WR 400 Strange starting issues. HELP PLEASE!



4 replies to this topic
  • charliemi16

Posted September 08, 2013 - 07:03 AM

#1

Hello all,

I'm really hoping someone can help me figure out what's going on, as I'm now at a loss.

I've got a 2000 model year UK spec WR 400. I've had it 2 years. When I got it, it started perfectly no matter what the conditions. Over time it got harder to start, particularly when hot. I put this down to valve clearances tightening up. Last time I rode it, I washed it, and put it away, not like usual where I take it for a quick ride to warm up and dry off. The next day it refused to start, and had very little compression. So little, that I could turn it over on the kick starter by hand without the decompression lever. Being as I'd already decided the valve clearances needed doing, I re shimmed then back within spec, hoping this was the problem. Unfortunately still no compression.

After reading on the forum about others experiencing similar problems after washing, or leaving the fuel tap on, I put a teaspoon of oil down the bore as recommended, and it worked a treat. Compression came back, and it started straight up. I ran the bike until it was hot, and turned it off. Kicked straight up hot too. Compression is good again now, even though all the oil in the bore has burnt off.

Today, I went to take the bike out for a ride with friends. Still had excellent compression, and started up very easily from cold, first kick. I was a little too fast turning the choke off, and it stalled. It now completely refuses to start again. It has good compression, and a spark.

I really can figure out what's wrong with it, and I'm hoping someone can help, please!

Thanks

Charlie

  • Krannie McKranface

Posted September 08, 2013 - 08:07 AM

#2

You need to do a leak down test to determine the problem

If you have not freshened your top end in the last 250 hours, it's time.

Most likely, you need piston, rings, and intake valve rebuild.



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  • charliemi16

Posted September 09, 2013 - 01:50 AM

#3

So, is that the general consensus then... Rebuild time?

I've no idea how many hours I've done, but it's a few thousand miles, and I've had it 2 years, with a ride out once or twice a month, and a few weekends away thrown in too.

Is it worth rebuilding the carb too, or are they fairly reliable?

Thanks

Charlie

  • Krannie McKranface

Posted September 09, 2013 - 05:12 AM

#4

So, is that the general consensus then... Rebuild time?

I've no idea how many hours I've done, but it's a few thousand miles, and I've had it 2 years, with a ride out once or twice a month, and a few weekends away thrown in too.

Is it worth rebuilding the carb too, or are they fairly reliable?

Thanks

Charlie

 

Your description is about 250+ hours. 

...plus the hours of the previous owner(s).

 

The less you ride the bike, the more you will need to refurbish the carb, due to corrosion and ethanol poisoning.



  • charliemi16

Posted September 10, 2013 - 07:58 AM

#5

Thanks Krannie,

What exactly would you replace when rebuilding the carb? Being in the UK, it's not as easy for me to find parts, so I'd like to try and get everything I need. The kits I've seen only contain a couple of seals, the float needle, and screws. Is that all I need?

I'd really like to put an upgraded (probably wiseco) piston kit in while I'm at it. Does anyone know of any UK sources with reasonable prices?

With regards to valves, do they generally just want lapping in again, or do the seats want re cutting, and maybe even valves replacing? Just interested in others experiences once they get the engine in bits.

Thanks again

Charlie




 
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