Jump to content
Sign in to follow this  

Another 50 pilot jet saga, in an 03 WR

Recommended Posts

A little background first. I bought the bike a few months ago and it's been running fine until the last few weeks. It started hanging up in rpm when I blipped the throttle before it was fully warmed up. I didn't ride it for a week or so and then it wouldn't start at all last time I tried it. Meant to get some Seafoam and put in but never got around to it. So last Sat I pulled the carb thinking the pilot was plugged; it was, so I cleaned it out good with carb cleaner and cleaned the other passages out while I was at it. The float bowl had some crud in it too. I went to reinstall the pilot and noticed it had a '50' stamped on it! I thought that sounded pretty big since I'd read a little of the jetting sticky thread, but the bike had been running fine, good idle, no real bog unless I whack it open at idle and lofts the front easily when the revs get up there. So I put the carb back on and had to leave, it was time to go watch the game. I tried to start it last night and no joy. I'm wondering if the plug is fouled. I checked the valve clearances maybe 4-5 hours ago and they were still in spec. The PO said he did shim a few valves but didn't remember which ones. I plan on changing the plug and checking the valves and getting fresh gas before attempting to start it again.

Present carb settings are:

Main jet 185

Pilot 50

Fuel screw 1 1/2 turns out

QS3 1 1/16 turns out

Power Now installed

Stock exhaust with GYTR insert

I didn't check the needle, but the bike came with a JD jet kit and there's a needle in the kit with a red top and one that's not colored. I'm assuming the blue needle is installed and don't know what position the clip is at. I'll check that when I go back in.

The bike currently has a little over 100 hours on it and there's a receipt in the paperwork for a new piston/rings and camchain install @ 65 hrs from a dealer in Jersey.

Any thoughts? Should I try a 42 pilot? It's been hot and muggy when I've rode it, but now it's cooling down. I'm confused...

Edited by not2shabby

Share this post


Link to post
Share on other sites

I'd buy a new #42 pilot (and a #45). Then:

Fuel Screw/Pilot Jet
Fuel screw settings in the 'book' are recommended starting points. Every bike is different, as is the temp and altitude. Set the screw according to this method. Do it with the bike fully heated up.
Gently turn the screw all the way in. Now back it out two turns. Start the bike and fully warm it up, go for a 10 minute ride. Set the idle to speed to 1,500~1,800 RPM as best you can (I know, without a tach this is tough, just set it to were it idles relatively smoothly).  Once warmed, slow the idle to the lowest possible speed.
*** When turning the fuel screw, keep an accurate 'count' of the amount you are turning it and record it in case you have to reset it for some reason. Makes life easier when you can just set it from notes Vs. going through the procedure again.***
Turn the screw in until the idle becomes rough or the bike stalls.
if it stalled, open the screw about 1/4 more turn. Restart it and slowly screw it in till you can just perceive a change.
If the screw can be turned all the way in and the bike still idles perfectly and does not stall, then you need to go down a size in pilot jet.
Now very slowly, open the fuel screw till the idle is smooth. Blip the throttle, let the bike return to an idle, wait say ten seconds. Confirm it is the same smooth idle.
If the screw has to be opened more than 3 turns to get a smooth idle, you need to go up a size in pilot jet.
If you find it does not stall with the larger jet but has to be open more than three turns with the smaller pilot jet, put the larger one in and set the fuel screw at 1/2 turn.
If the idle speed increased, adjust the idle speed knob to return the bike to a real slow idle speed. You must then re-visit the fuel screw. Keep doing this till the fuel screw is opened just enough to provide a nice steady idle at the lowest possible RPM. Once this is done, increase the idle speed to the normal one for your bike, typically about 1,850 rpm, but go by the spec in your manual.

 

I am no fan of the PowerNow, as it masks bad jetting and makes getting correct jetting near impossible.

Share this post


Link to post
Share on other sites

Thanks! Any idea why the PO would have put a 50 pilot in there? Due to the Power Now maybe?

I have a Vapor tach/speedo, so monitoring rpm is no problem...well, it does jump around a bit. Do you think the 185 main is OK?

I wish the PO would have bought an extended fuel screw too!

Almost forgot; the free mods have been done.

One more question; the QS3 eliminates the need to mess with the AP spring and leak jet, right?

Edited by not2shabby

Share this post


Link to post
Share on other sites

People usually put in big pilots to try to quench decel pops. Not the right thing to do. Instead, a better muffler or better still, ride the bike as it was designed.

 

The fact there is no extended screw is telling. Fuel screw and pilot work together, you cannot set it up right if you cannot adjust it.

 

QS3 is just an adjustable leak jet. You'd have to check to see if the spring has been changed. Stock springs have paint on them (different colors for different stifnesses). Aftermarket do not.

Share this post


Link to post
Share on other sites

Wouldn't the ACV prevent decell pops? I haven't heard one pop from this bike, unlike the DR350 I had.

 

I picked up an MSR fuel screw and a 42 and 45 PJ last night at Iron Pony along with a new spark plug. Now I'm just trying to decide if I wanna take the Power Now and Power Now Plus (forgot to mention it has both) out and see if I can get it dialed in. It ran great when I took it down to Wayne N.F. a month ago. I could chug up all the rutted, rocky hills and never had it stall.

 

I found the instructions for the QS3 and it just said to make the gap for the AP spring .1mm, I believe.

Share this post


Link to post
Share on other sites

I got around to changing the spark plug and put the MSR fuel screw in. I tried starting it after just changing the plug and no go. Then I noticed the kill switch was 'off'. Doh! I flicked it to on and it fired right up! In my defense, the Baja kit switch has 2 kill switches, one is a trigger for the index finger and the other is a switch that has 3 positions; headlight/tail light on, lights off and kill switch. Like this.

20131002_211953_zps34702e9f.jpg

I don't use the kill switch unless I drop the bike, but my stepson likes to sit on bikes in the garage and mess with the switches...Grrrrr!

Anyway, the carb did need cleaning and I wanted to put the fuel screw in also. The plug didn't look too bad, maybe a little rich but this wasn't a plug chop, just regular riding.

20131002_205149_zps0d60f584.jpg

I ended up having to pull  the carb to get the o ring from the stock fuel screw out and it wasn't in the best shape, kinda squished looking. I decided to swap a 45 PJ for the 50 and see how it ran. I warmed it up and did the fuel screw adjustment procedure and it didn't die when I thought I had the screw turned all the way in. It's still kinda hard to get to and I'm not too sure it was all the way seated but didn't want to squish the new o ring. It felt pretty good on the short test ride I took but it was dark by then and cooling off. I'm going to try it again tomorrow and see if it'll start with the screw all the way in. If it does, I'll try a 42. 

Share this post


Link to post
Share on other sites

Forgot to mention, I left the Power Now and Plus installed and checked the needle. It is the JD blue needle with the clip in the 4th position. I was afraid if I took the Power Now out it would mess up the rest of the jetting.

Share this post


Link to post
Share on other sites

Proceed as you are. Make one change and test.

 

Fuel screws are fully closed when turning is met with resistantance. Think gentle. I am sure you had it closed.

 

Keep in mind, some alloy fuel screw are not perfectly machined tips and therefore can require very small (like a 38) pilot where an brass or stainless would need a 42. Be wary of overtightening alloy screws, the tip is weak and can jam in the seat.

Share this post


Link to post
Share on other sites

Thanks William1, I'm sure the screw is aluminum so I will be careful not to overtighten it. Just eyeballing it next to the stock screw, it looks identical but I'm sure my old eyes can't detect .001 mm differences. It's still not too easy to adjust it with the motor warmed up!

Share this post


Link to post
Share on other sites

Well, I checked it last night and the fuel screw has to be turned all the way in to get the best idle. Crap, now I wonder if I should drop down to a 40 or try a 42 first.

I did notice it's running much crisper right off idle now. It'll pull the front up if I whack it at a walking pace in 1st. It wouldn't do that before!

Share this post


Link to post
Share on other sites

Well, I checked it last night and the fuel screw has to be turned all the way in to get the best idle. Crap, now I wonder if I should drop down to a 40 or try a 42 first.

I did notice it's running much crisper right off idle now. It'll pull the front up if I whack it at a walking pace in 1st. It wouldn't do that before!

"there is no right or wrong jetting spec's. The bike either runs great or it needs adjusting".

Be advised that during your testing, roll the throttle on so as to not have the AP circuit come into play. The AP circuit is the last thing to jet for.

Share this post


Link to post
Share on other sites

Yeah, I know the AP is the last thing to dial in. I should have said the off idle running is much smoother just rolling it on also. Before it felt soft and fluffy(way too rich!) but I was assuming that's the best the PO could get it, never having ridden a WR before and reading a bunch of posts complaining about the weak bottom end.

 

With the 50 PJ installed, there was no way the front would come up with a throttle blip at low rpm. With the 45 it will and I think it'll be even better with a 40 or 42. Time will tell!

Share this post


Link to post
Share on other sites

Damn. I put the 42 PJ in and set the fuel screw 2 turns out and tried to start it with the choke, no go. I turned the screw in to 1 turn and it still wouldn't start. I tried 3 turns, 2 1/2, 1 1/2, 1/2, all the way in and it still wouldn't start. I set it back to 1 turn out and tried giving it some throttle and it would start but the idle was real low even with the choke on and would die as soon as I let go of the throttle. I turned the idle adjuster all the way in and it still did the same thing! Then I noticed gas was leaking out from the choke knob!

 

Help! WTF is wrong?

Share this post


Link to post
Share on other sites

Arrrrrrrg! The clamp for the intake boot was binding the idle adjustment cable! I thought it was turned all the way in but it wasn't even close. Anyway, I just got done setting the fuel screw with the 42 PJ in there and it runs great! I'm not exactly sure how far out the screw is (lost track!), but I know it's not all the way in like with the 45. I took a little test ride and it pulls nice and smooth from a closed throttle at really low rpm in 1st and 2nd. Success at last!

I'll wait till it cools down and check how far out the screw is turned for future reference.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×