146cc BBK Problems.

[Dabomb]

went to install the 146 kit and big valve head today.

first time i had no seal between the head and barrel, leaked like a siv!

second time put the seals in and it didn't leak, but now it has a loud tapping noise, the timing is correct (checked twice), the valve clearances have been adjusted, still have this loud tapping noise...

didn't pay much attention to the head gasket sarga, will check that to be 100% sure.

could it be the piston hitting the head gasket? had a quick look, nothing obvious came to mind. it runs, but it wouldn't run if it had incorrect timing or a bent valve so im stumped.

 

[crazzy #1]

whats the distance between the spark plug, and piston at tdc? that and incorrect timing is the only real thing i can think off... could be a fuel knock? dont know... check the spark plug though

 

[Dabomb]

that would of stopped the bike from running and it hasnt failed to start yet.

heres a video of it running:

YouTube - Motovert RX BBK 146cc Kit Noise

 

[PocketHead]

my guess is it's the valves, maybe try other settings

 

[Dabomb]

gunna set them to 0mm gap to make sure its not the valves makin the noise.

 

[Panda_ET]

sounded like mine when i adjusted the exhaust valve wrong

 

[themountain]

what gasket do you use and what cam are running in the head??

 

[coolmodee01]

yeah what mountain asked is needed

your piiston may be hittig the valves you may be running to thin a gasket

maybe

you could also have a bent valve and it could be sticking open and the piston knocking

actually listening to the vid (shoulda done that first) have you re tensioned the timing chain after putting the new head on as it sounds more like chain slap than a tap

hope ya get her goin it sounds pretty good

 

[50freak]

Put the cam in the wrong way???

Happened to me and I had a loud tapping noise.

 

[Stubsy]

i agree with cool, sounds like cam chain slapping. thats what happened to mine when i took out the gasket. put a thicker gasket in if you can

 

[Dabomb]

what gasket do you use and what cam are running in the head??

using a Akuna A2 Cam and this headgasket on the right

yes i had removed the cam chain tensionpr and re tightened it.

 

[Dabomb]

Put the cam in the wrong way???

Happened to me and I had a loud tapping noise.

how can u put the cam in the wrong way? it wouldn't run?

 

[Dabomb]

i agree with cool, sounds like cam chain slapping. thats what happened to mine when i took out the gasket. put a thicker gasket in if you can

where the hell do i get a thicker head gasket for it?

 

[themountain]

"how can u put the cam in the wrong way? it wouldn't run"
actually it can!!

sorry to ask again, but what cam do you use??....and is your engine a lifan or a GPX bottom??

 

[Dabomb]

"how can u put the cam in the wrong way? it wouldn't run"
actually it can!!

sorry to ask again, but what cam do you use??....and is your engine a lifan or a GPX bottom??

my cam is an Akuna A2 Cam 6.7mm lift, its a jialing bottom.

 

[themountain]

aah..I see...and the base gasket you use is??
well...the problem is that your piston is forsure for small valve engine...you got that fat a$$ valve lifan one....so the compression is out of the roof...get a 1mm basegasket and you will be set!!
besides that I assume you got heavier valve springs too, have you?? if not better get some!!

 

[Dabomb]

i am runnin a lifan BVH 27/23 and HD valve springs.
im using the base gasket that came with the kit.

 

[themountain]

look at this post...maybe helpfull!!
146 tb kit? - Planet Minis

 

[Dabomb]

wats running a thicker bas gasket gunna do? it dont leak between the case and the cylinder base?

gunna take the head off and take some photos in 5mins.

 

[Dabomb]

heres a photo of the head gasket... see anything suspect?