Author Topic: High Performance Camshafts & Head Porting...  (Read 6956 times)

J6G1Z

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High Performance Camshafts & Head Porting...
« on: April 24, 2014, 09:35:21 AM »
A couple of ways to really increase the performance potential of a 4-stroke engine is to install a higher performance camshaft(s) & to port your cylinder heads.

Somewhere in my surfin' around on the internet, I had run across a camshaft grinder that listed camshafts for the VT500 engine. I thought it was MegaCycle. but there current brochure no longer lists it. http://www.megacyclecams.com/catalog/catalog.pdf
There is also Web Cam Inc: http://www.webcamshafts.com
Here is a primer on camshafts: http://www.oregoncamshaft.com/cam-basics.html

The FT500 Ascot is much easier to find a performance camshaft due to its close relation to the Honda XR/XL engines.

Now technically just about any factory OEM camshaft can be reground to a higher performance profile. This is done in several different ways. Probably about the simplest method is to reduce the diameter of the base circle of the camshaft. This in effect makes for a higher lift lobe profile once the material that was removed, is made up for by adjusting the length of the pushrods in that style of engine, or adjusting the extra lash out of the rocker arms. Another method is to weld additional material to the peak & surrounding area of the camshaft lobe, then grind the additional material to the proper new profile. After that is done, the camshaft is usually re-hardened or heat treated.

Another real trick modification to look into, is to install needle bearings at each end of the camshaft vs. a solid bushing & a thin film of oil. The needle bearings reduce some of the internal friction of the engine thereby releasing some additional power & throttle response.

Now for some type of modification that the average mechanically inclined person can perform at home. Some port & polish work. Now there are professional people out there that are highly talented at portwork & have a flow-bench to test their work with. If you can afford to have a "master" port your heads, you most likely will not regret it. But the average guy with a small hand grinder can still accomplish measureable performance gains with some study & some modest grinding/smoothing in the appropriate areas. The concept that we are after, is to try to "straighten" the port & to make any sharp radius less pronounced. Without the benefit of years of experience working with a flow-bench, you do not necessarily want to enlarge the port. For a street bike, we want to maintain a smaller port profile to enhance velocity of the charge. What the average Joe wants to look for, is casting flash that hangs down, or is rough. Something that obviously needs to be removed. Then try to imagine the flow of air, gas, or even the flow of water going through the port. We know that a charge that is moving doesn't like to change direction & will slow down. Now look down into your ports & try to see areas of the port that would resist smooth flow or transitions. Any sharp edges, machining marks, sharp radius with a peak to it, etc. We are not looking to redesign the port, simply make the best of what is already there. If there is a large protrusion around the valve guides, that is usually reduced to a minimum & tear drop shaped. Keep in mind while you are working that if there is more than one intake & exhaust port, you will need to match any changes that you make to one port, to the corresponding port. All intake ports should have as close to the same profile as possible & the same for the exhaust. I recommend that you start with the exhaust port as it will be less critical if you make a mistake. You want to pay special attention to the port "bowls" or "valve pockets" which is the area of the port closest to the backside of the valve. Most of your performance gains take place in the "bowl" & the valve seat area. A three-angle to a multi-angle valve seat really helps to improve the flow numbers. When doing your grinding/smoothing near the valve seats, you must excercise great care not to damage the valve seats. Often the valve seats are "high-lighted" with machinists bluing, or even a large red marker to make them easier to see.

These are some of my thoughts on performing some simple port work that can benefit your bike. The real beauty of port-work is that when it is performed properly, you can release large numbers of "free" power. Just think of the engine as an "air-pump". Anything that you can do to increase the amounts of air that is passed through the engine, or to reduce any frictional or pumping losses, will build power.

Below are several articles on performing port work.
http://www.diyporting.com
http://ascot500.com/index.php?topic=106.0
http://mototuneusa.com/power_news_--_think_fast.htm
http://mototuneusa.com/power_news_--_homework.htm
http://mototuneusa.com/power_news_--_the_2007_superbike.htm
http://mototuneusa.com/power_news_--_supersonic_nozzle.htm
http://mototuneusa.com/power_news_--_success_stories.htm
http://mototuneusa.com/thanx.htm
http://www.popularhotrodding.com/tech/0610phr_cylinder_head_porting
http://www.popularhotrodding.com/enginemasters/articles/hardcore/0412em_porting_cylinder_heads

I will add more to this topic as I run across more information.
J.

Dougie

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Re: High Performance Camshafts & Head Porting...
« Reply #1 on: April 24, 2014, 01:30:03 PM »

Ascot cams are still listed by Megacycle cams. Page 33

They are in with the 650 Hawk and Transalp which suggests that they could be interchangeable.

HONDA NT-650 HAWK (19881991) 500 ASCOT twin (19831984) .......................... (19831991) .......... 33





J6G1Z

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Re: High Performance Camshafts & Head Porting...
« Reply #2 on: April 24, 2014, 05:48:20 PM »
Excellent find! Thanks. 8)

J.

J6G1Z

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Re: High Performance Camshafts & Head Porting...
« Reply #3 on: April 26, 2014, 08:19:11 AM »
According to another forum member, this shop knows a thing or two about modifying the Ascots heads for some measureable power increases. http://www.hordpower.com

It looks like they do some excellent work on the Hawk engine & it appears that there may be some interchange possibilities. I noticed that they offer three stages of port work & install 2mm larger intake valves. They also offer big bore kits, highly worked over crankshafts, heavy duty connecting rods, etc. How much transfers over to the VT Ascot, I don't know. I will try to call them in the following week & see what they have to say.

J.

EDIT: I contacted Hordpower today & was able to speak to J.D. Hord. Unfortunately they do not provide any services for the Ascot.
« Last Edit: April 30, 2014, 11:11:47 AM by J6G1Z »

Dougie

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Re: High Performance Camshafts & Head Porting...
« Reply #4 on: April 27, 2014, 08:33:36 AM »
One of the difficulties is getting above 600cc. In the USA it should be possible to fit a Transalp 600 engine in and fit the shaft drive output mechanism from the original engine in place of the chain drive.
650 head is quite different as the front exhaust port fouls the frame downtube.

J6G1Z

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Re: High Performance Camshafts & Head Porting...
« Reply #5 on: April 27, 2014, 10:25:03 AM »
One of the difficulties is getting above 600cc. In the USA it should be possible to fit a Transalp 600 engine in and fit the shaft drive output mechanism from the original engine in place of the chain drive.
650 head is quite different as the front exhaust port fouls the frame downtube.

I have often wondered if there were some engine swap candidates. The VT Ascot is not bad stock & is a fun, well balanced bike. I always want a bit more after a while though.

Any idea how much larger the exterior package of the Transalp 600cc engine is than the VT500 engine?

Thanks
J.

Dougie

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Re: High Performance Camshafts & Head Porting...
« Reply #6 on: May 11, 2014, 05:17:13 AM »
They look exactly the same even down to the air cooled look.

Cylinders could be a little bit taller as the stoke is longer.

AscotDog

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Re: High Performance Camshafts & Head Porting...
« Reply #7 on: May 12, 2014, 09:39:55 PM »
I thought it was MegaCycle. but there current brochure no longer lists it. http://www.megacyclecams.com/catalog/catalog.pdf

See page 32 bottom in the PDF catalog, can be found searching for "Ascot".... they are close to me, in fact I may be driving through San Rafael tomorrow... and I have the camshaft off my ascot (middle of a head gasket replacement)... haha, I wonder what one performance camshaft would do. I think I'd have to drop the engine to replace the other. Not sure... is it hard to remove the airbox, it seems to be in the way of removing the cylinder head cover...


J6G1Z

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Re: High Performance Camshafts & Head Porting...
« Reply #8 on: May 13, 2014, 07:27:52 AM »
I thought it was MegaCycle. but there current brochure no longer lists it. http://www.megacyclecams.com/catalog/catalog.pdf

See page 32 bottom in the PDF catalog, can be found searching for "Ascot".... they are close to me, in fact I may be driving through San Rafael tomorrow... and I have the camshaft off my ascot (middle of a head gasket replacement)... haha, I wonder what one performance camshaft would do. I think I'd have to drop the engine to replace the other. Not sure... is it hard to remove the airbox, it seems to be in the way of removing the cylinder head cover... 

If you have a VT Ascot, you will need to replace both camshafts at the same time.

It is difficult to remove the air-box on a VT Ascot. You might have to drop out the swingarm & rear wheel, fender assembly to slide it out the back. I'm not sure if it will make it out one of the sides. The air-box has a crankcase vent oil seperator attached to the bottom of it. Plus the coolant recovery tank is located below the air-box. It is a very tight fit.

You probably need to drop the engine to remove the rear cylinder head. If you are replacing the front head gasket, isn't it a good idea to replace the rear also? The rear cylinder usually runs a bit hotter than the front cylinder does. I'm just wondering if the the front gasket failed, what are the chances that the rear gasket is bad also?

Probably not what you wanted to hear.

Good luck
J.

Buddy

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Re: High Performance Camshafts & Head Porting...
« Reply #9 on: May 13, 2014, 07:50:14 PM »
The rear valve cover will come off with the air box in place. The snorkel must be removed. Not sure about the head. But the valve cover will get you access to the cam.

The air box will come out of the VT Ascot and Shadow without pulling the swing arm. Remove the rear fender and battery box first. Wiggle the air box around and twist the crankcase vent catch chamber 1/4 turn to get it off the bottom. Removing the wheel might get it out the rear but I haven't tried that. The box will come out the side. The right side I think. Getting it back in will be a challenge. I haven't tried that yet either. But it's coming.

Hope that helps.

Buddy
83 VT500ft Ascot (x3)
09 Yamaha Venture Royal(Miss Vivian)
If ya can't dazzle 'em with brilliance, baffle 'em with B. S.

J6G1Z

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Re: High Performance Camshafts & Head Porting...
« Reply #10 on: May 14, 2014, 08:10:14 AM »
Thanks for that info Buddy. I recently removed a VT air-box, but I was primitive in removing it. The air-box had a couple of cracks in it & looked to be allowing dirty air into the clean side. I wasn't able to get it out of the frame, so I broke out the sawz-all & sliced the air-box. :-[ It came out real easy then. :D

I don't recommend taking the sawz-all to perfectly good parts. If my air-box hadn't been cracked I wouldn't have cut it.

Good luck
J.

Buddy

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Re: High Performance Camshafts & Head Porting...
« Reply #11 on: May 14, 2014, 04:49:46 PM »
Mine are cracked also. I'll bet it would be hard to find one that's not. Everyone should check theirs. Cracks in the box lets dirty air into the engine as you mentioned.

I'm gonna repair/modify mine and put them back. If it's made out of ABS I'll use acetone and Legos. If not I'll try some caulking I saw at the hardware store.

Buddy
83 VT500ft Ascot (x3)
09 Yamaha Venture Royal(Miss Vivian)
If ya can't dazzle 'em with brilliance, baffle 'em with B. S.

AscotDog

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Re: High Performance Camshafts & Head Porting...
« Reply #12 on: May 18, 2014, 08:59:48 AM »
Buddy, great info, thanks. Regarding replacing the rear head gasket--I know the compression is good, so I'm just going to roll with it.

But this does open up the camshaft upgrade as an easy possibility. Will have to give that place a call once the ascot is running and I'm searching for that extra tad of HP!

Dougie

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Re: High Performance Camshafts & Head Porting...
« Reply #13 on: May 21, 2014, 02:58:02 AM »
An issue may be the worm drive for the rev counter.

On the later engines (Hawk, Deauville etc) the rev counter is electronic and the cam covers have no outlet.

Maybe just convert to electronic from a Hawk?

J6G1Z

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Re: High Performance Camshafts & Head Porting...
« Reply #14 on: June 19, 2014, 08:07:52 AM »
Here is an automotive engine related link with several pictures of various Port & Chamber work:  http://caddy500.com/index.php?topic=61.0
There are also a few "How-To" articles on porting.



J.

Buddy

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Re: High Performance Camshafts & Head Porting...
« Reply #15 on: June 19, 2014, 09:12:01 PM »
Air box install update, they go back in real easy with the rear wheel and fender removed. Swing arm is not in the way at all.

I was once a member of that Cadillac forum. Like the Ascots, the big Cadillac engines don't get the appreciation they deserve. I once had a 500cid Caddy in a 91 Dodge Ramcharger. Plenty of power and 13 mpg. 

Buddy

83 VT500ft Ascot (x3)
09 Yamaha Venture Royal(Miss Vivian)
If ya can't dazzle 'em with brilliance, baffle 'em with B. S.

J6G1Z

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Re: High Performance Camshafts & Head Porting...
« Reply #16 on: June 20, 2014, 08:41:07 AM »
Air box install update, they go back in real easy with the rear wheel and fender removed. Swing arm is not in the way at all.

I was once a member of that Cadillac forum. Like the Ascots, the big Cadillac engines don't get the appreciation they deserve. I once had a 500cid Caddy in a 91 Dodge Ramcharger. Plenty of power and 13 mpg. 

Buddy

I managed to re-install my airbox without removing the rear tire. I did have to move the inner fender back & up against the tire. I don't recall how I managed to finally get the box through the side, but it wasn't easy. My bike does not have the coolant recovery tank in the original location & I'm not running the oil seperater either as I placed a filtered breather on the rear cylinder vent port. It is all a very tight fit & removing the rear tire was next on my agenda if I couldn't get it from the side.

So you were a member of Caddy500.com? I started that board originally. It was an active forum at first, then there was a falling out & several members left. Now the Cadillac popularity seems to be on the waning side as more folks look to the LS series of engines for their projects. Please send me a PM with the details on your Ramcharger. I'd like to hear all about it. Do you have a build post somewhere?

Thanks
J.

PS. Back to the Ascot airbox. I remember that I had to remove the upper airbox mounting bracket towards the rear, to have enough room to wiggle that box in there.

Dibingo

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Re: High Performance Camshafts & Head Porting...
« Reply #17 on: July 30, 2014, 04:37:06 PM »

They are in with the 650 Hawk and Transalp which suggests that they could be interchangeable.

HONDA NT-650 HAWK (19881991) 500 ASCOT twin (19831984) .......................... (19831991) .......... 33

Sorry, it's wrong !
It's not because it's not written, that it is suggested!  ;D

650 Hawk and Transalp 600 could be interchageable, but not with de VT500.
Cause of the gearing of the rev-counter.  ;)
http://www.v2-honda.com/

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J6G1Z

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Re: High Performance Camshafts & Head Porting...
« Reply #18 on: July 31, 2014, 06:57:19 AM »
According to the company's tech rep the camshafts work in the VT Ascot.

Now it's possible that you may lose the tach drive on some grinds. Allthough if you are sending in your original camshaft cores to be re-ground, you are pretty much guaranteed that you will still have the tach drive.

The question that I forgot to ask, is if there is a needle bearing option for the ends of the VT camshafts like the FT cams have.

J.

Dibingo

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Re: High Performance Camshafts & Head Porting...
« Reply #19 on: July 31, 2014, 10:49:39 AM »
 :-\
Quote
According to the company's tech rep the camshafts work in the VT Ascot.

I have both camshafts (hawk and VT5), they are really different in their length.
It is just that the timing of valves is identical. (10/40/40/10)

At your home, there is a mystery!  ;D
Or then: they re-cut everything?  :P

Quote
The question that I forgot to ask, is if there is a needle bearing option for the ends of the VT camshafts like the FT cams have.

I don't remember any more. I am going to take out again my parts, to see...
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Dougie

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Re: High Performance Camshafts & Head Porting...
« Reply #20 on: August 01, 2014, 03:10:15 PM »
:-\
Quote
According to the company's tech rep the camshafts work in the VT Ascot.

I have both camshafts (hawk and VT5), they are really different in their length.
It is just that the timing of valves is identical. (10/40/40/10)


Interesting, are the cams longer, more lift or the overall length of the whole shaft?

Dibingo

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Re: High Performance Camshafts & Head Porting...
« Reply #21 on: August 28, 2014, 01:21:27 PM »
No possible adaptation in my opinion!  ;D
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gravelordsmc

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Re: High Performance Camshafts & Head Porting...
« Reply #22 on: May 29, 2017, 07:03:10 PM »
How about this the vlx600 was modeled after the vt500 .... the 600s cylinder head is almost identical to the vt500 it looks as if the bolts will line right up. so im linking of boring my vt500 up to 600cc use the vlx600 pistons and cylinder heads and see how that goes ...