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I'm putting together a bike 1983 R100CS style and it is being made with mostly parts from a wrecked bike I bought. I started to adjust the valves today, there are freshly rebuilt heads on the engine.

I have the spark plugs out. The front cover is off. The starter is out. I've put the bike in high gear and am trying to turn it over by pulling up on the rear wheel. The pistons move but it will not turn all the way over. The valves move up and down when I am trying to turn it over. I had blocked the crank when I had the flywheel off so I don't suspect the shims have got out of place. I cannot remember if the engine turned over when it wasn't in the bike. I put a new main seal and cam seal before putting the engine in the bike.

I'm wondering if there is something right before my eyes? Other than a broken crank, what could make the engine turn over only a quarter or a third of a revolution?

Other things I've done that may be related: The alternator was off. I just bolted up the drive shaft with new bolts. Put in a clutch.

When the engine stops rotating, it does not make a metallic sound. In other words, I don't think a bolt is loose somewhere and hitting. The transmission seems to shift through all the gears.

What do I check first?

Chuey

I don't know what to check, but I always turn my engine over by the alternator screw with an allen socket on my 3/8" ratchet.
I probably got used to doing it this way because my bike always sat on the rear tire. I think the Type 247s rested on the front tire. I also remember reading a long time ago that BMWs would rest on either wheel. (This was pre-R65 days.)

Did you slacken all of the valve adjusters? I'm thinking if one was way to tight the valve might hit the piston at TDC.

Hi Chuey,
By any chance did you pull the pistons off the rods when you had the heads off? Do you hear a tiny click near top ded center? If the pistons move but don't go all the way to the top they or one of them might be on backwards. There is an arrow pointing to "vorn" (forward) on the top of the piston. The difference is about 1/32" of valve to piston cutout overlap. It makes it's own shiny modified cutout when fired up .... my bad.

Did you do anything to the oil pump? Maybe something caught in there?

Did you do any work on the timing chain? Anything in the timing chain chest?

Those are all I can think of that would lock up hte engine unless there is something in the tranmission?

Suerte!
Teo

Did you double check the stater is seated in squarely? The rotor can contact it if it is not.
Does it stop turning as it nears TDC? Don't forget how the crank has little leaverage advantage on the pistons near TDC. If it has sat a long time, the bores may just be dry? ??

Had the timing chain off? Is the valve timing correct? If not the piston may contacting a valve.......

Sterob

Hi all, thanks. I'm not out of the woods yet, but by taking the transmission out, the engine turns over very easily. Maybe I should have put rings in it! Just kidding.

One thing I had thought of was that the bolts that join the shaft to the transmission output were too long and hitting. You know, as if I'd gotten the ones that need washers but not used washers. That is not the problem. I checked and they are fine. Even if they were a little long, where they would hit is smooth so they would cause an even problem, and not one where it would go just so far and then stop.

At this point, I'd like to know if there is something I can do to check the transmission. Also, I'm going to check the final drive unit. Thing is, the way it felt was that it was something in the area of the flywheel that was stopping it. Yes, it was near TDC because I could get the OT in the window.

The clutch worked. I was levering the lever at the transmission with a stick because I don't have the cable or lever hooked up yet, but it worked that way.

I think the bike is messing with me. I have some rearsets that I thought I'd try but I didn't look at putting them on until I had the transmission in the bike and all buttoned up. Turns out that the swing arm needs to be pulled back or maybe even removed in order to install the rearsets. Now I have no excuse. Gotta try them. I think the bike wants rearsets. All of my bikes have guy names. This one may be displaying feminine traits manipulating me like this. I wonder.

I think I'll adjust the valves with the transmission out of the bike.

Chuey

The problem surfaced. The six bolts that hold the pressure plate to the flywheel were not tight. Two of them were sticking out just a tad and must have caught on the webs of the transmission. I am very fortunate they made the problem they did so I wouldn't have to tear into the bike once it is all together. I'm sure the clutch would have felt terrible at best.

Thanks for all the ideas.

Chuey

on my /2 I used /5 clutch bolts, they stood proud of the clutch housing, proud enough to hit the webbing on the trans housing! a few minutes with a die grinder and viola!! the motor turns all the way over!!

dang I was a minute late !!