Who has floated their ground here? Having trouble


7 replies to this topic
  • black_chrome

Posted May 01, 2013 - 06:54 AM

#1

In the process of converting my bike to DC power to run LED lights (street-legal supermoto), I unsoldered a lead from my stator and ran it to my trailtech regulator rectifier along with the original yellow wire running from the stator to the regulator in order to gain a floating ground as I had seen many people have done before both here and on supermotojunkie.com.

My question is the following, now that I cant get the bike to start since I rebuilt the engine and did all the wiring - Is all of the ignition circuit still chassis grounded (and AC power)? That is my intuition, and that only the "accessory" or lighting circuit is DC/floated ground.

The bike seems to have spark and fuel (shocks you when you stick a screwdriver in the plug boot), and backfires every once in a while but will not run. So this leaves me wondering if somehow the CDI isnt grounded properly, or the killswitch circuit is preventing it from running since it is wired wrong or something. The coil is still grounded to the frame as it is stock, and I think all my killswitch leads are frame-grounded as well but I will be double-checking that. Any other ideas on whats going on here?

It has hotcams in it now which I had installed when the engine was rebuilt, so Im having a hard time checking the timing on it, not being the same as stock as far as markings it seems. I know this could definitely be an issue as well if anyone knows how to figure out timing with hotcams (i.e. # of timing chain pins between timing marks or something). Also is it possible for the timing to be off by 180 degrees or something crazy where it would appear to be timed right, but wouldnt run?

Please help, I am frustrated as hell!

Thanks!

  • GottaHangOn

Posted May 01, 2013 - 12:20 PM

#2

I think you need to do the pink wire mod to put the cdi back to chassis ground. I suspect not doing that may have ungrounded the ignition system? I may be wrong but Im getting ready to do this mod so Ive been trying to read up as much as possible. I think the whole system made ground at the stator and when you unsoldered the copper wire to float the lighting circuit ground you ungrounded everything with out re-grounding the ignition.

  • Landcrab

Posted May 01, 2013 - 01:15 PM

#3

This is something I've also been researching in recent weeks. I'm taking my XR400 from AC to DC. After installing everything cleanly, I tested it out and bam it worked, even the honk! I was brimming with confidence. And then nothing the next day. Talked to Trail Tech guys, very good customer service btw, and apparently on my bike, probably same for yours you must "float the ground", and sometimes the system will work then suddenly not if you don't. At least one prob figured out!

I found a great step by step instruction manual online for floating the ground on a KTM stator from Trail Tech, just do a google search and it will come up as a pdf to download. Simple, sorry I don't have it to hyperlink to though.

On my bike, the only place I've found a ground in the igniton control module, right to the frame. As someone of limited understanding
of electrics & wiring, I don't see why there is a ground there in the stock wiring diagram. Seems you would just need to ground the Reg/Rec instead.

Still trying to make sense of it all....

  • RickyStator

Posted May 01, 2013 - 02:58 PM

#4

This is something I've also been researching in recent weeks. I'm taking my XR400 from AC to DC. After installing everything cleanly, I tested it out and bam it worked, even the honk! I was brimming with confidence. And then nothing the next day. Talked to Trail Tech guys, very good customer service btw, and apparently on my bike, probably same for yours you must "float the ground", and sometimes the system will work then suddenly not if you don't. At least one prob figured out!

I found a great step by step instruction manual online for floating the ground on a KTM stator from Trail Tech, just do a google search and it will come up as a pdf to download. Simple, sorry I don't have it to hyperlink to though.

On my bike, the only place I've found a ground in the igniton control module, right to the frame. As someone of limited understanding
of electrics & wiring, I don't see why there is a ground there in the stock wiring diagram. Seems you would just need to ground the Reg/Rec instead.

Still trying to make sense of it all....

Your stator already has a floating ground from Honda. On the XR400 no modification to the stator is needed to us the TT R/R. Call us if you need help.

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

Posted May 01, 2013 - 05:00 PM

#5

After continued research, we bike people sure do like to learn :prof: , it seems Ricky is right. I'm glad, because I really wanted to not have to float a ground. Still not sure why the system works fine then didn't. It is nice to rule something out in the chain of troubleshooting! Actually, I am pretty damn excited, I just fired the bike up after a final push to get the AC system to power the head light (low/high beam w/ switch), brake/tail LEDs, and the front LED turn signals AND everything WORKS :applause: Oh yeah, night ride test here I come!! The battery is still there, but I'm just happy to have lights again plus switch on/off power. Safety first! Have the original power wire to OEM headlight capped off, DOES ANYONE KNOW if I can use that to perhaps power a GPS (second wire going to ground of course?) Maybe I will take some pictures to celebrate! Hope you get your project completed so ya can go out and ride :D :busted:

  • black_chrome

Posted May 02, 2013 - 07:19 AM

#6

The "pink wire mod" is for YZ's only. The CDI's look the same but the pinouts for the wiring harness is not actually the same. I tried this on my WR and it did nothing, after some research using a YZ owners manual versus my own, they are not the same and this will not work....going to be soldering it back together.

The more I think about it I think my CDI box is fried for some reason. I dont know how it would have happened, but I read that when it fails it retards the timing way off...maybe thats why mine only occasionally backfires and doesnt run. Going to check all the coil resistances tonight and see what happens. If thats all good I will be on the hunt for a new CDI since I have triple checked all my wiring and it is correct. This sucks!

Edited by black_chrome, May 03, 2013 - 08:32 AM.


  • Birdy426

Posted May 05, 2013 - 01:18 PM

#7

Has the bike run since you rebuilt the motor? FWIW, the lighting side and ignition side of the stator are isolated from each other. If you are getting spark art the plug cap, it's not an issue with floating the ground. Typically, if you're getting spark, it's not the CDI box either.

Hot cams have timing marks on them just like the OEM cams do. You align the timing marks and don't need to count pins.

If it hasn't run since you rebuilt it, I would doublecheck the cam timing, then clean out the carb and make sure it's put together right. Putting the slide in backwards is a pretty common error that will make the bike darn near impossible to start...

  • William1

Posted May 05, 2013 - 04:23 PM

#8

Doubtful you have an electrical issue. Spark timing can only be off electronically by 'so much', certainly not enough to prevent running. Unplug the TPS to ensure you are in the 'fail safe' mode. So either you have spark or you do not. If you do have spark, either the cam timing is off (probably) or when you pit the flywheel on, you popped the key out and misaligned the flywheel (resulting in cam timing being off AND spark occurring at the wrong time).
Check actual TDC compared to timing marks. A chopskick in the sparkplug hole, slowly turn the engine over, see if the stick no longer rises just when the marks are visible. Better, is a dial indicator with a long arm.
Another possibility is if the cam sprockets are wrong (I'll assume you do not have adjustable ones and if you dfo, you did not remove them). At TDC on the firing stroke, the lobes should be at 2 and 10 o'clock.




 
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.