ADVrider

Go Back   ADVrider > Bikes > Thumpers
User Name
Password
Register Inmates Photos Site Rules Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
Old 06-19-2013, 12:12 AM   #1
Pursang OP
Bultaco !!!!!!!!!
 
Pursang's Avatar
 
Joined: Jul 2006
Location: Okanagan. Canada
Oddometer: 107
99 XT600 Severe popping under acceleration

Last couple rides the bike has been popping severely through the carbs, starts around 3500 rpm and up and is getting worse, it pops five or six times each time I start getting on the gas and with each pop it momentarily kills the power, not like a fuel starvation bog but requires gearing down to get up hills, no popping on decelartion, bike starts and idles perfect, valve clearances are all up to spec, plug looks fine, compression is 159, fuel flow is good, I'm thinking it might be electrical since I dismantled/cleaned the carbs only 2500km ago when I installed a new top end. my question is if it's electrical which is the most likely part to cause this ? don't have a lot of cash so I'd really like to get it right, any suggestions are welcomed and appreciated !
Pursang is offline   Reply With Quote
Old 06-19-2013, 03:44 AM   #2
BIG ED XT FAN
Beastly Adventurer
 
BIG ED XT FAN's Avatar
 
Joined: Feb 2006
Location: Finger Lakes Western New York
Oddometer: 1,184
Quote:
Originally Posted by Pursang View Post
Last couple rides the bike has been popping severely through the carbs, starts around 3500 rpm and up and is getting worse, it pops five or six times each time I start getting on the gas and with each pop it momentarily kills the power, not like a fuel starvation bog but requires gearing down to get up hills, no popping on decelartion, bike starts and idles perfect, valve clearances are all up to spec, plug looks fine, compression is 159, fuel flow is good, I'm thinking it might be electrical since I dismantled/cleaned the carbs only 2500km ago when I installed a new top end. my question is if it's electrical which is the most likely part to cause this ? don't have a lot of cash so I'd really like to get it right, any suggestions are welcomed and appreciated !
Plug Cap? or CDI unit?
BIG ED XT FAN is offline   Reply With Quote
Old 06-20-2013, 03:24 AM   #3
damo2010
damo
 
damo2010's Avatar
 
Joined: May 2010
Location: Roma, South Western QLD Aust
Oddometer: 412
I know u prob checked this, do u have a lge breather out top of the carb and is it routed correctly. This hose kills mid range revs similar to what your talking about
__________________
Damo

Yamaha Tenere XTZ660 4UX
http://share.findmespot.com/shared/f...rbiW8y1XLQCMtY
damo2010 is offline   Reply With Quote
Old 06-20-2013, 08:42 PM   #4
Pursang OP
Bultaco !!!!!!!!!
 
Pursang's Avatar
 
Joined: Jul 2006
Location: Okanagan. Canada
Oddometer: 107
Quote:
Originally Posted by BIG ED XT FAN View Post
Plug Cap? or CDI unit?
Plug caps looks good, not sure yet about the CDI still looking into it.
Pursang is offline   Reply With Quote
Old 06-20-2013, 08:45 PM   #5
Pursang OP
Bultaco !!!!!!!!!
 
Pursang's Avatar
 
Joined: Jul 2006
Location: Okanagan. Canada
Oddometer: 107
Quote:
Originally Posted by damo2010 View Post
I know u prob checked this, do u have a lge breather out top of the carb and is it routed correctly. This hose kills mid range revs similar to what your talking about
Yup if you mean the hose from the secondary diaphragm to atmosphere it's clean and tucked away in a safe place under the seat.
Pursang is offline   Reply With Quote
Old 06-22-2013, 04:26 AM   #6
thumpthumpthump
Thumpthumpthump
 
Joined: Jan 2013
Location: Cahah's Mountain N.C.
Oddometer: 187
Is the choke all the way off? thumpthump
thumpthumpthump is offline   Reply With Quote
Old 06-24-2013, 07:45 PM   #7
Pursang OP
Bultaco !!!!!!!!!
 
Pursang's Avatar
 
Joined: Jul 2006
Location: Okanagan. Canada
Oddometer: 107
Quote:
Originally Posted by thumpthumpthump View Post
Is the choke all the way off? thumpthump
I'm pretty sure it is, the bike starts, idles and runs perfect except for this popping which starts at about 3500 rpm.
Pursang is offline   Reply With Quote
Old 06-24-2013, 07:46 PM   #8
Pursang OP
Bultaco !!!!!!!!!
 
Pursang's Avatar
 
Joined: Jul 2006
Location: Okanagan. Canada
Oddometer: 107
Well the search is back on, I pulled the carbs and gave them a thorough cleaning, inspected every part except the coasting enricher and didn't notice anything obvious in the secondary carb, threw the bike back together and went for a short snort only 5 minutes into it the bike was popping like crazy, it seems to be getting worse with each ride cause on the previous ride it took half an hour to begin popping this bad, I'm wondering if it's an electrical issue ? would appreciate any suggestions.
I noticed the carb was sucking unfiltered air and discovered the original hose clamps even when bottomed out were not clamping tight enough, didn't take much effort to pull the rubber boot off the carb, will use another style of clamp that tightens more.
Pursang is offline   Reply With Quote
Old 06-30-2013, 03:19 PM   #9
Pursang OP
Bultaco !!!!!!!!!
 
Pursang's Avatar
 
Joined: Jul 2006
Location: Okanagan. Canada
Oddometer: 107
To eliminate a few more possible problems I drained the fuel tank/carb, pulled both of the fuel petcocks off the tank, removed the screen tubes and blew everything clean with compressed air, the screens were surprisingly clean and the tank only had a few grains of sand inside, refilled with fresh premium and installed another spark plug, hit the magic button and no spark now I'm wondering if this issue is related to the original popping under acceleration problem ? any and all help would be appreciated with what to do next !
Pursang is offline   Reply With Quote
Old 07-14-2013, 12:44 PM   #10
Pursang OP
Bultaco !!!!!!!!!
 
Pursang's Avatar
 
Joined: Jul 2006
Location: Okanagan. Canada
Oddometer: 107
Here are the results of some testing with an Ohm meter. I would appreciate any suggestions as to what to check out next, should I have the Ignitor checked out if I can find a service that does that ?
Ignition coil, primary: 4.5 (spec is 4)
Ignition coil, secondary: 14.0 (spec is 13)
Stator coil: 0.6 (spec is 0.65)
Pickup coil: 243 (spec is 230)
Sparkplug cap: 00.0 (spec is 10k)
Sparkplug wire: 00.0 (spec ?)
Pursang is offline   Reply With Quote
Old 07-14-2013, 07:45 PM   #11
damo2010
damo
 
damo2010's Avatar
 
Joined: May 2010
Location: Roma, South Western QLD Aust
Oddometer: 412
Do you have spark back yet?
I've been told that the high voltage stuff can be problematic, not sure if you have changed any of the spark plug leads and cap.
From one of your previous posts, seemed like the popping was starting once bike was warmed up, maybe elec connections are getting worse with heat.
I'm no expert with this side of it, but maybe sounds like week spark?
__________________
Damo

Yamaha Tenere XTZ660 4UX
http://share.findmespot.com/shared/f...rbiW8y1XLQCMtY
damo2010 is offline   Reply With Quote
Old 07-18-2013, 08:59 PM   #12
Pursang OP
Bultaco !!!!!!!!!
 
Pursang's Avatar
 
Joined: Jul 2006
Location: Okanagan. Canada
Oddometer: 107
Nope no spark at all, I tried another plug wire and cap from a set of automotive wires I had in the shop, they don't have the copper wire like the original but still I thought it would do if the plug wire/cap were the problem, still no spark.
Pursang is offline   Reply With Quote
Old 07-19-2013, 01:40 PM   #13
motomike14
Thumper Crusader
 
motomike14's Avatar
 
Joined: Jan 2010
Location: Florida
Oddometer: 1,668
Quote:
Originally Posted by Pursang View Post
Nope no spark at all, I tried another plug wire and cap from a set of automotive wires I had in the shop, they don't have the copper wire like the original but still I thought it would do if the plug wire/cap were the problem, still no spark.
Automotive stuff will likely have a higher resistance, which is no bueno on that ignition system.

Would start simple; test output from stator first then work your way up to the coil to see where the electricity stops at. Like most big bore singles, the Yamaha singles did have CDI issues (black boxes get hot, then boil themselves basically).
__________________
"The bold adventurer succeeds the best. - Ovid

I drink the koolaid too...just not the orange kind.
motomike14 is online now   Reply With Quote
Old 08-12-2013, 10:32 PM   #14
Pursang OP
Bultaco !!!!!!!!!
 
Pursang's Avatar
 
Joined: Jul 2006
Location: Okanagan. Canada
Oddometer: 107
Thanks motomike, can you explain the procedure for checking for juice to the coil ? I set my tester to 200 AC and placed one of each lead to each of the wires going to the coil, turned the engine over but the meter remained at zero, I've searched all over for stator output procedures and numbers going to the coil but nothing is coming up, can't find anything in the various XT600 service manuals I have on pdf files either, I'm probably not testing it right.
Pursang is offline   Reply With Quote
Old 08-13-2013, 02:28 AM   #15
webmonstro
A Aventura Continua....
 
webmonstro's Avatar
 
Joined: Jul 2008
Location: Portugal
Oddometer: 464
Quote:
Originally Posted by Pursang View Post
Thanks motomike, can you explain the procedure for checking for juice to the coil ? I set my tester to 200 AC and placed one of each lead to each of the wires going to the coil, turned the engine over but the meter remained at zero, I've searched all over for stator output procedures and numbers going to the coil but nothing is coming up, can't find anything in the various XT600 service manuals I have on pdf files either, I'm probably not testing it right.
testing is done by resistance test

you can build a high voltage spark tester (i did once and it worked) but make sure it's a CDI, since it's a '99 it 's most likely a TCI sistem (uses lower voltage ) i think you can test it with 12 v (not sure)

As for the popping the 1990-2003 models have two pick-ups in the stator one for low RPM and one for high RPM
Check the harnesse where the high RPM pick-up connectes to the CDI
they can sometimes brake (as it kinks on a sharp turn ) where the wire goes in the plug
I think it's the blue wire

As for the HT wire to the plug , if you can remove it from the coil just connect a normal copper wire and connect to a spark plug to test output


more info :

http://www.transmic.net/en/home.htm



good luck

webmonstro screwed with this post 08-13-2013 at 02:34 AM
webmonstro is offline   Reply With Quote
Reply

Share

Thread Tools Search this Thread
Search this Thread:

.
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 On

Forum Jump


Times are GMT -7.   It's 11:46 AM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2014