Leak and Starter Jets
Posted February 28, 2008 - 11:57 AM
Posted February 28, 2008 - 02:22 PM
Posted February 28, 2008 - 03:48 PM
Posted February 28, 2008 - 07:31 PM
Sudco only sells them in bags of four of each size. Contact Carb Parts Warehouse of the local dealer. Have teh parts monkey look on the YZ fiche. The WR fiche only shows the stock sizes. Also, if you look at thumperfaqs, you can find all the yamaha part numbers for all the jets. Pricing from Yamaha and Carb Parts Warehouse is about the same.
when did they start doing that? they sent me singles of everything i needed about a year ago.
i only needed a minimum order of $15
Posted February 29, 2008 - 01:20 AM
Here's where I'm at:Main Jet:170
JD Blue needle 3rd clip from top
I Ride Between 500' and 3000'. It's in the 70's now but I want to get ready for spring riding that goes from 60's to 90's here in Nor Cal.
My plan: main: 168
Red JD clip 5
1.5 turns on fuel screw.
I've got zero experience with jetting a carb, but while trying to get rid of the bog I figured I'd get into it and learn something about my bike. Alright people, Hit me with some reality! Thanks
Posted February 29, 2008 - 03:01 AM
I would not lean the main out. You have a much freer flowing exhaust. However, never hurts to try it. If WOT is better, then leaning is good, if not, bout the 170 back, maybe even go up another size and try that.
Why do you want to change the pilot jet? It affects idle only. Set it (and the fuel screw) this way:
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.
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 1,500 rpm, but go by the spec in your manual.
I think the change in leak jet will make a huge difference. Go for it. I think uoi will also find your change on the needle to be a good one too.
I would do the leak jet and needle change then go and test. Once you know these are right, I would then play with main jet selection.
Posted February 29, 2008 - 11:44 AM
Posted February 29, 2008 - 04:48 PM
Feel free to change any jet you want, if only to see the effect. Idle hands and a tool box make the dirt biker grin.