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Need INTAKE MANIFOLD on Honda Z50a K3 model with 72cc top end

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72cc carb ct70 intake z50
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HondaSL

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Discussion starter · #1 · (Edited)
Picked up a project Honda Z50a monkey bike where the PO cut into the neck of the frame to fit the OEM stock CT70 carb and intake to the 72cc upgraded top end(Z50 bottom end). Creative...Yikes. After the frame gets repaired, I will need to refit the carb to the engine & have read a few options like:

1-shaving the bottom of the current CT70 straight, right turnout intake around 4mm and that should give clearance & angle change enough. Or cutting the intake, turning & welding it to desire.

2-using the (20mm is what i need) 12-way rotating spacer CHP/TBowlt sales. But I have read that the extra height is counter-helpful.

3-Using a new intake which is left bending and low seems to be the best option if possible. Does anyone have experience with this issue and found a intake manifold which works? I have read TB sales a few (i believe the OEM Klein carb i have currently is 18mm)
AND?OR the Honda ATC 70 intake manifold may seamlessly (maybe Honda TRX70 too?) which have a left turnout


So any wisdom is appreciated here. I just need to mount it the best & cheapest way. And #3 is the preferred method. I figures someone out there has something that works & can point out where to order similar.
Also using the racing (right hand) petcock and raising the rear of the tank are the cheats of the tweaking i'm planning to need in the final hours.



edit:images added

 
#2 · (Edited)
Easiest option, get a TB intake manifold for stock head and but you will also need to buy the TB right angled fuel petcock as the new carb location clashes with the straight down exit factory petcock.
The TB stock head manifold tapers down from about 20mm at the carb to around 13mm to match the intake on a 50 head, if a 70 head is fitted you can open it up a little to match the intake opening on the head to gain a little more umph (0.05565 hp??) and get the best flow and make the most of the bigger (than a 50)carb and bigger valves of the 70 head. There are plenty of chinese 50/70/90/110 manifolds that will work but its one of those things you need to see in person and work out what will and wont fit where as the TB stuff has been done countless times before by z50 guys and known to work. If there is a local pit bike parts shop you can grab a few manifolds cheap, and trial fit to see what works. I have put a 125 with a chinese mikuni 26mm and a random manifold under the same size tank just by opening up/slotting the mount holes with a small round chainsaw sharpening file so i could spin the carb so the top cable exit from the carb ends up between the tank and the frame and putting a spacer made out of 8mm rubber under the rear tank mount. If you just want to get it going asap, you could change the angle of both ends of the 70 manifold with a belt sander or similar to get it to sit level, there's plenty of meat to be doing it to the base especially, then just adjust the angle of the mount bolt holes so you can tighten it down flush on its new angle
 
Discussion starter · #9 ·
good question. i've noticed the exhaust didn't not have the front heat shield like stock. I believe its aftermarket since i can't find OEM stamping or any ID numbering on it. It looks legit & fits flush though.
 
#10 ·
HondaSL said:
good question. i've noticed the exhaust didn't not have the front heat shield like stock. I believe its aftermarket since i can't find OEM stamping or any ID numbering on it. It looks legit & fits flush though.
View attachment 224818
Click to expand...
HaHa. Looks like a CT70 muffler that has been cut at the head tube, turned around backwards and welded back on.
 
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