compression diminishes to nothing from 1 to 4

[Paul's Zuki]

Typically after a topend rebuild what should the compression normally be at? Or better yet those that have rebuilt, what has your compression been after rebuild? I can't imagine it's my rings anymore, b/c I set the ring end gap to .004-.008". I honed the bore, but it's still felt smooth to the touch. Is it supposed to be a little rough? Could the gasket be leaking? I think I will perform a leak down test.

[Nessism]

Hiss noise is normal when turning over the engine with a wrench. I wouldn't worry about that. Honestly now, if you did as you say the engine should have compression. Are you sure the cams are timed correctly? You sure the rings were installed properly? Sure the cam chain tensioner is installed correctly? If the answers are yes, focus your energy on something else.

[tkent02]

Where is this bike located?

[Paul's Zuki]

Hiss noise is normal when turning over the engine with a wrench. I wouldn't worry about that. Honestly now, if you did as you say the engine should have compression. Are you sure the cams are timed correctly? You sure the rings were installed properly? Sure the cam chain tensioner is installed correctly? If the answers are yes, focus your energy on something else.

Actually the hissing was more a pffftttttt of air coming out of the carb part when trying to start the motor. I'm guessing it was ignitting the fuel?

Okay, Theoritically speaking, I have the TDC dead center, then pull my cam chain tight from the front of the motor, place my exhaust cam with the 1 even with the top of the cylinder head and 2 notch facing straight up, then count the 20 chain pins to the notch 3(facing straight up) on the intake cam. That is properly installed per book. i let loose the cam chain tensioner and spin it a few times to make sure everything looks good. I take it back to TDC after about 10 turns and make sure that my notch 2 & 3 have 20 chains pins between each other and they do. Could it still be off somehow? Just asking cause I dont know.

As far as the rings go. I put the chromed one on top, darker in the middle and oil rings at the bottom all with the ring end gap set to .004-.008". One thing that confuses me in the manual its talks about placing the middle ring right side up and but the rings i have don't look any different or have an angle as I've read on google searches. problem?

[Paul's Zuki]

Where is this bike located?

I'm in Katy, TX

[MisterCinders]

As far as the rings go. I put the chromed one on top, darker in the middle and oil rings at the bottom all with the ring end gap set to .004-.008". One thing that confuses me in the manual its talks about placing the middle ring right side up and but the rings i have don't look any different or have an angle as I've read on google searches. problem?

IIRC - the rings have a tiny letter stamped on them that should face up when you install them onto the piston. It is pretty hard to see, but you can find it right at the ring gap.

[Paul's Zuki]

If I pull the head, can I still use the rings I just put in? Again it has not been turned on so they would have not seated.

[niclpnut]

Of course. Unless they were damaged upon initial installation.

Nic

[chef1366]

Of course. Unless they were damaged upon initial installation.

Nic

With even compression who knows?
I'd love to see the hone on the cylinders

[Paul's Zuki]

With even compression who knows?
I'd love to see the hone on the cylinders

I think I'm gonna pull the head one more time to inspect the rings (which are new and properly spaced) and make sure they are facing the right way. I'll also take a picture of the hone. that was probably the easiest part. I use to hone so it's not unfamiliar to me on how to properly crosshatch a bore.

Check this out though, when I filed down the rings to the proper spacing within the bore, and I did that by placing the rings in the bore and leveling within it, I then used a feeler gauge to see the gap space. However when I placed the rings on the piston, I noticed they stuck out quite a bit and would even come off of the piston making it hard to slip into the cylinder, so I took them off the piston and squeezed them in enough that they sat withing the grove, still popping out, but quite as dramatic as before and they slipped into the sleeve better. Is that how you guys do it or did i do something wrong by doing it that way.

[mike_of_bbg]

The rings are supposed to have some outward spring to them. There's what's called the "free end gap", which measures the gap in the uncompressed spring. That's a measure of how "springy" they are. Yes the rings need to be compressed to get into the cylinder.

Please don't tell me that we're 100 posts into this and you have not been consulting the manual? Should be some pics in there of cylinder installation. Suzuki has an official ring compression tool; most of the ones you'll find at an auto parts store are for pistons that drop in but for the RBC motors we need something we can un-wrap entirely. Quite doable with large enough hose clamps or just finger pinching.

Did you buy oversized rings? I cannot imagine that new stock rings would have too small a gap when placed in a used cylinder bore. If you filed the ends of the rings you may have lost your stamped reference for which side is up.

[Paul's Zuki]

I have been consulting the manual. But I guess some things are just beyond me due to my lack of know how and this being my first time. I will add however that over the last 3-4 weeks, I have learned more about 4 stroke motors then I ever have. They do have some outward spring to them actually, but i guess after I filed them of course that "free end gap" was wider and sat really loose on the ring grove. I'm just curious if I took away some of the springiness, if you will, by doing that. Yeah, they were oversized rings, by 1.00mm.

[mike_of_bbg]

I don't think I'd pull the head again at this point, just the head cover. Please post pics of your timing mark on TDC and the side shot of your cam gears.

[Paul's Zuki]

I'll get those photos tonight.

[gearhead13]

I have been consulting the manual. But I guess some things are just beyond me due to my lack of know how and this being my first time. I will add however that over the last 3-4 weeks, I have learned more about 4 stroke motors then I ever have. They do have some outward spring to them actually, but i guess after I filed them of course that "free end gap" was wider and sat really loose on the ring grove. I'm just curious if I took away some of the springiness, if you will, by doing that. Yeah, they were oversized rings, by 1.00mm.

So, do you have oversized pistons and bored out cylinders too? I hope so.