Rebuild on a 1983 XC 250

[jimspac]

Some detail on the attached photographs.
As the bike is intended to be used in local VERI events I really wanted to prepare as a competition bike and not a show queen.
The Frame.
I made a few minor modifications to the frame. backing plate for rear brake pedal adjusting return bolt. Cover plates over the top shock joints that prevent dirt and water accumulating. Cover plate and filling around bottom of down tube on frame at front. Additional muffler restraint bracket. strengthening air cleaner box cleat. additional cleats for a bash plate. Strengthening of kickstand cleat. All work done by Geoff Morris Concepts (GMC) in Broadford.

The Color.
Sorry guys and dartypoint really changed my mind on this, (see his post). I could not come at the OEM dirty white, it had to be the Italian husky white.

Rear swingarm.
All new bits but some noticeable and non noticeable changes. The rear chain guide has nylon slipper plates installed requiring longer bolts. Looking to change out the OEM roller for proper roller as well. The chain tensioner is all new HVA item but I modified in assembly process to include larger and thicker washers to try and eliminate the pivot /torsional issues with OEM arrangement. Some additional rollers needed.
Swing arm bearings. Well probably should have used nylon / delrin but went OEM, however swapped out HVA needle rollers for needle rollers with a lip seal so hopefully should get longer service life. How is it they never last??????. I haven't as yet but thinking is also a oring sealer retaining washer to ensure some pressure is kept on oring to ensure it does not pop out. This is just a large diameter s/s washer that slides over the swing arm dowels.
Air cleaner box. It had some damage so fibreglassed the hole and repaired some cracks on box as well. I use old floor sanding belts to scuff roughen the area which gives a good rough surface for the new glass to bite into. Also repaired a side guard with a split in same fashion. Will see how long this lasts.
Foot pegs.
These are OEM modified units with a wider top by GMC.
Expansion Chamber.
GMC had to do some work on this and return area around spark plug is a bit damaged and shape altered but...... its a work of art until after first ride. I cleaned this again using old floor sanding belt material and then cleaned up with wet and dry and then really hot water and morning fresh and a scourer and then washed in really hot water. Our 30 degree days help. Tip for painting. I used VHT engine enamel in satin black and left pipe in sun for 4 hrs to get really dry and warm, first coat is applied, then I drop aerosol can in really hot water for about two minutes between coats, then shake can again and reapply 2nd coat, and continue process until can is finished. Result is brilliant, the increased pressure gives a better finish.
Ohlins Shocks.
I had these rebuilt by Mick Hughes in Bendigo, and new springs from Andy HVA. Although the refurbishment and cleaning of the ball joints took me by surprise. I reckon I spent easy 3 hours wire brushing, wet and dry removal of rust marks and cleaning with petrol all the swivel joints and retaining collars and bolts. Also some new HVA bits on shock as well.

Spring rates for shocks
The progressive rear springs I bought were from HVA and 160 pounds so around $300 landed here in OZ. These are the heavier of the two springs available from HVA. They are referred to as Promax 46-30-65-320 12/15. This is printed on the springs. So my understanding and from measurements of the spring 46mm is the internal diameter. 320mm is the length. The 30kg/mm is the softer spring rate and the 65kg/mm is the heavier spring rate. Not sure of the 12/15 either date of manufacture or for 12 -15 stone ???

The softer spring that HVA have is also a Promax with numbers of 46-25-55-320. So this is the same spring ID and length but with a lighter starting spring of 25 kg/mm and a heavier rate spring of 55kg/mm. These are also around $300 landed. These seem to be a popular choice.

I happened across YSS which is a suspension shop in Adelaide, Australia. They have a couple of listings on their website for rear springs and on their website see under Husqvarna. See also “All springs” where progressive are listed in 46mm ID and 320 long. Walter (owner and european) confirmed that these are the springs. They also have a lot of dual rate linear listings as well.


Overall Length
Inside Diameter
SPRINGRATE 1
SPRING RATE 2
COLOR
320
46
30
50
BLACK MW: This would appear to be the nearest to the HVA softer spring
320
46
20
30
BLACK
320
46
20
40
BLACK MW: probably OEM replacement



These are considerably cheaper as listed as AUD$191.20 plus postage. (I expect for a pair).

View attachment 85662View attachment 85663View attachment 85664View attachment 85666

The bearings only fail to years of neglect. I would think cleaning and lubrication should occur twice a year for muddy or silty runs and once a year for dryer normal service.

 

[Down Under XC]

Hi Surprize, yes interesting about the springs and rates, bit of a black art 30 yrs ago. But these days knowledge counts for a bit and I have not seen any data on spring rates at all on this site.
I had the modern husky (WR 165) all set up correctly and it is a beautiful bike to ride. As a result of that I always use a firmer front spring (0.44kg/mm) and stiffer rears.

I am hoping that now it is listed at least it will be a source for others.

Front forks springs are also being replaced as well on the husky with some Racetech FRSP 3452 in the 0.44kg/mm rate, which suits riders around 95-105kg and this is the softest spring available but can be mated with the standard spring for a slightly softer ride. The racetech site is a very hand tool for this.
Spent part of the day doing more fibreglass repairs on the air cleaner (clamp arrangement this time), and straightening the DLS reverse thread adjusting shaft which was bent. According to the racetech site the standard springs (probably when new) were rated at 0.38kg/mm.

 

[suprize]

nice to know all this stuff..make sure you get that brake rod spot on, it makes all the difference btw a crappy no feel brake and sharp front stopper

 

[Action Jonny]

I might be missing something here but how can you mate the Racetech springs with the standard spring? Do you mean standard rear spring?

 

[suprize]

match?

 

[Down Under XC]

Hi Action Jonny,
It might just be the language I am using, so here goes.

They are not meant as a match.

Fork springs are generally individually rated based on bike, type of work, speed, experience of rider and more than anything the weight of the rider.

Standard OEM fork springs were rated by racetech as being 0.38kg/mm on their site. Unsure what spring or year but sounds plausible to me. OEM springs from KDX and KTM of the day were around this.

Current available after market springs that fit the Husqvarna 40mm forks circa 82 - 87 from racetech have a spring rate of 0.44kg/mm and also heavier rates are available, but not lighter rates between 0.38 - 0.44kg/mm.

When I stated "mated", this is what I meant. left fork leg has a 0.44kg/mm spring rate. Right fork leg has a fork spring rate of 0.38kg/mm.
Overall result is 0.41kg/mm or slightly softer ride.

I would prefer a PM if this does not make sense, to not hijack the original thread.
thanks
Down under XC

 

[Down Under XC]

Hi Surprize,
re front brakes.
Well I sat and looked at rod and reverse thread and pondered, how do you set this up. then went looking on site and found an article on DLS arcing. Thought I might be able to disable one brake shoe, spin wheel until just chattering, then do same with other brake shoe but alas you can't . This will take some learning.

The alternate is a disc brake front end from an 84 CR that I have, which uses the single brembo.

I don't know what to make of the akron rims and date stamps. My rear wheel on 83XC says 2/84 this was the original wheel and the disc brake wheel has 10/83. I suppose there is a valid explanation.

I have two legs with caliper attachment and also two non disc DLS fork legs. Thought process was to have both brake set ups available, but prefer disc for wet events. It is a safety issue as far as I am concerned after riding moderns. But recognise the DLS is probably a fall back position if caliper/ master cylinder failure.
DLS is non grooved as well. Do you have grooved and presume they are available??

 

[suprize]

the trick with DLS is to have the shoes set at zero so both are flat on the cams. norm at bendigo brake and clutch can reline your shoes with good liner and lathe the shoes to your hub. he did my back brake and it is so much better than the std shoes. about to get my fronts done. EBC make grooved shoes but unless your racing, easy to put a centre groove with a hacksaw and then some angle grooves to channel water out.

 

[Bigbill]

I like the brighter color white looks awesome.

 

[Down Under XC]

Hi guys, just an observation after spending a lot of time trying to get air box and filter clamp in right position. What I discovered is that to position air cleaner on rubber boot the best and easiest way was to invert filter and insert with mouth to the rear and once within box rotate thru 90 degrees and fit to rubber boot. This way the shape of cage and filter follows the basic shape of lid and drops in relatively easy.
Hope this makes sense.

 

[suprize]

ill try it nxt time...the sides of the airbox have shrunk in...makes it tight to get into the abx

 

[MikeDi]

Nice job. I'm going to modify my chain guides with the wear inserts. good tip! keep up the good work. mikedi

 

[Picklito]

Front forks springs are also being replaced as well on the husky with some Racetech FRSP 3452 in the 0.44kg/mm rate, which suits riders around 95-105kg and this is the softest spring available but can be mated with the standard spring for a slightly softer ride. The racetech site is a very hand tool for this...<snip>... According to the racetech site the standard springs (probably when new) were rated at 0.38kg/mm.

That's the fork spring I use in the 40mm forks, installed with 3-5mm preload.

 

[arbortodd2]

Hey DownUnder, as I am stripping my 83 XC 250 it appears that the front downtube is bent. At first I thought "oh no" but after studying on it a bit, it may be designed that way to provide clearance for the exhaust pipe. The tube has a slight S bend and doesn't seem to affect the alignment of the frame. Hard to tell from your pics but is the bend part of the design or am I just screwed? Your build is coming along nicely, by the way.

 

[MikeDi]

it's not bent, that's the design to clear the exhaust port..

 

[arbortodd2]

That's a relief. It did look to be something other than a random bend. Wanted to be sure before putting $$ into powdercoating.

 

[MikeDi]

Yeah it's a shocker,,, that's the old "dude your frame's bent" head rush!!

 

[arbortodd2]

Yep, that's it. Nice build in progress there!

 

[MikeDi]

thanks, it's a fun project for sure... always wanted one of these since back in the day.

 

[justintendo]

That's a relief. It did look to be something other than a random bend. Wanted to be sure before putting $$ into powdercoating.

dont feel bad...weve all been there at some point. i dont think you could bend that tube riding if you tried.