This post is directed at whoever is somewhat knowledgeable at troubleshooting DS problems. jsimonh and myself are both having issues where our motors will not rev above 6500 to 7000 rpm. We have trouble shooted the CDI, Carb, Rectifier, and such and have not had any luck. Can someone please rescue us?? LOL! AZSAND, OMR, and whoever else wants to chime in, we're all ears.

 

I have never run the big gun cdi i run msd's vortex and ron woods so im not familar with the big gun.but is it bouncing off the rev limtiter or just droping of the throttle. on the msd low battery voltage will cause the cdi to drop at very low rpms but runs great at lower rpms.OMR is the carburation guy so ill leave that to him voltage is my profession.[img]i/expressions/face-icon-small-wink.gif[/img]But i would belive as long as youv'e been around you already know all the voltage tricks.And two bikes doing the same thing ???? can you explain it in a little more detail.

 

Here is what is happening. It starts and runs great, when I hit the throttle to rev it up it stops revving and sputters at around 6500 rpm. I have put the stock CDI back on, and same problem. I put my stock carb on and same problem so I'm almost positive it's not a carb issue. jsimonh tried a new Rectifier and that didn't work. Now I'm not sure if we have the exact same problem but it seems like our symptoms are the same. Could it be a valve problem. Let me know if you need more detail.

 

im going to throw this out have you looked into the rubber that connects the carb to the manifold mine seem to not rev out changed it and it would rev rubber had cracks in it hope this helps

 

I had something similar to this one time when i had the timing off a little bit, but unless you've had it apart recently i doubt thats the issue. Bad batteries can do funny things, if you havn't already you could check the amps on it and the ground.

 

Step #:
1- Has any electrical component been recently changed? Especially bulbs
2- Does issue occur with lights on and ok with lights off?
3- When was the last time negative battery connection was removed, cleaned and retightened?
4- When was the last time ground to frame was removed, cleaned and retightened?
5- Do you have a kill switch? When was it last cleaned
6- What do the spark plugs look like? Both light, both dark or one light and one dark. Remember which ignition wire went to which plug
7- Plug that is dark - Check to see if brass plug in ignition spark plug boot is tight. If tight - remove and review if hole is out of round and does it hold tightly when placed over spark plug. If spark plug falls out of brass plug - replace.
Note - Be careful when removing the brass plug, there may be a contact spacer that you do not want to lose.

OMR

 

<div class="FTQUOTE"><begin quote>Originally posted by: SilverBomb

Here is what is happening. It starts and runs great, when I hit the throttle to rev it up it stops revving and sputters at around 6500 rpm. I have put the stock CDI back on, and same problem. I put my stock carb on and same problem so I'm almost positive it's not a carb issue. jsimonh tried a new Rectifier and that didn't work. Now I'm not sure if we have the exact same problem but it seems like our symptoms are the same. Could it be a valve problem. Let me know if you need more detail.</end quote></div>


You are describing exactly the same problem as mine. I'm about 99% sure it's electrical, but I've metered everything except the coils (checking them tommorow) and everything seems good. The stator wires (3 yellow wires) measured a little higher than they were supposed to but I left them unhooked and ran the bike on just the battery and it did the same thing. I've switched from a RW CDI to the stock and back to the RW and in my case the stocker seemed to perform a little worse.

Mine pulls like a train until about 7000 then sputters and bogs and won't run at all. Very frustrating!

 

What kind of cams are you running. I've see a few cams broke in half and running off one lobe that acts like this.

 

I know Silverbomb did some work lately maybe you both should tell everyone everything you have done and see if they can do process of elimination. Just an idea.

 

I just recently rebuilt my motor with the OMW730 jug. I'm running a Lectron 48mm carb, RW CDI, lightened flywheel, mild ported head with stock valves, web 109's, and a RW inframe.

I had almost this exact problem a few months ago when I had switched to a DYNA FS CDI. This was before my rebuild and I thought it was my TM45. After much frustration and lots of jetting and rejetting, I simply reinstalled the RW and the problem went away. So I chalked it up to the DYNA being bad. I'm thinking now that there is an underlying problem that cleared itself up when I was messing with reinstalling the RW CDI.