• Ciao Guest - You’ve landed at the ultimate Guzzi site. NEW FORUM REGISTRATIONS REQUIRE EMAIL ACTIVATION - CHECK YOUR SPAM FOLDER - Use the CONTACT above if you need help. New to the forum? For all new members, we require ONE post in the Introductions section at the bottom, in order to post in most of the other sections. ALWAYS TRY A SEARCH BEFORE STARTING A NEW TOPIC - Most questions you may have, have likely been already answered. DON'T BE A DRIVE-BY POSTER: As a common courtesy, check back in and reply within 24 hours, or your post will be deleted. Note there's decades of heavily experienced Guzzi professionals on this site, all whom happily give endless amounts of their VALUABLE time for free; BE COURTEOUS AND RESPECTFUL!
  • There is ZERO tolerance on personal attacks and ANY HYPERLINKS to PRODUCT(S) or other competing website(s), including personal pages, social media or other Forums. This ALSO INCLUDES ECU DIAGnostic software, questions and mapping. We work very hard to offer commercially supported products and to keep info relevant here. First offense is a note, second is a warning, third time will get you banned from the site. We don't have the time to chase repeat (and ignorant) offenders. This is NOT a social media platform; It's an ad-free, privately funded website, in small help with user donations. Be sure to see the GTM STORE link above; ALL product purchases help support the site, or you can upgrade your Forum profile or DONATE via the link above.
  • Be sure to see the GTM STORE link also above for our 700+ product inventory, including OEM parts and many of our 100% Made-in-SoCal-USA GTM products and engine kits. In SoCal? Click the SERVICE tab above for the best in service, tires, tuning and installation of our products or custom work, and don't miss our GT MotoCycles® (not) art on the BUILDS tab above. WE'RE HERE ONLINE ONLY - NO PHONE CALLS MADE OR RECEIVED - DO NOT EMAIL AND ASK QUESTIONS OR ASK TO CALL YOU.
  • Like the new V100, GuzziTech is full throttle into the future! We're now running on an all-new server and we've updated our Forum software. The visual differences are obvious, but hopefully you'll notice the super-fast speed. If you notice any glitches or have any issues, please post on the Site Support section at the bottom. If you haven't yet, please upgrade your account which is covered in the Site Support section or via the DONATE tab above, which gives you full site access including the DOWNLOADS section. We really appreciate every $ and your support to keep this site ad-free. Create an account, sign in, upgrade your account, and enjoy. See you on the road in 2024.

Cam Gear... All Those Holes

Tonerjockey

Tonerjockey

High Miler
GT Contributor
Joined
Oct 28, 2008
Messages
788
Location
San Jose
Yo Guzzi Folks,

What is with the 5 holes in the cam gear of round fins? Anyone know if I can get a 2 or 4 degree retard by selecting a different hole for the dowel? (which one?)

Big long cam in skinny old bike. I am looking at Crowler advance/retard bushings and figure to save a few bucks by utilizing what is already there... if poss.

Whatcha think?

Tonerjockey
 
Hey Pete,

Stock 73 V7 Sport cam drive gear. Has 5 holes for the dowel that positions the drive gear to the cam.

Do any of these generate a 2 to 4 degree retard?

Tonerjockey
 
There shouldn't be any extra holes in the stock sprocket. Someone may have modified it. Use at your own risk. BTW, if its a stock V7 sport cam that's in there, simply tossing it in a garbage bin will probably do more for the bike's performance than retarding it a few degrees.

Ed
 
Actually, (S.E. is incorrect) the stock gear (it has timing GEARS, not chain, correct?) does have 5 dowel holes, but only 1 of them is correct. The only way to tell how much you are moving the cam by changing one of the holes or teeth is to measure it. (I've checked before I just can't remember). If this is the bike that is being used on the Salt Flats, then that is a great cam because it has dogshit power until 5000 rpm, then it's a rocket. But it's a terrible street cam.

ps if it is timing chain then there should only be 1 hole
 
If these are the helically cut steel gears then yes you can alter the timing using the holes, set up a degree wheel and experiment. The other thing is that you can use the gear helix by shimming the cam gear away from the end of the cam so it engages differently with the crank gear to alter the timing very precisely.

pete
 
guzzitech wrote:
BTW, if its a stock V7 sport cam that's in there, simply tossing it in a garbage bin will probably do more for the bike's performance than retarding it a few degrees.

Ed
Click to expand...

That bad, Ed?
A wee bit better for this purpose than the stock cams for later models (e.g. LM1-2-3, etc). Or perhaps not?

(BTW still dreaming of a Megacycle cam for the V7 track bike, for some later time.)

rolf j
Norway
lm3
V7 Sport
 
Great stuff guys!

The currently installed cam is a stock V7 Sport but the idea of a cheap way to retard is for a Megacycle 620X7 cam. I attempted to run that Mega cam using 12:1 pistons cut for nicely done heads but got REAL LOW HP (42). Adjusting the valves to .030 allowed 103 MPH. The only thing more embarrasing was attempting to start it in gear while 5th inline. Amazing how fast you can pick up that bike. (tip: ALWAYS start the bike while seated on it).

Talking to Mike R. the idea of a 2 to 4 degree retard for testing came up. So now I'm tryin to find a cheap way to do that.

I really like the idea of shimming the cam and using the helical cut to retard/advance. After El Mirage (Nov 15?) I'll set the idea up and see what happens. Seems I can find the desired retard on the degree wheel and make up a shim. The stock dowel should be long enough to pass through a few thousandths shim.

For this November run I put the stock V7 Sport cam back in and relieved my last 2 new 12:1 pistons for that stock cam and the nicely done heads. I hope to get that combination on the dyno this week.

Thanks for the ideas.

Tonerjockey
 
If you're going to shim the cam gear remember that not only will the shim have to be perfectly flat to maintain the correct gear mesh but also it isn't the peg that drives the cam, it is friction between the back of the gear, (Or the shim.) and the front of the cam. For this reason it is best to manuafacture a shim or shim using a surface grinder with a magnetic chuck to ensure flatness and accuracy.

Pete
 
I misspoke- I thought that you had timing sprockets, not gears-sorry.

Stock V7 sport cam would probably be a complete waste of time for real performance in a LSR bike....useful as a last resort, I suppose. Not sure which class you are running, but if it’s a stock class, you probably have some other overriding issue- What exhaust system are you running? If it’s the stockish V7 Sport system, that is probably the issue especially with a top end performance cam such as the Megacycle x7 (Norris 382). 42hp is way down on power (that’s about the same as a fresh Eldorado motor…). I would expect some other large scale tuning issue other than the small (~5% max) change in peak power that cam timing variation can afford.

Pete’s idea of shimming cam and or crank helical gears to change timing might give you some variability. mcmaster.com probably has shims that will fit. You can also match up a few degrees offset cam key or ovalize the cam gear dowel to change cam timing a few deg. Sounds like you currently have some other overriding problem, though.

Ed
 
10/4 on the flatness of the shim and ensuring the pin isn't driving the cam, Pete.

Regarding the exhaust Ed, I have a gutted Slientium stock set up and a nice crispy new LaFranconi Competition setup. I prefer the gutted old ones. I am now working on the Xover as I feel this is very restrictive.

The class I run is 750 P-PP. Stock frame, stock looking engine, no non-stock streamlining. I need to review the rules regarding exhaust diameters but I know I need to run the make/year/model carbs. In this case Dellortto VHB30 or comparables. I am looking for either Dellortto 30mm's or Amals that I can bore to increase ID.

I too feel that there is something that I am missing. I'm still looking. But that's racing so I am lead to believe...

Tonerjockey
 
Crossover is probably the least of your worries. More like carbs and exhaust length. You have a top end cam that peaks above 8k RPM, but your exhaust is too long and your intake is severely restricted. Hence 42hp. X7 cam is the wrong cam with those intakes and exhaust. First things I would do is shorten effective length of mufflers ...maybe by completely gutting the mufflers and making them mostly for appearance...hide ~6 inches of reverse megaphone inside them. Otherwise, if you're stuck with stock appearance, you're possibly better off tuning for lower rpm power with an X10 cam and then gearing way up to suit your lower peak hp RPM.

I believe Mark at Guzzi Classics has inexpensive 30mm round slides. 562 986 0070.
 
I have a pair of Amals from a 74 Eldo I picked up that you can have for nothing. I already have a set of delOrtos to replace them.

I'm not sure of the diameter, as I am not at home right now, but they must be around 30mm.
 
Yo,

Hey Sgt, I sent ya a msg on yer very generous offer. 10Q,

GuzziTech yer spot on on that in out prob. IMHO. Just now educatin' mahself on legnths etc from MEZ at http://www.mez.co.uk/mezporting/exhaust_length.html

For current stock cam the needed tuning modifications are less severe than for the X7.

For stock I get an intake legnth from end of vel stack (bell) to valve of 7.915 inches. The exhaust primary legnth from valve is
25" with a ID of 1.537". Tailpipe legnth of 22.317" with ID of 2.07".

Peak torque at 7500 RPM.

This tells me that I need to shorten the intake, open the exhaust a little, shorten the primary, and shorten the tailpipe. hmmm that sounds familiar.

Shortening the intake: I may be able to use one of my shorter velocity stacks to get closer. I need to retain the stock air box
(for what that's worth) so I really can't modify the intake manifolds too much. I need to get an inch or so shorter.

Open the exhaust: 1 5/8" 18 gauge exhaust tubing should put me close to 1.5" ID for primary. My head exh port is 1.5" now. Currently stock exh tube is about 1.285" Secondary might be my battered ol Silentiums with the reverse cone inside. I like that sneaky idea! Gotta move it up though and might be a foot controll interference. I'll see after I make the primarys.

For X7 I figure 1.75" OD .049 wall tubing should be close to getting me the needed 1.6". Primary exh legnth is shorter by 4 inches, the tailpipe is 1/4 wider and 5 inches shorter. The intake needs to be about 1" shorter than the stock. These are for 9000 RPM Max torque.

According to Dellortto, to achieve 30 to 40 HP per cyl. 32 to 40mm carbs are needed. Since EL Mirage, Bonneville, and
soon LoveLock, have high density altitudes, (read thin O2) I may get by with bored out 30's. Or I may just wind up with
another set of trashed carbs as offering to the gods of speed (so to speak).

Great fun here. I appreciate the input.

Today I finish assembling with stock in out's to see where I stand. The exh is next.

Tonerjockey
 
Hey, TJ....

I got your message and address. I sent you one back, but this this forum throws me out if I don't respond immediately, so I don't know if the message to you went through.
 
Completely unrelated, but Crumpy...I wonder if anyone here besides me acknowledges that you have a Wonder Warthog avatar...

Ed
 
Hey Ed,

Well, many of these youngsters are too...welll...young!

There will never be another super hero like Wonder Warthog......he set the standard that all the modern copycats strive to meet

Somehow, i'm not surprised that you knew..........

Besides....Walter, the mooning gnome, was not a good role model for the younger members of the forum, hence the drastic change.....
 
El Crumpo- to a Guzzi those Anals are only good for one thing: leaving the intake manifold open for Del Lortos. :woohoo:
 
Hey Sean,

I agree totally, that is why I already bought a pair of "D's" for it.

The last time I owned a Brit bike was about 1980, an 850 Commando, and the first thing I did to that was buy one of Sonny Angel's home-made manifolds with single Mkuni on it......much less headache.
 
You must log in or register to reply here.
Back
Top