A Racing XS11!

[chevy45412001]

1,000,000 dollars

chain drive,chain drive....we want chain drive.Also i tried looking good but lack of undermotor oilfilter? looks like the oil cooler lines go to the sides of the lower engine case? and cam oil feed line at the rear of the motor? So many questions so little time.

[Geezer]

Re: Endurance bike..

Originally posted by superdave
Wheres the case savers or sliders? 1 drop and oil slick or no spark pickup. The front end took some work. Would have been simpler to take a fzr or canadian gsxr upside down forks, for the adjustability and ridgitity. Other than that I want 1. How much $? This the type of modifing I like to see. Push that envelope!!!!

I can't answer the rest of the qwestions but the front end is a 21st century version of the girder front end. The main advantages are they're strong as hell and they don't dive.

I had a chance to ride a Vincent Black Shadow with a similar front end and it was impressive to grab a handful of brake and the front end would stay perfectly level.

Geezer

[superdave]

hey Geezer.

There is nothing wrong with a little front end dive, I personaly like to transfer weight over the front tire on heavy breaking. The key here is to leave some suspention to suck up the bumps in the tarmac. There was this guy at Road America raceway back in the late 80's. He had fabricated this telescopic front end with scissor type steering. I believe it was somthing he did for school. The whole thing looked like the nose gear on a lear jet. 1 last comment;If the vincent suspension was so good ,why isnt it used today in moto gp or fim superbike racing? Don't get me wrong I like thing that are different, They just have to be funtional

[TopCatGr58]

Hey Chevy,

No problem, I'll type S L O W E R next time!!!

As for Chain drive, PGGG has started things rolling, and I'm going to follow up with an attempt at a conversion myself, keeping track of what steps are needed, parts, etc., so that I can make a Tech Tip. But I've got to get my 79SF basket case done first, now that the weather is turning a little bit cooler, I can now tolerate being out in the unA/C'd Garage!

But, so far it seems like a person will need to be able to WELD, have a spare XS11 Swingarm, and other Chain Drive swingarm slotted rear sections. And unless you have lots of parts, it'll be a ONE WAY conversion, destroying the Middle Gear case in the process!
T.C.

[pggg]

That thing has been swapping rear wheels - front sprocket looks to be 13T, rear sprocket hard to tell but looks around 40 or over. Back wheel looks like 18". Probably sits on 10,000 plus revs! I'm picking the drive unit spline has been cut,shortened, regrooved, and reflanged at the engine side and probably a 25mm I.D. bearing set to the spline to replace the original R/H 30mm I.D. bearing to bring in the sprocket so that the L/H bearing could be ditched. Would narrow down the available rear tyre size though.

P.S. I'll have some pics of my rear wheel setup soon. Have found a fat Kawasaki wheel sprocket axle and disc with the right measurements. Never fear Chev, soon TC "I'll try anything" Gresham will be churning out sleek new drive conversions a dime a dozen.

[Geezer]

Re: hey Geezer.

Originally posted by superdave
There is nothing wrong with a little front end dive, I personaly like to transfer weight over the front tire on heavy breaking. The key here is to leave some suspention to suck up the bumps in the tarmac. There was this guy at Road America raceway back in the late 80's. He had fabricated this telescopic front end with scissor type steering. I believe it was somthing he did for school. The whole thing looked like the nose gear on a lear jet. 1 last comment;If the vincent suspension was so good ,why isnt it used today in moto gp or fim superbike racing? Don't get me wrong I like thing that are different, They just have to be funtional

Just becase tube front ends are on most bikes today doesn't mean they're better, only cheaper. The Vincent was an engineer's machine and everything on them was was too expensive. It's amazing they lasted until 1958. They were a great bike then and now but good examples cost as much as a house.

I'm not suprised some one has revised the girder frront end but I didn't think it would take this long.

Geezer

[chevy45412001]

parts

just so happens....i have an xstra swing arm and a mid gear box just lying around. The adjustable rear section can be had easily enough. The even sell 2,4,6,8,12,inch extentions for the crotch crowd ebay has them often.And "i'll try " i got a pocket full of dimes...lol

[GNEPIG]

their is some pretty cool stuff on this bike, a lot of good ideas
.. i see what looks like a voltage regulator under the carbs so there must be a battery stuffed in there somewere
the ignition modules need a battery and so do the lights
.. 24 hours means all night too
the vincent handled so good that every one that raced them took the motors out and put them in norton frames.. every chopper that i have ever riden or riden next to that had a girder front end
did not even work, the only movment i seen was in the frame[sorry geezer]

i would kill for a chance to ride even a stock vincent .. a bike way too cool for the 50s

[pggg]

I should say here that converting an XS/XJ to chain drive isn't something you'd want to make as permanent. Why run high maintenance sprockets and chains when an Xs has a perfectly designed , smooth, non maintenance shaft system. My conversion job is strictly a 'bolt on - unbolt off' performance tweak, with the shaft drive always there as the No 1 choice.

The jury's still out on the performance increase anyway - who's to say there will be one? Dunno yet. With one good XS, two spare parters, and a heap of other bits and peices, carving, hacking and experimenting components 'willy nilly' is no big deal. If owning just one good machine, a fella would be crazy to start butchering it for chain drive.

Mine's casually being done on the cheap, but if a person weren't too worried about splashing cash at a 25 y/o motorbike, fitting a whole rear end off an FJ? GSX? FZR? Bandit? ZRX? - would probably be easier. (Swingarm pivots and sprocket positions are the catch there) Even so, you'd still want a SPARE drive unit to play with.

[DiverRay]

Gnepig;
Look at the fourth picture down, just behind the seat. The battery is sitting in a box in the rear fairing. Some of the later pictures, the battery is out, and you can see the battery box.
Ray

[xs650mike]

Good eye Ray!

[xs1100yam]

Hi there,

I'm really surprised by your interest in this bike !!!!!

I'm not the "happy owner" (unfortunately !...) but I can try to give you some infos.


For the battery question: YES, there is a battery because the TCI must be permanently supplied with 12V DC. On one of the pictures, you can see (some of you did it) the battery location : the rectangular aperture behind the seat. This is a very easy place to reach. For weight reduction reason, the charging circuit had been removed.
On the right end of the crankcase, you can see the smaller cover; the AC generator had been replaced by a thinner and lighter flywheel. The consequence is an idle of 4 or 5,000 rpm, ... and no more charging circuit !!!
During the 24 hours races, the battery was interchanged at every 2 pit stops (with daylight). At night, the 2 headlights consume more power, so the battery was replaced at each tank filling (every 45 minutes)!



Why this engine ???

This bike had been designed, made, built and ran by Claude FIOR, an engineer, in 1979 / 80. If you remember those years, it was the biggest bore (on japanese production bikes) with KAWA Z1000 and HONDA 900 "Bol d'Or".
The reliability of the 1100 was already well known

[xs1100yam]

Now the steering:

As PAT KELLY said : It's like a BMW although the BMW still have sliding tubes. Here, it is more like a bicycle fork but with the axis sliding in a frame tube. On the top, you can see the connecting rod with attachment on the shock absorber (like the rear "cantilever" style suspension.
More: the handlebar is not mounted on the fork but is acting through smalls connecting rods ! You can also see sevral dampers, probably to improve stability on straight lines.

The chain drive was probably a small problem regarding the others features ! I havn't info on it but I've sent to T.C. some pictures of a "chain kit". He will probably post them in a future chapter


Ouf !... You probably don't know how difficult it is to explain technical stuff when it's not your own language
And I know that Top Cat, my "private English teacher", is watching my errors and mistakes

[jimg1au]

24hour race xs1100


hi i sent this page to mk pitman the builder of the 1st chain drive yamaha race bike and this is his reply
Hello Jim,

Thanks for the info on the Yamaha 24HR XS1100.

I noticed a heap of questions everyone was asking about the engine, so I thought I should let you know what it is.

This bike has been fitted with a factory engine kit supplied by Yamaha in 1980. I used one of these kits for the engine, in the chain drive I built for Greg Pretty in 1981.
The kit consisted of;

- Crankshaft - reduced mass
- Conrods - increased strength, I beam section. Big end bolts screwed into the rods, with no nuts.
- Cylinder head - bigger valves, increased comp, porting to suit Mikuni Solex carbs, twin plug per cylinder (C size plugs), machined in the bucket area to accomodate higher lift cams, under bucket shim sets to cope with higher RPM
- Camshafts - Two options, one set longer duration for top end, and one set shorter duration for short tracks.
- Degree drilled cam wheels
- Camchains -H/D to cope with new cam profiles
- Primary chain - H/D for improved durability
- H/D Valve springs and under bucket valve train components, ie retainers, small size shims and buckets. The valve train components came from Toyota racing, as at that time Yamaha were making heads for Toyota.
- Head gaskets - reduced thickness
- Base gaskets - thin size for compression setting.
- Pistons - forged high dome, thin ring,std bore size, with L/weight gudgeon pins
- Rings - special to suit pistons
- Crank bearings - H/D to suit higher engine power demands
- H/D clutch springs
- Hydraulic clutch lever assembly. This required machining the side cover to fit a slave cylinder through it to push against the pressure plate. The old cable system was discarded. The clutch master cylinder was supplied, including braided hose and end fittings.
- Exhaust system to suit the new engine configuration. The system was all spring clipped together with a muffler running out the right side parallel to the ground. On the bike I built I modified this to point up at about 30 degrees, for extra ground clearance. This endurance bike has been modified the same.
-Engine mount kit - This was a set of aluminium inserts made to press into the old rubber mount positions to stop engine flex in the chassis and to increase chassis rigidity, by using the engine as more of a stress member. An additional set of front plates, allowed the motor front to be lifted 25mm to assist with ground clearance. I elected not to use these on my bike, as I wanted the better rigidity of the bolts through the frame and engine.
- Ignition - This was not supplied with the kit, but the fitting info supplied, recommended using the original crank pickup system, delete the vacuum advance part and the connect two TCI units to run all the plugs. The photo's here show the two boxes outboard of the countershaft area. I opted to use the crank pickup from a XJ650, because of its small size, and then piggy backed the two TCI units. No ignition drama's, except for the cold plugs, they recommended. ND U31EGU. I ran warmer plugs for our shorter tracks(29's). On the bike I built, I cast up ignition covers, that were 50mm narrower than the stock item, and extra thick to cope with crashes.
- Tacho - This was an electronic unit that ran from the low tension side of the coils.
- Alternator - This was a magnesium housing bolted to the crankcases, with the L/weight stator bolted to this, and an outer domed cover to enclose it all. The rotor was also L/weight, and narrow to give better ground clearance, and less power loss. As shown in the photo's.
- Carburettors - These were side draught Mikuni Solex 44mm, sleeved back to 40mm. The carbs came with special manifolds, compehensive jet and nozzle kit for adjustment, inlet funnels and cable linkage system. The down side with these carbs, was they did not like sideways G force, as the float system was designed for a car, so in the bike it made them snatchy on various corners.
- Quick action throttle - This was billet aluminium and included cables to suit. This part looked expensive.
- Engine blanking kit - various plates and plugs to facilitate the removal of starter motor, kickstarter etc.
- Oil cooler kit - Magnesium oil cooler connector plate and oil filter cover. Large capacity oil cooler, with braided lines and Aluminium connection nuts.
- Magnesium sump for increased capacity, exhaust pipe clearance and improved baffling inside.

This was the conents of the kit from Yamaha, which was made available to their distributors around the world. Not many people used it, as they felt a tuned up shaft drive bike was not good enough to competitively race.

In addition to this kit I chose to do the following on my bike.
- Chain drive conversion plates for the engine. I noticed the bike in this photo has a chain drive conversion fitted. They have used the original shaft from the middle gearbox, cut it short and used the inner bearing and spline of the shaft to support the shaft. The sprocket fits onto the original spine of the middle gear shaft, and they have fitted a circlip to hold the sprocket onto the shaft. I don't particularly like this method of conversion, as it loads the spline of the output shaft and would wear badly with continual use.
What I did was to cast a new gearchange cover which had provision for an outer bearing in it. I also cast an inner cover, and then used the original middle gear shaft, fitted with a sprocket and bearings at each end, and spacers either side of the sprocket, with the original lock nut from the middle gearbox to lock it all together. This was very strong and put no sideways load on the output shaft of the gearbox.
- Chrome moly braced underside swingarm increased in length.
- Koni rear shocks - increased length.
- Front swingarm mount plates to shift the S/A pivot 55mm closer to the back of the engine(this was the reason for the longer S/Arm).
- Higher ratio first gear(supplied by Yamaha at my request).
- Lower ratio gearbox output gears(supplied by Yamaha at my request). I based my secondary gearing ratio's on those of the TZ750, as I wanted to rotate wheels and gearing from one bike to the another at major race meetings.
- Machined cases - I machined the crankcases to take a 17T front sprocket, and modified the gearchange cover to suit this. Lots of work. Also internal machining to assist with pressure buildup inside cases.
- Wheels front and rear were Magnesium units to suit TZ750.
- Brakes Std XS1100 with braided lines
- Sprockets - TZ750 (Aluminium rear)
- Fork brace
- Rear set footpegs and levers.
- Small size battery
- L/weight wire harness set
- Steering damper

We raced this bike three times and achieved exceptional results.

Best regards,

Mal Pitman.
hope this helps understand the bike
cheers
jim garvey
sydney
australia

[pggg]

Jim, I did wonder why he removed the rubber mounts like you mentioned before. Stiffens the frame and handling eh. The 17T TZ750 sprocket needs big crankcase mods to fit. And yeah without both spline bearings supporting the spline, the forces are gonna be uneven - even if the spline has been shortened. His list of mods show how far removed a race bike can be, compared to the road equivalent.