CCT stopper mod question

[KermitLeFrog]

Yes, this is all possible. You can gauge where the compression stroke is by removing one sparkplug. I did the stopper mod myself and was tempted to do this. But, I thought it was best to check the valve clearances at the same time which can only be done with the cam covers off.

This enabled me to see the cams and not make any mistakes.

[VTRDark]

The difference being 4 cylinders. As AMQ explained with a four cylinder bike it's not as crucial when you remove the tensioner because the cam lobes on the other cylinders will hold things in place so they don't move. With a two cylinder bike if you remove a tensioner while it's under a pressure load from the opposite cylinder it will move (spring around) moving the one your working on causing the chain to jump.

You could simply put the rear at RT without checking. You have a 50/50 chance and it will either fall on the compression or exhaust stroke. The problem here is that you then don't know how many revolutions is required at the crank to then move onto the front and can end up 180 degrees out on the timing. Remove the rear cam cover to check and you wont end up having to remove the front cam cover which is a lot more work than 4 bolts.

[wbonx]

Hi Cyber,

thanks for the explanation. My suggestion was involving keeping still the shaft (maybe a friend) ... so that the other cylinder is not applying any energy.

And anyway... does the tension provided by the valves of the second cylinder rotate the main shaft? mmmmm, and the two pistons are not at the top compression point together so...

... if I ever do the job I would be curious about finding out if an optimal timing point that allows the CCT exchange without touching the heads exists.

[AMCQ46]

Hi Cyber,

thanks for the explanation. My suggestion was involving keeping still the shaft (maybe a friend) ... so that the other cylinder is not applying any energy.

And anyway... does the tension provided by the valves of the second cylinder rotate the main shaft? mmmmm, and the two pistons are not at the top compression point together so...

... if I ever do the job I would be curious about finding out if an optimal timing point that allows the CCT exchange without touching the heads exists.

its the cams that rotate [not the crank as Carl said] If the flank is pushing against the valve spring. it needs the cam chain in tension to hold it in place against the spring force, and if you remove the tensioner then the chain goes slack, the cam then moves and your timing is out.


Please, please, please ..... just remove the back cam cover and don't look for short cuts

[wbonx]

Hi Cyber,

thanks for the explanation. My suggestion was involving keeping still the shaft (maybe a friend) ... so that the other cylinder is not applying any energy.

And anyway... does the tension provided by the valves of the second cylinder rotate the main shaft? mmmmm, and the two pistons are not at the top compression point together so...

... if I ever do the job I would be curious about finding out if an optimal timing point that allows the CCT exchange without touching the heads exists.

its the cams that rotate [not the crank as Carl said] If the flank is pushing against the valve spring. it needs the cam chain in tension to hold it in place against the spring force, and if you remove the tensioner then the chain goes slack, the cam then moves and your timing is out.


Please, please, please ..... just remove the back cam cover and don't look for short cuts

Ok! I will you convinced me!

... but the point was to put the first cylinder in a position (timing) where there is no tension on the CAMS... then a friend holds on the generator to prevent rotations from the other cylinder due to the valves on CAMS tension, replace CCT. Do the same for the other.

[AMCQ46]

ok, there is no need to hold the crank, the other cylinder wont put forces on that will move the crank. so you can do it with one man

[KermitLeFrog]

No.

With the rear cylinder at TDC on the compression stroke you can remove and replace the rear CCT.

To remove the CCT on the front cylinder the front cylinder MUST be at TDC on the compression stroke. So, after you have fitted the rear CCT you must rotate the crankshaft so that the front piston is in the correct position.

You MUST NOT try and remove both CCTs at the same time.

[wbonx]

No.

With the rear cylinder at TDC on the compression stroke you can remove and replace the rear CCT.

To remove the CCT on the front cylinder the front cylinder MUST be at TDC on the compression stroke. So, after you have fitted the rear CCT you must rotate the crankshaft so that the front piston is in the correct position.

You MUST NOT try and remove both CCTs at the same time.

For sure Kermit. This was out of question.

Point was to put the cylinder in use on its TDC without checking the tdc on the head by disassemblic the heads cap but simply by checking the generator marks.

[VTRDark]

The problem is that both RT and FT (TDC) don't discriminate between Compression TDC or Exhaust TDC and you need to know your starting point ie are you at Compression TDC or Exhaust TDC. Otherwise you timing could be 180 out when you move onto the front. Unless off course you want to remove both cam covers Cylinders don't fire in and even number of revolutions due to positioning of the crank in relation to the cylinders.

Another diagram that may help you get your head around it. Note the uneven firing pattern.

[wbonx]

Ok. Got it, thanks a lot for the diagram.

Once I built an electronic RPM counter. It was rising in function of the changes in the magnetic field due to the ignition system. Was on a TT.
Maybe checking the ignition timing one could guess the compression point of the piston.... maybe connecting a tester to the "ignition controller"... anyway... i will do the job the old way ;)

[artee]

Just follow the guide.
http://www.vtr1000.org/phpBB3/viewtopic ... 83#p264315

Roger

[adewhitmarsh]

You could just fit manual ccts ?once fitted only need checking & adjusting every few thousand miles.

[KermitLeFrog]

You could just fit manual ccts ?once fitted only need checking & adjusting every few thousand miles.

Idle curiosity. What interval do you recommend to check the manual adjustment? 3000 miles? More? Less?

Interested to know.

[popkat]

You could just fit manual ccts ?once fitted only need checking & adjusting every few thousand miles.

Idle curiosity. What interval do you recommend to check the manual adjustment? 3000 miles? More? Less?

Interested to know.

Adjust when you start hearing a slight rattle, no need to check them unless it's for leaks but that's just a visual.


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