knok knok knok

[WICHOL98]

i turned my bike on and it knocked for a wile and one of the header pipe didnt worm up is my motor in need of a rebuild if so were can i get that done

[Rick V]

Don't be too hasty to write the engine off. Even if the engine has a knock that goes away like you said,it should run on all cylinders.What you need to do is a little checking. Is there spark on the cold cylinder? Does it have sufficient compression ? Is it getting gas? Check the spark plug and plug cap. A quick check is to switch them with a different cylinder to see if it stops running. If the spark plug is wet, it is probably getting gas.Get the engine running on all four first and if the knock persists ,that is the time to consider a rebuild.Remember to look for the easy things first.

[WICHOL98]

there is spark and i checked if the plug was wet and it was not dry but not soaked either  and it runs the same if the plug wire is on there or if its not. the bike was siting for a long time when the idle is very low u hear the knok  but if its a lil higher its not loud

[Rod_Knockin]

rick v is right on you have a dead cylinder. I had the same issue. My issue was in the carb. At idle the cylinder wouldn't fire. Once I would get above 3000 rpm the cylinder would kick in. 1st do a compression check on the cylinder. This eliminates burnt vales, bent valves, poor valve lift. Compare to other cylinders. A cylinder only needs 3 things to fire. Spark at the right time, compression and fuel. If the compression check is ok. Swap the spark plug with another cylinder. Swap the plug wire. swap the coils. Do these one at a time to get the issue to move to isolate the bad part.  With it being only 1 cylinder I'm going to bet on the carb as 2 cylinders share a coil. Mine ended up being the slow speed jet plugged. The only reason I suggested to try the spark first is that its easier to do than the carbs. What cylinder is it? Mine was #2. I speculate this was caused because its the first carb to get fuel and the first carb to get crap in it.

[WICHOL98]

wut should the compresion be on all cilinders

[gonebiking-2]

As these engines only have a 9-1 compression ratio, I`m taking a guess that they should all be around 160 -175 PSI per cylinder