Degreeing hotcams to suit application

I just read the excellent writeup by KVO-TN1-tobeat on how to degree hotcams using the hotcams degree kit

http://www.thumpertalk.com/forum/showthread.php?t=470426

It was mentioned later in the thread that

You can also play with advanement and retardation. Advancing or retarding a cam, consists of moving the lobe center forward or backward in it's timing in relation to the piston position. Doing this is a way to taylor the motors performance to a persons specific riding style or for specific riding conditions.

Say that you wantd to have more bottom end for heavy woods riding. You wold be needing to stick a gear and open up the throttle at a verry low RPM, so obviously you would want more power down low and it would be a waste to have your cams degreed for top end performance. You would retard the intake a few degrees and advance the exhaust slightly. This would widen the powerband but give you less performance up top. Here is what the Muzzy article says about it,

"Very generally speaking, the effect of moving lobe centers is as follows:

Advancing the intake and retarding the exhaust (“closing up the centers”) increases overlap and should move the power up in the RPM range, usually at the sacrifice of bottom end power. The result would be lower numerical values on both intake and exhaust lobe centers.

Retarding the intake and advancing the exhaust (“spreading the centers”) decreases overlap and should result in a wider power band at the sacrifice of some top end power. This condition would be indicated by higher numerical values on both intake and exhaust lobe centers. By moving only one cam the results are less predictable, but usually it is the intake that is moved to change power characteristics since small changes here seem to have a greater effect. With twin cam engines we have the luxury of moving the cams independently."

Have any forum members degreed their hotcams outside of the hotcams factory specs, to suit a particular application ?

If so, where did you get your custom specs from ?

Alternatively, is it better for most of us to stick with hotcams factory specs when degreeing the cams, regardless of application ?

the stock hotcams lobe center offer the better overall spread of powers. you can change them to move the power around. however,lobe center drastically affects piston to valve clearance and need to be checked any time you stray from 108/104.

the stock hotcams lobe center offer the better overall spread of powers. you can change them to move the power around. however,lobe center drastically affects piston to valve clearance and need to be checked any time you stray from 108/104.

Good to know.

I'll stick with HC's stock specs and see how that goes.

Couple more questions

Does anyone have pictures/specs of a threaded stand off to adapt the degree wheel to the crank end from outside the stator cover ?

Sounds like a handy tool to get machined up given one has to make something anyway to hold the degree wheel securely in place.

and

Just for a matter of interest, does the E base gasket mod done to an S/SM have any effect on the cam timing since it effectively brings the cam sprockets closer to the primary sprocket.

If so, does it retard or advance the timing and by how much ?

Couple more questions

Does anyone have pictures/specs of a threaded stand off to adapt the degree wheel to the crank end from outside the stator cover ?

Sounds like a handy tool to get machined up given one has to make something anyway to hold the degree wheel securely in place.

and

Just for a matter of interest, does the E base gasket mod done to an S/SM have any effect on the cam timing since it effectively brings the cam sprockets closer to the primary sprocket.

If so, does it retard or advance the timing and by how much ?

I do not have a pic handy.. but it is simple to make.

35mm long end to end. Both ends drilled and tapped M12x1.25.

The end for the crank side is simply faced.

The end for the wheel side has a step cut 3mm wide with an OD that fits YOUR degree wheel. (Hotcams is .6875 (11/16) if I remember right. Motion Pro is smaller, others I do not know.)

Screw the adapter on to the end of the crank shaft, place a square cut O ring on the adapter end, then the degree wheel, then a 12mm washer, and secure the wheel to the adapter with a M12x1.25 bolt.

The adapter can be shorter if you’re going to have the side cover off during use, and only use this on a DRZ.

Each gasket layer is about .010 thick.. so going from 3 layer to 1 layer, your lowering the head about .020". Yes it will change the timing advancing and retarding timing respectively on each cam.. But not anything worth worrying about unless your building a very high tune motor..

A thinner base gasket will retard both cams giving you a smaller lobe center number on the ex. cam and a larger number on the intake. And to add to what Eddie said, as long as your going to a larger lobe center number, like from 104 to 107, on either the in. or the ex. it's safe. It's when you close up the lobe centers or go to a smaller number on either cam is when you can get into trouble with valve to piston and valve to valve clearance.

I do not have a pic handy.. but it is simple to make.

35mm long end to end. Both ends drilled and tapped M12x1.25.

The end for the crank side is simply faced.

The end for the wheel side has a step cut 3mm wide with an OD that fits YOUR degree wheel. (Hotcams is .6875 (11/16) if I remember right. Motion Pro is smaller, others I do not know.)

Screw the adapter on to the end of the crank shaft, place a square cut O ring on the adapter end, then the degree wheel, then a 12mm washer, and secure the wheel to the adapter with a M12x1.25 bolt.

The adapter can be shorter if you’re going to have the side cover off during use, and only use this on a DRZ.

Thanks for that

I guess you use ~1"round rod ?

Can the threaded hole degree wheel end be 10mm to allow more meat between the hole and 11/16" dia shoulder ?

The degree wheel side can be what ever you want it to be, based on your wheels center hole.

making it M12x1.25 was just for a common use of the tap needed for the other end. And it is a large enough fastener (shank and head)to turn the crank with.

The shoulder is not required.. you could make a small bushing (cap) that clamps and locates the wheel, or just clamp it between the fastener and the adapter.

My adapter started as a left over hunk of SS 1.5" hex stock...

The degree wheel side can be what ever you want it to be, based on your wheels center hole.

making it M12x1.25 was just for a common use of the tap needed for the other end. And it is a large enough fastener (shank and head)to turn the crank with.

The shoulder is not required.. you could make a small bushing (cap) that clamps and locates the wheel, or just clamp it between the fastener and the adapter.

My adapter started as a left over hunk of SS 1.5" hex stock...

Yep, thanks :cheers:

I do not have a pic handy.. but it is simple to make.

35mm long end to end. Both ends drilled and tapped M12x1.25.

The end for the crank side is simply faced.

The end for the wheel side has a step cut 3mm wide with an OD that fits YOUR degree wheel. (Hotcams is .6875 (11/16) if I remember right. Motion Pro is smaller, others I do not know.)

Screw the adapter on to the end of the crank shaft, place a square cut O ring on the adapter end, then the degree wheel, then a 12mm washer, and secure the wheel to the adapter with a M12x1.25 bolt.

The adapter can be shorter if you’re going to have the side cover off during use, and only use this on a DRZ.

More questions with regards to degreeing the cams without taking off the stator cover and using a standoff.

I don't have a pneumatic impact wrench to remove the nut on the end of the crankshaft.

Can I put the bike in gear with rear brake applied to stop the crank from rotating while I remove/refit the nut with a normal 17mm socket and bar ?

If so, which gear should I put it in, 1st, 2nd .......5th ??.

For those that do this with stator cover on and a standoff, how do you stop the crank from turning when using a tension wrench to torque up the rotor nut ?

More questions with regards to degreeing the cams without taking off the stator cover and using a standoff.

I don't have a pneumatic impact wrench to remove the nut on the end of the crankshaft.

Can I put the bike in gear with rear brake applied to stop the crank from rotating while I remove/refit the nut with a normal 17mm socket and bar ?

If so, which gear should I put it in, 1st, 2nd .......5th ??.

For those that do this with stator cover on and a standoff, how do you stop the crank from turning when using a tension wrench to torque up the rotor nut ?

To hold the OEM flywheel (all models but the kicker) you use a tool like this.

attachment.php?attachmentid=8483&d=1217105503

For an after-market flywheel or the OEM kicker one you use a strap wrench.

The stator cover has a reusable gasket.. Simply remove the cover, so you can properly hold the flywheel while torquing the nut.

The degree wheel adapter is just that, a way to attach it to the crank..... I've never found the need to try and do the job with the stator cover on.

I've been running the Hotcams IN and EX / CW 434 BB for around 5k miles now .

The cams have never been altered from factory spec timing and were installed with a new timing chain.

I would like to shift the power lower in the rev range for my type of offroad riding.

Should I just swap the HC EX for the OEM EX cam, or can I get a better result by retaining both IN and EX HC's and adjusting the lobe centers ?

Are there any proven HC lobe center settings that would achieve my aim ?

You can retard the intake and advance the exhaust to make a little more mid range power...You will gain about 1/2 of what you lose from the top end...

Straying beyond 104-108 on either cam requires you checking piston to valve clearance using clay..

I would PM Eddie for tried and tested settings...

You can retard the intake and advance the exhaust to make a little more mid range power...You will gain about 1/2 of what you lose from the top end...

Straying beyond 104-108 on either cam requires you checking piston to valve clearance using clay..

I would PM Eddie for tried and tested settings...

Yes, known safe settings would be good.

You would use 5th gear but with the primary gear reduction I'm not sure you can hold the torque with the rear brake. You can use a piston stop to hold the motor from turning. The stop should stop the piston at mid stroke but I hesitate to use one above 50 lb torque. Perhaps someone else can say it it is a good or bad idea.

You would use 5th gear but with the primary gear reduction I'm not sure you can hold the torque with the rear brake. You can use a piston stop to hold the motor from turning. The stop should stop the piston at mid stroke but I hesitate to use one above 50 lb torque. Perhaps someone else can say it it is a good or bad idea.

I might just do it when its due for an oil change and pull the stator cover so I can use an offset wrench to hold the rotor.

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