GS650 build, engine rattle?

[Guest]

Hi, I have been reading for a while and many thanks for all the info, I have been building (I use the word building loosely as I have mainly been cutting and playing with the easy stuff) the donor bike was running OK and other than sorting a noisy clutch, I then took it off the road to play with frame, tank and other cosmetic things, once sorted I put it in for a service and got it back with a warning that the fuel had leaked into my engine as I had it on pri, but all oils changed, sparks and filters, carbs balanced (not sure about valve clearance) but when I got it back I went for a drive and after a short drive it lost power and started to make a small rattle, I put the power loss down to low on petrol but I could hardly keep the bike ticking over, I then popped out and got some fuel, filled up the bike and it started great but the noise was there and started to get worse, the bike lasted for another 20 mins and never truly fired on power, now the noise is there from start and not great sounding, I have pulled the spark leads one at a time and the noise is the same?

Sooo gutted as I was sooo looking forward to taking this out in the summer, if anyone has any ideas I would massively appreciate it?

https://drive.google.com/open?id=0B-LUlxGpgGLqSUk1bDYxbEtiNFE

https://drive.google.com/open?id=0B-LUlxGpgGLqemFseGR4cU12NUE

[tiger cub]

Sorry to hear that your having issues with your bike. I'm only guessing from what I heard in your video but I think it might be related to your valves....It's only a guess because every time i listen to it i think i hear something different . Try taking off your valve cover to see if there is anything visibly wrong and the valve clearances.

P.S. I don't think spark is an issue although it was a good thing to check.

[Steve]

Could be exhaust leak (especially in the left-side video), could be a REALLY loose valve.

Just so you know, a carb sync without a valve adjustment is probably wasted effort.
If you have to adjust any of the clearances, the valve timing/lift/duration will change ever so slightly, which will affect how much air that cylinder is trying to suck through the carb. Change the amount of air, you will change the vacuum, so you will need to adjust that carb to match what the cylinder wants.

When doing both jobs (valve adjust and carb sync), always do the valves first.

.

[tom203]

About how long did you run it before discovering your oil was contaminated with fuel?

[Runeight]

I'll go with exhaust leak. My best guess.

[stuart]

Ok went out for another look, im pretty sure its coming from the first cylinder on left took spark out and started and its much louder, piston looks OK from the small bit I can see?

I called the guys who serviced to ask him about valve timing as the valve cover has not been removed in a while ????

if its a valve its it bad?

Thanks so much guys this is a massive help!

[MechMessiah]

Ok went out for another look, im pretty sure its coming from the first cylinder on left took spark out and started and its much louder, piston looks OK from the small bit I can see?

I called the guys who serviced to ask him about valve timing as the valve cover has not been removed in a while ????

if its a valve its it bad?

Thanks so much guys this is a massive help!

I'm also thinking it's valve related. Be careful taking the valve cover off if it hasn't been removed in a while. Those bolts snap very easily.

[stuart]

Thx, got cover off, and yes bolts were stiff, TBH i don't know what I'm looking at, I can see the shims on the valves I suspect are noisy and they and not loose but have no feeler gauges so cant check clearance :/

whats the worst it can be .. answers on a post card, is this project coming to an end before I get to ride

Tom, I didn't ride with fuel in the engine, started it a few times standing and got a few big exhaust explosions....?

[BigD_83]

It sounds like a valve clearance issue to me, rather than the usual duller sounding exhaust leak, but can't rule that out 100% without being there. Worst is a bent valve.

Can't do much without ticking off the list...a rough guide on valve clearances is to see if the shim will spin under the cam lobe, when the lobe is in the proper position for checking. If so, you have at least some clearance and can swap in one size thinner shim.

Get some feeler gauges so you can take a systematic approach. I don't think you are dead in the water, but this is not a throwing parts at it situation.

[stuart]

Thanks guys, I can cope with even a bent valve as long as it hasn't hit the piston, I hope it is just a clearance thing...... I have booked someone to come get it as I will cause more issues than solve I think!

[tiger cub]

Do you have a copy of the service manual? If not you should be able to download it from bikecliff's website.

http://members.dslextreme.com/users/bikecliff/

[dantodd]

Thx, got cover off, and yes bolts were stiff, TBH i don't know what I'm looking at, I can see the shims on the valves I suspect are noisy and they and not loose but have no feeler gauges so cant check clearance :/

On these bikes the valves typically get tight rather than loose. There's a worksheet for calculating shim requirements somewhere.

whats the worst it can be .. answers on a post card, is this project coming to an end before I get to ride :

Worst case us always really bad but it is rarely the worst case so work through the most likely things. Uggs I've valve has a lot mute clearance than the others there is certainly the possibility of a bent valve.

[fastbysuzuki]

Where in the uk are you? There may be someone close that could lend a hand.

[stuart]

Where in the uk are you? There may be someone close that could lend a hand.

Im in Stevenage Hertfordshire bud?

beencalling about and not many people want to know when it's an old jap bike 😕

[fastbysuzuki]

To far from me unfortunately, perhaps someone will pick it up.