Got it started, but now a not-so-good-noise

[Anonymous]

I finally got my '82 GS450 started after an engine swap (see the "How long to start when dry" thread) but it's now making a knocking/pinging noise. Argh. The fun never ends :-(

The noise seems to be coming from the cylinder head area; my first thought was something really bad like a piston hitting a valve. I shut the bike off immediately.

I pulled the plugs and with the bike in gear I spun the rear tire to turn the engine. No odd noises there that I could hear. My next thought then was perhaps the timing was off, but in reading through my Haynes manual it appears the bike has "automatic" timing.

I'm sure there is something I am missing - can anyone share their wisdom with me?

Thanks!
Brad
brad@cds-inc.com

 

[earlfor]

Re: Got it started, but now a not-so-good-noise

Brad
There is a possibility that someone put the wrong type of plugs in the engine and the plug reach could be wrong. Some plugs are long enough for the piston to strike them. Turning over the engine with the plugs removed (obviously.. ) would not show this fault. I would remove the plugs and spin the engine with the starter. That will turn it over much faster than you could by spinning the rear wheel. Also, having the plugs out will magnify any knocking sound you might hear. Try this and let us know what sound you hear.

Earl

I finally got my '82 GS450 started after an engine swap (see the "How long to start when dry" thread) but it's now making a knocking/pinging noise. Argh. The fun never ends :-(

The noise seems to be coming from the cylinder head area; my first thought was something really bad like a piston hitting a valve. I shut the bike off immediately.

I pulled the plugs and with the bike in gear I spun the rear tire to turn the engine. No odd noises there that I could hear. My next thought then was perhaps the timing was off, but in reading through my Haynes manual it appears the bike has "automatic" timing.

I'm sure there is something I am missing - can anyone share their wisdom with me?

Thanks!
Brad
brad@cds-inc.com

 

[Billy Ricks]

If it's not a parts hitting each other it could be an overly lean mixture problem. Did you check valve clearances?

 

[Anonymous]

Re: Got it started, but now a not-so-good-noise

Thanks for the suggestion - I gave it a try with the starter and didn't hear any odd noises with the plugs out. I checked the plugs against the ones on my old engine; they're the same part # so I think they're the correct ones (but will remember your comment about the long plugs for future reference - good stuff to know!). With the plugs in, there was a definate knock coming from the cylinder head area.

Ok, so off with the seat/tank/etc. and pull the camshaft cover. I stared at it for a while and pulled the engine through (with the plugs out) and didn't see anything out of the ordinary UNTIL I happened to notice that the camshaft retaining brackets had arrows pointing backwards. I thought that was odd; I seemed to recall that the arrows all were supposed to point forward when I had the camshaft cover off my old engine a while ago. Sure enough, in checking the Haynes manual, the brackets are installed in the wrong locations i.e. the right front bracket is in the left rear location etc. I *suspect* this is the source of the knocking since the shop manual is pretty specific about putting them on and matching the letter marked on the bracket with the letter marked on the head. Does that make sense?

I sure appreciate your suggestions & comments - these little buggers are sure a different ball of wax than the aircraft engines I'm used to working on (even besides the english vs. metric stuff!).

Thanks!
Brad
brad@cds-inc.com

Brad
There is a possibility that someone put the wrong type of plugs in the engine and the plug reach could be wrong. Some plugs are long enough for the piston to strike them. Turning over the engine with the plugs removed (obviously.. ) would not show this fault. I would remove the plugs and spin the engine with the starter. That will turn it over much faster than you could by spinning the rear wheel. Also, having the plugs out will magnify any knocking sound you might hear. Try this and let us know what sound you hear.

Earl

 

[Anonymous]

The valve clearances are not perfect, but they are within acceptable limits. Is the mixture a big deal to adjust? The manual I have for the bike (Haynes) is kind of light on carb info.

Thanks!
Brad
brad@cds-inc.com

If it's not a parts hitting each other it could be an overly lean mixture problem. Did you check valve clearances?

 

[Anonymous]

The valve clearances are not perfect, but they are within acceptable limits. Is the mixture a big deal to adjust? The manual I have for the bike (Haynes) is kind of light on carb info.

Thanks!
Brad
brad@cds-inc.com

If it's not a parts hitting each other it could be an overly lean mixture problem. Did you check valve clearances?

what color are your plugs burning

 

[Anonymous]

They're a nice mid-gray color; they aren't fouled or covered with oil/crud/etc or anything like that. That said, I do not know how much running time is on these plugs as they were on the engine when I got it. The plugs on my old engine (which used the same set of carbs without any adjustments) are roughly the same appearance. If these were aircraft plugs, I'd say they look pretty good.

Thanks!
Brad
brad@cds-inc.com

what color are your plugs burning

 

[moto_dan]

They're a nice mid-gray color; they aren't fouled or covered with oil/crud/etc or anything like that. That said, I do not know how much running time is on these plugs as they were on the engine when I got it. The plugs on my old engine (which used the same set of carbs without any adjustments) are roughly the same appearance. If these were aircraft plugs, I'd say they look pretty good.

Thanks!
Brad
brad@cds-inc.com

what color are your plugs burning

Mid Gray color sounds a little lean to me. Should be light tan if all is well.

 

[Anonymous]

I know there are many diferent opions and the prevailing one is the light tan..I myself always shoot for the mid grey and when i end up with anything in the brown family i will leave it unless i have the desire to be extra fussy

 

[moto_dan]

I know there are many diferent opions and the prevailing one is the light tan..I myself always shoot for the mid grey and when i end up with anything in the brown family i will leave it unless i have the desire to be extra fussy

And then you get into the impossible to read old plugs, additives in fuel, and it really isn't the electrodes that many mistakenly look at when "reading the plugs" rather the porcelan under the electrode...etc, etc, etc. Our old '80's suzukis typically run leaner, hence the requirements for rejetting with improved air flow so you're probably right about the color(mid Gray) on a stock GS.

 

[Anonymous]

Solution!

Solution!

As a followup for folks who might find the same thing (bad knocking), I found that whoever had the engine apart last had put the cam bearing caps on backwards. Assuming those were trashed, I replaced them with a set known to be good and the engine runs well now. I had my first bike ride today in almost three months and it's nice to have it running again . Especially since winter is just around the corner here in Minnesota.....

Thanks again to everyone for their help and suggestions!

Brad
brad@cds-inc.com