performance cams

royfisk · Posted: August 9, 2006, 5:18 pm Post subject: performance cams

Ok here we go I would like to know of all the cams comercially available today what is the best selection for a street driven xs, with stock bore, 34mm vm carbs, only real engine mods would be good quality porting? I live and ride in the green mountains of vermont and serious torq is what I want. I want to pull the big hills effortlessly with a stock bored bike. Also this machine will have custom pipes, A 2 into1 probably into a trapp can, does anyone know what length headpipe would be required for maximum torq. thanks for the info.

royfisk · Posted: August 11, 2006, 8:16 pm Post subject: Re: performance cams

Comon guys I know some of you have tried more then one , and have opinions

Jack · Full Member Joined: Mar 15, 2005 Posts: 411

Hey Roy! You and I both have something in common,we live in mountainous regions,we're both building cafes, demand engines that delivery greater amounts of torque but our differences might be our riding styles Laughing

and your off to a great start by asking what mods and parts correlate in producing a solid running XS thats street friendly to rider. How aggressive of a rider are your in attacking the curves and how hard do you plan on pushing the motor?...................Jack

royfisk · Posted: August 11, 2006, 8:57 pm Post subject: Re: performance cams

I ride hard at times real hard. But this bike will be used quite often on dirt roads. I am basically looking for real strong low end. The bike will be outfitted with a dual sport type tire 90% street, So there probably wont be much nee draging. But will see lots of corner slides. I think that as far as pushing the motor I will use whatever it has. Probably not daily but alot. I have had zx900"s, sportsters etc. I also have slowed down some with the gray hair setting in.

royfisk · Posted: August 12, 2006, 7:28 am Post subject: Re: performance cams

Hey jack what are your thoughts on decompressors, I have riden vintage flat trackers Triumph,s and when you start into a corner and grab the decompressor it will throw the bike into a slide then when released at full throtle you have just went hard and deep enough to be able to control the slide. will the stock decompressor work like this and what would valve life be like? probably burn the left exhaust valve freaquently wouldnt I? More parts I have on the shelf that I dont know what I am going to do with.

Jack · Full Member Joined: Mar 15, 2005 Posts: 411

Roy,sorry can't give suggestive use on the decompressor for slide control,other than Yamaha used this device to releave mechanical compressive during start up do to the way cam lobe timing effected cylinder pressure build up over static compression.

two camshafts that come to mind are the Web 159,not the A model and shell #1 grind,both are excellent chioces for building low end torque more so with the web 159.

Spigot manifolds, 34mm, should be in length of atleast 1 3/4 to 2 inches to increase the cfm flow in the low to mid lifts and to enhance port velocity.
Open the spigot cross sectional area in the head to 36mm and use inside deviders mic at 36mms and work the port to this dimension and on the spigot manifold radius bore the last 1/2" to 35.5 what this'll do is help reduce laminar flow turbulence within the port as piston speeds reach their maxium velocity at higher RPMs.
The header primary tube diameter needs to be 1 1/2 to keep exhaust gas pulse velocities at their highest momentum to scavenge the cylinder more effectively during overalp for increase HP and torque. The length also helps to shuttle and alter peak torque and the longer the primary tube,the lower in the RPM range it'll peak out.

Use the largest available KN filter that'll clamp on the bell mouth to offer the greatest area of volume for the caburetors to draw air in, incase the filters get clogged up. Hope this helps you in being selective in choosing a good running combination............Jack

royfisk · Posted: August 12, 2006, 7:01 pm Post subject: Re: performance cams

Jack I went to mikes site and he does not offer the 59 grind just the a grind. So I went to webs site and they have a part # for the 59. Butr still dont know who carries them . I wonder if mike can get one if I have a part#. according to webs site that cam does not need any other engine mods, where as the a grind requires springs.. I assume this is the correct grind cause I see you have 159 which is not listed at either site. I will still use springs of course.What is the cam that 650 central calls the streetfighter?
I like the spigot manifold lengths, I have to check mine cause there off of a 72 bike. GOT TO LOVE THEM CHOPPER GUYS. I beleive that they were a kit from the 80's. I have some newer carbs from snowmobiles which would have to be totally rebuilt and jetted, I beleive even the slides would need to be changed for a 4 cycle. but i kept them because there off of 2002. Bodies I think are the same.
As for the port and manifold matching, I think that will be handled by jack. I have played before with ports and I just ruined them before I was done. I think for once I might just get them done. I would like to do it with someone sometime and just pay attention. Sort of like polishing. I ruined a few pieces before I learned hoe to polish cast alluminum. That was a expensive hobbie dam buffer cost $400.00. So nasty dirty that I dont do it anymore. still got everything but no thanks.

Jack · Full Member Joined: Mar 15, 2005 Posts: 411

Roy.........go to www.webcamshafts.com for the 59 grind # or call them.As for the streetfighter grind,that maybe one of 3Ms speacial grinds. I'd be glad to port your head,just drop me line. and you think you ruined a few heads Laughing

but thats the fun part of gaining knowledge and besides they're aluminum,so any mistakes can be corrected by welding with the aid of a flow bench Wink

...........Jack

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

So guys, what's wrong with just a good runnin' stock motor? I'm sure it would be more than enough for your back road adventures, roy.

As an aside, come back to the "Garage" Jack, we miss ya .... 5twins

royfisk · Posted: August 13, 2006, 5:38 am Post subject: Re: performance cams

5twins if you have to ask that queestion you wouldnt understand

royfisk · Posted: August 13, 2006, 5:41 am Post subject: Re: performance cams

Awesome jack; like we descussed earlier with the head I to wont be ready till fall early winter.

grizld1 · Posted: August 13, 2006, 8:18 pm Post subject: Re: performance cams

Just broke in a motor with the Shell #1, Roy; ported head, 77.5 mm Venolias, VM36's. I'm liking the cam for point-and-pull backroading--nice kick out of the corners and very tractable.

Don't know as you'll like the Mac 2-1 exhaust; had to pull mine off and sell it before it ground all the way through. The outside pipe and collector tend to scrape asphalt.

Hope to see ya at the Rendezvous, Jack! If the rain don't fall (too hard) and the river don't rise (too high) I'll be riding the D-model out.

royfisk · Posted: August 13, 2006, 8:35 pm Post subject: Re: performance cams

I dont have a mac . I have a kirker on it but want to build a upswept like a cb -350. or modified 1mile pipe. With a super trapp can. but had questioned tube length between port and can. Ive seen some say 26" or more for low end torq. im still not 100% clear on it.

grizld1 · Posted: August 13, 2006, 10:32 pm Post subject: Re: performance cams

Sorry--don't know where I got that! There's a Kerker 2-1 system hangin' in my barn--had the same grief with it in right-handers. A 2-1 high pipe would be really trick, but I'd guess the hard part of the design would be getting the port-to-collector distance and collector diameter right without interference.

royfisk · Posted: August 14, 2006, 5:07 am Post subject: Re: performance cams

My mac pipe's tubes ran down below the foot pegs and was very obvious would bottom on right handers. The kirker's runs down the center of the bottom of the engine and rises up out of where the center stand once was seems to have no problem there. The mac was all road rashed complete with holes, wouldnt have another one for anything. The kirker however has a nasty problem of very low bottoming out due to no ground clearance. It hits going in and out of the garage. Not real suitable for dirt roads. Jack has recomended 1 1/5 " tubes. Now for lengths thats the key getting it right the first time.

grizld1 · Posted: August 14, 2006, 9:14 am Post subject: Re: performance cams

Yeah, 1.5" makes for good flow and tractability. The classic "Building a Better 650" article by Gordon Jennings recommended a pipe around 32" long with 1.5" ID if I remember right, but that was for a 2-pipe setup. I don't have a clue when it comes to collector design. If you're going to run two pipes into a common can the Jennings specs will probably work real well. Right now I'm running a less-than-ideal exhaust--Mac 2-2 (1 3/8" ID) with straight-thru baffles. The engine's strong, but there'd be more power available from a better exhaust system--winter work. Wish Bub's 1.5" pipes were still available.

kingwj · Posted: August 14, 2006, 11:18 am Post subject: Re: performance cams

Bub will make a special run of 50 units. I'm in if 49 others care to join me.

grizld1 · Posted: August 14, 2006, 12:02 pm Post subject: Re: performance cams

I'm in--48 to go.

royfisk · Posted: August 14, 2006, 1:42 pm Post subject: Re: performance cams

I havent seen the pipe or a price but maybe

Jack · Full Member Joined: Mar 15, 2005 Posts: 411

Roy.........Go to headers by ed and just read,then you'll gain the basic knowledge to build your headers to suit you and but mosty important around the power band you want your motor to peak out at. Heads and headers have alot in common in controlling where HP and torque will peak at by area of volume and length,you just need to make a decision where but at a designated RPM range without over stressing the engine..

I 'm out guys,building my own system.....Cheaper plus where's the enjoyment and satisfaction ?.............Jack

Griz.........I'll be there for a day if it doesn't rain

royfisk · Posted: August 14, 2006, 7:06 pm Post subject: Re: performance cams

I agree jack my bike is me and the pipes should be too, why else did I by a welder for?

Barrett · Posted: January 22, 2007, 11:59 pm Post subject: Re: performance cams

There is a guy who lives here in Tulsa that used to build race XS 650's for Yamaha racers before Shell. He said 18-24 inches on the header length(depending on your intake length and powerband). He talked me out of the "twingle", into a 650 with big pistons(12 to 1!, a Shell #1 cam, then into a 750 kit when I had it apart again, I built two headers both 2-into-2's.

One low set with reverse cones, the other set are high-pipes that look like those on an XR-750, more for looks than power(look like Jemco's, only down the left side). Headers were not too bad with the flange kit I bought. I thought it was 1 3/4" pipe (I will look and measure). I used stainless hand rails (made for a bathroom) for exhaust tubing, mocked it up and had a buddy TiGit together for the 2-into-2 low on the right(might not offer the ground clearance for a Cafe though, lloked cool & turned gold with use) I swapped between reverse cones and universal SuperTrapps. They are on my buddy's dirt tracker right now, he used a heat crayon and shortened them up to match is motor combo (drew a line lengthwise on the pipes, made a few practice laps in the power band, then cut the pipes where the line had not burned away, intant tuned header, per cylinder I might add, you could also add a crossover at the same point if running mufflers or cones etc.)

royfisk · Posted: January 23, 2007, 8:24 am Post subject: Re: performance cams

barret that header tuneing trick is cool , I never would have thought of it, but makes perfect sense. real cool tip.

Barrett · Posted: January 25, 2007, 1:36 pm Post subject: Re: performance cams

I have done my fair share of torturing different stuff...don't get me started on convergent cones and divergent cones...two stroke stuff is wierd...port timing, pistons...180 degrees.... Adding the cross over helps with scavenging and makes bikes quieter without giving up a good sound or power. Never understood Triumph adding the cross over just past the port though? It works better to have the cross over in the straight pipe, before/ahead of the mufflers.

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