Hi Dave,
I've used Sprocket Specialists for a long time. Their hole pattern number for all Ducati bucket cush sprocket carriers is #187Z. Tell them chain size, number of teeth, and their standard brushed aluminum will last quite a while with a properly lubed race bike chain. They're pretty quick too.
Bill
http://sprocketspecialists.com/

I second Sprocket Specialists. You can spend very little on it, or jazz it up. Ed Milich has a variety of fronts for your bike. MikeV

Thanks for the suggestion. I gave them a call and they had just about every sprocket I could imagine and everything was in stock.

Progress is happening with my Pantah race bike. I now have a set of Oscams that need a coat of paint. Carbs are in the process of being rebuilt, and the cooked ignition wires will be changed soon as well. I also have some stainless brake lines and good ferodo race pads for the front and ferodo platinums for the rear. Suspension is the next set of projects. As I said before, I am sticking with the Marzocchi forks and shocks and modifying them to suit my needs. I am taking Bill's advice and getting a set of race tech straight rate springs. I am also going to rebuild my stradas at the rear. I have the rebuild kit and instructions. I do have a question about the oil for the shocks. I contacted Marzocchi and they recommended 5w oil. Now I have read on other Pantah sites that the stradas were over sprung and under damped, but I also read on the race tech site that for racing applications because of the higher speeds it might not be a good thing to have a lot of compression and rebound damping. Does anybody have a suggestion on oil for the shocks, 5w or 10w? Just for reference I am 190 lbs.

I also had an engine question. The class that I really want to race in is called Vintage Superbike Light, but it has a limit of 470cc's for OHC twins. I think it will be easier to build a 470cc engine than try to get AHRMA to bump the limit to 500cc's. With that being said, I have 2 routes I can take, 51mm stroke or 58mm stroke. I will use 500 pantah heads and crankcases. Doing the math I can go up to 76.5mm bore with a 51mm stroke, or a 71.5mm bore with my current 58mm stroke. Custom pistons will be required of course. I am kind of leaning towards the short stroke larger bore. Anybody have experience with this or any suggestions?

Thanks
Dave

Hi Dave,
Off the top of my very non-suspension-expert head, what about splitting the difference and use a good shock specific oil of 7 or 7 1/2 wt. as a place to start? I say that because we know your Oscam wheels will give you a rather hefty amount of un-sprung weight to work with. Have you visited the AHRMA forums?

http://www.vintagebikeracing.com/index.php

I have always been impressed with how experienced racers will bend over backwards to help. Are you shooting for Road America this June? If so, my best suggestion would be to get that thing up and running, ready to go thru tech, asap, as the engine is now, and enter whatever class it will fit into, say Vintage Superbike Middleweight or BOT3. I believe the lead time for special pistons is pretty lengthy, and what you learn about it from running it now will be huge. When building up a race bike, that first practice session will get here INCREDIBLY fast. We're all rooting for you.
Bill

Bill,

Maybe I should have specified that building an engine is my plan for next winter. Yes, RA is my goal, but I actually have a vintage track day on may 16th at Blackhawk Farms that will be the bikes first track time. I am leaving the 500 engine totally stock for this year except for k&n filters and a 2-1 pipe. I am going to run superbike mid this year, build a smaller engine over the winter and move to light next year.

Yes I have been to the AHRMA forum, lots of knowledge, but I thought I would try here first.

Dave

Sounds like a plan. It might not be a bad idea to talk your engine mods over with Cindy or Andrew Cowell when you're there, to double check that it would be actually then be legal in lightweight with the reduced cc's and how you could verify that easily. I'm sure nobody would really care unless you start running up front. Cindy runs the whole show, and puts up a good front of being tough, but she's really a sweetheart. Andrew runs the school for licensing and races hard come race day, but he's just as helpful as Cindy. They're both great. You're in for a really fun time.
Bill

So I took the Pantah to its first vintage track day on Friday the 16th at Blackhawk Farms. It was semi successful. The positives were I had a great time, I got my race license, and the bike ran like an absolute raped ape! The negatives were I had a wicked wobble from the swingarm and I have to address the front brakes. The bike ran so well and so strong that I got more than a few comments on it and I was able keep up with a couple of track prepped SOHC 750 Hondas. But in the turns it almost felt like I was doing a hula hoop. I knew I had a little side to side play in the swingarm, but I had no I idea that the bearings were in such bad shape as well. I do have a set of NOS bushings that came with the bike that I will have to install. Now every other time that I have installed bronze bushings or guides in other bikes I have always had to hone or ream them out since they got smaller once installed. I am guessing that these will be no different, however, since they are open to the inside of the cases, how does one keep bronze shavings from making their way into the bowels of the engine? Also, the manual does not give a side to side measurement for shimming the swingarm. I would assume that it would be best to get as close to nil as possible while still maintaining good fluid motion, correct?

I also had some pretty decent pulsation from the front brakes. The calipers are rebuilt, new stainless lines, new pads, and a good master cylinder. I am planning on tearing the discs off and making sure that there is no crud between them and the wheel preventing them from sitting flat. I have a runnout of .004" to .005" on the innermost portion of the braking surface and .007" at the outermost braking surface, which leads me to believe that they are not sitting flat on the wheel. I installed the oscam wheels but re-used the rotors that came on the FPS wheels. They seemed to bolt up fine but some investigation is warranted.

So on the whole I feel pretty good. I have a few things to sort out, brakes, belly pan, catch can, and swingarm, but the engine surpassed my expectations for a stock 500. It is 3 weeks till Road America....I think I should be ready by then. Here is a pic of how it looks now. I am just not the kind of guy who can pull of purple and blue.

Dave

Looks great Dave!

Unless someone knows specifically that Marzocchi Strada piggyback shocks need to be mounted reservoir down, you can reduce your rear un-sprung weight if you flip your shocks over.

Bill

flames?