I did the ton (CB 400T)

dirceucorsetti

New Member
I just want to share with you an accomplishment of mine. After redoing the carbs, crossover and a lot of tuning I finally got the bike to 100mph. And she stayed there. Man, what a joy. Unfortunately there is no motorcycle specific Dyno to tune the bike so this is the way I have to test her.

I also had to get a new sprocket and stiffer clutch springs.

For anyone wondering, I have a Honda CB400T from the late 70's.
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8) If it's a later model 'Super Dream' 400N (1981~82) it may be good for around 108mph. Some of the later ones had different cam timing and were actually pretty quick (plus didn't handle too bad either) Is it stock dual disc? If it's a 400T, good going
 
crazypj said:
8) If it's a later model 'Super Dream' 400N (1981~82) it may be good for around 108mph. Some of the later ones had different cam timing and were actually pretty quick (plus didn't handle too bad either) Is it stock dual disc? If it's a 400T, good going
The previous owner had the duel disks installed. It is an 1982 Brazilian model which translates to the 1978 US model. We have the CB450DX that is probably enough strong to hit the 108mph. As we have a 30% ethanol mandatory mix I doubt the timing is aggressive enough to get a 400cc to the 108 mark.

Cheers!
 
It's more impressive as the 'South American' models were often de-tuned to run with high ethanol fuels (even back in 80's)
The Yamaha RZ350 YPVS was a 130mph bike in Europe but the few South American' imports I rode were struggling at 85mph.
Pity the timing is fixed, I know it's possible to pull generator rotor and elongate the mounting holes into slots but it isn't easy. I think you can get around +/= 5 degrees by modifying the trigger mounting holes (although you'll probably have to drill out rivets?)
Have fun, ride safe
 
crazypj said:
It's more impressive as the 'South American' models were often de-tuned to run with high ethanol fuels (even back in 80's)
The Yamaha RZ350 YPVS was a 130mph bike in Europe but the few South American' imports I rode were struggling at 85mph.
Pity the timing is fixed, I know it's possible to pull generator rotor and elongate the mounting holes into slots but it isn't easy. I think you can get around +/= 5 degrees by modifying the trigger mounting holes (although you'll probably have to drill out rivets?)
Have fun, ride safe
Nice! Did not know that. We received the first batch of bikes directly from Japan and those are known for having more power, probably due to the timing setting.

We have 30% of ethanol mixed with gas (sometimes more) so this probably also has an effect. She was always very lean on the mix so I had to rejet the carbs with larger gicleurs to make the mix even. That probably helps.
 
Good possibility you have te full power one. The only issue with te first ones was the generator 'low speed' coil would fail and it didn't come without the completes stator. (including flywheel which 'never' went faulty) Later models were able to get stator only but you would probably need UK or Australian replacement as they had same (or even 'better' timing tan almost everywhere else
 
I remember the joy (and amazement) of first hitting the (indicated) ton on my XS250...WOOHOO

it never did that again

then I got the later model XS250 with the twin cam motor and that never went anywhere near the ton, handled and stopped a lot better but that's no compensation for lack of tonnage though

then I got a GS750 which would do it with ease, followed by a GS850 which would do it but didn't want to, then a GSX1100 which would do 150MPH with me hiding behind the fairing, the Vmax I've got now will do about 155 if pushed but theres nowhere safe to do that sort of thing anymore (radar guns, speed cameras, hidden cops, nosey busybodies that will drop you in the shit with the cops for your own good) only safe place left is the on ramps to freeways, the Vmax will usually hit about 130 before its time to back off or way out in the back blocks in the country where the roads are so shit its dangerous for all the wrong reasons

a couple of years ago someone got clocked on a freeway out in the country doing somewhere around 320kmh (200mph) the cops couldn't get near him but got a speed camera pic. the cops did pop round to someones house (whose brother in law I knew) a couple of weeks later and told him they had digitally enhanced the pic they had of the bike and they were there to arrest him for his miscreance. he told them that if they had had proof of this at the time it happened they would have been waiting for him at home on the day when he got home (except it wasn't him and therefore had not been out that day) and they could therefore sod off which they did
 
crazypj said:
It's more impressive as the 'South American' models were often de-tuned to run with high ethanol fuels (even back in 80's)
The Yamaha RZ350 YPVS was a 130mph bike in Europe but the few South American' imports I rode were struggling at 85mph.
Pity the timing is fixed, I know it's possible to pull generator rotor and elongate the mounting holes into slots but it isn't easy. I think you can get around +/= 5 degrees by modifying the trigger mounting holes (although you'll probably have to drill out rivets?)
Have fun, ride safe
My UK one did about 120 mph indicated standard, a little bit of tuning and a set of Kim Lomas pipes and it did a genuine 135 mph, my mate with a GSXR1100K said he had trouble keeping up with it to 130.

Sent from my SM-T560 using Tapatalk
 
julian.allard66 said:
My UK one did about 120 mph indicated standard, a little bit of tuning and a set of Kim Lomas pipes and it did a genuine 135 mph, my mate with a GSXR1100K said he had trouble keeping up with it to 130.

Sent from my SM-T560 using Tapatalk


I assume your talking about the British RD350YPVS? I was running Suzuki /Yamaha workshops at the time and saw some really dumb stuff done to them. ('porting', rear of pistons cut off, etc) There were a few mods that worked incredibly well, mainly modifying reed blocks and carbs then fitting 'spannies' (Micron, etc)
 
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