Bog! WR450 2008
Posted August 07, 2013 - 05:30 AM
Shorter throttle stop
Grey wire disconnected.
Operating in Western Australia.
Increasingly competent novice rider.
I recently noticed that when I snap open the throttle the engine just cuts out. I have read all the threads and it seems I have all the symptoms of the dreaded bog! So, my bike is now in pieces and I have got myself down to the carb! I have watched the pilot jet in operation and the jet does spray beyond the slide line, just, and for less than 1 second. Certainly not a super soaker streaming to the back of the carb!
It is my plan to remove the carb and inspect the diagphram and the ap adjustments.
Q. Does the reported typically weak spring on the AP apply to the 2008.
Q. Does the above mods typically require rejetting?
Q. Should I stop reading thumper talk in the same way I don't read medical journals now my bike is in pieces and I'm concerned I'll never get it back together!
Posted August 07, 2013 - 06:11 AM
Thats not the pilot jet, it's the apump nozzle.
If you get a slightly less than 1 second squirt all the way into the head, it's working fine.
If the stream is not getting out of the carb and into the head, it's not doing it's job.
Time to clean and replace the apump system parts ( 50 leak jet, short rivet diaphragm, nozzle cleaning) and add a R&D or Merge racing linkage spring.
Posted August 08, 2013 - 10:05 AM
... plus where is the best place to get a leak jet and upgraded accel pump diaphragm. If I can get them both from the same place it might save me on postage!? Any ideas?
Search for the parts places in your area.
JD's kit does not include a leak jet.
Posted August 09, 2013 - 04:51 AM
It is a National pass time not to search the local stores but rather find some far flung Online store who can supply the part cheaper and create a carbon footprint with airfreight the size of an ocean!
Posted August 09, 2013 - 11:00 AM
Your bike will run better with an aftermarket pipe then the stock pipe bastardized.
You can get the correct jetting on this site and not have to do the JD kit. It's all available from Yamaha.
I put an adjustable leak jet and fuel screw on mine. It makes dialing it in much faster and easier. You turn screws instead of taking the carb apart.
Posted August 09, 2013 - 12:25 PM
The leak jet is not technically a jet, as it does not work on vacuum, so it does not ever need adjusting/changing once it's right.
Posted August 09, 2013 - 12:41 PM
I dunno about technically but it's a piece of brass with a hole in it.
It's much easier to find the sweet spot on a bike by turning a screw in and out than taking the carb all apart.
When it gets cold here my bike can bog unless I turn the screw in.
Posted August 11, 2013 - 05:32 AM
Posted September 21, 2013 - 05:49 PM
Posted September 21, 2013 - 06:18 PM
So, had the carb and bike together now for a couple of weeks. Have fitted new AP spring and diaphragm. Have also fitted an R&D adjustable fuel screw. Having trouble dialling it in despite guidance found on the forum. I find turning it in to then turn out 2 turns as a starting point is proving difficult. It turns but I cannot feel when it's all the way in? Is it possible to turn it too far in and stuff it up?
It may be broken inside the rubber sheath.
I bend the metal mounting 'wire' to be more open, not clamp the top.
Start with one turn out.
Then start the bike, lower the idle as low as it will go
Now raise the idle with the fuel screw.
If the idle goes to high, drop it again with the idle screw.
Repeat till you get the smoothest idle.
Now raise the idle to 1800-2000 rpm, and turn the fuel screw in or out 1/8 turns at at time, blipping the throttle in between, and listen to the rpms drop. You want the fastest rpm drop.
Posted September 22, 2013 - 03:53 AM
Posted September 28, 2013 - 06:48 AM
Turned out 1 as instructed having taken the idle down to almost a stall. Revs noticeably raised after half turn in (leaner). Adjusted idle and pretty much kept it there. Did try winding it all the way in. It didn't stall but figured the point at the raised revs was probably best. Anyway, sounds ok, ticks over ok, revs ok. I must have got it about right!?
Posted September 28, 2013 - 05:39 PM
Sounds like it.
Keep playing with the fuel screw adjustment, when fully hot, to get the fastest dropping idle.
Posted September 30, 2013 - 04:27 AM