Chassis Mods and the mysterious parts book

[BrettS]

Members G'day,

I have tried searching the forum before asking this Q and forgive me if I have missed it. What chassis mods were done through the series to assist ride ability etc?

And an exert from Wiki

"The XS went endurance racing in Oz for promo reasons. The chassis was developed for months and as stated in Cycle World then "after which "parts book engineering"...(that is, the parts book gave the modified parts official existence, but just try ordering them)." The XS enjoyed a series of wins."

What is this parts book they speak of and what modified parts were utilised?

Cheers

I think what Chich is referring to here is that for production racing all parts used had to be available as options on the bike. These parts where listed in the parts books as per the rules but if you tried to order the part they came up as unavailable.
Obviously they had some for the racing team so they did exist but how many are actually out there and if any were sold or optioned at all is not stated. From memory the parts book listed them as heavy duty I'll have to look at my parts book again which is the H+police bike models.
 
Chich, there are parts books floating around for various models, not sure if any are available for download. Mine was given to me by a very nice online parts dealer.
The latest model xs1100 has a braced chassi. I believe this came from development in racing and then incorporated into the production bike.

[Jaymo]

I'll have a warm inner feeling when I get all the problems on my XS sorted.
Which, honestly, aren't that many.
Needs new front brake pistons.
Needs carbs cleaned and a flooding carb pinpointed and repaired.
Needs clutch switch replaced.
Needs a proper choke lever/cable installed, so I don't have to hold the choke knob out while warming up.

[Jonesy :-)]

I'll have a warm inner glow when Re-Hab is back in one piece

[AussiXS11G]

There is the warm inner glow factor to consider too, tho

[Jonesy :-)]

Hey Bryan, i followed up on your offline suggestion to do the mod
And spoke to M about it, since mine were apart and he concurred it might get you an extra horse down the main straight at revs beyond what most of us would see on the street

[AussiXS11G]

I doubt the crankcase mod would be of any benefit unless running the engine at high revs most of the time -
race bike like....

[Jaymo]

As far as the air horn thing goes: Here in the US, carburetors generally consisted of three main castings.
The bottom (on a downflow carb) was called the throttle body.
The center was the float bowl.
The top was called the air horn.

I guess I could see why the mother ship would call the velocity stacks "air horns".
Maybe. Kinda-sorta?

As far as the crank case mods go:
Grinding off the ribs for #s 2 and 4 crank journals?
Are we talking about the stiffening ribs that would extend from the journals to the sides of the case halves?
Is it worth losing stiffness in the crankshaft support, in order to gain a few ponies?
For us on the street, I mean. On a race bike, with replacement engines available, I can see it.
I'd just be afraid it could cause problems down the line, on a daily driver.

Or, am I just wrong as hell?

[Chich46]

Away on an OS trip with intermittent wifi so have recently caught up. For an XS greenhorn this is amazing. Again big cheers for all the info and contributions. Massive thanks to Bryan for sharing those docs. Gold.

[AussiXS11G]

This just in from M Pitman regarding the origin of those notes....

That list of pages was the paperwork that came with the race kits that we received from Yamaha, back in 1980.
I used one of these race kits in the chain drive superbike I built for the Coke 800 and Bathurst.

Only three of these kits came to Australia, two going to Pitmans and one going to Annand & Thompson in Queensland.
Joe Klavitter from Annand & Thompson built a chain drive bike the same as Pitmans for Dave Robbins, with me supplying the chain drive parts and swingarm.
I think Dave may have been injured then and unfortunately Joe sold the bike to a guy in South Africa and so it never raced here in anger.

At the rally in Wellington I spoke to a number of guys and told them that after Japan tested the XS1100?s in South Australia in December 1977 we convinced them we needed suspension options for racing and two up touring.
For the 6Hr in 1978 we only had paperwork from Yamaha advising that the suspension was a parts book listed option, and we were able to use it.
In 1979 the parts book came out with these suspension options listed.
For the 1979 6Hr it was all correct with the optional suspension listed in the ?F? model parts boo

[AussiXS11G]

dunno the origin,  Jeff
I trawled all that off the internet - M Pitman was aware of this material tho -
particularly the mod to the cases item 7 - 

[excess.11]

Thx Bryan....nice historical read.
A lot of kafaffin about in the netherlands by some dealer there.
Were these notes for one of their later race teams do you think ?
Can t see a year relating to the info.

[AussiXS11G]

I wondered where the air horn thing came from.....WTF? you blokes....

the dope on carbs is not much help - they used 2 dual throat carbs seen on Mals 1981 superbike

[excess.11]

Hey Bryan...do you have any consecutive pages you can post
Aside from wrinkly paper pics...photobucket seems to just show the one page you posted.

[Jonesy :-)]

Ha ha nice one Errol, at least someone here is on the ball

[Eveready1100]

Erm, guys. I'm pretty sure they're talking about the velocity stack trumpets, as we are in the carburettor section of the page