Bonneville America Forums Forums Technical Forums Performance Mods MegaCycle Cams installed - Review

OK OK OK, I'll clarify a bit more than that.

First of all, thanks to my bestest buddy, Brent, for setting me up with the deal in the first place, and for all the other deals we work out. You da man Brent!
Thanks to Roundslide and BUDWEISER for tools, and to the race track for letting me borrow the big arse snap ring tool, I needed them all!
And thanks to chy, cause he knew off the top of his head which cam was inlet/exhaust. Oops, I forgot my manual over at Matt's work. Didn't weant to mess them up, or my motor, so I hadda check with a pro.

Ok, the cams were used cams, I didn't ask, I won't tell, got a deal, bought em in a heartbeat.
I had to remove the backlash mechanisms from these cams and replace them with mine from my stock cams. They were really loose and sloppy and there was only 1/2 a tooth difference for the backlash, now it has 4 teeth difference. Kinda hard to splain that, but they were so loose to start with, I could turn them by hand and install the backlash retainers. Hmmmm? Too loose I fingered. So I swapped a few bits out to make them tight again.

Got them all installed, really easy, just plug and play, old ones out, new ones in. No special work, just had to be sure I had the left cylinder at Top Dead Center and all the timing marks aligned, tighten the back up, put it all together and turn it over by hand about 5 times to be sure everything was aligned.
No noises or pressure, I figure I'm good to go.
Yeah, right, good doesn't even come close to describing
the results.
I started it up, hit starter once, Vroooooooom. OOOh I go, it sounds different very obviously different. I like it!

I let it warm up to about 100ºF and putt down the road about a mile slowly going through the gears to meke absolutely sure everything is cool to go.
Ok, we good, Let's whack it now. HOLY CRAP!! I am astounded by the increase in power and the speed that is far quicker than before. I run it up to the redline in 1st, slam it into second.....whoaaaaaa let off, the friggin front wheel was coming up and I don't like that, very cool, but I kinda like to have both wheels on the ground on my bike. I slow down, do it again...it does it again!! Now my face is starting to hurt from the grinning, my ears are ringing due to the little girlie squeals I am emitting too. Ok, a little too much info, but you really had to be there.

I ride around for an hour or so, running it really hard and it is a whole new machine. The power and speed from 3000rpm is amazing. Below that it runs like it did before but once you hit 3k, hold on tightly! It launches all the way to the red line and I had no problem hitting a ton in 4th gear, in a very very short time!

Whoa doggie, I like it!

That's my review, now all I gotta do next is put on a set of the Mikunis and I'll be seeing y'all much later! I'll wait at the light fo ya.

Oh yeah, here's the specs too:
Megacycle Cams
90 Mitchell Blvd
San Rafeal, Ca 94903
(415) 472-3195

Timing Card: Make and Model: TRIUMPH 904cc Speedmaster
Cam# 520-x1 in/ 520x3 exh
Timing at 0.040" lift at valve
Timing checked with ZERO clearance
(see running clearance - lash below)
Intake:
open - 24º BTC
Close - 52º ABC
Valve Lift - 0.408"
Duration - 256º
Lobe Center - 104º
Lash or Running Clearance (cold) - 0.006" to 0.008"

Exhaust
Open - 54º BBC
Close - 18º ATC
Valve Lift - 0.385"
Duration - 252º
Lobe Center - 108º
Lash or Running clearance (cold) - 0.010" to 0.012"

Sweet dude!!! Now are these cams the buisness for us mere mortal 790 motors too? Not that I have anymore money laying around, but someone had to ask

Absolutely Benny. They custom make every cam for your particular bike.
the only drawback is that you need to send them your cams to have "modified". They are not just a simple grind either, they remove the lobes and add new material and make them from the stock shafts. If I recall, MC's price is about $600-700 from the conversation I last had with them.
If you are thinking of the big bore, wait till then before you do them if you decide on this route.
See what I do for youz guyz?
Then agian, I would pretty much guarantee that Graeme's cams from Thunderbike as just as good if not even better, with no swap needed.

Well anything I do has gotta wait. Unless I win the lottery (that I never play). But it is all good to know. I think if I can squeek anymore money out for mods, it'll be the carb setup. That at least can get adapted to the other mods down the road...

Thanks for the laugh, Pat. As soon as I saw the pic in the first post and re-read the title I busted out laughing

Great news, Pat! Congrats. Guess you'll be looking for some 1200 Sportsters in the near future.

Congratulations on your mods Dinqua! I can only hope mine feels as fast as yours sounds when I get her back from the dealership!

Hey Dinqua...do you plan to do any dyno runs?

Janet was asking me last night what I was going to do if I wanted a new bike. I could only say "Huh? Get rid of Raven? No way!" I see a couple thou for performance mods in her instead....

Man, I'd really, really, really like to see a dyno report!

Does this more or less summarize (performance-wise) where you are at right now?

Big Bore Kit
Megacycle Cams
Thunderbike pipes
Mikuni/Amals

Man, i wish i never read thay review !

i would be very interested in dyno numbers because this is the only mod done since last dyno correct? that should give a pretty accurate look at how much the difference the cams made

Frank

Phil,
I forgot to finish.
904 Big bore
Ported heads
Thunderbike pipes
Megacycle "medium street grind" cams
Stock carbs
150/42/thruxton needles/freaked
QPD Belt drive
Progressive 440AIS
Feces eating grin at all times.
Life is good....

Pat, if I recall correctly your last dyno was about 76rwhp? What does your butt-dyno tell you in terms of hp gain...feels like 10+? less than 10? what kind of minimum hp would you expect that would pull the front wheel off the ground!!?? This sounds like some smokin' machine you've put together there.

Quote:

---

Feces eating grin at all times.

---

Priceless...

Wolfster,
My butt dyno is not that acurate, but I will ponder to guess between 5-10hp increase. Don't hold me to it. The power is just way more effecient and quicker. We'll see....
I will add though, that the guys in the high perfromance bonnie groups are getting 80+, without cams, but with the Mikunis. I have previously run the Mikuni 42s before, but the cams added MORE than the carbs did according to my hinnie.

Thats awsome, I'm sure everyone that reads this post is green with envy!
Can't wait to see your dyno results... thanks for setting the standard and opening our eyes to what we can achieve!

Heh, just kiddin' Pat, but I've been looking for opening to post that banner since I lifted it off another board.

Thanks for being the guinea pig.

Maybe one of these days....once you get all the options sorted out.

Do you have any specs for the cams, or is that a Mega secret?

The bad part....it rained cats and dogs all day and night right after I went for my only ride. Maybe after I get Jane's wheel to the stealer I can ride it some more today. I keep telling her I need to break the cams in. I don't think she beleives me though.

Pat,
You should offer a Shelby like service so guys can have their bikes Dinquafied.

Sitting on a bone stock TBA... feeling so depressed. I can just see money gushing out of my bank account in the next couple of years. I hear mods are addictive too... damn...

extremely.

WOBF'd,
Sudco does not offer a mikuni setup, but ProFlo does. You can fit two of thier Mikuni 38mm flatside carbs, without accel pumps, and they work great. Ed (biker) has a set on his and I even get to play with his too. I am seriously considering that as my next attempt at carbs.
The 42 mikunis were to much, especially with the pumps enabled. They would flood the motor without trying.
The FCR carbs, British Customs ooffers a set for about $1600US, are very nice, but they are more for serious racing and are also too much, but I have not seen them and cannot comment on their performance. I know that the Ducatis use them and they are very fussy and will stall if you gas them too quickly. You have to roll the throttle from a dead stop of you risk flooding them and stalling out.
The new 38mm Amals, alas I tried, were well built and nice carbs, but I could not get them to stop leaking gas no matter what I did. Norman Hyde finally gave up and told me to send them back for a refund. Which I did a few weeks ago.
I went out riding last night some more with the bike and I really like how it runs. One problem I have is now I keep hitting my rev limiter. It gets there so quick that even as I try to shift as late as I can, it creeps up just enough in the split second that it cuts out anyway. Frustarting, but I just need to not rev it so high I guess. But it like it so much it is hard not to do.

It idles just fine and I have not done anything yet as far as additional tuning. I will get a dyno run before i make any changes so I can see exactly what difference, if any (It may just be in my mind ) it gave me.

what kind of shim adjustments did you need?

Frank

Argo, you can downsize those air bleed jets by soldering them shut and then redrilling them smaller than stock. Try to estimate your initial hole size on the small side and then go larger as needed. As you probably know, there are inch drill bits up in the high numbers, from #60 to #80 (higher the number, smaller the hole) and you hold them in a "pin vise", which is just a hand held drill bit chuck. You may have something like that in metric, too. Be sure to check your stock hole size before covering it up.

You could also cover over the jets with good epoxy, like the J-B Weld brand. I used to use J-B Weld on modified Holley car carbs with great effectiveness. It works particularly well if you can "bake" the carb at about 220º for awhile.

If you prefer to solder those brass jets, use a very low temp solder and just a tiny amount of acid flux.

Hey Pat, the sudco link I posted has carb sizing recommendations on the first page. Sudco does a 35mm FCR Kit for 750/850 Norton Twins, I reckon 35mm FCR would do just fine for a 900 twin, 39mm FCR's could be too big.
What do you think of the 36mm TM MIkuni pumpers?
Have you gone off pumpers because of previous problems with the 42 HSR's?

WO,
I've seen the site many times and have even called and spoken with the Sudco folks. They are the guys that supply the carbs to British Customs and Bonneville performance. They also make CRS kit made for our bikes. Several folks here run them already. They are sold by Brent and BelaCorse too.
When I spoke with the Sudco guys, they were the ones that told me to go with a 38/39mm carb due to head porting and open air filters like the freaks and street cams.
Pumpers? Well, the jury's still out on them as far as i am concerned. I'm sure I could fob one up to work properly, just that it was a big issue with the 42s, which I felt were too large already.
When we went to the flat track races over in Syracuse a few weeks back, every single bike was running the Mikuni 42s, from the smaller Yammers all the way to the big HDs and Buells. But, they also run at pretty much full throttle all the time and they are all bored/ported/cammed/baked and smoked.

This conversation makes me wonder if my 35mm CRS carbs might actually serve to limit the maximum power my engine can develop once it comes out of the dealership. Before my oil pump gear failure, I already had cams, free-flowing pipes, and the K&N pod filters; now that the bike will have the 904 big bore and the intakes match-ported to the head, I wonder if perhaps I should consider the 37mm CRS carburetor set-up. I couldn't afford to do this anytime soon, but it does give me something to ponder!

RS,
You can get a pair of the mikuni 38s from proflow, or wait until we have some to sell. We are working on some now. Ed's are dialed in nicely and I would think you would use the same setup as mine will eventually end up with.

Appreciate the heads up Dinqua, keep us posted eh?

They'll be non pumper Mikuni TM 38mm flatslides??

We're gonna make up the 36mm ones first. See how they function then maybe get some of the 38s afterwards to mess with.
Flatside, non pumpers.

Well, sent an email to Sudco regarding the possibility of a 37mm CRS carb kit with the Triumph dimensions. To their credit, they responded about an hour ago, but they basically told me that they didn't plan on marketing a 37mm CRS carb kit anytime soon! Dang!