Rockers very clicky/noisy

[Reight]

Hi guys, maybe someone can shed some light my problem, i'm replacing my Pitster Pro z160HO with a new one, i figured while i was at it i'd throw in a 64mm TB barrel and piston.

So the starting point of this adventure is

1: Virgin engine, fresh outta the box, no running in at all.
2: TB 64mm barrel and piston kit for a 2 valve head.

I had some timing chain issues due to the TB barrel being about 0.7mm longer than the one that came out, i couldn't get the chain on the cam shaft at all.

I resorted to removing the bottom gasket and just using Silastic to get the bee's d$&k extra slack to get the sprocket on the cam shaft, i also had to reshape a bit of rubber from the block of the lower chain guide as the hole for it is different in the TB barrel.

It went back together fine after that, pretty straight forward, the bike turned over seems to run ok, But the thing rattled a heap, seemed to be coming from the head, redid the valve clearances to .003 and .004.

I turned it over by hand at the stator as slow as possible to check for anything funny wiht the top rocker cover off, near BDC with the intake just about to close the moment it changes from opening to closing it doesn't do it smoothly, it moves really quickly and with a loud audible click. checked and it does it for te exhaust too, just when it changes direction from opening to closing

Is this normal? is it just because of the new cams having really sharp unworn profiles?

Would the timing chain with very little slack have anthing to do with it?

I was worried that maybe pulling out the gasket put the piston too close to the valves but it's happening at BDC not TDC, so i don't think it's that.


cheers any help would be appreciated

 

[The_GDFP]

Even with the tensioner out, it was tight? It shouldn't be. I leave the base gasket out, most of the time. ThreeBond is a good substitute. Possibly, you've buggered the cam chain and/or sprocket by forcing it on? Seen it happen.

 

[Reight]

It was rather lacking in slack, the tensioner only went in about 3 or 4 clicks when i put the spring in it, but there was no tight links and the only forcing on the chain/sprocket to get it on cam shaft was only by fingers.

If the chain or sprocket was stuffed what would be wrong with them? stuffed teeth? out of round? kinked/stiff links?

Do you normally just leave out the bottom gasket for more compression, or for other reasons as well?

 

[sean01]

id be checking piston to head clearance and make sure the piston is installed the correct way.. remove the head and look for contact marks on the piston..

did you compare barrels with verniers or a micrometer..
generally zongers dont like no base gasket but if the .7mm is a correct measurement then i can't see why you couldnt remove it..

were you fitting the cam chain and sprocket on the cam with the complete tensioner removed? or at least with the tensioner properly collapsed?

tb barrel is a direct change over, im never had issues with cam chain guides.. you do how ever need to install it before sliding the head gasket on..

too tight of cam chain can cause noise but not clicking noise unless it has a bent or damaged link and is catching on something..

also check ya havent dropped something in the valve spring area as it may be obstructing something..

but since it sounds like you have modified things instead of finding the problem you could have all sorts of drama's going on..

 

[Reight]

id be checking piston to head clearance and make sure the piston is installed the correct way.. remove the head and look for contact marks on the piston..

Haven't done that yet, will hopefully get to that tonight or tomorrow arvo, thought the TB Piston had pretty clearly marked the exhaust and intake sides, you never know, all it takes is one stupid mistake to make a mess and that might be the one i have made.
,

did you compare barrels with verniers or a micrometer..
generally zongers dont like no base gasket but if the .7mm is a correct measurement then i can't see why you couldnt remove it..

Yeah, i measured about .4mm difference allowed for about .7mm because i had read it some where else that it was supposed to be a .7mm difference, and i measured the gasket as .5mm, threw the barrel on and clamped it down to check it the piston cleared the barrel which looked good.

were you fitting the cam chain and sprocket on the cam with the complete tensioner removed? or at least with the tensioner properly collapsed?

yep tensioner fully, removed, i even did a dummy test without the bottom chain guide to see if it gave me more slack. (which it didn't)

tb barrel is a direct change over, im never had issues with cam chain guides.. you do how ever need to install it before sliding the head gasket on..

yep that's the order i did it in

also check ya havent dropped something in the valve spring area as it may be obstructing something..

checked for the with a stupidly bright torch and turned it over by hand to have a look to see if anything was floating around. turned up nothing

but since it sounds like you have modified things instead of finding the problem you could have all sorts of drama's going on..

The only two things i changed up at the end of it all, firstly the bottom chain follower, of which was only the big rectangle hunk the holds it in the barrel, the shape of it is different (smaller) on the TB barrel.

and second the omission of the bottom gasket.

i guess one of my original thoughts was that maybe because of the chain being brand new it hadn't stretched at all making this whole ordeal difficult.

That and if if the cam lobes are really aggressive could it simply be the followers snapping down as the it drops off the top of the steep lobe, something that may smooth out as the engine wears in.

might go take a few videos to show what's going on.

 

[Reight]

Well i went down to the garage to have another look at the engine to do a few videos to show what was going on, dunno how i missed it but it seems all sorted now, it was the cam sprocket screws :lol_hitting:
i forgot to tighten one of them don't ask me how, in too much of a hurry to get this thing together perhaps, so what was happening was that every time either valve just started to close, the valve spring tension would push the cam shaft a degree or two off in relation to the sprocket then flop back once the cam angle/valve spring tension wasn't as strong :lol_hitting:

now i'll go hide in the corner like any idiot should :duhman:

 

[The_GDFP]

That was gonna be my next guess. You are not the first...

I've seen the big rubber block need a trim to fit well in TB jugs, too. That's why there's a razor knife blade on the window sill over the work bench.

The jug height difference is why I leave the gasket out. Gets the compression up a tad. Gotta watch piston to head clearance. .5mm in the hole at TDC as a minimum, since the HG is only .25mm. Much closer than .75 total, and the rod stretch, crank flex and piston rock will team up and start letting piston tap head. Ring land snaps off, sunshine turns to sourballs.

 

[K.Jansson]

Also had to run without base gasket. had no problem with doing that.

haha also made the mistake of forget the screws. was about to mention that but i saw that you have fixed it

 

[Reight]

Thanks for the input guys, always handy to bounce a few thoughts around rather than going around in circles in me own head

Ring land snaps off, sunshine turns to sourballs.

Hehehe that's one way to put it