Rieju & GasGas Legacy Riders Club Forum  

Go Back   Rieju & GasGas Legacy Riders Club Forum > GasGas Enduro Technical Forums > Enduro Electrical & Wiring

Enduro Electrical & Wiring Lighting, Ignition, Wiring, Plugs, etc.


Reply
 
Thread Tools Display Modes
  #1  
Old 02-24-2009, 05:46 PM
buzzard buzzard is offline
Member
 
Join Date: Jan 2009
Posts: 20
Default Kokusan Blues

I have some recent experiences that I hope help someone else. I had one of the devil bikes (2002 250xc) that I just couldn't jet. It started and ran fine right up to mid-range, then refused to take throttle, and wouldn't rev out. It turned out to be ignition problems. I put a timing light on it, and it had the wierdest advance curve you could imagine. Right above idle, it jumped to full advance, then about midrange, it went back to no advance. I always thought that a CDI either worked, or it didn't. I was wrong!


I used an inductive timing light. It uses a pickup that clamps over the plug wire, and any old 12v battery. I put the piston at TDC, and marked a line on the rotor, and a corresponding line on the engine case. Using a dial indicator, I also marked a line on the engine case representing 1mm BTDC.


I was fortunate to find an ignition on this site, in the For Sale forum. When it got here, I installled it and checked it's advance curve. I wouldn't call it a curve, exactly. Just above idle, it went from no advance to full advance. It stays at full advance until the engine returns to idle. Actually, my 250 runs great with this ignition. I wondered if this was normal. I have a friend with a 2006 300EC. I went over to his house, timing light in hand, and we checked his bike's "curve". My friend has never been able to get his bikes top end jetted correctly. It has never had that top end rip. Well, his ignition started at full advance, right at idle, and smoothly went back to no advance as the RPM increased. BAD IGNITION!


My friend ordered a new ignition. They go $300+. When it got here, we installed it. It is different than mine, in that mine uses 7 wires to connect to the wiring harness, his uses a multi pin plug. Looks like the same unit otherwise. We timed it. It has the same curve (or lack there-of) as the used unit I purchased. Right above idle, it jumps directly to full advance, and stays there. His 300 now runs great. The top end rip is there. He never even thought he might have a bad ignition. He's been jetting it for about a year.


Here is an odd side note. I searched kokusan on eBay. Up came shifter kart ignitions, by Kokusan. I bought one for $50. It has exactly the same wiring harness as my Gasgas ignition, same colors and connectors. I installed that one, and guess what? The same advance "curve", and it runs great. It is a black box (hence the name, I guess), about 3"x4"x3/4". I mounted it to the rear fender.


So I guess the take home message here is to put a timing light on your bike. It's quick and easy to do, and you may just find out a lot. Also, it pays to set your initial timing. I had to slightly modify my stator plate to allow it to rotate enough to set the timing at 1mm BTDC.


If anyone has knowledge of different advance curves, or ignitions, I would like to hear about it. I'm going to check another friend's 2005 KTM 250EXC soon, and see what Kokusan sells to KTM. I am a little disappointed in the lack of technology in the ignition on these 2stroke GasGas bikes. I have to wonder how they might run with an ignition that actually has a curve, in that it advances continuosly as the RPM increases. Thanks, Buzzard


Reply With Quote


  #2  
Old 02-24-2009, 07:08 PM
GMP's Avatar
GMP GMP is offline
Senior Member
 
Join Date: Jul 2006
Location: Jefferson Twp., NJ
Posts: 7,597
Default

I did the same thing on my '03 EC250, and your right it advances quick and stays there until the revs drop. I was trying to see if I could tell a difference between the OEM CDI and one from an '00 XC250 that gave better low and mid power. I could not, using this crude visual method, but there was definately a difference in performance. I did not have a tach, and I did not rev the bike full out. I think what appears to be an instant advance is actually a curve but one with limited resolution over a narrow RPM bandwidth. It would depend on the processing power of whats in the CDI box. Also, with no load (I'm assuming you just reved the bike in neutral like I did) its easy to blow through this RPM range. With the bike on a dyno with a tach you could probably learn a bit more. The trigger pulse is actually received by the CDI at or greater than max advance (deg BTDC), and the box acts as a variable delay device.

If I could power the CDI from an external source, and had the time to do so at work, it would be fairly easy to set up a test rig with a PC and some I/O hardware I have to trigger the input and wait for the output, at the full range of simulated RPM, and plot the time delay (advance curve).

Theoreticly the curve should advance up until the peak power and then retard in the "overrev" range. If your interested in this Google it there is a lot of info especially related to tuning 2-stroke road race bikes. Its nothing like a 4-stroke. Interesting stuff.

BTW, the CDI with the multi-pin connector is the newer dual map unit, used on some '06s and up.
Reply With Quote
  #3  
Old 02-24-2009, 08:58 PM
2 strokes 4 life's Avatar
2 strokes 4 life 2 strokes 4 life is offline
Senior Member
 
Join Date: Apr 2008
Location: Grande Prairie, Alberta, CND
Posts: 678
Default

I have heard that the XC250 bikes and EC200 ignitions have a more avdanced curve that gives you more power.
__________________
2002 Gasgas EC250 (gone not forgotten)
2012 Ktm 300xc
2001 Gasgas EC300
Lifes journey is not to arrive safely at the grave in a well preserved body, But rather to skid in sideways totally worn out shouting holy cow what a ride !!!!
Reply With Quote
  #4  
Old 02-25-2009, 07:26 AM
blitz11's Avatar
blitz11 blitz11 is offline
Silver Level Site Supporter
 
Join Date: Oct 2006
Location: SW Montana
Posts: 702
Default

What was your source for that ignition? FOr $50, it might be worth having a spare.

Thanks.

blitz
Reply With Quote
  #5  
Old 02-25-2009, 07:54 AM
Skidad's Avatar
Skidad Skidad is offline
Senior Member
 
Join Date: Dec 2007
Location: Littleton Massachusetts
Posts: 1,209
Default

Great info buzzard and GMP

I have a hunch the KTM will be the same but please do test that as well. I also wonder if various KTM boxes would work on the Gassers. They have quite a few different ones for sure.

It seems kind of odd to me in my relatively short time on the GG site that these bikes seem to have far more ignition issues than the KTM's. I have been a member on the KTM Talk site for years and just don't recall seeing so many ignition issues as the Gassers and the volume of bikes is HUGE over there.
__________________
07 EC 300 (under 500 miles, selling soon)
97 KTM 250 EXC (sold)
2016 Trek Remedy 29er
Reply With Quote
  #6  
Old 02-25-2009, 08:21 AM
2 strokes 4 life's Avatar
2 strokes 4 life 2 strokes 4 life is offline
Senior Member
 
Join Date: Apr 2008
Location: Grande Prairie, Alberta, CND
Posts: 678
Default

Well come to think of it, dont most bikes use a kousan ignition? Mabe I can get some of my friends bikes ignitions and see if there are any gains.
__________________
2002 Gasgas EC250 (gone not forgotten)
2012 Ktm 300xc
2001 Gasgas EC300
Lifes journey is not to arrive safely at the grave in a well preserved body, But rather to skid in sideways totally worn out shouting holy cow what a ride !!!!
Reply With Quote
  #7  
Old 02-25-2009, 08:53 AM
jiauka jiauka is offline
Member
 
Join Date: Nov 2008
Posts: 57
Default

Take a look at this:
http://www.sportdevices.com/ignition/ignition.htm
that guy has made a DIY CDI and a test machine. I'm thinking about doing something similar with a small USB microcontroller like the ATMEL AT90USB162.

have fun,

j.
Reply With Quote
  #8  
Old 02-25-2009, 08:58 AM
gasgasman's Avatar
gasgasman gasgasman is offline
Super Moderator
 
Join Date: Jul 2006
Location: Pearland Texas
Posts: 4,594
Default

On the 24hr Perry Mountain bike we built last year, the lighting coil and CDI module came off a KTM.
The stator plate had to be advanced a lot more that the GG stator plate.
The bike never really reved out like the GG stock CDI unit.
Reply With Quote
  #9  
Old 02-25-2009, 10:16 AM
widebear's Avatar
widebear widebear is offline
Banned
 
Join Date: Nov 2006
Location: Kamloops B.C.
Posts: 723
Default

I'm curios to know what full advance under load would be. I like run a little more static advance, 1.5 degrees for crisper off idle perf, would be nice to know how far you could go on pump gas without courting pre ign? Production tolerances vary so much on mass produced items theres prob thousands of defective ign's in circulation.Back in the day when I was involved in stock car racing a 500 cfm carburator rule was put in to place. We flow tested over 30 new out of the box Holly 500 cfm two barrels. The best one, the keeper, flowed 600 cfm the worst 425!
Reply With Quote
  #10  
Old 02-25-2009, 10:27 AM
GMP's Avatar
GMP GMP is offline
Senior Member
 
Join Date: Jul 2006
Location: Jefferson Twp., NJ
Posts: 7,597
Default

Quote:
Originally Posted by jiauka View Post
Take a look at this:
http://www.sportdevices.com/ignition/ignition.htm
that guy has made a DIY CDI and a test machine. I'm thinking about doing something similar with a small USB microcontroller like the ATMEL AT90USB162.
I saw that. While very interesting for research purposes, you would be hard pressed to eaisly implement it in a package that would survive on the bike. It would be neccessary to find an appropriate enclosue and potting material. Also, you have no idea of its suseptability to EMI/RFI.

If I had the time I would do it a different way. I would implement the test CDI as an interface only, and use a computer and my own software to control the prototype ignition and develop the proper map or maps, on a dyno. This would then be implemented in a microcontroller and properly packaged.

As far as ignition issues with GGs, how many of those are verified? I don't think a GG Kokusan is any different than a KTM Kokusan as far as reliability. IMO, if its a real ignition problem, it may be more of an issue with connections, grounding, wire lengths, etc. on the bike that may make it more prone to EMI/RFI issues. Also, maintanence can play a part. I see so many pics of flywheel/stators that look like rusted shipwrecks, and can only imagine what can happen as far as current leakage paths across the internal connections and the effect. FWIW, no GG I have had or worked on has had an ignition problem. I do however, on a new bike, go through the electrical system. The ignition is always clean and dry as well.

I've been doing this stuff for a long time and have seen a lot of strange things with various pieces of instrumentation and equipment.
Reply With Quote
Reply



Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
flywheel weights kokusan generator Caravan Monster All Other Bikes... 5 06-14-2010 11:21 PM
Darn it...new bike blues SpeedyManiac General Discussions & Announcements 10 04-30-2009 12:13 PM
Kokusan wiring schematic and some test values jostby Enduro Electrical & Wiring 0 01-25-2009 07:13 PM
Battery Blues andye General Discussions & Announcements 0 05-24-2008 09:17 AM




All times are GMT -5. The time now is 07:09 PM.


Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright 2009 - GasGasRider.org