Tick tick clunk!

[Goose51683]

Also, for some reason I can't delete those last post.

Anyways, I'm going to talk this out and see if it makes any sense.

I adjusted my timing 180 degrees from where it was. Currently at TDC on the compression stroke I have both valves closed, however when I pump the motor to check compression I am getting a lot of blowback through the carb. It would make sense that the intake valves are not seated but I've checked the clearances several times.

With checking the loves on the cam I know that the valves are in the correct positions. Is there any thing I'm missing

[jonathan180iq]

Originally Posted by JohnC

The single cam on the 250 does not act directly on the valves. It pushes 2 rocker arms, one intake and one exhaust, up and each rocker arm pushes its 2 valves down.

+1 on Water Warrior's comment. One, ore maybe even 2 teeth out and it might still run, but not well. Any more than that and you risk hitting a valve with the piston and putting yourself back to square one...

Certainly. Just making sure he understands what needs to be happening. The gif is much better at doing that, rocker arms aside.

[jonathan180iq]

Originally Posted by Goose51683

... however when I pump the motor to check compression I am getting a lot of blowback through the carb...

Which parts that you used were not factory and were not from the Gz, again?
(I'm not being an ass. I seriously don't remember.)

[JohnC]

A little pump back through the carbs at cranking speed is normal. The intake valve doesn't close until a little past the point where the piston starts up on the compression stroke. However, if the photo you posted of the cam is taken with the crankshaft at TDC, then I'd say the cam timing could be off a tooth or two as the two lobes of the cam do not appear to be symmetrical with respect to the valves. It may be OK, but I'd want to make absolutely certain that when the crank is exactly at TDC the cam is exactly where it belongs. I'm also a little puzzled as to why I can see daylight between the chain and the chain wheel. Could it be off a half a tooth? Something just doesn't look right there!

[Goose51683]

the chain is on tight, I may of had the tensioner removed at that point. I did switch the cam 180 degrees after looking at it. I think it was off the entire time. I am getting a substantial puff out of the carb at this point.

My next question is if my cam and my TDC mark are lined up can I be off on my timing. I am still not getting any firing.

Jon to answer your question, the piston head, cylinder, valves, and top of the cylinder (where the valve seats are located) were all replaced

[Goose51683]

Hey everyone, I haven't had much time to work on the bike lately but I did try and turn her over after loosening up my valve clearance a little (i was concerned that I have to little clearance and are therefore opening the valves to quickly)

When I turned it over I stuck my hand behind the carb because I wanted to see if it was sucking or blowing. Fist it is blowing, second it is blowing our gas.

Here's the assumptions I am making from that. I am getting fuel through the carb, and my exhaust valves are not closed at the correct time. Can anyone validate my assumptions.

I know that my valves not being closed could be a timing issue or a valve clearance issue I just want to make sure I am in the right mindset at this point.

Thanks

[JohnC]

An easy, quick way to get a gross check of the valve timing is to put the engine at TDC on the exhaust stroke (not the TDC where you adjust the valves!) Then, rock the engine back and forth a little past TDC and a little before TDC. The two sets of valves should be "rocking", in other words, as you rotate the engine from before TDC towards after TDC, the exhaust valves should be closing and the intakes opening. As you rotate the engine backwards from after TDC to before TDC the intake valves should be closing and the exhaust valves opening. If this is what you observe, the valve timing is close enough to run.

Valve adjustment won't make the difference between running and not running as long as you are close. If they are so tight (no clearance) that the valves don't actually close you will have little to no compression and it won't run, but if you have huge clearances, say .010 instead of .001, it will still run, albeit not that great.

[Goose51683]

Sorry I haven't been around much lately. Work has been killing me lately and I just haven't had a chance to get to my bike lately. Hopefully this week ill have some more time.

[plato1]

I want to thank you all for contributing to this post. My bike has a similar ticking noise issue that none of the mechanics in my area can seem to help me identify it...I am going on guesswork now. My post is in the troubleshooting section-- "Need help with diagnosis."

Although I have a running bike with compression, I still have an awful ticking noise. I replaced the exhaust rocker, but still have same noise (you would think it should have at least gotten better?). Probably going to replace the camshaft and other rocker arm, and maybe take of the head and inspect the valves---I am wondering about the valve seats being worn....

Anyhow, reading this post has helped me a lot in terms of making sure the TDC is the TDC. I too, had been going by the T mark in the site glass, which Suzuki mechanics told me they don't even rely on. I have mine in the correct position, so I am going after looking for some worn out part.....I don't know....

[JohnC]

Originally Posted by plato1

(you would think it should have at least gotten better?).

Consider the possibility you are barking up the wrong tree...