Valves hitting piston

[mutley]

on a zzr1100. piston at tdc number 1.
camshafts lined up spot on
on T mark on rotor is right ,but
the valves hit at tdc, if loosen cam caps 2 -3 mm the engine will turn
nothing has changed no head skim ect.

any ider's
it should not happen

[johnafish]

Valves, pistons conrods, crank, camshafts - have any of these changed?

If nothing has changed and it worked before it can only be valve timing. I'd check that again.
____________________
John Fish,
Bikelug Collapsible Motorcycle Trailers
www.bikelug.co.uk

[Kickstart]

Hi

Does seem strange. I would double check the positions of the cams and crank in relation to the pulley wheels / flywheel. For example the woodruff key locating the flywheel to the crank could have sheared off allowing it to move slightly.

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Ninja]

Has the head been off at any stage? (going for the idiotically obvious like - forgotten gasket ... cough ... )
____________________
James
4 wheels transport the Body ... 2 wheels transport the SOUL

[stinkwheel]

Sounds like you are 360 degrees out of alignment. Remember that each 'T' mark comes past twice for every full engine revolution as you have a compression and exhaust stroke.

When you put the cams back in, your manual should have told you which direction to have the cam sprockets facing (either with 'IN' and 'EX' marks or just stamped dots which line up with the top of the rocker box. I suspect you may have got them transposed so the engine is on a compression stroke whilst the cams are set for an exhaust stroke thus causing you to ding the exhaust valve.

It is also possible that you have the wrong 'T' mark, some bikes have more than one and it is not always made clear which is which. In this case you will be 180 degrees out.

If you haven't had the cams out, I would be concerned.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[mutley]

[mutley]

[mutley]

[mutley]

[stinkwheel]

What were you doing when you found out this was happening? It obviously wasn't when you were riding or your question would have been "How do I get a bent valvestem out of the head and does anyone have a spare crank for my bike?"

You must have fiddled with something or had a suspicion that there was something wrong as in my experience people don't generally go out to the shed and think "I'd better just check the piston isn't fouling the valves today.".

It might point us in the right direction.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Guest]

Yep, complete history req'd please.

On some bikes the cam profiles are different between exhaust and inlet so it's possible to get them the wrong way round if they've been out.

If nothing's been touched then I'd think you're looking at a crank/big end problem.

[Kickstart]

Hi

Seems strange. Something must have changed recently to allow this to happen.

If nothing has changed than has the bike recently been over revved? Valve bounce, resulting in bent valves, resulting in them now no longer closing.

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[mutley]

[Guest]

Ah, I see now

[mutley]

[kasandrich]

You seem reluctant to give any information, theefore people are finding it hard to help.

The engine was working when you dismantled it?

Why did you dismantle it?

So you've had the head off, correct?

This entails resetting valve timing on reassembly.

Did you remove the camshafts from the head?

If not, then your problem has to be valve timing, if you did remove the camshafts, you could have switched them?
____________________
Richard

CBR1000FM

[mutley]

[Guest]

Yep, come on mate. Spill the beans, we'll take the p*ss, then we'll try and help you fix it

[mutley]

[sickpup]

As everyone else has covered the obvious I'll do the obscure.

Is the tensioner working properly?

Are you turning the engine in the correct direction?

Do you have adjustable cam-sprockets?

Whats the condition of the cam-chain?

Why did the head need cleaning?

Which valves hit, in, ex or both?

[Ninja]

You've not picked up the wrong cams from your bench? (cos like, you've got two or three stripped motors lying about and those GPZ1000RX ones look similar ... ahem )

is the ZZR11 a bucket-n-shims motor? although having said that you're unlikely to lose 2 or 3 mm clearance on a valve fitting the wrong shims ... unless you stacked all sixteen at the one valve ...

you were having a pot noodle at the time you were putting it back together, sneezed, and a semi dehydrated pea shot into an open intake and is now wedging the valve open ...

I'm with Stinkwheely - sounds like they're out of phase 180deg. Have you had the sprockets off the shafts themselves?

Strip it and build it / time it again from the beginning ... something fundamental is obviously awry so you'll have to do most of it again anyway ... at least if you simply start all over again, you can make doubly sure everythings OK at each stage.
____________________
James
4 wheels transport the Body ... 2 wheels transport the SOUL

[mutley]

[mutley]

all done was reading wrong markins . duhhhh
thanks anyway

[Guest]

Easy done, glad you've got it sorted A mate of mine re-built his engine with the cams in wrong and when it 'stuck' as he was turning it over with a spanner he forced it round - cost him 3 new valves

Check once, check twice, then check again just to be sure