HI PERFORMANCE & RACING INFO needed

vintagedude · Post by **vintagedude** » Sat Jan 10, 2004 1:07 am

Hello... My name is "Wilbur Wiggins" (alias). I race Vintage MX very heavily. We have just built a NEW weapon, a CL77 scrambler with Elsinore suspension and wheels, and Elsinore forks. Elsinore seat, open exhaust Etc. I work at a HONDA dealer, and right now we are in the process of building a cheater motor for AHRMA events. We are looking for the correct information on how to hop this motor up and from people who have done it, not just heresay. We just bought a 337CC big bore kit, (which is simply 3MM oversize)but we hear rumours that the CL450 cylinders and pistons bring it to 420cc. We know the 420 is possible, because weve seen pictures of a bike with the mod. We tried to figure out how to get the CL450 liners in the cylinder, and well hell, they hit the inner cylinder studs. They can be fit, but would have to be radically offset forward. So We have some questions, and maybe an expert can help us answer these questions for the benefit of all. So here goes: 1. We know the CL72 cylinder head has a smaller combustion chamber, is it better to use it? We plan to shave the head some, we want high compression, but we dont want a grenade either. 2. Who currently has a good race cam for these engines? 3. Who has, or what are people using to big bore this engine? We can get liners from LA sleeve about any DIA. we want, but the piston is the problem. Yes, weve heard that XL125 pistons will work, and well its not true, we tried. We tried an XR200 piston, and they will work, but simply have no dome! We know the rod uses a 15mm pin dia. Its the dome problem guys! 4. What are the general race tricks for this engine? We know that DOUG FERGUS raced one in SO cal District 37, back in the day, and held the No1 plate. Im going to try and contact him. I also know HRC made a bunch of stuff for these engines. We can do all of our own machine work, so that is no problem. In closing, I would appreciate this hard core information, and any expert on these engines who would like to talk to me, I would appreciate it. I know some of you have the answers we need. We need your knowledge![/b]

vintagedude · Post by **vintagedude** » Sun Jan 11, 2004 12:37 am

Hello... Oh boy, did I hit the jackpot. Got off the phone with NEIL FERGUS, FORMER NUMBER #1 (district 37, SO-CAL) AMA plate holder, and HONDA dealer from 1959 to 1964. Want to see his pictures and go down memory lane? go to My website www.gas-it-n-go.com and click on "Dougs Vintage Page". Anyway Neil got the No.1 plate from racing a CL72 250cc scrambler. HE WAS THE VERY FIRST GUY TO RECIEVE AND RACE A CL72 in the USA in 1963! He gave me some info on what they did to win back in the day, and boy is it interesting. So here goes on what he has to say: REMEMBER, this is 1963!!! 1. He Used stock cams. 2. He used stock ignition system with a battery, he replaced the battery every race to prevent plate failure due to vibration. 3. He used stock bore and pistons. They did fool around with a FULL 350cc big bore kit, and FORGETRUE used to make the pistons. But, they had a problem, and that is that the cast in combustion chamber "SKULL" as he calls it would loosen due to the cylinder liner not pressing against it. The SKULL is literally the combustion chamber, and the aluminum was cast around it. He said they would put in huge liners, and the SKULL would loosen, causing an oil leak near the spark plug, and an overheating problem due to improper heat transfer from the SKULL to the head. His advice was go big bore WITHIN the stock liners diameter. NOTE #1 The CL77 COMBUSTION IS LARGER than the CL72. It has an additional "step" in it. As Neil never Big bored a CL72 using the CL77 head, the mystery remains as to wether this SKULL is held sufficiently by the cylinder liners versus the CL72 head when using the large 350cc kit with larger liners. In our case, Its looking like we will be using the CL77 337cc big bore kit, WITH STOCK LINERS, AND CL 77 head. And our pistons are really a P12 or +3.0MM oversize piston. More on this later as we discover more... NOTE #2 In addition, Neil gave some more information on the SKULL problem with big bore kit. He discovered that the early CA77 (not sure if it was a CA77, or similar) Dream head, with TWIN PORT head, using single carb, DID NOT have a SKULL cast into the head. As this head had a gear driven cam, they simply removed the cam gear, installed chain driven cam, ran a chain like a CL72, and thus the SKULL problem was solved for running a BIG BORE KIT! NOTE#3 MILLING HEADS. Neil says that was a NO-NO for desert racing, as he was deathly afraid of creating more HEAT. We are inclined to go ahead and add some compression for our MX engine because it sees such short runs. We may mill our heads .020" to .040", and we wont be afraid to use hi-octane gas. Neil said he used ethel pump gas in his racers, but remeber that "ETHEL" grade fuel in 1963 was pretty hi octane! 4. They did use S&W valve springs sometimes, and he was very good friends with S&W people ART SPARKS (deceased) and TIM WITHAM (deceased) These two guys are quite famous in the motorcycle world, and TIM WITHAM was a noted TRIUMPH tuner. NOTE* We do know that HONDA HRC ( Honda Racing Company) made a valve spring for these engines. Want to be a HERO? post the part numbers! 5. He said they used to run a BARNETT CLUTCH. Note, that some CL72's and CL77's use a 5 DISC or a 6 DISC clutch! What is better or what is earlier or later, we dont know. In our case we have both setups, and we will be running the 6 disc clutch. BOTH clutches (the friction discs) are still available from HONDA! We do not know if the Barnett clutch is still available. 6. OIL SLINGER. Neil says: RUN IT! He said it was incredibally efficient, and uses little to no power. Clean it regularly. 7. AIR CLEANERS. Neil gave some good information here, he says K&N DID NOT invent the washable filter. He says a company called "BOBBY J" did, and that they sold out to K&N. He said a paper filter was worthless, will not flow, and clogs easily. 8.Engine oil: He says they used to run an oil called "HUZ", yes thats right, HUZ. He says in the MOJAVE desert with a sytem that only holds 1.5 qts, its the only oil that held up. Interesting! 9. TRANSMISSION: Neil says they were a tough transmission. He says for OFF ROAD, you had to "X" the inner four gears. Simply put, turn engine upsdide down, pull bottom case half. You will see two shafts and 4 gears per shaft. (4 speed) take the 2 MIDDLE GEARS on each shaft, and Move them in an X pattern. this creates a closer gear pattern, however creates a larger span between 3rd and 4th. Neil says you MUST DO THIS for off road, because it let the engine stay in the power band regardless of final gearing ratio. Simply put, there was too much spacing in the gears. NOTE* This trick is and was well known. We were NOT going to do this until we talked to Neil. Now we are, with his blessing. 10. Frame and suspension..Neil says the bike was a lard ass. He says the absolute biggest problem with the bike, BAR NONE, is the RAKE! The secret trick they did was strip the tank and front wheel off, then place a jack between the front axle and frame, heat up the frame in the neck area with a torch, and bend it out EXACTLY 2 inches, thus increasing the rake. MOST important thing you could do to the bike. It absolutely cured its Ill-handling at speed, and his mod could be done with no cutting. We do know the bike had a very bad handling reputation. Neil says they never did figure out why his bike handled so well. Now we know. He also says you can add 1 inch front travel with stock forks by re positioning stop ring. In our case we are running 73-74 Elsinore front forks. SECRET: how did we do it? We used a CB77 LOWER TRIPLE TREE and stem and a CR250 Aluminum upper tree. We had to machine the stem hole in the elsie tree to fit the larger stem. It took us days to figure it out, because the stem is so long in a CL77. The CB77 lower tree is 1mm smaller, to allow the Elsinore forks to slip right in! (SENDme $10.00 if you use our secret and then feel guilty ok!) And so here we come to end in this post. We are off to a good start on HI-PERF mods for these engines in todays AHRMA racing, on and off road. As a parting Note, Neil says that the CL72 and CL77 was the beginning of the end for the british bikes, as he said that they were faster, but rarely were as reliable. He said that he would rev up that CL72 in a sand wash, and rally on by the lumbering british bikes. We know now that neil was right! The above written by "WILBUR WIGGENS" (alias) I use an alias so I dont get caught cheating while racing, I dont want my name out as outside the rules. You think I cheat, you ought to see what they do! Those BRIT guys hate to see us unload our jap bikes!

vintagedude · Post by **vintagedude** » Sun Jan 11, 2004 12:51 am

Hello Once again..! the information keeps flowing in! Got a hold of COLT CAMS in Canada. Theyoffer a HI-PERF CAM for the CB72/CB77. It is part Number: And, thank you for your request. I can offer the following racing parts, for the CB72/77 Hondas : Right side racing cam, P/N 14111-268-810, US $200.00ea. + mail Left side racing cam, P/N 14121-268-810, US $200.00ea. + mail. E mail: Michel Lussier apozopiclone@hotmail.com WOW! The first solid info we have seen on HI-PERF cams for these engines. (send me $10.00 for the info please yuk-yuk) Well, super expensive, but available! I wander what these cams do and what are there specs, I dont know. Cb being a street version, it is possible there may be a loss of low end for top end. Im sure you have to use stiffer springs. In any case, if anybody else knows of any other cams available, please post WILBUR WIGGINS

vintagedude · Post by **vintagedude** » Sun Jan 11, 2004 12:59 am

CL72 and CL77 EXHAUST. I forgot to mention that NEIL FERGUS told me that the stock pipes on a CL72/77 were power robbers, no matter the diameter, with or without mufflers. He said do you want to pick up big power? Well, I said yeah", he said OK..Pssst.Uh Ok, Ill tell you but dont tell anybody else, I said OK (fingers crossed) He said use CB77 SUPERHAWK HEAD PIPES with an 18" extension where the muffler goes. I said what? are you crazy? A low pipe? he says" Ya, the sharp quick bends in the stock pipes where just too much. The long sweeping bends of the superhawk pipes added big power, and the extension put it right on the mark. Woah I said, what about ground clearance? Who cares! Ever heard of a twin pipe CZ? Do you want to win or what? Ok, we are looking for CB77 pipes, got any? E mail me vintagedude&msn.com

87we4turbo · Post by **87we4turbo** » Sun Jan 11, 2004 1:05 pm

I don't know if it is already posted on the site, but Megacycle Cams still lists a selection of grinds for the 250/305 and many other vintage bikes. I used one of their cams in a CB77 in the late 70's with both 337cc and 347cc displacement and was very happy with the performance. Here is a link to the specific page: http://www.megacyclecams.com/catalog/page23.pdf Or just go to http://www.megacyclecams.com John

vintagedude · Post by **vintagedude** » Fri Jan 23, 2004 4:23 am

Since my last post we have learned alot, and the engine is near completion. We performed the following: 1. Eliminated oil slinger (built solid pipe to take its place) placed extra "cone washer to take place of gear. 2 . X'ed the center gears, set em up with offset fork washers 3. Used the 337cc big bore pistons we bought off Ebay. 4. To complete the 250 ruse, we installed the 305 liners in the 250 cylinder, was nec to bore cylinder to accept 305 liners. 5. To complete the 250 ruse,we used fully prepped CL72 inner cases. 6. Installed an oil cooler. We welded the LH clutch cover oil passage halfway through, tapped for lines. 7. Used stock cams, springs, valves. 8. Stock carbs and K&N filters 9. TRICK 2-1 downpipe exhaust with upswept tapered cone CONSIDERING: Raking the forks lengthening the swingarm

Post by **Michael Stoic** » Sun Jan 25, 2004 2:42 am

[forwarded from email] The 350 here in Chicago is somewhat incomplete and could go either way -- short stroke 6 speed, or almost stock 64 mm high compression, big valves, our own cams, etc. The frame has been somewhat modified to steepen the steering head angle and to add a little lateral rigidity. As you know a CB72 frame is not over endowed with any sort of rigidity and on the race track it is a flexy flier. For brakes I have the choices of CB72 (fades badly and the drum expands away from the shoes when hot, XS1 Yamaha, reasonably light, Suzuki Titan T500, lighter than the Yamaha with nice wide shoes and those scalloped fins, but it is flimsy or the big daddy GT750 double sided TLS which weighs about the same as two of anything else (about 20 pounds !!!) I'm thinking Yamaha and a set of RZ or late Rd400 forks with special triple clamps to reduce the offset and increase trail. I also have to add about 3 inches to the swing arm and get longer shocks to suit the changes. Regards, Richard Rgnemd@aol.com

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HI PERFORMANCE & RACING INFO needed

HI PERFORMANCE & RACING INFO needed

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