MY GILERA 172 WONT START (PLS HELP)

Hello people, i have a prob with my bike , just had a rebuild first night i put petrol in bike it started drove it around for 20 mins or so , went bed woke up in morning first kick and bike started got to end of road and bike back fired as far as i can remember and then just cut out, tryed kicking would not start been unable to get the bike started since..today i took spark plug out and it was wet and black , went got a new spark plug and try kicking bike and still wont start any help please....

 

just did a compression test on my gilera runner 172 here is the results can anyone tell me if this ok or not?? thanks

 

that sounds mega low im sure its 120 ish for decent compression.

as for the description my runner 172 did the same but would start after the backfire, check your reeds. my carbon reed had snapped into the engine whilst idling. i had to fish it out before it did damage. I would check yours. if it has gone into the engine whilst driving it may have caused a lot of damage to the barrel.

pop some oil down the plug hole and test the compression again, it should spike right up, this will indicate damaged or worn rings.

 

also when i take spark out and put it in cap and kick it i dont have a spark, got 2 brand new spark plugs same thing with both

 

that compression is seriously low , when you took it out did you take it easy or did you just rag it for 20 min straight if so you have probably just fucked the new top end and as cream soda said check your reeds are ok and are not broke or stuck open , my rs50 with fucked piston rings and a leaking head gasket still put 60 psi on the pressure gauge

 

as for the none sparking issue that can be down to faulty cdi / coil / ht lead /cap , faulty stator plate and so on but id sort that compression problem out first

 

ok thanks for all your replys, and no i just had a new engine rebuild the first night i put it togther it started and drove around for 20 mins or so and parked up went bed woke next day it kicked first time got to end of road and from what i rememeber it made like a back fire sound then bike cut of and was unable to start it again, i just tryed a new plug and kicked it and it gave me a slight shock no blue spark tho, and about the compression should i take the top end off first?? or check the reeds?? or do both i just had my engine rebuilt by shiny red and didnt want to start taking the engine apart if the top end isnt the prob

 

is it a good idea to attempt to start the bike with starting spray??

 

nope, as that compression isnt a fueling issue.

take the reeds out and look at them, simply undo the 2 bolts on the carb inlet and pull it off then the reeds will slide out, inspect them for cracks etc and make sure they are closed, there shouldnt be a gap.

if they are fine its time to get that head and barrel off i think as somthings not gone well.

as for the spark, are you touching the spark to the top of the head where the spark plug goes? if your just holding it it wont spark but will shock you lol, rest it on the head and kick it and have someone look for you.

 

That compression is seriously low ! My Piaggio nrg 50cc pulls out at 126 PSI and runs like a beauty As Creamsodauk said, Check the reed valves. However Normally lack of compression is to do with Piston rings or is related to something else. Like score marks in the cyclinder allowing air to go through therefore no compression. Replace the top end and it should work. Well thats if you get a spark of course

 

Mate I have same problem think it's spark plug if u find out what it is let me no as I got same problem lol headache

 

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