull the engine I figured might aswell take it all apart and start over since it has been 5 years since it was first built I think it was due!

 

[Street Ryderz]

MZ 65 belly pipe conversion!I started by using a thin cutting disc to cut through the center of the welds,Once sectioned I was inspecting the welds and the amount of slag between the joints.At the first step from header into the first formed radius they left a half inch lip inside and just filled around the mismatched dia.At the next step again a formed radius the slag between the joints had an 1/8th of an inch inside or more in some places blocked.Not so bad for the initail pulse but terrible for the return wave,many are suprised that they work as well as they do seeing these flaws.I cleand every thing up and am using a slightly larger header dia had to to match my port area and the down tube is just slightly bigger as well,the total lenght has been shortened by 3 inches because the stock pipe hit at around 6k and that's just to low for my setup I'm hoping that it will now hit around 7k I'm curious to see how this pipe will perform with a modded engine.I also have one fully stock untouched on a stocker engine to evaluate it in it's intended form and that one works pretty good but doesn't like the stock cdi's timming or the unbalanced crank it really pronounces it at higher rpm!

 

[Spare_Parts]

I noticed all that junk when I cut mine up

 

[gary55]

MZ 65 belly pipe conversion!I started by using a thin cutting disc to cut through the center of the welds,Once sectioned I was inspecting the welds and the amount of slag between the joints.At the first step from header into the first formed radius they left a half inch lip inside and just filled around the mismatched dia.At the next step again a formed radius the slag between the joints had an 1/8th of an inch inside or more in some places blocked.Not so bad for the initail pulse but terrible for the return wave,many are suprised that they work as well as they do seeing these flaws.I cleand every thing up and am using a slightly larger header dia had to to match my port area and the down tube is just slightly bigger as well,the total lenght has been shortened by 3 inches because the stock pipe hit at around 6k and that's just to low for my setup I'm hoping that it will now hit around 7k I'm curious to see how this pipe will perform with a modded engine.I also have one fully stock untouched on a stocker engine to evaluate it in it's intended form and that one works pretty good but doesn't like the stock cdi's timming or the unbalanced crank it really pronounces it at higher rpm!View attachment 83376View attachment 83378View attachment 83379View attachment 83380View attachment 83382

Bad assed bike as usual.

 

[Street Ryderz]

Bad assed bike as usual.

Thanks Brother!

 

[FurryOnTheInside]

Clean your lens!

 

[Street Ryderz]

Clean your lens!

I know right!LOL it's just my phones camera it's old and doesn't adjust to lighting very well.The gopro take's great pic's but has no veiw finder or screen to see what your shooting,so I've been using the phone so I can use the zoom,auto focus and such.

 

[Spare_Parts]

So how long is your header? I imagine it looks so long because you straightened it out?

 

[Street Ryderz]

So how long is your header? I imagine it looks so long because you straightened it out?

Yes it's a bit deceiving,it's 9 and 3/4 inches. Some of what I've found so far is that the MZ likes to be much leaner than my previous pipe and dosen't hit as hard (pull) with a very narrow band width of around 2k rpm, when it is pushed past it's peak it's way to lean not having the extra charge the pipe delivers.The shortened length of header that should have shifted the peak up higher didn't really the chamber get's pressurized to soon and it still hit's early.

 

[Stoneman]

im learning that knife edging the cylinder on a piston port is not ideal and i tend to agree, a rounded edge makes much more sense if you think about flow

i doubt its a big game changer though

 

[Street Ryderz]

im learning that knife edging the cylinder on a piston port is not ideal and i tend to agree, a rounded edge makes much more sense if you think about flow

i doubt its a big game changer though

My referance to knife edging is for the rod to reduce the turbulance caused by it's passing through the charge, if you look at the pic's above the transfer area of cylinder base is both it has a thin edge with a cruved radius into the track.