MikesXS Camshaft - Anyone running it?

Punkskalar

Punkskalar

Hugh's HandBuilt
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I've got a bike here with a MikesXS camshaft, upgraded springs, etc... I can't tune this thing for the life of me. 4500 RPM and it falls flat on its face... Valves are adjusted properly, cam chain is good, carbs are VM34's from 650 Central and should be good to go. Plugs are right on the money. Also has MikesXS 2-1 Exhaust with a good muffler. The rest of the engine is stock, with a Pamco.

Not terribly happy that the cam doesn't allow for any adjustment as far as degreeing in to the engine, but I didn't purchase it...
 
Its got the cheap k&n style ripoff filters with "XS" stamped on the chrome cover. Already checked to make sure they weren't blocking anything on the bell of the carbs.

Might pull the muffler in the morning.... Never had this much trouble getting one of these running. BUT, I didn't build this motor :laugh:
 
The carbs could be a culprit if it happens at a specific RPM as well.. Dealing with the crap on my Honda CB350s with the stock carbs at 4500rpm. I'm pretty sure it's the jetting in the carbs. In my case, it is getting too fat and choking the engine with gas.
 
Yeah, Hugh, I'm using that Taiwanese clone of the Megacycle 250-00. Should have asked more questions before I bought it; I was told by Paul Bertaut that the sprocket could be mounted on the slots, but like you, I didn't trust two 7 mm. screws to hold the sprocket in place if mounted that way. I controlled valve timing by adjusting deck height.

Anyway, as you're already well aware, it's not a "drop in" camshaft (how the hell could there be a drop in fast-ramp camshaft?!), and if the owner installed an Athena or XS Performance head gasket (.013" thicker than OEM) the valve timing is probably advanced to the point that it's killing power in a serious way. With that setup, the motor should just be waking up good at 4500.
 
Yep, he used the gasket set from Mikes as well. I'm thinking of slotting the gear, timing it, and then Si Bronze Weld the gear to the cam to keep it from changing. Could be easily reversed if needed.

BUT, I'm gonna uncork the exhaust and see if that helps. PS Griz, what valve timing did you end up with?
 
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There was quite a bit of grind error in my sample, and I computed the intake valve events that put intake lobe centers closest to 106*. That turned out to be IO at 29*, IC at 61* on the right cylinder, and IO 28*/IC 61* on the left. You need to see what you have in terms of the way the individual cam was ground and substitute values in the formula to get the best compromise. Formula: Lobe Center= ((opening event in degrees+closing event in degrees+180*)/2)-smaller event. In the case of my camshaft, LC=((29*+61*+180*)/2)-29*=106*.
 
Griz, thanks for the help...


I've tried everything. It runs decent in the low end (below 4500 RPM) and then it just goes all to crap after that. Timing is dead on. Filters off - No Change.... Baffle Out - No Change.... Filters and Baffle Out - No Change... Makes me think it has to be cam timing related....

I'm gonna remove this stupid camshaft and toss it in the trash, install a used stock cam, and see what happens...
 
Man what's even the point of that cam? Seems like a half assed version of a stocker to a complete rephase....
 
You might want to do a quick inspection first, Hugh; it's not a big deal to set up a degree wheel and dial indicator and see what's going on. If the lobe centers turn out to be within +/- 3 or 4 degrees of spec, the camshaft isn't the problem.

The point of the cam, blackbetty? Faster ramps, higher lift, and serious wailin' in the upper rpm range--if it's dialed in right.
 
grizld1 said:
You might want to do a quick inspection first, Hugh; it's not a big deal to set up a degree wheel and dial indicator and see what's going on. If the lobe centers turn out to be within +/- 3 or 4 degrees of spec, the camshaft isn't the problem.
Click to expand...

You are correct... I am planning on degreeing the whole thing in for sure before teardown. I'm just overly frustrated with this whole bike in general. The Owner had the spark plug threads recoiled using one of those kits made for cast iron heads, so now I have to remove the head and weld up those and rethread them as the inserts keep coming out with the plugs when I try to check the plugs for tuning this thing. Left Cylinder Plug is good, right cylinder plug is a tad rich...


PS, does it make ANY sense for the air screws to make no difference when adjusting this thing? I can turn them all the way and then get a little stumble, and all the way out and it idles just the same as it would anywhere in between... VM34's from 650 Central...
 
Hugh, nonresponse to mixture screw settings is usually an indication that something's wrong with fuel level; level adjustment, defective float, garf in the float valve, in the case of VM's, floats sticking on the posts, and obstructed float chamber vents are all likely suspects. Also check to be sure that air feed to the pilot circuit is clear. The float level adjustment is frequently off on new carbs--when carbs get shipped they're dry, with no liquid to keep the floats from slamming around, so no matter how the vendor sets up the carbies, they often arrive with float level way out of whack. I keep telling guys to strip, flush and adjust a new carb set as soon as they get it, but you probably know from dealing with your customers just how much attention gets paid to that advice!
 
Punkskalar, Did you check out the Camshaft Specs and Instructions from mikes web page
http://www.mikesxs.net/parts/docs/05-0025.pdf. It does say "Designed as a bolt in kit requiring timing to stock marks to install."


sounds like Griz1 may have found the problem.

Why does mikes get the blame all the time.................Shell no1 cams that was the rage and also had variations in the lobes...............

hope you know what you are doing making statements, dissing things,(rip offs, I'm gonna remove this stupid camshaft and toss it in the trash). A lot of people are looking up to you and if you keep saying things like that you are believed and then, people who know nothing are saying the same thing..........And people wounder why Mike would not join up as a member................I hope you have the decency to apologize if it is not the cam........................
 
Skull, don't put me in the position of defending that product. There's definitely a design problem with that camshaft, as I made clear above. You can get away with a lot of error with the OEM camshaft due to its slow ramps; not so the quick-ramp XS Performance Taiwanese clone of the Megacycle 250-00.

Aligning the camshaft to the stock marks isn't enough, as variations in deck height will have a major impact. Also, if the one I received is any indication, you can expect up to 4* grind error, which needs to be compensated for.

As Hugh noted, you can't accurately degree the thing in without welding the sprocket, as a pair of 7 mm. bolts is marginal at best for securing the sprocket in the slots; every other adjustable sprocket setup I know of uses no fewer than 3 7 mm. fasteners. It's a badly engineered design, advertising it as a "drop in" unit is misleading at best, and I wouldn't recommend that item to anyone.

Ah, but there's an out in that advertising claim. Lalonde and Heiden claim only that the camshaft is "designed as" a drop-in, no guarantees re. what happens in the actual installation. Lots of wiggle room in that assertion, isn't there?
 
Wasn't trying to get you to defend the cam Grizld1. I am curious as to how you overcame the negative aspects of the cam, I am assuming by your post you are still using it.

It does say on the web page to time it to the marks, but in the instructions he says.

C. Align Cam to OEM timing marks OR degree in cam with a dial indicator on the valve collar and a degree wheel on the crankshaft. Seek a qualified professional mechanic if you do not have this expertise.
 
Yeah, he says that. Degree it in by mounting it on the slots on two fasteners, great. I mentioned how I dialed it in--by adjusting deck height with a pretty wide selection of base and head gaskets. It was a serious PITA and forced me to make a compromise on compression I'd rather not have made.

The thing is pitched as a drop in, to hook folks who don't know any better. In standard position (on the holes), the punch marks on that sprocket will not be parallel with the head, and the buyer is going to need the dial indicator and degree wheel to tell which way to tilt 'em. There's only one way to install an aftermarket camshaft and that's the right way. Any advertising or instructions that imply that the right way is optional is in my opinion a deceptive attempt to take advantage of buyers' ignorance.

But maybe I have the wrong attitude! We make a buck when John Q. Citizen screws the job up and needs it redone, so maybe Lalonde and Heiden are serving the greater good after all.
 
"0" Lash, intake valve opens at 21 degress BTDC... "Stock" timing marks are all proper, timing pins are at TDC, etc... Haven't gotten any further with it then that. I tore into the carbs as well, all specs were fine, float levels were right. I swapped another Pamco in, as well as another coil just to try and narrow it down to something else. Ignition is fine, coil is fine, carbs seem to be fine, plugs are a perfect brown.


Sorry if you guys think I'm a MikesXS hater. I'm not, but if I have this much trouble with something, I like to know if others like Griz have had similar trouble. Besides, its not like I can call MikesXS for any kind of customer service.

That said, I've installed Megacycle and Webb Cams, and once degreed in, they were perfect to use and easy to tune with. This particular engine was not build by me, and I would never have chosen a cam with no adjustability in the gear personally.
 
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The LC's will tell the story when you calculate them, Hugh; that IO figure could indicate a setting that's anywhere between marginally OK and FUBAR. A few degrees of retard usually results in moving the power peak higher up the rpm scale; but that cam may be set up, uh, hopelessly retarded.
 

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