Cam timing FXR150

[hmurphy]

Hey I thought I might as well post here just in case I'm not happy with my current method for timing my new cams.

My question is does anybody (particularly in the Wellington area) have a proper degree wheel and a spark plug type piston stop?

Currently I am using a large 360 degree protractor that is blue tacked to the extension rod for the 17mm socket that turns the flywheel. Needless to say I don't like it much at all. I am trying to think of more reliable ways, but never done this sorta thing before (done lots of reading and watching videos so I know what is supposed to happen though).

I am fairly sure a 10mm bolt would go down the plug hole to stop the piston but haven't tried it yet. Any help appreciated.

[koba]

Hey I thought I might as well post here just in case I'm not happy with my current method for timing my new cams.

My question is does anybody (particularly in the Wellington area) have a proper degree wheel and a spark plug type piston stop?

Currently I am using a large 360 degree protractor that is blue tacked to the extension rod for the 17mm socket that turns the flywheel. Needless to say I don't like it much at all. I am trying to think of more reliable ways, but never done this sorta thing before (done lots of reading and watching videos so I know what is supposed to happen though).

I am fairly sure a 10mm bolt would go down the plug hole to stop the piston but haven't tried it yet. Any help appreciated.

A good protractor is all you need but a more reliable way of fixing it to the flywheel is a must. You have access to machine tools don't you?

Modifying an old spark plug would work for a stop.

[hmurphy]

Just needa sort out a dial gauge (push pin type) then I'm sorted. Thought I had one sorted but that didn't end up happening.

So yeah... anyone trust me with their dial gauge? You know how good I am with tools...

[kel]

I've just done my cam timing, used a 100mm 360deg protractor taped to the flywheel (true bucket racer style) with a wire pointer. The flywheel has a TDC mark on it that lines a with a casing marker (see manual) so its pretty damn easy to sort. I modified an old spark plug by hammering a piece of wire for finding true TDC (more bucket racer cunning). You will need to make up an adapter for the DTI as its shaft wont be able to get around the cam to the valve bucket I used a piece of 2mm wire. Have attached a photo of what I used as the description isnt that clear, have also attached photo of an attempt to check timing while still in the frame so you can see the DTI wire adapter/extension, you need to take the motor out and set it up on a bench. Dont forget to bump the compression while you have it apart. My motor certainly feels stronger but really needs to go back on the dyno to see what effect the changes have had.



Edit - dont use a 10mm bolt unless you want to wreck the valves, they'll smack against it as they open. You need something nice and thin like the spark plug adapter picture, even then you need to turn the crank nice and slow to make sure there's no contact. Once you have set the cam timing double check the valve to piston clearance at around 5 to 10deg BTDC, this is the most important part as any contact will destroy the motor.

[hmurphy]

Sweet thanks, I will make the same adapter for the gauge. I will be doing all of this in the frame though because I physically cant take the motor out at the moment. I have found TDC no worries now but just waiting until later tonight or tomorrow night when my dial gauge gets here.

Cheers heaps for your input and advice!!

[F5 Dave]

. . .unless you want to wreck the valves, they'll smack against it as they open. You need something nice and thin like the spark plug adapter picture, even then you need to turn the crank nice and slow to make sure there's no contact. Once you have set the cam timing double check the valve to piston clearance at around 5 to 10deg BTDC, this is the most important part as any contact will destroy the motor.

Gee these 4 stroke things sound fragile All these bits of metal flailing about inside the engine, seems to be a design flaw.

[Arronduke]

Great info Kel...

How much differance was there from standard setup as per the manual?

[kel]

How much differance was there from standard setup as per the manual?

Manual dosent give valve timing figures just gives the info to set the timing between inlet and exhaust based on TDC and cam sprocket markers. I measured the standard timing as a reference point for changing the timing using sloted cam sprockets.

[TZ350]

What people often don't realise is, that its pretty easy to set the cam timing from scratch without any timing marks as cam overlap is prety much symmetrical about TDC.

If you have a garden varity motor in a pile of bits, one cam or two and no other information or timing marks the motor can be assembled with the cam inlet/exhaust lobes opening/closing symetricaly about TDC and it will run, a tooth out either way will be too much and obvious. And you can do this by eye, no timing gauges needed.



Its only when you have adjustable sprockets and special grinds that you need more info to get the best out of the engine. But assemble it symetrical and it will at least run.

From my experiance the difference required on an adjustable sprocket will be less than one tooth on the cam wheel.

[kel]

From my experiance the difference required on an adjustable sprocket will be less than one tooth on the cam wheel.

Correct, on the FXR 1 tooth on the cam sprocket is approximately 20 deg at the crank.

[hmurphy]

This is all useful stuff you guys are saying. I have set the cams up in the way the manual says to (however at true TDC) and this is where I will start from. I will continue from here tomorrow or Wednesday.

I was told one of the cam sprockets didn't need to be shifted from its original bolting points but the other cam will need the sprocket to be mounted in a different place (requiring drilling of new holes in it). From your experience, did you have to modify the cam sprockets much?

Cheers

[richban]

I was told one of the cam sprockets didn't need to be shifted from its original bolting points but the other cam will need the sprocket to be mounted in a different place (requiring drilling of new holes in it). From your experience, did you have to modify the cam sprockets much?

Cheers

You may still need to slot both cam wheels to get it perfect. It will depend on the cam and timing spec as to how much you will need to slot the holes but it should not be much. Take your time and get it perfect to your spec sheet. If its not bang on it won't perform as good as it could. Look forward to seeing how she goes after all the work.

[kel]

I was told one of the cam sprockets didn't need to be shifted from its original bolting points but the other cam will need the sprocket to be mounted in a different place (requiring drilling of new holes in it). From your experience, did you have to modify the cam sprockets much?

Cheers

Ah that would be the nonsense about not altering the standard exhaust timing.
Dont know what cams your using but Im assuming you're dialing in standard cams, you will need to slot both inlet and exhaust sprockets for about 5 deg movement. Wallace has an excellent system of modification that makes setup super simple, dont know how much he charges but could be worth asking. 'marshland@marshland.co.nz'
Make sure you lift the compression ratio or you'll never see the full benefit.

[koba]

What people often don't realise is, that its pretty easy to set the cam timing from scratch without any timing marks as cam overlap is prety much symmetrical about TDC.

If you have a garden varity motor in a pile of bits, one cam or two and no other information or timing marks the motor can be assembled with the cam inlet/exhaust lobes opening/closing symetricaly about TDC and it will run, a tooth out either way will be too much and obvious. And you can do this by eye, no timing gauges needed.



Its only when you have adjustable sprockets and special grinds that you need more info to get the best out of the engine. But assemble it symetrical and it will at least run.

From my experiance the difference required on an adjustable sprocket will be less than one tooth on the cam wheel.

I didn't know about this before I had a go at it on my old GSXR250. It bloody well worked. It still took me ages to decipher the standard markings but I eventually worked it out to confirm it was correct.

[kel]

Posted this in the ESE thread but should have gone here, bit of a double up but never mind.
Ive been playing with engine performance and evaluation software called lesoft. With all my FXR data entered (64mm piston, 12:1 comp, etc) its suggesting the standard cam timing can be tweeked to give it a bit more go. Have attached the simulators output graph for standard timing, inlet change only and optimised inlet and exhaust timing (the -deg refers to inlet open BTDC and the +deg refers to exhaust closing ATDC, its my own convention designed to confuse everyone but me), Ill update with a dyno run vs the simulators prediction in the near future. In the mean time if anyone else wants to give this software a go its available free from
http://www.lotuscars.com/engineering...ware-downloads