DirtRider . Net MX, SX, Arena Cross, Off-Road Community

This is the text version of DirtRider.Net
Click Here for the Full Version

Pages: 1

Megacycle cams
(Click here to view the original thread with full colors/images)

Posted by: Taliesin---------------------

Does anybody know of a performance cam available for a Husky 610/570.I have heared that Megacycle make one but can find any info.Anybody know of any manufacturer which make one?

Posted by: SFO---------------------

I believe the megacycle grind is an all arounder drop in.
Web Cam also does a husky grind too.
What is the application and what kind of power delivery are you looking for?

Posted by: Taliesin---------------------

The application is for supemotad I am working on a 2001 SMR570.Going for a 100mm piston & head flowed.Looking for approx 70HP at rear wheel.I could use the TC cam from Husky which has twice the inlet duration of the TE cam.However this is still a mild cam with a good spead of torque.Looking for more top end rush.Is there any web based sites with details of these cams?I am also aware that Uptite Husky makes a radical cam but they are out of stock.

Posted by: SFO---------------------

The uptite cam is manufactured by web. (I believe)
Give them a holler with your needs.

http://www.webcaminc.net/

Laurie and Debbie are great, BTW.

70RWHP is going to be a very tall order.
I have heard a few 70rwhp claims that out of SMR's that are all race prepped but I have never seen any dyno runs to back it up. Gonna need a head that moves ALOT of air.
A national level 600cc DT bike was making mid 60's at the rw a few years ago, I would be very happy if a 570cc sm bike would just break the 60rwhp barrier.
This is on a dynojet.
Keep us posted.

Posted by: Taliesin---------------------

SFO Yes you are right 70HP is a tall order.A standard SMR 570 with a different silencer & air box mods normally put out 54RWHP.The NOX puts out 60-62RWHP as standard which runs an FCR41mm & Titanium tappered Akropovic exhaust & a TC camshaft.
The SMR I am building for a customer will have all the above plus a 100mm piston giving 601cc compared to standard 577cc.Hence I am looking to achieve 65RWHP.There are 1mm oversize inlet valves available @ 36mm from Blackdiamond not sure if I will go for these or a more radical cam.
In Italy/Germany there is talk of 75HP from some teams but everybody I speak to still runs the mild TC cam.Maybe torque & diveability is more important in SM racing than outright power.

Posted by: Rich Rohrich---------------------

Quote:

Originally posted by Taliesin
Maybe torque & diveability is more important in SM racing than outright power.

It sure seems to be in American dirt track racing. :thumb:

Posted by: SFO---------------------

My #'s for a standard 610~570 put it around 46~48rwhp.
Part of the beauty of KTM poaching the husaberg head is that we now have 3 different brands running a nearly identical cylinder head.
KTM
Husaberg
Husqvarna
All the old style husaberg valve train drops into the husky.
When I worked at KMPI I worked on a 5mm valve stem conversion for my husaberg, from the stock 6.5mm valve stem.
If you talk to them they might have some of this stuff still hanging out.
Some of our customers reported up to a 15% gain on the flow bench by just reducing the stem dia.
I believe you can go up to a 40mm head on that stem size. Of course KMPI can do all of this custom for you.
Between the 3 brands you will also probably find that pistons, rods, and cam profiles are pretty interchangeable if you want to tinker with your rod ratios.
As I said on thumpertalk, Dale Lineaweaver is a real gentleman and has all of these combinations pretty mapped out, along with his own cam profiles based on untuned exhaust which allow him to get a broader torque curve.
Thunder Alley will also make custom one off down pipes for DTX or motard set-ups, I think without the constraint of fitting into and through the frame you might get better results out of a tuned megaphone.

Besides Dale you might want to try contacting-

http://www.gw-racing-parts.de/gross...lt/english.html

Friedhelm is another huge wealth of knowledge, he has a dyno and a cnc cam grinder.

The best #'s for a single I have seen were from a 720cc rotax and that was low 70's. It also has a short life span, around one race.

Posted by: Taliesin---------------------

Excellent info SFO.You are right about the heads very similar loads of people don't beleive me when I tell them that KTM has copied a lot of their 400/520 engine from the Husky design.
Any info of which Berg cam could be utilised in the Husky motor?I havene't got the time to get a custom made cam.This could be in the future.
I shall keep posting the progress of the project.I shall also post the Dyno readings on my web site.

Posted by: SFO---------------------

The history is really rich on this head.
Husky bought the Mailey speedway motor.
The Mailey head was based on the xl-350 honda, for interchangability ie, off the shelf valve train.
Maybe Bill Bell (Precision Concepts) would have some insight into our new motors based on the baja bullets he built?
I hope I have the history correct, maybe ol'89'r can straighten it out if I am wrong.
Be careful with the stock berg cam grinds they are convex flanked and very destructive to valve train due to excessive acceleration.

Posted by: Ol'89r---------------------

Quote:

Originally posted by SFO
The history is really rich on this head.
Husky bought the Mailey speedway motor.
The Mailey head was based on the xl-350 honda, for interchangability ie, off the shelf valve train.
Maybe Bill Bell (Precision Concepts) would have some insight into our new motors based on the baja bullets he built?
I hope I have the history correct, maybe ol'89'r can straighten it out if I am wrong.

SFO. You are correct as usual sir. :thumb:

Maely's head was a total knock-off of the XL350 head and used all of the stock Honda valve components. Valves, guides, rocker arms, etc.

If you are referring to the late Bill Bell from Long Beach Honda Racing, the cams that he used on Al Bakers Baja winning XL and all of the other XL engines were Web cams.

TALIESON.

SFO's suggestion to talk to Lauri Dunlap at Web Cam is a good one. If you have a specific grind that you would like to try, they may custom grind it for you. Jim at Megacycle is a wealth of information also, if you can get through to him.

Just my $ .02

Posted by: SFO---------------------

So, the pentroof xl-350 head was influenced pretty heavily by the cosworth 4v heads of that era which in turn were influenced by Weslakes work on the shallow included valve angle 4v heads.
Now when the mailey was purchased by husky it also was said to be the inspiration for the godden speedway motor.
How ironic that the godden motor was going head to head with the weslake motor.

Posted by: Swiss---------------------

Bell also used the 2740 Megacycle cams in the bigger motors, and MAY have used some of the bigger 2760/90 cams in specialty engines. The "Bill Bell" article that was done on the XL engines in the '70s showed the -40 as being the most radical cam recommended, but the -60 and -90 cams were developed later than the smaller -40. Bell did a lot of development work on these early heads with an old Offy expert, and worked closely with Jerry Branch of Branch Flowmetrics for his port designs.
And it is Maely, not Mailey. The Shoe Man!
As Ol'89r said, Bill Bell died a number of years ago. He left the Honda shop (Long Beach Honda) VERY shortly after the nice article was written about him and his XL Hondas, and went to manage the Yamaha MX Racing Team where his son Mike Bell was a Factory MX rider. He MIGHT have been the Rob Muzzy of the '70s if he had not died.

A friend of mine in Sweden built a pipe for his Husaberg FS650 Motard and he dyno'ed out at 70 hp at 8k rpms. Didn't mention what brand of dyno he used.

Swiss

Posted by: Ol'89r---------------------

Quote:

Originally posted by Swiss
Bell also used the 2740 Megacycle cams

Swiss

Swiss.

You Sir are also correct.

The reason that I know this is because I was employed by Long Beach Honda Racing during that period in time doing R&D on the thumper motors.

And yes, we did use the Megacycle cam in some of the engines. Mostly the 2740 with the needle bearing configuration. As you may know, the XL heads did not have removable cam bearings. The cams ran in an aluminum journal that was part of the head. When they ran low on oil the cams would seize on the journal and destroy the heads.

Megacycle came out with a needle bearing cam that with a little machine work would fit in a damaged head. We did use a lot of those. Megacycle makes a great cam. I ran a 2740 in my own XL350/410 motor in a C&J frame. I have some photos of that bike that I will post if I can ever figure out how to. :confused:

The cam we used for the standard production engines was the Web cam.

The other guy in the shop was Herb Litch. Herb ran the machine shop and did the stroker cranks.

A lot of the things that we played with in those days are just now coming out in factory production engines. It was great to be a part of that and I consider myself very lucky to have been able to work along side of guys like that.

Ol'89r

Posted by: Swiss---------------------

Ol'89r
My understanding was that Herb (didn't know who it was at that time) used a torch to soften the rods for shortening them? Paul at Powroll used a high current to heat them up. He told me years ago, when I pointed out that the article mentioned the torch softening, that the rods would give off I believe Arsenic gas or some other poisonous gas and would certainly need to be well ventilated. Still working on my 486cc motor. 3mm os SS valves and the 2790 NB cam. 1/4" stroker with an 89mm XR500 piston. Put a 41mm carb on it back in the mid '80s after working up from a 36-38mm units. Built a 2" od pipe for it back in about '85. When I first put it together in '75, it weighed 219 lbs with oil/no gas. XL125 magneto and Mototek CDI. Been waiting a while for the Factory bikes to get it right. So they are running what now--450cc, 39-41mm carbs and 2" pipes? Still a bit heavy, but looking pretty good and they are a LOT tougher than our old home-builts.
I was on a trip from Tacoma, WA down to Powroll and then planned on going to Long Beach to do my crank/rod, but Paul said that he would do it for me. I made it to LB Honda a couple of years later and they told me that Bill wasn't with them anymore.
Now I kind of wish that I had the stock stroke with a Carillo rod, figure that even with the os valves, it would give me about another 1000 rpms with the short stroke and work about right for the head work. I had Al Oppie (University Honda Seattle and then with Bob Braverman at Powerhouse Performance) convert my early XL head over to centerport before the Factory centerport units were brought into the country. He was also an old Offy engineer if I remember right. I have thought about using a 48mm cv carb off of one of the newer 1000 Honda twins. I have a pair of them and it would be interesting for trail riding in my old age. <grin>
Just got an older 4054 inverted KTM front end for it (just need a caliper) and want to convert it to a single shock, maybe with a seat/tank fron one of the early '90s ATK MX versions. Still think that they were one of the best looking Factory Thumpers ever made. VERY narrow before it was just something that the Japanese Factories did. Want to do a primary gearing change to it to lessen the problems with the 3rd/4th gear sets. I just switched over to a 250 Trials gearbox for the wide ratio set. XLWR350/486.
Back when I had more time and money, I used to come out to the old 4-Stroke Nationals, that was BEFORE they made it a series, like in the early '80s.

Swiss

Posted by: Ol'89r---------------------

Quote:

Originally posted by Swiss
Ol'89r
My understanding was that Herb (didn't know who it was at that time) used a torch to soften the rods for shortening them?

Swiss

Yes, Herb did use a torch for that. He had a fixture that crushed them down to the proper length. Never did have one let go that I know of.

That sounds like quite an engine that you have put together.

We found that the long rod and stroker engines were two completly different engines. The long rods worked very good and would rev to the moon. The strokers had gobs of torque off the bottom, but would run out of r's very early. It would depend on what the customer was going to use the bike for.

Mine used a 410cc Venolia piston with a stock rod length. Plenty fast enough for me and much easier on engine life. The strokers were very hard on gearboxes and that was the XL engines weak point.

It's kinda funny that a lot of the technoligy that we see today has been around for so many years.

Ol'89r

Text Version Home

This is the text version of DirtRider.Net Click Here for the Full Version

Megacycle cams

This is the text version of DirtRider.Net
Click Here for the Full Version