1986 400WR Rebuild

[jimspac]

Hi

I got this project in 2007 as part of a jumble of Husqvarna and Kawasaki KX basket cases. I parted out the KX stuff to pay for the top end rebuild in several Husqvarna engines including this one. I pulled the bottom end out of storage to ready it for the XC frame being prepped for it. The problem I have is that the rear engine mount sleeve fit into the case very sloppy and putting all 3 pieces in the crankcase shows the spotfaces are under the inside shoulder of the sleeve both left and right.

Before anyone asks because of the intro, yes, I did verify they have the correct id for the singleshock swingarm. All other sleeves I have are for twinshock.

So my theory is that the previous owner having access to machinery may have bored the rear mount open and spotfaced the case surfaces lower for whatever reason. I checked the parts catalog and did not see any washers under the heads or any bushings between the case and the sleeves.

My suspicion is such because of history. One artifact in the parts jumble was the Ralphenstein. This was a 85 KX125 rolling chassis with an 82 Husqvarna 250WR engine mounted into it. He opened up the rear mount so it would accept the KX swinarm pivot. The 82 WR cradle grafted in was the worst.

 

[jimspac]

My question is how to deal with the 400WR rear mount. Because of the play between the inserts and the engine cases. I see the need to make a long thin wall sleeve to reinforce the crankcases. If anyone knows of a better way without replacing the crankcases I would really like to hear it

 

[fran...k.]

That section rattles around and gets all kinds of deformed. Even the inside of the insert gets hammered. The insert even though it continues through the older single cam section is no longer available. Well it was a few years ago, I bought one when they were available more years ago. The technique I and others use is to machine up a new insert and essentially glue it in. Last time I used 3m panel bond as suggested by old husky chuck who has been absent for a long time on here. You might think the sides have been machined in on the cases but that is from rattling around. Sometimes there is cracking around the front mounts, in the frame, which makess things worse. There are a number of different configurations of the frame tubes under the engine and some swingarms have another cross member closer to the pivot. Sorry that is a design defect with all the mono shock models in this section, 87-88 is a bit improved but the real fix came in the older single cam section where real rigid pockets for the end of the swingarm pivot were created. My opinion/observation. I suppose using a vacuum technique to get them in with one side for guidance and the other side glue as I have done might be better. I have bought some supposedly factory replacement cases from a guy on here and it turned out to be a newish left case and bondo and sports tape inside that swingarm pivot insert on the other. At least it isn't cracked and in need of welding. I got past fixing up the rear engine mounts and now have to do case split stuff for more engines.

Oh and there is a locating pin to keep the rear case halves in perfect alignment that can be missing or not able to do the perfect alignment thing.

Fran

 

[jimspac]

I have never seen a hole get deformed perfectly round

 

[dukkman]

I reamed my cases out until they were round [ dowel has to be removed first] then machined up a new pair of inserts out of x4140 , heated them with my oxy till blue, chucked them in oil too cool then warmed the cases and pressed them in.
Also did some tricky stuff with the holes in the frame.
Worked great.
Photos in the 85 500 vibration thread.
http://www.cafehusky.com/threads/85-500-engine-vibration-cure.4955/

 

[fran...k.]

If I am interpreting what is being called spot faced lower as what I have seen a rather lot would have to be removed to get round and cylindrical. I tried to discuss those inserts not long after I joined as they have a recess which I suspect compounds the problem though no one really discussed the recess aspect. I put a picture here of the inserts from a 420 auto, the smaller ones and a water cooled (standard shift two stroke mag case) one. The glue/epoxey fills this in. Boring and sleeving or making a slightly larger insert could work if the wear is not so much as to make the amount of material removed worrysome. If I recall right on my 510, 1988 which I think is aluminum it just needed a bit of filler an adjustable ream I borrowed with a long rod and some taper device or devics to get it aligned. That one has gone through a few timing chains without further issue at that spot however I doubt I ride it like the origional guy.

 

[ruwfo]

My question is how to deal with the 400WR rear mount. Because of the play between the inserts and the engine cases. I see the need to make a long thin wall sleeve to reinforce the crankcases. If anyone knows of a better way without replacing the crankcases I would really like to hear it

Jim,
Mc Master Carr makes bearing sleeves , i used them on my 510 project.
http://www.mcmaster.com/#standard-sleeve-bearings/=lsdpkr
plenty of sizes & types to choose from.

Husky John

 

[jimspac]

I am back from Georgia as of June 14 so the restoration has resumed. Because the previous owner claimed the burgundy paint all over the frame, triple, and several other non approriate places was powdercoat I thought I was stuck with that obnoxious color. The bike was stored in a tarp shelter for one winter 5 years ago. The shelter went over in a windstorm and something fell on the rear subframe. There was a big chip in the paint that revealed that the 'powdercoat' was applied over 4 previous coats of paint including OEM epoxy primer. So during that winter I started stripping all that paint off the frame and related components

 

[oldbikedude]

Wow, I bet you were never so happy not to have powdercoat where you thought you had it. That is an obnoxious color. I feel your joy.

 

[jimspac]

Yes I was happy to find it was merely automotive paint that responded nicely to aircraft paint stripper. After stripping down the WR frame 4 years ago and finding an XCframe on eBay for $100 shipped I decided to build on it since I was not happy with the crushed guard loop and the broken seat tab on th WR frame after deciding to do a nice job rather than patch as a rider

 

[oldbikedude]

Smart move I'd say...& you still could sell the other frame to get some money back.