1978 390 Auto build

[oldbikedude]

belt sander

 

[WayneL]

A big Hammer?

 

[84scrambler]

use your caliper. put both clips in piston and use the bottom of your caliper (depth probe) to measure between the clips then write it down. then file , sand the pin to that measurement. hope this helps

 

[suprize]

pin should be no drama for a little workshop adjustment.... trick is to get the right end float!

 

[grouty]

I put the engine back in the frame, mainly to be able to tighten up the crank nut without it scooting around the bench. The left cover is now all finally fitted and tightened up. All that should need now is oil. The front bolts are only temporary until I decide what to do about a sump guard.

 

[grouty]

Nice new piston.
Had to go to 84mm in the end to get rid of the distortion and un-even wear.
The other issue was that the pin cheeks are closer together than on the original piston. A Kawasaki KX250 small end does the job perfectly.

It looks almost too good to hide in there ....

 

[grouty]

Finally all in and tightened down. It did put up a fight though. I set the piston pin up in the cutter grinder and ground the bevel on the end of the pin back a few thou. The piston clip now fits perfectly. As we had gone to 84mm, we lost most of the taper at the bottom of the barrel. This was going to make nipping the ring in with my fingers difficult. So out with the Lisle ring compressor band. The longest job there was getting it out of the tool box. All done, I flipped the small lever that releases the spring tension on the band. It broke off and probably headed off to keep the piston clip company in some dark corner. Another 15 minutes later the band is off, albeit now consigned to the bin as it is not fixable ...... bye old friend !

 

[oldbikedude]

Looking real nice. Good for you paying close attention to the fitment of the wrist pin clip. That could of been disastrous! Great pictures along the way as well.

 

[Michel Dufayard]

Clean !

 

[grouty]

It is clean at the moment Michel. Trouble is I cannot wait to get it dirty.

 

[dartyppyt]

Nice job Grouty!

 

[troy deck]

yes indeed looks nice

 

[justintendo]

i was going to ask if you were going to be able to get it dirty

 

[WayneL]

Great work it looks fantastic!

 

[dartyppyt]

Grouty,

Explain the KX 250 piston reasoning? Did you have to use a KX 250 rod? Or didn't make a piston big enough for Overbore?
I have a 390 so I am interested in your concept/reasons?

What year KX 250 piston? Needle bearing? Any other info or part numbers?

Wossner piston?

 

[grouty]

It was only the small end bearing from a KX250 that I used. The piston is a Husqvarna 390 84mm Wossner. The piston pictured above has a narrow boss where the rod fits. There is not room to fit the std small end bearing and the spacers.
So i used a slightly wider bearing which just happens to be one from a KX250 (and many others). This bearing is 24mm wide and so takes up most of the gap (gap is 25mm). It lets a small amount of bearing protrude each side of the rod, so may help with lubrication. If anyone is interested I will find the part number for the bearing when I get to the workshop.

 

[troy deck]

Hay grouty who's foot pegs are those not having any luck finding any for my 87 those look like they might work

 

[grouty]

The footpegs are from Andy at HVA Factory.
Not sure if they will fit the 87 though. I had to mod them very slightly to fit the 78 ML frame.

http://hva-factory.com/frame-fixings/husqvarna-large-foot-rests-stainless-1

 

[dartyppyt]

Hay grouty who's foot pegs are those not having any luck finding any for my 87 those look like they might work

Yes get us a part number cause I will be using Wossner as well.

Ok, got your method to madness now.

 

[stormer254]

A couple of photos here show how the Swedish Army had the rear hand brake sorted

https://www.facebook.com/photo.php?...252.1073741827.100003352114036&type=1&theater