finally running!

[XSLevi]

THanks to much help from this site, my bike is finally running. -That is; it will start and idle. Issue I'm having now is that it pops & spits occasionally, and sometimes will backfire through the intake. Also, it does not rev appropriately when the throttle is opened.

I may have one or both of the following problems:

(1) Valve timing. Exhaust cam was misaligned when I got the bike. I lined the dots on the cam bosses up with the corresponding arrows, all with Piston 1 @ TDC. Before I started the bike, I forgot to cinch down the cam chain tensioner. After hearing the chain slap at idle, I tightend it down. This fixed the chain slap noise, but there is still an occasional "chunking" kind of noise that jars the whole bike. Is this indicative of valves hitting pistons?

(2) Carb tuning. I have just gone completey through the carbs: new jets, ran compressed air through all of the vacuum circuits, checked all pilot screws for broken tips, etc. I am sure the carbs are clean, but I am not sure that they are tuned correctly.

Please help, I know you guys will have some ideas.

[XS1100_OEM4ME]

Run

Was the bike ever turned over with the cams out of sync by you or PO? Did you remove the amulsion tubes when you cleaned the carbs (I had a back fire prob when just one was dirty) I wouldn't run the motor with that kind of noise till I knew what was up, could have skiped a notch when cam chain adj was loose, poping through the intake means finding out more before running again. You could pull the valve cover, check for jumped chain and check to see if any valves are sticking by hand turnning, might need to pull head to make sure nothing is bent good luck with your bike

THanks to much help from this site, my bike is finally running. -That is; it will start and idle. Issue I'm having now is that it pops & spits occasionally, and sometimes will backfire through the intake. Also, it does not rev appropriately when the throttle is opened.

I may have one or both of the following problems:

(1) Valve timing. Exhaust cam was misaligned when I got the bike. I lined the dots on the cam bosses up with the corresponding arrows, all with Piston 1 @ TDC. Before I started the bike, I forgot to cinch down the cam chain tensioner. After hearing the chain slap at idle, I tightend it down. This fixed the chain slap noise, but there is still an occasional "chunking" kind of noise that jars the whole bike. Is this indicative of valves hitting pistons?

(2) Carb tuning. I have just gone completey through the carbs: new jets, ran compressed air through all of the vacuum circuits, checked all pilot screws for broken tips, etc. I am sure the carbs are clean, but I am not sure that they are tuned correctly.

Please help, I know you guys will have some ideas.

[petejw]

I may have one or both of the following problems:

(1) Valve timing. Exhaust cam was misaligned when I got the bike. I lined the dots on the cam bosses up with the corresponding arrows, all with Piston 1 @ TDC. Before I started the bike, I forgot to cinch down the cam chain tensioner. After hearing the chain slap at idle, I tightend it down. This fixed the chain slap noise, but there is still an occasional "chunking" kind of noise that jars the whole bike. Is this indicative of valves hitting pistons?

that doesnt sound to good, pull the plugs out and give it a compression test,
if u havent got a compression tester, stick ur thumb over the plug hole,
if uve bent a valve u wont have any compression.

[Barnfresh]

an occasional "chunking" kind of noise that jars the whole bike. Is this indicative of valves hitting pistons?
.

YES! That is the sound of piston vs valve. And now you have a backfire - through the bent intake valve. Pull the head and save your engine... don't run it anymore. <voice of experience>

[cywelchjr]

YES! That is the sound of piston vs valve. And now you have a backfire - through the bent intake valve. Pull the head and save your engine... don't run it anymore. <voice of experience>

It can certainly be that. It can ALSO be a misfire. A key way to tell is if it's missing after that chunk. If it's not missing there is still an issue but it's NOT the valve hitting the piston as that will almost for sure cause damage the first time it happens.

[Barnfresh]

I know that sound. After we got mine running, and drove it around the block, it was sitting in the driveway at an idle and all of a sudden it sounded like someone hit the head with a ballpeen hammer. I Felt it all the way through the frame and handlebars. We all looked at each other like "What was that?" If I had faced facts and pulled the head, that engine would still be in the bike instead of the scrap pile. Instead we kept trying to tune out the miss & backfire - carbs, coils, sync, etc... At the very least do a compression test with all plugs out and WOT. Just sayin - better safe than sorry. Pulling the head is a one hour job with the engine in the frame.

[petejw]

if u didnt want to crank the engine over by the starter,
you could remove the valve cover and plugs, check the
valve clearances rotating the engine by hand,
if u have a bent valve/s it will be stuck open,
youll have a lot larger clearance. jat