'86 WR400 rebuild

[wrx]

if the power is disapponiting on your 400 something is wrong ****************************************

 

[wrx]

mine absolutely rocks ****************************************

 

[justintendo]

if the power is disapponiting on your 400 something is wrong

this...the 400/430 should wheelie at will in 3rd. it is a bit tractorish compared to a 250 perhaps but is no slug on top end, especially the 400. your jetting/timing is likely off.

 

[oldbikedude]

Suspension setup could effect the front lifting or not. Does the rear squat when you think it should be lifting the front?

 

[suprize]

summats wrong, it should loft the wheel at will. ol mates was the same, super tractor but signed off way too early. he was impressed until he rode mine then he realised there was a major issue and the spanners were spinning. it was a restrictive muffler. he put a bigger bore silencer on it and away it went.

 

[Eurofreak]

your jetting/timing is likely off.

I'll investigate once the weather warms. The timing could be off perhaps.
My suspension has been stiffened in the rear

it was a restrictive muffler. he put a bigger bore silencer on it and away it went.

Pretty sure this is a stock silencer-will investigate.

Exhaust pipe has been cleaned, no rats fell out.

Stock jetting anyone? Needle is in the middle position

 

[suprize]

I think I ended up with a 430 main in the end, stock is 400 from memory

 

[Eric The Leg]

I measured the opening at the back of my spark arrestor, it's about 35-36 mm wide opening, both 400's ('85, '86). The '85 stock silencer is all black like yours, but the spark arrestor was bigger/round, and has USFS Approved stamped into it. The '86 silencer is oblong and aluminum. Similar black round spark arrestor with the USFS Approved stamping. I took pictures, but my phone and my computer aren't cooperating this evening.

 

[Eric The Leg]

For stock jetting, the parts manual has:
6DH3 Needle
Q6 Needle Jet
400 main jet
PJ 35 Pilot Jet
2.0 air jet.

 

[dukkman]

My 85/400 only stands up rarely but man does it get fast quick , it also climbs hills a couple of gears higher than it should.

 

[ajcmbrown]

I found that my 400 is sensitive to exhaust length, mine had a muffler that had been cut down to exit just behind the left side number plate, I tried a Up-Tite pipe and hated it, until I put the original 88 400WR muffler on and it is now a very different bike to ride, dial-a-wheelie!
Tony.

 

[Eurofreak]

Thanks guys-I'll pull the carb apart today and check jetting. The silencer had the spark arrestor removed. Worth checking the dimensions.
I haven't ridden it much other than to run it around the field a few times. Very muddy or very cold out right now.

 

[Eric The Leg]

I haven't ridden it much other than to run it around the field a few times. Very muddy or very cold out right now.

Guy at my local (former/old) husky shop would probably tell you to ride it a bit more before judging anything. Especially if it doesn't have that many recent miles, sometimes you've gotta' let things "settle in and loosen up" to revive the bike.
Also, depending on the size of the field, on a cold day, my 400s might not start popping until the second or third time around. The one I've ridden most is jetted a touch rich too. Any more I don't even roll the throttle into high power band territory for the first few minutes anyway. Plenty of fun to be had in the low power band, and once the bike is ready for the serious riding, it'll pipe up and tell you.

 

[Eurofreak]

When I got it out it was in the 60's. It had enough time to get to temp.
The weather here dropped into the 20's overnight with winds up to 60mph-bit of a change.
main pilot and idle are stock. The needle was 1 slot low- I assume the stock position is the middle notch, so I raised it one notch. We'll try again in a bit. The silencer end measures 32mm

 

[Eric The Leg]

32 vs 36 mm might not sound like much, but keep in mind that the area of a circle is calculated using the square of the radius. You've got 20% less exhaust capacity than the stock silencer/spark arrestor.

 

[jonhicks]

The taillight that came on my '86 (pretty sure was stock), looked a lot like this:

(image stolen from ebay).

Is this the tai light you're after ? It's a UFO part # 1307

 

[Eurofreak]

Thanks Jon. I found a stock replacement at the York swapmeet. The stock one has a larger black plastic back, same design lens.

 

[Eurofreak]

I'll look for markings on my silencer. If it was aluminum in 86 definitely have the wrong silencer.

 

[jimspac]

It was aluminum in 1986 and I have one from 1987 that aluminum but longer than the 1986 silencer. I have a Dirt Rider test that showed the 1986 400 Cross Country showed over 3 hp less than the 1985 400WRX. My WRX came with the last steel silencer and was missing it's end cap. DR used an Answer oval aluminum silencer/spark arrestor to get the missing power from the 1986 400 Cross Country. I was told the 1987 silencer is even more restrictive than the 1986. I am sure the 400 moving up to 430 lessened the effect somewhat

 

[Bigbill]

My '86/400 wrx had no lack in power. Just point it, wick it and hang on. The power was smooth and linear to the twistie.