Cdh66, zeda88, bbr expansion chamber header shortening

Joined
Sep 26, 2018
Messages
117
Hey guys.
I've been looking around at different expansion Chambers and the mz65 Chambers are a tad expensive compared to the other, lower end tuned pipes. Has anyone shortened the longer header pipes? Is it a good idea for tuning flexibility?
 


M

Mikeee P

Guest
A shorter head pipe gives you more top end at a loss of bottom and mid-range on an expansion chamber.
 
Joined
Sep 26, 2018
Messages
117
Update to this post, I went for a YZ85 pipe with an effective range of 3,000 to 7,000 rpm. Power peak 5000-7000 rpm. Header elongated by 2.5 inches
 
Joined
Sep 26, 2018
Messages
117
Pictures?
I blew the engine, got a new bottom end from CR Machine and made a new engine, and broke my bike frame in half (DIO Reed, 21mm oko, 38mm stroke with 0.6mm squish, CDH power high compression head). I'll try to post the new bike once it's remade. But first, I need to get a 32-29 tooth sprocket because the old frame was a 28 inch and the new bike is a 26. Plus, I topped out at 35mph approx. Way too quick for me.
 
Joined
Sep 26, 2018
Messages
117
35 is too quick and you want the toppest speed sprocket you can get? lol
No, lmao! I hit 35 too quick and the power hits a wall because the pipe is out of range. So I'm raising the power band up by putting a smaller sprocket. Because a 41 on a 28 inch (my stock setup) is very similar to a 36 on a 26 inch. So 36 isn't going to cut it and 32-28 teeth seems to be a better option for my riding.
 

JerboaJohn

Active Member
Joined
Jul 29, 2018
Messages
559
oh I see what ya mean now,, I run 40T on my 700c, the calc says it's really close to 37t on a 26",,
32T will def get you on the pipe @ 40mph!
go fast or go home!
 
Joined
Sep 26, 2018
Messages
117
oh I see what ya mean now,, I run 40T on my 700c, the calc says it's really close to 37t on a 26",,
32T will def get you on the pipe @ 40mph!
go fast or go home!
Yah, I had a boat load of torque and could climb any hill with ease on the "36" tooth. Its just people here are fast and they aren't too fond of me going 45 mph with a tailwind downhill. So it's time I gear up for traffic.
 

Sumsloppymeet

Active Member
Joined
Aug 7, 2017
Messages
405
i prefer keeping a 32t perfect if you weigh around 160 im not even running a matched crankcase and cylinder i literally did nothing to the bottomend im using right now only ported the intake and exhaust ports to match mz65 exhaust, oz reed, and mikuni vm18 on my current set up and this 2016 grubee ES does a cruising speed of 50+ easily i cant wait to put this gold one i just finished polishing and totally reworking the bottomend on running i feel itll do 65 if my guestimation is correct
 

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