Topic: Yoshimura 400/4 spec ?

[Chris Tyler]

Hi

400/4 re registered as a Yoshimura 458cc.
Any ideas what the specification would be?
Standard cam, came in a bag.
Carbs seem standard.
oil cooler is in a state
ARE wheels
interestingly twin disc front end? 500t?
Unfortunately only one caliper.
What else should I be looking for?

Thanks Chris

[Greggo]

You should show us a picture

[Tim2005]

Agreed, pics would be very handy, I also wonder if it is a Mocheck Harrier, I can't see any other way it's likely to have been registered as a Yoshimura. Was it registered in 78/79 or later even?

[Chris Tyler]

Hi
ie my son Davids project
found the note for the camshaft part YH-3-1 Road & track cam. so at least thats in there
Couple of photos to be going on with.


Chris

[Greggo]

COOL!  Looks like some nice bits 'n pieces on there, with that swing arm, oil cooler adapter, dual discs, neat shocks too!

Too bad we can't see through the motor

[Tim2005]

Interesting stuff indeed. All looks intact and in pretty good condition. Definitely ARE wheels (which are great), Dresda swinging arm and Paioli shocks, I think. Are the forks 35mm, by chance?  As for a guess at history,  I'd think it's a road bike, no sign of racewear on it, and 1980s tyres too so it's been off the road a long while. Next step for me would be I'd take the rocker cover off & check the cam chain is tensioning properly, also run a compression check and drain the oil to check for water or debris, inless you are planning to strip it anyway.

BTW, in pic 1, what's that behind it, is that a Seeley or a Rickman?

[Chris Tyler]

Hi

We are waiting for the return of the log book. Then I will trace the original builder. This one has always been a road bike & appears to have been off the road for over 15 years.

My project in the background is a Seeley. Hope to be out in 500 group2 period 2. Its a Yamsel that has been badly butchered. I have started a dry build with my Daytona engine fitted.

Thanks for the advice, that is exactly what I intend to do. The engine might also end up on the track before it gets on the road.

The item I am most concererned about is the radiator but we have time.

all the best Chris

ps forks are 33mm Just found a caliper from the K4 pile of spares.

[Tim2005]

Sounds a good plan. As for the radiator, I'd just head over to the local bike breakers & check out whatever oil coolers they have got. Yamsel project sounds a great thing to have on the go. As for 33mm forks, AFAIK the only r/h one with the 400f type caliper mount was an RSC (HRC) part, it is almost a mirror image of the l/h one but the casting is much sharper quality.

[Chris Tyler]

Hi

Thought I would update my page here. (forgot my password)

Twin disc fork leg is a homer. the bracket has been hacksawed off one leg & welded on another. Its straight but not pretty. Cant see myself trusting it, although my friend has offered to crack test it.
The engine  sad to say, all the covers came off too easily. Seems to have been stripped to the same point & left open for many years. (the amount of dead wild life in the oil & grit & stuff is stunning) So questioned the previous owner. 18 years sat in the shed as a project the engine had been sprayed black while still in the frame. Seems he just had a look at the insides. Says it ran!
So decision time.
Wheels are now in my sons race project. I have decided to put the engine in the race bike as well so will strip it & see what we find.
Carbs are off to be bored out
The fork leg is going to be looked at but I will probably have a bracket made to take a second caliper as per the Foale.
Been offered a exhaust system.
I have everything else just no space, little time, no money. The usual
Time to start stipping cleaning & getting ready to paint (basic home spray, which I am naff at)

Chris

[turboguzzi]

not exactly managing to follow all the details regarding what component goes to which bike, etc, but when i read on one hand "no money" and on the other "boring carbs", all i have to say is try find something cheap and ready. with bored carbs youll be on your own regarding jetting, needles that might not be long enough, etc., might be the expensive way around actually.

i run the so called VM26 (actually 27mm bores) in a 500. a bit heavy but really easy to find, cheap, nice and easy to work on carbs. thye were fitted to various 750 or bigger fours

[Chris Tyler]

Hi

Thanks turboguzzi. Carb details are usefull. I did wonder about looking for something else I can use, as good carbs make such a difference to a bike. However in this case I have the original maker of the bike telling me that he bored stock carbs out in the period as the first year you had to use stock size carbs. The next year this rule changed but he found larger better carbs made very little difference to the bike. Ie the stock carbs bored out were good straight off. Hopefully he is going to be able to give me the settings. I have 3 sets of carbs & my mate Terry will machine up 2 sets, he also runs a Foale. I have the o rings on order & an ultrasonic tub, so costwise not much in it.  The only concern I have is how much silencing will effect the jetting.
I am not looking to be up the sharp end with these bikes because as you know they cost a lot of money to really get them going. I am building the spare engine up with 125 pistons as my Foale has a stock engine.
Just looking to run a good handling bike with a sweet engine.
As usual, too many projecta on the go but I should finish them all by the time I retire

All the best Chris

[specweld]

Chris,
if you intend to put this on the track, suggest you check the conrods to make sure they are not standard, if they are ,they WILL fail, yes even on a 460 unless you intend to keep the revs way down 

[specweld]

.Sorry Chris , wrong photo's , diferent blow up,these are the ones I meant to show.

[turboguzzi]

that's a proper sohc4 yummy mess!

[iomtt9]

Oh yes , and it was not me who was riding it !!!!
Col

[Chris Tyler]

Hi Specweld & you too Col.

I am going to have a look over the winter as I have 3 engines to strip & see what I have. Never got the works rods or 2 ring pistons etc I was promised Cant find alternative rods that I can afford ie modern stuff & note that no one lists s Suzyamakwak model that might suit. Just looking to have fun at the moment & know the rods are a risk.
Glad you both had good seasons

Chris

[iomtt9]

Hi Chris, i still have the race rods for sale. They are a bit expensive but so is  a blow up like Daves.
Yes had a good season, not done any CRMC this year but done Assen, Chimay, Germany, Croft, East Fortune and the Manx GP.
Thanks
Col PM me if you like and we can see what we can do, or ring me .

[turboguzzi]

Hi Specweld & you too Col.

I am going to have a look over the winter as I have 3 engines to strip & see what I have. Never got the works rods or 2 ring pistons etc I was promised Cant find alternative rods that I can afford ie modern stuff & note that no one lists s Suzyamakwak model that might suit. Just looking to have fun at the moment & know the rods are a risk.
Glad you both had good seasons

Chris

what's the big end diameter/width on those 400 motors? just in case...