did valve clearances, made my sons bike worse????

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all good mate, i really appreciate the help :) im not to sure where that tab was il check it in the morning, a little cold at my house out side atm
 
this may help you master spanner spinners?
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i know you have adjusted valves before, but when you turned it over to TDC, was the spark plug out?

sometimes they can turn over a bit and then when you adjust it they be out.

if it did, it may have bent a valve ?


as the valves bed in and get a bit of use, they seat deeper into the head, causing less clearance.
this will make the rocker noise less though.
and will start making the bike harder to start, especially when warm.
 
yeah i did have the spark plug out when i did it, do you reckon its got a bent valve? i will say tho it still has plenty of compression, and starts really easily, all though i havnt ran it for long enough to test warm start
 
do you no what style exhaust port the v2 heads have? considering buying that as dhz didnt seem to have valves for the gpx head. also will a oko 26mm carb fit the tb inlet manifold and adapter?
 
V2 is Klx port mate. Yes an oko will fit a tb manifold with adaptor.

What's a GPx head? Isn't it just a yx?
 
i think just for peace of mind,
i'd be pulling the head to check things out, you can reuse your head gasket etc.
check for bent valves, and worn/wiped rockers


i tried searching for the GPX125 head too, i couldn't find many parts that were specific to it.


i thought they might have been just a Lifan Big Valve Head, 28mm inlet/23mm exhaust, and better camshaft maybe ?
i'm pretty sure they run the Zongshen thin head gasket for better compression ?
but going by some pics, they seem to have the Ducar style screw in rocker covers ?


i have a spare pair of 28/23 valves that might fit ? you can have them for the price of postage if they do.
i can measure them up, but will need to know your measurements too.
 
really appreciate the offer mate, il pull it down in the next couple of days and see if they are suitable. if not i reckon il invest in the v2 head, just means my bike build goes on the back burner again :bigcry:
 
gottagetacheaperhobby said:
do you no what style exhaust port the v2 heads have? considering buying that as dhz didnt seem to have valves for the gpx head. also will a oko 26mm carb fit the tb inlet manifold and adapter?
Click to expand...
firepower minis would have some..

yeah 26mm will fit no problem
whats different about the "gpx head" same as zongshen?
 
i have no idea if there even is any difference between them, i just havnt found anything that says suitable for gpx etc and dont wanna **** it any more than i already have. there doesnt seem to be a great deal on the gpx hi comp engine, i cant seem to find any parts for it, like head ,valve springs etc all i have found are the piston and ring kit. tbh i reckon as soon as i have the coin il just buy a v2 and exhaust as i really want to see how much the v2 opens the gpx up. plus i reckon it will teach my ten year old the meaning of 'threottle control' lol
 
I don't know a whole heap about engines so bare with me I'm just trying to help. But my atomik had the same problem when I put a new carby on it, it would start fine and idle but once I got past 1/4 throttle it'd backfire and miss and all sorts of carry on. I took it to my local pit bike shop and the guy fixed it and told me that he did the valve timing, tuned the carby and cleaned the carby. Now it runs like a dream and hasn't had a problem in 3 months


Sent from my iPhone using Tapatalk
 
TYE said:
I don't know a whole heap about engines so bare with me I'm just trying to help. But my atomik had the same problem when I put a new carby on it, it would start fine and idle but once I got past 1/4 throttle it'd backfire and miss and all sorts of carry on. I took it to my local pit bike shop and the guy fixed it and told me that he did the valve timing, tuned the carby and cleaned the carby. Now it runs like a dream and hasn't had a problem in 3 months


Sent from my iPhone using Tapatalk
Click to expand...
it would have been valve clearances most likley
thats what happens when they get tight
also could have just been crud in the carby
 
yeh me atomik fury had this problem, also my 125, both were a pilot jet blockage. once cleaned, both bikes rev freely, no backfire, no problem at all :)
 
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