Author Topic: Bat out of hell Build (Read 27399 times)

1980cm400t · « **Reply #50 on:** March 07, 2011, 07:08:03 AM »

The air cleaner was completely packed with acorns and other nuts. Apparently squirrels view air boxes as a pantry.

1980cm400t · « **Reply #51 on:** July 26, 2011, 02:15:12 PM »

Time for some updates. I stripped the black paint off the front and rear wheels and cleaned and polished the brake rotors. I even went and polished up the rotor bolts

1980cm400t · « **Reply #52 on:** July 26, 2011, 02:18:13 PM »

The new tires are bridgestone spitfires I mounted and balanced them myself, The old ones were so corroded and dry rotted that I had to cut the back one off with a jigsaw. Here is my improvised wheel balancing rig it worked brilliantly.

1980cm400t · « **Reply #53 on:** July 26, 2011, 02:23:01 PM »

I repainted the frame and triple Ts, rebuilt the front forks, replaced the triple T bearings (one of them was binding), and cleaned up the rear diff. The board is a stand in for replacement shocks

1980cm400t · « **Reply #54 on:** July 26, 2011, 02:27:05 PM »

Here is the frame with the wheels on it (repacked all 4 wheel bearings)

I also took the paint off the rear brake caliper holder, it was chipped and the older is alloy so it won't rust anyway

In lieu of a front fender i installed a tkat front fork brace (it barley fits over the oversize tires)

1980cm400t · « **Reply #55 on:** July 26, 2011, 02:33:02 PM »

I did a compression test and fount that cylinder #1 had no compression so I pulled the head and found a bent exhaust valve (you probably can't tell from the picture)

I got a new set of valves, valve seals, and valve springs and took the head to a machine shop to get the valve seats redone

I also ordered new rings while I'm in the neighborhood I might as well replace them

1980cm400t · « **Reply #56 on:** July 26, 2011, 02:37:18 PM »

I tried painting the side cover and the valve cover with aluminum colored engine enamel

It turned out so well that i think i will do all the side covers this color. here is the side with the generator cover painted as compared to the clutch cover which is unpainted (the painted matches the crankcase color almost perfectly)

Really? · « **Reply #57 on:** July 26, 2011, 02:43:49 PM »

Nice, an XS Eleven Special build. I have been looking for another one of these beasts. I need redemption!

There is a drive shaft to chain kit on that XS site. Just don't goose it too hard coming out of a corner on one these, you won't like it. Don't ask me how I know!

Well, I am subscribed now.

Retro Rocket · « **Reply #58 on:** July 26, 2011, 04:51:16 PM »

Quote from: TipperT on July 26, 2011, 02:43:49 PM

Nice, an XS Eleven Special build. I have been looking for another one of these beasts. I need redemption!

There is a drive shaft to chain kit on that XS site. Just don't goose it too hard coming out of a corner on one these, you won't like it. Don't ask me how I know!

Well, I am subscribed now.

One of these bikes won the Castrol 6 hour endurance race in the late 70's or early 80's, as long as you are ready for the rear lift under acceleration they handle quite well. I have considered one for touring many times and if i saw a cheap one laying around i would be all over it. Great engine....

The story...
http://www.motorsportretro.com/2009/09/the-day-the-yamaha-xs1100-won-the-castrol-six-hour-%E2%80%93-part-ii/

Another nice one...

Chain drive conversions are common on these bikes here....

Really? · « **Reply #59 on:** July 26, 2011, 08:56:46 PM »

The bike did handle well even though it felt a bit long in the corners. The two drawbacks I found were the stock carbs and the drive shaft.

1980cm400t · « **Reply #60 on:** July 27, 2011, 08:45:04 AM »

What exactly is the problem with shaft drives? I haven't ridden a bike with one extensively yet but it seems to me that they would be better than chain drive. Granted with a chain drive you can play god with the gear ratio, but chains and sprockets require lubrication and replacements more often than a shaft drive which only needs its oil changed periodically.

Really? · « **Reply #61 on:** July 27, 2011, 09:07:06 AM »

For normal riding, they are very nice and quiet. Change the oil when you are supposed to and you are good. No oil slinging around like a chain.

On any bike, the transmission steals some power. The drive shaft steals some more.

The way the shaft drive reacts under load is different than a chain. A chain driven bike will pull the bike down where a shaft drive will lift it. Let me give you a picture. Your at a light, you are holding the front brake, you have the clutch in and you are twisting the throttle. While not letting go of the front brake, you start to slide the clutch out - the back of the bike will lift up. I have not noticed a chain driven bike do this.

So, to the part that will get ya. Your canyon carving the bike, your in a turn leaned over perty good and you goose it too hard coming out of the corner. That lift can push the tire out from under the bike.

When it happened to be, about 4 times, it would kick the back tire out while in a curve and fall back enough to slide on the K1 baffle I had on it and slide for a bit. Then, as it would start to slow down while sliding, the front tires would touch the ground and grab, flip up and over onto the other side and smash itself on the ground. Each time the tank had to be fixed.

If you ride it that hard, just know that is possible or just don't ride that hard.

The bike attached was mine, it was only about 1 year old off the showroom floor. No rear disk, no tach and speedo, that black engine cover had bondo in the hole and painted, the rear turn signals came off the front and it is not Ruby Red (it was twice).

dragracer · « **Reply #62 on:** July 27, 2011, 09:57:04 AM »

Quote from: 1980cm400t on September 05, 2010, 09:32:29 AM

spent a day stripping down the bike

i found a few interesting things in the airbox. I will definitely reuse the velocity stacks

Are those acorns in the box?

Or in the case of someone from Ohio, buckeyes?

1980cm400t · « **Reply #63 on:** July 27, 2011, 11:12:49 AM »

acorns

1980cm400t · « **Reply #64 on:** July 27, 2011, 12:12:08 PM »

What causes the rear end to lose traction on the shaft drive bikes? is it the lack of the centrifugal force provided by the chain, or is it that shaft drives do not have the slack that is inherent in a chain and instant application of power makes it easier to break traction?

Really? · « **Reply #65 on:** July 27, 2011, 12:14:09 PM »

From my experience and the only thing I have left to offer is the separation at the suspension. There may be a more detailed answer on the XS11 site.

Retro Rocket · « **Reply #66 on:** July 27, 2011, 03:59:51 PM »

You are correct Tipper, the shafts torque reaction is to raise the rear where as a chain pulls the rear down, it can be very unnerving being half way through a corner and grabbing the throttle only to have the rear end rise up and change the geometry of the bike mid corner, they take a different technique to ride hard......

1980cm400t · « **Reply #67 on:** August 03, 2011, 06:20:27 AM »

I have hit something of a speed bump. Some of the old rings were corroded onto the pistons, while tapping the last stuck on off I cracked the skirt off one of the pistons.

1980cm400t · « **Reply #68 on:** August 03, 2011, 06:28:10 AM »

I went on ebay and bought another set that was listed for a 1980-81 xs1100 and found out they are not all the same. While the piston diameters match the weight of the pistons do not. My original pistons are 201 grams, the ones I bought were 207 grams. I did a little bit of looking and there are 2 different part numbers for pistons: one spans from year 78-79 the other spans from 80-81. So either: ebay sellers don't actually know what bikes their parts came from, or my engine has the previous years set up. I attempted to get the mass of the pistons currently being sold on ebay to make sure they were the correct but no one wants to provide this information. Rather than spend another ~$100 on another set of pistons that may be useless I modified the heavy pistons.

1980cm400t · « **Reply #69 on:** August 03, 2011, 06:31:31 AM »

If i were to instal the heavy pistons as is the crankshaft would not be properly counterbalanced and the engine would probably fly apart. To correct this I ground down the skirt of the heavy pistons so they are now 201 grams.

1980cm400t · « **Reply #70 on:** August 03, 2011, 06:38:17 AM »

My question is: Is there any reason why this won't work? I see 3 potential issues

Actual piston mass not matching the original: likely to be a non-issue my scale is fairly accurate

Change in center of gravity: by grinding down the skirt of the pistons they are now slightly more top heavy, the originals top heavy to begin with (around the piston rod) and the change in mass is only 6 grams so don't think this will be a problem

The shorter skirt may cause the piston to be able to flex more around the piston rod: There isn't that much clearance between the piston and the cylinder so I don't think this will be a problem. If it is a problem I suspect the result would be shorter ring life

1980cm400t · « **Reply #71 on:** August 03, 2011, 06:40:37 AM »

If anyone can think of any other potential issues or if anyone else has done a similar modification feel free to throw in your 2 cents
here are some comparison pics:

1980cm400t · « **Reply #72 on:** August 05, 2011, 06:23:48 AM »

Got some new shock absorbers for the rear and an xs1100 standard tank

hoodellyhoo · « **Reply #73 on:** August 05, 2011, 08:20:37 AM »

Been reading a lot of Kevin Cameron lately and one problem you may have with that modified piston is heat. The piston skirt is one of the main pathways that heat from the piston crown uses to get to the cylinder sidewalls so it can be disapated by the cooling fins. I personally would look for a correct one.

1980cm400t · « **Reply #74 on:** August 05, 2011, 11:11:53 AM »

That is a good point. I would get new pistons but the its either get all new pistons for ~$550 which is too expensive or buy another used set for ~$70 and risk them being as useless as the set I just bought.

News:

Author Topic: Bat out of hell Build (Read 27399 times)