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Has anybody got any experience with dialing in cam gears. Just got a set and am now wondering do you set them with no clearance between cam and bucket or set the clearance first than do dial in.
 

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Has anybody got any experience with dialing in cam gears. Just got a set and am now wondering do you set them with no clearance between cam and bucket or set the clearance first than do dial in.

To find the "lobe centre" first, it doesn't matter what the valve clearance is since you are measuring the crank degree at the same point on each side of the lobe.
Does the manufacturer of your adjustable sprockets provide dialing-in instructions?
 

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Thanks Bladeracer. The cam gears are APE gears so don't come with any instructions.The reason I am doing this is to increase torque down low a bit since I put velocity stacks in. What you said does make sense so all I need to do is advance the centrelines. Would you have any idea how far to advance the factory cams. Now the question is the factory centreline is 96.5ATDC and 99.5BTDC. Does anyone know what to set them to. Thanks
 

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Thanks Bladeracer. The cam gears are APE gears so don't come with any instructions.The reason I am doing this is to increase torque down low a bit since I put velocity stacks in. What you said does make sense so all I need to do is advance the centrelines. Would you have any idea how far to advance the factory cams. Now the question is the factory centreline is 96.5ATDC and 99.5BTDC. Does anyone know what to set them to. Thanks

Probably the best, simplest description of cam timing adjustment I've seen is from Web.
Web Cam Inc. - Performance and Racing Camshafts
 

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Discussion Starter #6
Have you done any of this cam adjusting Bladeracer. Obviously I don't want to go to far so hopefully someone knows what too far is. Is 1 degree too far, is it not worth the effort until 2 degrees
 

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Have you done any of this cam adjusting Bladeracer. Obviously I don't want to go to far so hopefully someone knows what too far is. Is 1 degree too far, is it not worth the effort until 2 degrees

There are many variables, but more than two degrees would be unusual.

One example I have handy is from the '85 GSXR750 race manual.
For sprint racing they specify (at 1mm):
Ex opens at 45BBDC and closes at 20ATDC
In opens at 22BTDC and closes at 42ABDC
Whereas for endurance racing they specify:
Ex opens at 47.5BBDC and closes at 17.5ATDC
In opens at 20BTDC and closes at 44ABDC

So they're not changing the lobe timing, they're just increasing the duration for endurance.

Really, to decide if it's where you want it you are going to have to ride it after you make changes, or at least do a dyno graph.

BTW, I forgot to ask earlier, what do you mean you "put velocity stacks in"?
Are they longer or shorter than the stock ones? It seems counter productive to make one modification that reduces your midrange and then make another modification to increase it again, why not just take the stacks out?
 

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Thanks Bladeracer. The cam gears are APE gears so don't come with any instructions.The reason I am doing this is to increase torque down low a bit since I put velocity stacks in. What you said does make sense so all I need to do is advance the centrelines. Would you have any idea how far to advance the factory cams. Now the question is the factory centreline is 96.5ATDC and 99.5BTDC. Does anyone know what to set them to. Thanks

I would start by setting them to those stock settings first so you have a base feel for the engine. Put some miles on it and then I would suggest trying 95 and 98 and see how you like it. Be _sure_ to check piston-to-valve clearance after every adjustment. I'd be surprised if two degrees from stock is going to cause piston contact in a stock engine, but it never hurts to be sure.
What sort of engine are we talking about? I assume they're pressed onto the cams?
 

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Discussion Starter #9
The bike is a 954. I went 1 degree each (which was 95.5 and 100 I hope) so hopefully that will bring back some mid torque. I left the valve overlap the same so should be right.Velocity stacks are shorter so will reduce torque. If I can improve that a bit thats all im after. Im not a fan of running 2 cylinders lean,2 rich and vice versa after certain rev range.
 

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The bike is a 954. I went 1 degree each (which was 95.5 and 100 I hope) so hopefully that will bring back some mid torque. I left the valve overlap the same so should be right.Velocity stacks are shorter so will reduce torque. If I can improve that a bit thats all im after. Im not a fan of running 2 cylinders lean,2 rich and vice versa after certain rev range.

Why would you be running two cylinders lean and two rich?
 

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because of the different length stacks

You mean the OEM stacks?
How did you determine that two cylinders were running leaner than the others? And now they're all running the same?
 

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Discussion Starter #13
Yeah the oem ones are shorter runners on the outer and longer runners on the inside. Now because of that two cylinders on the inside will be tuned for torque and outer ones will have less torque and then when the revs hit a certain rpm the shorter ones will come into play and provide the power. So 2 cylinders work better low rpm and then the other 2 work better in high rpm.
 

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Yeah the oem ones are shorter runners on the outer and longer runners on the inside. Now because of that two cylinders on the inside will be tuned for torque and outer ones will have less torque and then when the revs hit a certain rpm the shorter ones will come into play and provide the power. So 2 cylinders work better low rpm and then the other 2 work better in high rpm.

As I asked, how did you determine that two run leaner than the others though?
And are they burning equally now?
 
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