WK400 owners thread.

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Hugh
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Re: WK400 owners thread.

Post by Hugh »

Greetings,

Might this link be of any use (I have no knowledge of the company though);

https://www.polymax.co.uk/anti-vibratio ... ded-bushes

TTFN

Hugh.
Andi_Archer
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Re: WK400 owners thread.

Post by Andi_Archer »

Cheers Hugh I shall have a look.
EdwardCollings
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Re: WK400 owners thread.

Post by EdwardCollings »

Scotriders wrote: Thu Jan 28, 2021 4:05 pm
netsonic wrote:Stripped the exhaust off the WK400 to give them a refurbish, thought about modifying it to a single pipe but the original still has plenty of life in it once cleaned up
Looking good, obviously yours weren't suffering from the vibration fractures mine had.

I'm now toying with the idea of fitting a lambda sensor mount on my aftermarket pipes as it's running very rich and still occasionally cutting out under hard acceleration.

Got my GS back on the road so I've got time to work on the 400, though toying with the idea of selling it.

Will see how I feel once lockdown is over and we can get back out again.

Sent from my FIG-LX1 using Tapatalk
Hello Ned

Recently given mine a good going over, after a 30 mile trip in heavy rain the bike was a bit worse for wear!

I have ended up putting mine back to stock and now it runs much better, less power at the mid to top end, the 38 tooth rear sprocket now makes the bike lug between 4th and 5th. I have a 40 tooth sprocket to fit.

I would go with having a threaded Lambda sensor collar welded onto your headers, the part throttle at low revs is much better now and the bike ticks over much better.

I've now completed around 600 miles with no problems.

Steve what brand of paint did you use for your headers? The original paint appears to be flaking off at the y-piece on mine and the high temp satin black I used with it.

Your exhausts look great too!
catcitrus
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Re: WK400 owners thread.

Post by catcitrus »

On lambda sensors I have a Yam WR250R and stock in Europe it has a sensor. However, Yamaha did their GYTR muffler (Genuine Yamaha Technology Racing) in the US WITHOUT a lambda sensor(not required in the US). I had already got rid of the EXUP motor, cables and stuff and fitted a small piece of electronics to kid the ECU that the stuff was still there in the link pipe so when the system arrived from the US(and its a work of art) I bought a boss off fleabay and took new and old link pipes to my local fabricator and got him to weld on a new boss in the same position--its a tight fit behind a frame member. The point about all of this is that the lambda sensor does play a large part in controlling idle mixture and all I can say is that it has behaved like a clock for several years--so worth doing--the ECU still still thinks it has the EXUP as well as it does a cleaning sweep on start up and unless it gets the feedback throws a wobbly fault code. Performance wise I don't think the EXUP does much(people have videoed the valve movement on the road under various throttle conditions and it just gives a blip occasionally.) However, it adds a huge amount of complexity and fragile stuff to a trail bike frequently immersed in mud and water(now just a match box sized sized circuit board sealed with silicone).
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netsonic
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Re: WK400 owners thread.

Post by netsonic »

EdwardCollings wrote: Thu Apr 29, 2021 12:33 am
Scotriders wrote: Thu Jan 28, 2021 4:05 pm
netsonic wrote:Stripped the exhaust off the WK400 to give them a refurbish, thought about modifying it to a single pipe but the original still has plenty of life in it once cleaned up
Looking good, obviously yours weren't suffering from the vibration fractures mine had.

I'm now toying with the idea of fitting a lambda sensor mount on my aftermarket pipes as it's running very rich and still occasionally cutting out under hard acceleration.

Got my GS back on the road so I've got time to work on the 400, though toying with the idea of selling it.

Will see how I feel once lockdown is over and we can get back out again.

Sent from my FIG-LX1 using Tapatalk
Hello Ned

Recently given mine a good going over, after a 30 mile trip in heavy rain the bike was a bit worse for wear!

I have ended up putting mine back to stock and now it runs much better, less power at the mid to top end, the 38 tooth rear sprocket now makes the bike lug between 4th and 5th. I have a 40 tooth sprocket to fit.

I would go with having a threaded Lambda sensor collar welded onto your headers, the part throttle at low revs is much better now and the bike ticks over much better.

I've now completed around 600 miles with no problems.

Steve what brand of paint did you use for your headers? The original paint appears to be flaking off at the y-piece on mine and the high temp satin black I used with it.

Your exhausts look great too!
Hi Ed, I used Hammarite High Heat Paint. I had used other heat paint before but also found it didn't last..........I did however notice the header metal is not good quality and mine became very pitted which held rust that helped the paint to deteriorate so this time i spent time with a metal sanding wheel sanding the pits out so it was smooth metal. In addition you need to let the paint dry for a day or two then run the bike for a minute or two to cure the paint, I did this twice before a ride.......seems to help the paint last............wont last forever especially if the header gets mud and water on it .
On a side note when I did the exhaust refurb I got some new exhaust port gaskets and they were noticeably better than what came out, feels like you get a better seal which again can help with the running of the engine..........
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Re: WK400 owners thread.

Post by EdwardCollings »

Thanks Steve, that's two cans on order!

In your experience do you find copper or the silver fibre type exhaust gasket work better?

Did you ever find a shorter clutch lever in the end?

I was going to offer up the lever from my CRF this afternoon.

I've used the WK to get to work all month, after adding a top box and Givi handlebar muffs has been good fun.

What has been surprising is how a temperature variation of a few degrees equates to the oil temperature running 10 - 15 degrees cooler. Temp on the dip stick gauge ranging from 80 - 100.
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netsonic
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Re: WK400 owners thread.

Post by netsonic »

the new header gaskets were copper, very different to what came out which must have been fibre

Still have the original clutch lever not sure it was me that was planning to change to a shorter one although it was trimmed to get the handguard's to locate properly shown way back in this thread

I have been out on mine since lockdown ended and as the weather has been a tad chilly it does run better when the weather is cooler
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Re: WK400 owners thread.

Post by Rutlandflyer »

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Re: WK400 owners thread.

Post by EdwardCollings »

I really like how unique your Wk... More Honda XR now!

Is the exhaust system new?
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Re: WK400 owners thread.

Post by Rutlandflyer »

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