Setting the timing properly

[timebombprod]

Having a bit of trouble with getting my timing set properly on my bike, it is a gs650gl with the
cruzin-image big bore pistons that makes it a 740cc after properly machining the cylinder walls. They fit great in the cylinder walls and the gap is right on the tight end of the ring clearance spec, so all that seems to be very well done in my opinion.

There have been two people I know of that have had these pistons installed, one guy was on this forum and said they did not fit properly and they were hitting the valves, another person i have spoke to personally had absolutely no issue with the pistons being installed on his bike, but he also had a shop do it and it's possible they may have shaved the faces of the valves a bit but they did not mention any of that to the owner.

So my issue is I'm not entirely sure if I'm doing the timing procedure properly, i have a clymers manual that im following and I guess this is one of those times I wish I had the OEM manual as it may explain it in a better depth with better pictures.

The Clymer manual specifically says

"while holding down the timing chain, rotate the crankshaft in the normal direction to bring the T mark to the timing mark"

Easy enough, that was done right, then it says to distinguish between the intake and exhaust camshaft and that is easy to do aswell.

Then this is where i get a bit confused but i believe in doing it properly

"exhaust sprocket bears an arrow marked 1, turn over the exhaust camshaft so that the arrow points flush with the gasketed surface of the cylinder head, engage the timing chain with this sprocket."

In my opinion that would mean it wants the arrow to be pointing directly down as the cylinder head gasket is below the cams, but I could easily be wrong.

Next it says

"the other arrow marked 2 is now pointing straight upward"

So that is only true if the arrow marked 1 is pointing to the surface of the cylinder head meaning it is pointing to the valve cover gasket, but anyways this is how I have it set up as of right now.

then it says to count the chain roller pins towards the intake camshaft, starting from the pin marked at the arrow 2 and end with the 20th rolling pin and install the intake camshaft with the arrow 3 on the 20th pin.

I will take a video and post it in the comments to let you all visualize it and see if I'm making any possible mistakes.

Also I should add that my cam chain tensioner is currently not installed but I figured if the timing is proper and there are no spark plugs in the cylinders meaning no compression building that it should be easy to rotate without the possibility of it slipping a tooth

 

[timebombprod]

https://youtu.be/HdTyb16C3gA

Video showing and explaining everything

 

[Rich82GS750TZ]

I can’t speak knowledgeably about the orings but I would think that Suzuki had a spec for the proper size there. Are they no longer available?

And I’m not positive about this, but I believe you may have counted the pins incorrectly. Most instructions clearly state that you start counting pin # 1 being the pin directly above the # 2 mark on the exhaust cam sprocket and you end with pin # (whatever your book says) directly over the # 3 on the intake cam sprocket. Not saying you’re wrong. Just saying be absolutely sure. I believe you started counting # 1 as the pin to the rear of the mark. I have done this grand total of 1 time on a completely different engine. So take my advice for whatever you think it’s worth. Hopefully some more experiences engine builders chime in here with some sound advice. You’ve come this far, you want to be certain.

 

[timebombprod]

The Orings come with the headgasket not seperately from suzuki but since I have larger pistons the original gasket won't work, now I could order it just for the Orings but that might be a bit excessive, unless I could get the oem headgasket to work as it's a better style than the one that comes with the bigbore kit.

I believe I counted them right but I'll revisit forsure, sometimes camera angle can mess things up a bit, i remember i would line up the timing mark when I was working in the ignition and I'd take a video and it would look off on the camera, drove me nuts.

I'll be counting the pins, triple checking that I have everything lined up properly, and tightening things down and hopefully it works well, I might have to put thinner shims in the buckets before I tighten stuff down just to get rid of the possibility that the clearance is too tight possibly causing interference, bit of a long shot but nothing too hard to change to make sure it isn't the problem.

 

[chuck hahn]

Exhaust cam is correct. You count the pin the 2 arrow points at as 1, so from that pin you count 1,,2,,3 and so on till you hit pin 20 and set arrow 3 inline with pin 20. Install the cam journal caps and just snug them down. Then install the cam gain tensioner and everything comes tight. Now tighten cap bolts to specified torque in te manual. A small 1/4 inch drive torque wrench will go low enough to meet the job. Then you roll the engine over with the 19mm nut on the crank two full revolutions bringing the timing mark as shown in the video. At this point the arrows should be back to the proper places. Also tge notces on the ends of the cams on the right side should be parallel to the head surface. Recount pind from the one at the 2 arrow and see vtgat pin 20 iscat the 3 arrow. If alls well the camscare timed. DO NOT roll engine over with an empty shim bucket and IF you meet any locking up while rolling engine over DO NOT FORCE it. Stop and evaluate whats happening.. AMD MOST IMPORTANTLY use a wrench to roll over the engine the 2 turns and not the starter. Should the timing e off and a valve hits the piston the starter wont care.. it will damage a valve without a hickup.

Factory manual here..........

https://gsarchive.bwringer.com/

EDIT... Dont change any shims till caps are on, tetioners in, and you verify pin count. At that point do valve adjustments as outlined in the service manual under alve clearance

 

[timebombprod]

Having a completely different issue now, my camshafts do not fit the cylinder head anymore, I'm hoping this is a common issue and had a simple fix but it's really bugging me as I don't know what to do.

I did have the cylinder head dropped off at a shop to get the head resurfaced and I've brought the same shop my cylinders to get bored out without an issue so I don't think it's something on their end like giving me maybe a 550 head but it's just really odd that my cams literally do not fit, it's like they're too wide but its my the smallest bit.

Here's the video https://youtu.be/_5wrPjuA2Ww

 

[rphillips]

If you are sure "that is the cam" you took out of the head you sent to them, it seems to be fore sure you don't have the same head now. Cams and heads sure don't expand and contract anywhere near that much..

 

[timebombprod]

Well I don't have any other cams except another Suzuki GS650 exhaust Cam sat but again my intake doesn't fit properly also and I never disassembled the camp's himself so there shouldn't be any sort of gap between the sprocket

I was looking online at GS550 and GS650 cylinder heads and other than the difference in the 16th versus 17th bolt from the updated version for the valve cover I can't find a clear difference and unfortunately there isn't a part number that I can find on them either that will help me refer if this one is A550 or 650

 

[timebombprod]

Well....this might be a bit farfetched, atleast in my experience which isn't too much.

So, this is the right cylinder head, and the cams do fit it properly now, what wasn't right are the orings that sit on the four corner studs of the cylinder walls to cylinder head mating surface.

In the big bore kit you get a headgasket but you don't get the orings like the original headgasket does, and you can't order them separately so I just improvised with orings that were the proper diameter instead. I already said that I believe they are too thick causing the headgasket not to be sealing at all but I figured I'd address it after I ensure that the motor does not interfere whatsoever, well I should've addressed the issue with the gasket first as the orings being too thick and being on the corners caused the head to bend a bit when torqued down. So I'm gonna ask this one guy if it's okay to run the head without o rings as it's also a crush style headgasket and not the one that is oem.

But anyways, I guess it can be considered a rookie mistake as I technically didn't use the right part even though I can't order them and had to improvise. I still haven't timed the motor but I did loosen the studs and confirm that the orings were the underlying issue.

I dont know if the guy is on these forums but his name is Joe Marshall and he has helped me an insane amount, I know you guys have aswell no doubt but this guy is just so damn good with helping somebody like me. I am literally going to pay him a well deserved visit and he is halfway across the world.

I will report either tonight or tomorrow on how the timing procedure goes and if the motor interferes.

 

[Grimly]

Wow, never heard of that before. Keep your fingers crossed you haven't distorted the head. It must have been bowing like hell for the camshaft length gaps to get closer together.

 

[rphillips]

That's what I thought, if it's bent that bad, possibly it could be put in a hydraulic press and bent back the opposite direction to get it back straight. Find a good straight edge to be sure.

 

[chuck hahn]

You need the orings to properly seal the oil gallies

 

[timebombprod]

You need the orings to properly seal the oil gallies

That's the big question, to put o rings or to not put them, I've had opinions on both sides of this, one guy said most big bore kits don't come with them and since I have a crush style head gasket I really shouldn't use orings, and another said use o rings.

I guess I will have to see how it goes.

 

[timebombprod]

That's what I thought, if it's bent that bad, possibly it could be put in a hydraulic press and bent back the opposite direction to get it back straight. Find a good straight edge to be sure.

Bending will be checked for

 

[zed1015]

To check if it's warped enough to cause problems just bolt the bare head ( valves and springs removed) to the motor and fit the cams .
If they spin freely with the head torqued up you are good to go.

 

[chuck hahn]

unbolted and setting on the bench do cams go in normally?

 

[timebombprod]

Okay so the head is fine, tightened down without gasket and cams sit just fine, but these pistons do interfere with the valves, it's not the indented area where the valves go but on the sides of the pistons. I'll end up taking a video more than likely to show where they hit and all that but I was also thinking I could just get some gs750 pistons if I can't work this out as those are 65mm pistons.

 

[timebombprod]

https://youtu.be/dfmGPZAT40Y

https://youtube.com/shorts/6JZNCi_Es40?feature=share

 

[Suzukian]

The overhead cam is cast iron, if you try and bend it, it will crack for sure. Torquing the head down onto it really is the only way to get the cam straight again. The thing with steel/iron is that after it gets spinning, and hot, all lubed up, it will want to find it's center again. It will straighten itself out. I highly advise against bending it. It is very brittle and will crack on you.

 

[timebombprod]

The overhead cam is cast iron, if you try and bend it, it will crack for sure. Torquing the head down onto it really is the only way to get the cam straight again. The thing with steel/iron is that after it gets spinning, and hot, all lubed up, it will want to find it's center again. It will straighten itself out. I highly advise against bending it. It is very brittle and will crack on you.

Its fine, no bending, the issue now is that the pistons do hit the cylinder head, but it can be solved by dremmeling the surrounding areas.