What is the defference between a B1 and a B1 XR top and back covers (1999) ?.

In 99 the back covers are the same, just the decal. The top covers have different depths for the race that the thrust bearing rides on. Once you get to an OM serial number the caps are the same until you get to an XR ribbed cap..

Hope that helps.
Dick

Mr Gadgets

The drive that i have is a 1999 B1.The top cap that i have has a XR decal on it and is not ribbed. Is there anyway the XR cap can be identified, i do not know what year it is

Ken,
Measure the the race on the tower. If it is close to 1" tall then it ISN'T an XR. If the race measures close to 7/8" then it IS an XR cap. But, if it does not have the ribs on it.. then it is no stronger than the B1 cap.
I have never seen a top cap with a decal on it... Back caps are basically the same, just a decal difference.

Hope this helps
Dick

Mr, Gadgets

You are correct i confused the top cap with the back cover, the XR decal is on the back cover.
By using the XR top cap on a B1 drive do i have to change the thrust washer and the flat needle bearing ,and are all the B1 drives top caps machine the same?.

Ken N.

Ken,
the XR top cap will only fit the new X gears. The races that the thrust bearings ride on, are varied to set the lash on the teeth of the gear. In order to keep the proper distance when switching from a B1 top cap (the B1 must have the X gears in it) to the XR, the distance from the race seat to the top of case surface that the cap sits on, has to be measured and compared.

You can't directly replace a B1 top cap with an XR unless you have the new X gears. The 99 drive will have the old style gears in it, unless it has been upgraded at some time..

I hope this clears the confusion.. If not, give me a call and I can explain..

Dick

Mr. Gadget

I measure the race on the tower it is closr to 1" tall, its staring to look like a stock B1 cap.

Thanks for the help

Ken N.

Your welcome!

Mr Gadgets

I all so have a 1999 ZT28 ft. Checkmate with a 502 MPI / 500HP. Can you tell me your top speed and what kind of prop you are turning

Ken N.

I am running a 26" Bravo1 and the best I have seen was 87.7mph/gps. That was only one pass. I had all the weight removed from the from the cabin area.. I didnt look at the tach, ended up being in shallow water that I didnt know about. It was still pulling when I got out of it. Wanted to make another pass the next weekend and found loose rocker arms.. 5 bad cam lobes. I had to be right at 6k rpm to do that. This year I hope to be able to pull a 32" Bravo 1.. with the new motor..
Dick