Race start.


74 replies to this topic
  • Thumper_Bloke

Posted November 12, 2007 - 10:10 PM

#21

No problem Dave, thanks for the answer.
I'm more interested in the blue/white wire unplug and any adverse complications, then my original question anyway. Jeff S


After a few months of riding hard, I'm noticing something since i took the blue/white wire out. It's hard to explain, a few times i've had the electric start sound like the battery was almost dead, and a couple of times i needed to use the kicker to move the piston a little. More than half the time, it definately starts so fast its awesome, just tap the starter button and its idling. My battery seems fine, i think the extra little dead revs in stock form allows the e-starter to gain some momentum. I think i will be switching it back, to give it a final evaluation. Also, i don't need it to start that fast, since i'm not racing.

  • WR_Dave

Posted November 13, 2007 - 05:04 AM

#22

My bike does the hard crank thing every now and then as well, I think it's just because the engine is at or near TDC and the starter isn't torquey enough to roll it past that spot. I'm more concerned with the inverse voltage that might be created, taking something out in the CDI or the electronic display. ???? WR Dave.

  • rbn14

Posted November 13, 2007 - 09:51 AM

#23

Well looking at the wiring schematic it looks like the diode is actually a zener and switching diode in series and in opposite directions (to balance the temperature coefficient to near zero). So the starer relay diode is actually acting as a voltage stabilizer rather than a "check valve" so inverse voltage should not be a concern. My electronics is pretty rusty so I will have to run this by a couple friends of mine but I think the chances of it causing a problem are pretty slim. All you are really doing is removing the neutral and clutch switches from the circuit which means the starter will crank anytime you push the button regardless (I believe KTM's are like this). What I would do is wire in a toggle switch so I could have the quick e-start at the line and then flip the switch so everything is back to normal. But like I said, I will run this by some people who understand this stuff better than me.

  • rbn14

Posted November 13, 2007 - 12:49 PM

#24

So I ran it buy a couple of friends and they agree, the diode is just a voltage regulator for the starter relay. What I was wrong about is that the clutch and neutral switches along with the diode will still remain in the loop. Cutting the wire should do no harm. All it is doing is sending a signal to the CDI. All that I can think that signal is doing is telling the computer you are starting the bike with the e-start. So with it cut, the computer thinks you are kick starting it. For what ever reason, when the computer thinks you are using the e-start it delays the spark for a couple revolutions. Maybe Yamaha determined it starts best in all conditions (temps, altitude, dropped bike, weak battery, whatever) if it spins a couple times first or maybe it is to let the starter build up a little speed. Whatever the reason, they don't want it to do this when kick starting because it would take one hell of a kick to get it to spin a few revolutions before it fired. I don't see any reason not to cut the wire, but I would probably wire in a switch and use it just for race starts.

  • Just_a_trail_rider

Posted November 13, 2007 - 03:11 PM

#25

... i don't need it to start that fast, since i'm not racing.


But you should be! Its quite a bit of fun. More than I initially expected.

Its a challenge, but pretty rewarding when you are done.

I can definitely see why getting the bike started quickly is important.

  • Chooch68

Posted November 13, 2007 - 05:38 PM

#26

So I ran it buy a couple of friends and they agree, the diode is just a voltage regulator for the starter relay. What I was wrong about is that the clutch and neutral switches along with the diode will still remain in the loop. Cutting the wire should do no harm. All it is doing is sending a signal to the CDI. All that I can think that signal is doing is telling the computer you are starting the bike with the e-start. So with it cut, the computer thinks you are kick starting it. For what ever reason, when the computer thinks you are using the e-start it delays the spark for a couple revolutions. Maybe Yamaha determined it starts best in all conditions (temps, altitude, dropped bike, weak battery, whatever) if it spins a couple times first or maybe it is to let the starter build up a little speed. Whatever the reason, they don't want it to do this when kick starting because it would take one hell of a kick to get it to spin a few revolutions before it fired. I don't see any reason not to cut the wire, but I would probably wire in a switch and use it just for race starts.

It doesnt sound like your "electronics" is rusty to me. Nice job. I'm definetly going to try this asap. Thanks to whoever hijacked this thread.

  • Thumper_Bloke

Posted November 13, 2007 - 06:46 PM

#27

Yes, the blue/white wire's sole purpose is to add one or two dead revs while cranking, when the e-starter button is pressed. Verified with scope.

Kickstarting with the sparkplug OUT, i was only getting three or four complete revolutions with a good kick. But, no spark/cut deadrevs at all, just spark on all revolutions.

I think starter hardparts like the motor or sprague will suffer with this mod. That is my disclaimer to anyone who removes the blue/white wire. Starts can be wicked fast, but there is a reason the original engineers put a spark delay for a couple of revs.

So racers i think could benefit from this. Because if you want to use both, the button and kick, if you pressed the button first, you are killing a couple of revs. The opposite of what is trying to be accomplished.

hey Maurice, i'm not saying i will never race, I'm just sayin i don't currently race! My last ride with you guys have sparked my interest mostly because you guys make it sound like fun. . Right, Jule?

  • redswr

Posted November 13, 2007 - 06:47 PM

#28

maybe it is on there so that when you do to start the bike and the piston is at TDC or BDC it notices it and won't let the starter turn and burn up... so you have to manually do it with the kick. i've had times where the button wouldn't work because of this and i think when you cut the wire it will give it to much juice and fry the motor...

just my thoughts....

good post Thumper_Bloke didn't see it before i posted.

  • rbn14

Posted November 13, 2007 - 10:38 PM

#29

maybe it is on there so that when you do to start the bike and the piston is at TDC or BDC it notices it and won't let the starter turn and burn up... so you have to manually do it with the kick. i've had times where the button wouldn't work because of this and i think when you cut the wire it will give it to much juice and fry the motor...

just my thoughts....

good post Thumper_Bloke didn't see it before i posted.


No part of the circuit does any sensing of where the engine is in the cycle so I don't think there is any need for concern there.

I think starter hardparts like the motor or sprague will suffer with this mod. That is my disclaimer to anyone who removes the blue/white wire. Starts can be wicked fast, but there is a reason the original engineers put a spark delay for a couple of revs.


I agree that there is some uncertainty to the long term results. I will do it when I get my WR but like I mentioned it will be switch so I will use it just for race starts. I do however find it unlikely that it will turn out to damage the starter motor or the sprag. The starter is a supper simple brush motor and I have heard of very few sprag failures. I think it is most likely the stock setup ensures the most consistent starting. But all that said, I did not design the system and am no expert, so do at your own risk.

Oh and Jeff wont mind the hijacking if it means he gets better starts!

  • redswr

Posted November 13, 2007 - 10:54 PM

#30

No part of the circuit does any sensing of where the engine is in the cycle so I don't think there is any need for concern there.


sorry just reread it and i didn't type what i was thinking...:thumbsup: i was meaning that it would be easier on the starter if just a little bit of the power was going to it instead of alot of power. that way if the motor is at TDC or BDC it gives you time to let off the botton instead of having more power go to it which might burn it up because the starter will be trying to move with the motor froze...

if that didn't make since... sorry, i'm tired and recovering from a concussion Posted Image

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • SXP

Posted November 15, 2007 - 08:57 AM

#31

I own a 2000 Toyota Tundra V8 and the starter spins the motor a couple of times before the motor is allowed to fire. I remember when I first bought the truck thinking something was wrong. Turns out it is a designed in feature that allows some build-up in oil pressure before allowing the motor to fire. I wonder if that's the intent here:thinking:

  • rbn14

Posted November 15, 2007 - 09:25 AM

#32

sorry just reread it and i didn't type what i was thinking...:thumbsup: i was meaning that it would be easier on the starter if just a little bit of the power was going to it instead of alot of power. that way if the motor is at TDC or BDC it gives you time to let off the botton instead of having more power go to it which might burn it up because the starter will be trying to move with the motor froze...

if that didn't make since... sorry, i'm tired and recovering from a concussion Posted Image


I'm pickin' up what your puttin down but all that is changing is whether the bike sparks on the first rotation or not.

I own a 2000 Toyota Tundra V8 and the starter spins the motor a couple of times before the motor is allowed to fire. I remember when I first bought the truck thinking something was wrong. Turns out it is a designed in feature that allows some build-up in oil pressure before allowing the motor to fire. I wonder if that's the intent here:thinking:


Could be but I still see no cause for concern here because this would still not happen if you kick started the bike.

  • SJMC_DON

Posted November 19, 2007 - 10:40 AM

#33

The blu/wht wire mod works awesome:thumbsup: Iam very pleased with the way my bike starts now:applause:

  • Jeff_Steckline

Posted November 19, 2007 - 11:44 AM

#34

Be forewarned this guy RBN14 has also posed as a Doctor, my lawyer and a hot woman. He sounds like a post grad student that knows it all, ya know "210-220 what ever volt will work," be careful of his advice. Now I hear he's been bumped to the expert class, nice job poser. Jeff S

  • rbn14

Posted November 19, 2007 - 03:40 PM

#35

I still cant believe that hot woman thing worked! As far as the expert class goes, I think I'm going to see if they will let me race Lovelock as an amateur so I can get a big trophy, otherwise Derek will get it (if he races). Oh and I hope you had a good Friday night, heard it was a late one!

  • snakesausage

Posted November 24, 2007 - 09:01 PM

#36

I just started a cross country series that requires dead engine start and just stumbled across this thread. Holy Cow!!! after warm-up with the blue/white wire disconnected it starts immediately after pressing the button. The starter barely works at all.

I rode my buddies WR250 awhile back and it started immediately like this, I wonder if they even have this blue wire? I always chalked up the extra revolutions to the extra load of the 450.

Thanks Thumper_Bloke for the tip, you just put me two or three places ahead every race start from now on!

Just to clarify to anyone else that tries this, there are two blue/white wires that are associated with the CDI, one that comes straight from the CDI and enters the connector next to the gray wire (that we have all disconnected) and another wire that exits the CDI as sky blue and changes to blue/white at another connector (at least on the 05' US version).

This mod requires that you disconnect the blue/white that directly exits the CDI and enters the connector next to the disconnected gray wire.

Snake

  • SXP

Posted November 26, 2007 - 08:38 PM

#37

I suggested this mod to a friend who races and he ran it by his mechanic. He came back with the following:

"Do not cut that wire. My mechanic says it allows the starter to wind the motor past the backfire point. If it is disconnected and the bike backfires it may strip the starter gear. He kicks his WR at races."

What do you guys think? I remember the broken starter gears the 03's had when they backfired. The Yamaha engineers must have had a good reason for designing this feature in.

  • Alternative

Posted November 27, 2007 - 04:12 AM

#38

Did the '03 WRs have this blue/white wire? Maybe that's why the stripped starter gears... :thumbsup:

  • grayracer513

Posted November 27, 2007 - 07:11 AM

#39

The "feature" doesn't exist. The blue/white wire on the WR has the same function as on the YZ450, that is, to retard the timing in neutral. It does NOT "provide a couple of dead strokes".

The way it works is that there is a contact in the neutral switch that grounds the blue/white lead when the trans is in neutral. The CDI responds by retarding the timing a few degrees to lower the idle speed and make the engine less likely to kick back at the rider while starting (speaking from experience, that's a serious concern). Since the lead is grounded only in neutral, all one need do to "disconnect" it is to put the bike in gear, any gear. The lead is then open, and the ignition map returns to normal.

This bit of mythology went around the 426 world for a while. People decided that the blue/white lead weakened the spark (although no one ever provided any logical cause for deliberately doing that) and that disconnecting it made the bike start better. The fact in both the 426 and the WR cases is that some bikes with different jetting setups will start better with more advance than with less. Jetted right, they should start more reliably and with less effort in neutral.

WR Dave is correct in saying that the kick starter spins the engine faster, and as to combining the use of the two devices, there is no hazard whatsoever in doing so, or even in bump starting it while doing both.

All 3 of my 450's start so much easier in neutral than in gear (with the blue/white effectively disconnected) that the real "cheat" for me would be to put a button on the handle bar that I could use to ground the wire while in gear, not the other way around. All you need to know is whether your bike starts better in gear or out. If you're starting it in gear now, then disconnecting the blue/white will have the same effect as Dumbo's black feather.

Incidentally, the starter drive in the WR is equipped with a torque limiting device intended to protect it from damage if the the engine kicks back. There is no such device on the kick starter to protect your foot.

  • SJMC_DON

Posted November 27, 2007 - 08:21 AM

#40

The "feature" doesn't exist. The blue/white wire on the WR has the same function as on the YZ450, that is, to retard the timing in neutral. It does NOT "provide a couple of dead strokes".

The way it works is that there is a contact in the neutral switch that grounds the blue/white lead when the trans is in neutral. The CDI responds by retarding the timing a few degrees to lower the idle speed and make the engine less likely to kick back at the rider while starting (speaking from experience, that's a serious concern). Since the lead is grounded only in neutral, all one need do to "disconnect" it is to put the bike in gear, any gear. The lead is then open, and the ignition map returns to normal.

This bit of mythology went around the 426 world for a while. People decided that the blue/white lead weakened the spark (although no one ever provided any logical cause for deliberately doing that) and that disconnecting it made the bike start better. The fact in both the 426 and the WR cases is that some bikes with different jetting setups will start better with more advance than with less. Jetted right, they should start more reliably and with less effort in neutral.

WR Dave is correct in saying that the kick starter spins the engine faster, and as to combining the use of the two devices, there is no hazard whatsoever in doing so, or even in bump starting it while doing both.

All 3 of my 450's start so much easier in neutral than in gear (with the blue/white effectively disconnected) that the real "cheat" for me would be to put a button on the handle bar that I could use to ground the wire while in gear, not the other way around. All you need to know is whether your bike starts better in gear or out. If you're starting it in gear now, then disconnecting the blue/white will have the same effect as Dumbo's black feather.

Incidentally, the starter drive in the WR is equipped with a torque limiting device intended to protect it from damage if the the engine kicks back. There is no such device on the kick starter to protect your foot.


Blu/Wht disconnected for 1 week - My WR starts instataneously now in gear or neutral. No more 2 dead revs and then start:excuseme:




 
x

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.