knocking-need help!

[cheezy]

well, i cleaned the carbs, and proceeded to crank it over and try starting. cranked for about 30 sec, and she sputtered to life. then i noticed the high pitch knocking. the bike ran fine about 3yrs ago, but sat untouched until now. i checked the oil before i started it. the bike has only 16k mi on it, so i don't think it's piston slap. it sounds like it's coming from #1 cyl. i've never dug into an engine like this before. any ideas? i have $100 stuck into the bike(title fees), so i'm really not out any money yet, and i'm not sure how far i want to go with this bike. cosmetically its pretty rough, needs paint and tlc. what do you guys think, a bad valve? i'm really bummed out right now, i wasn't expecting this, i figured i'd have it on the road soon. good thing i still have my nighthawk!

[dbeardslee]

As a rule, these heads tend to be a little noisy. First thing to do is make sure the cam chain is properly adjusted. They get real noisy when there's too much slack.

[motoman]

Don't know what idle rpm you've set it at, but 1100rpm's is where you should be, at least close to that. Set that after warmed up and see that it stays steady, no fluxuation on the tach. If it does, there is several other small issues, all carb related cept for one.....cam chain adjustment, if not set correctly(tight), can and will cause a lope and a bit erratic at idle. So, as you see, there can be several minor issuses causing your symptoms.

[tinman905]

If you haven't changed the oil that would be the next thing you might want to do if you plan on staring it again. Get a can of Sea foam and read the directions and put some in through back of the carbs let it sit for a while and start it up again that will clean some of the crap out of the combustion chambers.

[latexeses]

Be sure and get a manual from the link on "CatonicBug"s signature line before you mess with the cam tensioner. Follow the procedure carefully. Bad things can happen if done improperly.

[Crazcnuk]

Try unplugging the vacuum advance hose and plug the port and listen (while running of course).

The advance unit can really knock if it is hooked up to the wrong port.

[perurider]

Mine had really loud engine noises when i first got it running, so much that my stomach turned thinking oh nuts. but after it ran and everything got moving it got quieter. The loping that someone was talking about cam chains need adj., mine lopes at idle, I like it, too bad its a bad thing. Is there a pictoral on cam chain adj? pretend i am from missouri and show me!

[cheezy]

i'll try to set the cam tension tomorrow. i thought of that after i was at work tonight. thanks for the suggestions. will the bike still run with bent valves, or a broken valve spring? when i increased the rpm, the noise seemed to quiet down, and was more noticeable at idle, around 1krpm. i used a splice and hooked up the advance to the vac line on #2. i don't have the octopus rig on, just a bottle of gas splitting off to the fuel inlet tubes. when i accelerate, the bike sounds clean, although i only ran it for 30sec to 1min. well, i'll know more tomorrow, here's hoping for the best!!

[latexeses]

will the bike still run with bent valves, or a broken valve spring?

Let's hope you don't have to find out.

[Crazcnuk]

Technically, the only way to bend the valves, normally, is if the cam chain slips. If this happens then it will hit all 4 valves, either int or exhaust, and then it will not run.

In the two I have had with this problem neither would even fire.

[dbeardslee]

If the carbs are far enough out of sync you can get some really interesting noises out of a motor. You mentioned cleaning the carbs - did you adjust and vacuum sync them afterwards?

[cheezy]

ok, here's where i'm at. i pulled the plugs, rotated the engine to the "c" mark. i loosened the 12mm nut on the cam adj. i tried to turn the 10mm bolt in, and it feels like it's bottomed out. i backed it out 1/2 turn, and i was able to get about 1/4 of a turn past the start point. i'm thinking i may have to replace the cam chain. but before i do that, i will set up my color tune plug and adj. the a/f mix, then i'll sync the carbs. i guess i never thought that the carbs could be giving me a knocking sound, but i'll go through everything that i can before i start taking engine covers off. i'll post updates as i go. we have a bunch of family stuff this weekend, so i'm not sure how far i'll get. what will a broken valve spring sound like, and can i check it by removing the valve cover? thanks everyone, i really appreciate the advice. i can't afford a new bike, so i really want to turn this one into something "special"(get it, midnight special...

[dbeardslee]

I doubt seriously that you've got any broken springs. If it sat for three years chances are one or two of the valves were open during that time. That means that on the valves that were open the springs have been compressed the whole time. That could cause them to be a little on the short side of the specs, but again, I kind of doubt it - particularly when the motor only has 16k miles on it. The other thing - that probably did happen - is that the seating surfaces of the open valves probably have a little rust and minor pitting on them. That's going to affect the seal, and also the draw through the carbs, which affects the sync. I think you've got the right idea - do the simple stuff first, and make sure everything is properly adjusted, and go from there.

Also - be careful with that cam chain tensioner - it's only supposed to have 5 foot pounds of torque on the center bolt (10mm), and maybe 7-10 on the locking nut (12mm). Too much torque can easily strip the threads on the tensioner - steel bolt in an aluminum hole and all.

And lastly - when I adjust my carbs I do the sync and colortune at the same time. I connect my gauges and adjust the sync, colortune with the gauges still attached, and then do a final tweak on the sync. The sync and adjustment both kind of affect each other, which is why I do them together. JAT

[motoman]

cheezy! Your headed for catastrofic engine failure. Rotate that crank in the direction of the arrow to TDC, loosen the lock nut, LOOSEN the bolt a bit and you may hear a slight tick noise. Tighten bolt(it is like a set screw so to speak) CAREFULLY as the housing is aluminum and WILL strip easily. Snug is good, then hold that in place and tighten lock nut. Internal that is a spring loaded tensioner and the rod portion has a flat side full length for bolt to seat against, like I said, it is a set-screw holding the spring loaded tensioner in place. VERY important you follow correct steps or your "special" no longer will be special!

[cywelchjr]

i'll try to set the cam tension tomorrow. i thought of that after i was at work tonight. thanks for the suggestions. will the bike still run with bent valves, or a broken valve spring? when i increased the rpm, the noise seemed to quiet down, and was more noticeable at idle, around 1krpm. i used a splice and hooked up the advance to the vac line on #2. i don't have the octopus rig on, just a bottle of gas splitting off to the fuel inlet tubes. when i accelerate, the bike sounds clean, although i only ran it for 30sec to 1min. well, i'll know more tomorrow, here's hoping for the best!!

That will cause a knock. It doesn't go the the same place that the octo would have gone, that should be plugged. it goes to a connection ON the #2 carb, not to the carb boot. If it goes to the boot it will bang back and forth violently at idle and appear to smooth out at higher RPM's.