BRAND NEW YD100

GreasyChris

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Joined
Jan 3, 2019
Messages
1,268
My Raw Racer 100 locked up today with less than 100mi. on it, good luck!
thats a craapy deal,sorry to hear that. did you happen to look if they installed the piston correctly before using? there have been lots of reports about the pistons being installed backwards
 


MTBNewf

New Member
Joined
Jan 19, 2020
Messages
27
thats a craapy deal,sorry to hear that. did you happen to look if they installed the piston correctly before using? there have been lots of reports about the pistons being installed backwards
once again, for clarity, what is the correct orientation of the ring pins?
 

CrazyDan

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Jul 9, 2016
Messages
2,723
once again, for clarity, what is the correct orientation of the ring pins?
You want the ring gaps to be where they won't pass a port. If the piston is on backwards, the gap will pass a port and get hung up. The arrow on the piston might be marked wrong, don't go by the arrow.
 

GreasyChris

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Joined
Jan 3, 2019
Messages
1,268
Piston and head have to be installed. Ring gap toward the intake, Disassembled and found a large groove in cylinder near exhaust. will post pic later.
your circlip that holds the wristpin in broke off and gouged your piston and no doubt your cylinder, youll need a new piston,rings,circlips and cylinder. never reuse the circlips or that will happen again.
https://www.cdhpower.com/yd100-cdh-cylinder-50mm-two-in-one.html
you can find the parts you need here
 

headleyjoey

New Member
Joined
Mar 25, 2020
Messages
1
I heard they (yd100's) come with the piston installed BACKWARDS,... so the first thing you need to do is GET THAT JUG OFF AND CHECK.

and while youre there,...turn the engine upside down and give it a thorough, solid 20 second shake. you would be amazed what gets past Chinese quality control (cigarette butts,...metal chunks,...etc...) people have found insane debris in lower ends over the years. don't get burned. 20 seconds.

i would skip the belt drive idea until your second or third build. by then you will better understand these things front-to-back,...and what is neccessary,..and what just isn't.

my yd-style motor (pictured) got me from Poughkeepsie ny. to richmond va. and back..... thru the crazy state of pennsylvania twice,...which is nothing but insane hills after insane hills. on an overloaded 29" surly cross-check bicycle.

yd's are the real deal.

i'm not defending zeda,...BUT,....lots of people have had horrible, horrible experiences with zeda's customer service,...so remember to factor that into your interpretation of the overall general opinion of your particular motor.
i have the yd100 got it from bmw the position was on backwards changed that sucker around cut out transfer walls redirected them ported intake and added third transfer also boost port opened up and reshaped exhaust port raised and dropped both ports windowed my piston and cut the cylinder mounted me a dio reed yeah baby dio on it and run a 28mm vm24 round slide carb and it's a straight beast
 

mony0_3

Member
Joined
Jan 18, 2020
Messages
51
i have the yd100 got it from bmw the position was on backwards changed that sucker around cut out transfer walls redirected them ported intake and added third transfer also boost port opened up and reshaped exhaust port raised and dropped both ports windowed my piston and cut the cylinder mounted me a dio reed yeah baby dio on it and run a 28mm vm24 round slide carb and it's a straight beast
L hope you didn't use the piston cir-clips that came with it. They break and ruin the top end!
 
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