the story continues

[rigwit]

 as you all know i,m doing a 400-4 cafe/racer well the saga continues, one thing as you seen from does 4 liners etc Ive found a suppler that can do 54mm hi comp pistons Honda say don't bore out more than 1mm  but liners seem to have plenty of meat to out to 54mm this leaves the stepped land at the bottom with a 1.5mm sidewall, depending on what the chappie thats going to be gas flowing heads crank lightened balanced etc if doable would be a 458cc Joby also got clutch parts back and are better than Honda new cost a bit though and having a custom billet cover made for generator is so far

[Bryanj]

That sidewall will be OK as long as the man boring it is real good and carefull not to crack the liner

[Rozabikes Tim]

Wasn't the yoshi kit for these 460cc - so similar bore? Were these reliable?

[rigwit]

Tuner says its ok to bore to 54mm one thing i did ask him as i was a bit concerned at the stepped landing only being 1.5mm thick was to have Hindle reman, submerged weld the bottom and then turn down so a thicker bottom land would ensue, dave  said that probably the cost for this would be greater than haveing new liners made i enqured at the price of them and the company who makes them for him befor he machines them down ar

[UK Pete]

so be a nice xmass gift to myself methinks ...........

I like the thinking i will have to go and buy myself some xmas presents as well,

[ttr400]

Hi.

The 54mm and the 54.5mm pistons are OK with the stock sleeves. 54mm =458cc. 54.5mm=466cc.
Some info for you.
Stock sleeve:
Upper OD= 59mm
Lower OD=57mm
Upper wall with 54mm pistons=2.5mm, lower=1.5mm
Upper wall with 54.5mm pistons=2.25mm, lower=1.25mm

The 54.5mm is the largest I would go with stock sleeves.

Any more info on where to get those 54mm pistons you have?

Kevin

[rigwit]

00 raceing
and link to the piston is .............   http://www.ooracing.com/store/index.php?act=viewProd&productId=1396

and part of the e mail recived (i had already worked out the cc b4 this though)


If you give us the stroke we can work out the CC
They are made by a company for our engines OOR branded
We run them up to 13000 rpm with our engines.

[Yoshi823]

so be a nice xmass gift to myself methinks ...........

I like the thinking i will have to go and buy myself some xmas presents as well,

Isn't it called 'retail therapy' by those of the female type of humans...?

[z1100r]

Wasn't the yoshi kit for these 460cc - so similar bore? Were these reliable?

Yes, very reliable and I think at the time performance % wise the 460 kit was the best kit Yoshimura did. Ok, I know a 400 wasn't the fastest think on the planet to start with but the pep up with just a R&T cam and 60cc's was incredible. There were alot of 460's in racing at one time so I'm surprised I don't see more 400-4's advertised with 460's.  If I got the gearing wrong - which I did at Silvertone once - mine would rev to 13,500+.

 I never saw one of those Futura 500's with Carrillo rods and god knows what but I hear they were quick. My 460 was on a par with a Stan Stevens tuned Yamaha 350LC...my bigger 500/550 bored to 600 was on a par with the later stock fully fared Powervalve 350's. A fully tuned later fully fared 350 F1/F2  powervalve would annihilate both of them.

[Yoshi823]

A friend of mine had a 460 Yoshi when I first met him in 1978 when he was an apprentice at an engineering firm that I started working at when I left the Navy. I had a CB550F1 at the time & there were times when I struggled to keep ahead of him on the twisty bits. But then his bike was built by Dixon Racing, & when we had the head off to do the head gasket & lap in the valves we found that the ports on the head were sadly wanting. The were clean but not 'gas-flowed' in the correct sense. Even the part of the valve guide that protrudes into the ports wasn't modified or even made of a better material than standard. So it did look as though it was literally a 460c piston kit & a standard/modified cam, as there was only a slight differance between the base circle to the tip of the lobe from a standard cam that my friend also had. The Devil exhaust did make a differance to the sound though, but while we had the carbs off so as to get the head of, we checked the jetting, & this was on standard main jets together with the OEM air filter. Plenty of room for improvement there then, which we did when my friend's funds allowed him.

[rigwit]

Right I,m Back  got a little beauty 400-4 F2 21.300 miles will run standard for this year  then do my Wotan Honda Mk2.