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Discussion Starter #1
how high does it rev and what has to be done to make it happen?

carillo type rods? custom crank? bigger chain for the cam?

what breaks first or second in these when really spun to the stratosphere and shown no mercy?

biggest dyno numbers from a CB350? torque and HP? anyone ever gotten more than 40 ft/lbs of torque out of one?

and talking normally apsirated but I do have a new tiny turbo just perfect for one but don't know enough about the oiing on them to even think if it's worthwhile and viable.

I know some local guys that have raced them and haven't run into them for a while, but I may think about building one for myself.

Would rather do a 305 but all the go fast bits for them have to be rarer than a virgin 14 year old around here and worth more than their weight in platinum.

I am still kicking myself for not buying that 6 speed 305 off ebay about 3 years ago, and I am told it had lots of other goodies in it.
 

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chris' put out 48. coated pistons, and cyls. dyna ig. todd pistons. he ran some prototype cams, obviously porting, ti valves, springs.....claimed to have 3k into it. there are others like it. but it was a monster. todd had them, buff, and a few others. chris was one of the fastest in the country. if hes watching, im sure hell chime in.

jc
 

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Discussion Starter #3
so what breaks or fails first in a hopped up and beaten stocker?

say one that has the 286 or nastier cam, big ports and carbs, good header, and ignition?

is there a well proven list of commonly weak items?

has anyone force fed one?

micro-squirted one?
 

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stock cam chain tensioners have rubber wheels that become brittle and crumble apart. there are aftermarket teflon slippers made as replacements.

i'd love to pick on up but every time i look at them i can't help but think it's only few dollars in materials and not a lot of time a CNC for the price. anyone out there reverse engineered them? anyone interested if in cheaper ones if i did?
 

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My race bike from the 80's was built pretty well. I never had it on a dyno. It had a ported head Norris cam and valve springs with Aluminum retainers, 3mm over pistons, stock camchain tensioners and bottom end and 30mm Lectron carbs. It would rev to 12K but broke the aluminum valve spring retainers. I rebuilt it the same but used the stock steel retainers. It would only rev to 11.2K then but didn't drop valves again. It had a tendency to leak oil past the points seal, I think the heavy valve springs caused the cam to move too much in the bearing block. I never bothered trying to fix the problem since I just cleaned the points off before every race and kept running it. I ran that motor for probably 30 race weekends or more without tearing it down and some weekends I would run it in 6 or 8 classes. It had a lot of race miles and wins. I finally parked it when I moved on to another bike but it was getting pretty worn out by then both motor and chassis. I wonder where it is now? I just parked it, along with my old 400f racebike, at my brother's rented place behind the barn in 1986. He passed on in 1988 and his wife moved without touching them. I wonder if they are still there? I wouldn't mind having that Norris cam again, I think it worked pretty good. I am also curious how big you can take a 350 motor with ore and stroke? I have heard that you can fit a cb450 crank into the cases.

Ken
 

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Discussion Starter #8
thanks, great info

do you know if roller tip rocker arms can be had for one?

cool to know the crank and rods are ok to 12K

I wonder if Ti valves and retainers would cure the valve dropping to the point of making the valve train bullet proof

maybe that and rollers

but Berrillium seats aren't cheap if a man wanted to do it right

the valves and retainers aren't too terribly bad on the wallet

btw...... what other bikes, stock or race, would yours run with?

would it whoop up on a stock 650 triumph?

I've never had a stock 650 triumph that would run flat out with a cb350, superslab and pin the cb throttle to the stop, see if the 650 can keep up and if so, for how many miles

a good cb350 will hold about 90ish for as long as you have the road

people tell me I am FOS when I say that but the stock triumph is geared for crappy slow roads and will shake itself apart with UK gearing just trying to maintain 70

so when I build one for me, it's geared way taller than stock and I like them to loaf around 2800-3000 rpm at 70

instead of 5500 at 70

don't know much of anything about poking and stroking a cb

but I'd like to learn
 

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HackA,
It is kind of hard to say how it would do against a stock 650. Back in the day when WERA only had an above 500cc vintage and below 500cc vintage classes, I could win both classes on the 350, but I don't remember if any of the other bikes were stockish 650s. I suspect a good 650 would have top end on it. I did beat a 650 Triton on occasion, but when I borrowed the Triton for a few races, I was faster than I was on my 350. Of course that was back when I was fast, too. I am sure that a more modern valve train would be beneficial. I have not heard of any roller rockers for the 350. Maybe stock rockers could be modified they are just cast steel pieces that are not fancy at all. It might be fun to see what kind and size motor could be built if there were no vintage race restrictions on it.
Ken
 

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kens right. i think most guys only build enough to keep ahead. id say if you went full tilt, you could drop 5k into a top end pretty easily. then another 2 or 3 on the bottom end with tranny and bits. todd did the mnost with them. of course vintage legal. ive seen numbers of over 50 hp. but not from anyone credible. you can have anything made, roller rockers, an whatever, but there is the theory of diminishing return. ive run against fairly stock 500's w/ average riders and had no problem beating them. but guys like dylan eustace, and tony the knife are different stories. its been sooo long since ive have the t120 out i dont remember. but then thats comparing a race bike to a street bike. but my t120 always felt faster an meaner.

jc
 

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Discussion Starter #11
Thanks Ken

I agree a 650 will have it on the top end

but unless geared very tall, like 3:1 overall (which is where I gear my street brit bikes) instead of closer to 5:1

they simply will not sustain those speeds

the vibration makes the handle bars grow to the size of ball bats and you really know there is an angry jackhammer you are sitting on

the CB will just do all it will do, anytime, and all day long

an average 650 triumph will put about 35-40 horses to the back tire

my short rod 750 puts 52 to the Super Venom

the Triumph engine is also lighter than the CB350

I am pretty sure as it's been a while since I weighed a 350

the Triumph 650 weighs 140 without carbs

I think I need to snag myself an engine off a parts bike and would prefer one in very good condition

have any of you ever heard or seen of a turbocharged 350 honda?
 

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stock motor without carbs or starter weighs 110 lbs. with oil.

biggest bore I have ever heard of is 500cc.

the yosh and cyb tuned 350 racers both claimed 50hp with a complete bike weight of 250lbs. (wet or not? no idea)

pretty sure it's all been tried and most of the standard upgrades are documented and easy to get info on. pretty easy to get decent power but once you are in the high 40's it gets like Joe said, diminishing returns... hell, there was even an 8 valve head at one point.


I'd love to see one. I have seen a piston for an 8 valve cb450 head.
 

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Discussion Starter #13
how much does it weight with carbs and starter?

how much for a bare 450 and one with carbs/starter too?

I truly had no idea 4V heads could be had for the 350 and 450.



here are some rare 4V heads for a HD

seldom seen and will flow enough for 150 horses without opening the ports
 
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