Dyno rebuild on B7100

85Hokie

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SO when I bought the ol' girl, I know a disease that I am not cured of yet, The PO said that the bearings where shot and actually had the price correct for a new dyno....about $200 with gasket and shipping.

Getting that magical nut off was not too bad, NIW and others gave great suggestions on what type of offset 10mm wrench to use. I ordered this guy, 10 bucks and it has a 5 degree ratchet, which is much needed. And the swivel head was a good choice too.




Looking inside the housing, there are supposed to be TWO bearings, there are parts to one on the left of the photo - and the rest of one is, well, stuck to the 4 permanent magnets!

Notice the iron shavings and a few balls......the pieces - the inner and outer race were all that was left of bearing #2



Breaking it all down, and cleaning it up a bit - It is hard as hell to get metal shavings off a magnet!!!!



New bearings and a little light sanding and getting it back together - getting that bearing in was a press fit - amazing what a nice flat washer and socket in a vice work!




All the parts back together :


Since there is a "nut" on the back side - I could "test" the dyno - taking the drill and spinning it as fast as possible , I did get an "AC" voltage on the meter.

Cleaned up face on the block :



notice the water inlet on the left.......this is completely closed off to the back of the dyno - so was this created for those engines that HAD a water pump ? I am thinking not - since the dyno is open to the rear, water would flow in there if NOT for the gasket in place.

I am waiting on the gasket from Colemans...it should be in here soon.

As for the bearings, the two cost a total of $9.04, with the $3.00 gasket and shipping, should be under $15.00.

The bearings in case you need them are very popular - and can be obtained at any NAPA or other auto shop

http://www.vxb.com/6201-Bearing-Deep-Groove-6201-p/6201bearing.htm



question for the group -

when the gasket comes in, should I place a sealant around BOTH sides of the gasket, block side only , OR no sealant at ALL????

I damn sure do not want to take it off.....again,......for a while!
 

D2Cat

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85Hokie, nice report. That magnetism must have been tremendous, to be able to hold those pieces on the paneling like that!

I think everyone has a preference to sealing a gasket. In theory the gasket is to stop all leaks by sealing between both parts.

I put a very light touch of silicone on both sides only on the mating surface area. In my mind it gives a touch of added protection, and I hate doing things twice if I could have solved it the first time.

If I have to take it apart and it give me some trouble, that's the price I pay.
 

Daren Todd

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I agree with d2cat. I'll apply black rtv or silicone in s thin coat then place the gasket. This gives the added protection but also help to keep the seal in place on install :D


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85Hokie

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BX-25D ,PTB. Under Armor, '90&'92-B7100HST's, '06 BX1850 FEL
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I agree with d2cat. I'll apply black rtv or silicone in s thin coat then place the gasket. This gives the added protection but also help to keep the seal in place on install :D


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I like the way y'all think!!!:D:)
 

North Idaho Wolfman

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oh and just to be a pill... It's not the block that the dyno attaches to, it's the head
And yes the ports in the head are for models that have a water pump. ;)
 

85Hokie

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BX-25D ,PTB. Under Armor, '90&'92-B7100HST's, '06 BX1850 FEL
Jul 13, 2013
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Bedford - VA
oh and just to be a pill... It's not the block that the dyno attaches to, it's the head
And yes the ports in the head are for models that have a water pump. ;)
true....true......is that kinda like a block-head?
(tthink charlie brown):D:)