cam timing

[homer]

Hi folks. Nice to have the original forum back. So I have a question about cam timing. I have ape slotted cam gears and cams are now 110in and 112ex. But I had to jump 1 tooth to get the exhaust cam to 112 degrees. So there is now 21 teeth between the marks. Did I make a mistake or is this normal?

Edit: stock cams, true tdc and cam opening/closing several times checked

Edited July 8, 2015 by homer

[wraith]

I know I have slotted cam sprockets on my GS1000 and had no probs with the 20 teeth bit, I'm using Falcon sprockets and Andersons S3 cams.

I'd recheck the timing so you don't hit a valve, I'm shoure some one will be along in a bit who knows more

[arnout]

What bike (engine) are you talking about?

For a GSX1100 (if indeed that is the case) LC's of around 109 would seem applicable to me, but it depends on what cams (stock)  you have and where in the rev range you want your power..

Not sure if I ever needed to skip a tooth setting the cam timing with slotted cam sprockets.. But double check your timing (as mentioned already), and always turn the engine over by hand first after having done timing adjustments.. Also check cam chain wear by measuring the length between x links (lookup in manual) while you're at it just to be sure..

[homer]

Engine is 1100 efe, turbo 1327. New camchain, new cam gears, new crank gear. Engine is turning nicely by hand. Just checked the tdc once again and measure the lobe centers again IN 110 deg EX 112 deg as I wanted. Cams are the stock efe ones but there are two kind of them as suzuki manual says.

A version:

Duration

IN 280, EX 272

Lobe centerline

IN 106, EX 104

B version:

Duration

IN and EX 256

Lobe centerline

IN and EX 102

If my cams are the B ones, I need to move EX 10deg to get 112 centerline. It seems that adjustable gears won´t do the job.

 

 

[KATANAMANGLER]

I have only ever dialled in standard cams on slotted sprockets and I have only ever gone as far as 110 IN 110 Ex . They were in reach of the slots. I didn't need to to jump a pin but I have been told by others who are in the know  that  pin count is not essential as long as you have calculated TDC accurately and your degree wheel is showing  you are getting the correct lobe centre calculations with good repeatability.

Hopefully someone who has actually been there will confirm.

[homer]

Yes the pin count is for the stock timing. Maybe if you go over 110 degrees you have to jump a pin then. I have done my homework and sure about my calculations so there should not be nothing to worry about. Thanks for the reply

[Blower1]

I have stock EFE cams dialled 110 In / 111 Ex in my Supercharged 1327 EFE and there is 21 pins between the marks.

If your intake valve lift is 7 mm and exhaust 6,5 mm, then you have B cams. If intake lift is 8 mm and exhaust 7,5 mm, then you have A cams.

[homer]

Thanks Blower1 have to check the lift to sort out which cams I have. I have a feeling that they are B-version. Bike is originally from Sweden...

[arnout]

Engine is 1100 efe, turbo 1327. New camchain, new cam gears, new crank gear.

..

 

Ah.. A turbo engine! Perhaps you used a spacer to reduce the piston compression ratio for the turbo application, and so increased the distance between the sprocket and the crank and those on the cams? (Which would take up more chain length thus explaining running out of the cam slot adjusting range..)

[Biker66]

As stated earlier the pin count isn't essential. Any cam setting can be achieved and retain the 20 pin count.
I don't care on my own bikes, the red one is presently at 21 pins, TDC and lobe centers are the things that matter.

However, when tampering with a friends bike I make sure there's 20 pins as per the manual. Wouldn't want them to lift their cams and then have a ruined motor at startup because they reassembled it as the Haynes manual told them to... 

Edited July 9, 2015 by Biker66

[homer]

No spacers under the cylinder. You just won't get 112 degrees without a pin jump. Maybe it is possible in different setup. Every engine build is unique ;)