Topic: SAMOTO CB400SS story

[turboguzzi]

This month's issue of Motociclismo d'epoca, italy has a 12 page, in depth feature on the glory days of the SAMOTO (A Roman dealership) tuned CB400SS in italian "production" racing in the seventies, lots of stories, including an interview with Murelli, the only non-japanese technician to have worked on the oval piston NR500. Their bike won quite few races and titles back at the time.

Too long to translate and dont want to infinge in copyrights, but interesting bottom line is that with a 498cc kit and the tiny stock carbs required in production racing, he was getting 45 hp, while with 29/28mm carbs for national level 500GP racing, he was up to 55-58hp.
Very quickly the 400/498 became faster than the older CB500 fours even if the later seemingly had the edge on power on longer tracks.

Another interesting tidbit is that a certain "Futura" company (from Rome too) was making at the time cams with needle roller bearings for the 400..... timing was similar to megacycle's: 25-55 55-25.

TG









 

[bwaller]

There have been plenty of guys on much larger bikes talk about huge battles with a wildman on a 400F. I find it a bit alluring doing more with less, but you were right a long time ago when you mentioned it takes a boatload of cash to make a really fast 400 that will stay together. 

Cool story, too bad I can't enjoy it.

[Tintop]

Great story TG, thanks for posting.  Let's see, I've got a 400SS, red tank, an extra disk and caliper....oh yah money.

[turboguzzi]

There have been plenty of guys on much larger bikes talk about huge battles with a wildman on a 400F. I find it a bit alluring doing more with less, but you were right a long time ago when you mentioned it takes a boatload of cash to make a really fast 400 that will stay together.  

Cool story, too bad I can't enjoy it.

I knew for years about Kaz Yoshima exploits butwas not so aware of the whole HIPO aftermarket industry that existed in the mid 70's for the 400-500-550's in italy, driven by the Success of SAMOTO.

Those races were usally 200-300 miles long with two riders, so reliability HAD to be good, strangely enough, didnt see anything mentioned about conrods but that could have been SAMOTO's "little secret"....

Great story TG, thanks for posting.  Let's see, I've got a 400SS, red tank, an extra disk and caliper....oh yah money.

those tanks were really nice, same style as the original 400's just longer for more capacity. They really needed it for those long races. Nowadays i go out to the race with a half tank, never used more than 8-9 liters in a 25 minutes race.

BTW, SAMOTO used to sell at the time a kit that let you add a caliper to the second fork leg in a 400, would be interesting to see just how.... hard to see in the magazine's pictures.  

[Bill/BentON Racing]

Interesting read Yossef, perhaps the 400 had a better power to weight ratio over the 500   oh, and Mr Murelli had an English colleague named Ron Williams who wrapped a new frame round the NR motor when Honda couldn't get it to handle.

Sam.
 

[turboguzzi]

Interesting read Yossef, perhaps the 400 had a better power to weight ratio over the 500   oh, and Mr Murelli had an English colleague named Ron Williams who wrapped a new frame round the NR motor when Honda couldn't get it to handle.

Sam.
 

could be, they claimed they got the 400/498 down to 125 kilogram... my 500 is 145!

[specweld]

TG your right that futura made cams for the CB400, but if anyone out there comes across one ,make sure you check it out properly.
They are stamped FUTURA SR1 and the lobes on one side of the cam are ground back to front ie.fast ramp in, slow ramp out.
On a really well tuned motor this is disaster waiting to happen.
If you go to 'MY CB400' (page 2 on this forum) and look at the pics of the blown motor this is the result.
If anyone doubts that a back to front cam can come direct from the factory, I have 2 of them in my possession and lots of bits of blown engines.

dave

[turboguzzi]

hi spec, long time no see....

What can i say..... typically italian !
 or rather typically Roman.....
 

were your cams the needle roller version? was curious (as the article doesn't mention), how it was done.

split outer bearing races? did it require to bore the head?

TG

PS - know the whereabouts of Col? havent seen him round here in a while

[specweld]

the cam only had needle rollers on the ends, the end journals had been turned down (and hopefully hardened), the OD of the needle rollers was the same as standard and the cam just dropped in as normal.
As it happens ,I have an experiment going on at the moment.

Ony one of the Futura SR1 cam's came with needle rollers, and as both of the cams  are knackered ,I have fitted the bearings to the webcam#69. which is in the bike now.

Col is alive and kicking , but as he has had no bike to play with for a while (in transit from OZ) he has immersed himself back into his other great love (no it's not alsations) Rugby.
6 nations and all that,
Col is racing at Croft (9 -10th April) I believe Dave Martin and Frank Lempstra are riding as well so it's a bit of a Phillip Island reunion for them.

regards

Dave

[turboguzzi]

thanks on the updates and good luck this season

TG

[corser85]

hi these is my first post, to date i've only read, but these is a post where i've something to write:-) i've 2 cb 400 four samoto a 500cc and a 450cc, built same years ago by Murelli, if you want ipost some photos, yossuf cant report the articles but i can post some consideration on these bike and on what Murelli say when built the bike:
The 400 four 500cc was prepared whit the original fork, and the original baking disk and capilers(che second was taken by the four 750) because the marzocchi 35 and the brembo capilers, the best at the time in italy(i've put these on my bike)  were too heavy to that of pilots and trainer, Murelli infact says:''where you have to go with all that stuff to the front, it seems that you slip into the dish at Monza to 200 hours! the bike has them but you do you feel? original forks is more than enough for this bike altrmenti Can you become good only for going straight and you lose in handling'', but the bike were buil to run in the Pergusa track that is a high speed trak...
Anyway, another interesting thing is the origin of oil radiator, these is take from a 2cv citroen, In fact it is the radiator of the machine, in the 70 were simple to by find or by, now is almost impossible to find:-)
now i dont forget other thing :-)

ps: sorry for my terrible english:-)

[corser85]

e now the photos:-)

[turboguzzi]

nice stuff in there! (but cant see the first picture)

where are you located?

If you are coming to the race in Adria this weekend, you are welcome to pass and say hello

White bike number 999 (not a sohc )

[bwaller]

Cool race bikes corser85. Any idea of exact weights?

[corser85]

i'm from Catania, turboguzzi I sent an email for advice on the 500 some time ago, but I have very little time just to fix that, I think this year will only''trofeo del Mediterraneo'' races that run in Sicily
about the wheight i'm not sure, but I think they weigh is about 150kg whit oil