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Discussion Starter #1
I just bought a 1999 1200LT. 42,000 km on odo.
I reside in Asia and its hot and humid all year round.
When I bought it, it would not idle properly and would die off. Riding it with an open throttle was good.
The bike was probably not ridden much and the bike initially could not start because of bad batteries. It needed a jump start from a good battery (since replaced).
Have had the fuel pump, fuel filter, fuel lines, fuel pressure regulator replaced. New KN air filter and new fluids.
Some cleaning of the throttle bodies was done by the workshop. It was pretty 'gummed'. Since cleaning it looked clean.

Now the bike idles. There seems to be a little of idling variation from about 900-1100 rpm.
However, cold riding for about 3-5 miles is ok, but when the engine temperature gauge reaches about 1/2 mark, it bucks when I open the throttle and pull off. At cruising its ok.
Does anybody have any suggestions on what could be the problem here ?
Thanks
 

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krider08 said:
Have had the fuel pump, fuel filter, fuel lines, fuel pressure regulator replaced. New KN air filter and new fluids. Some cleaning of the throttle bodies was done by the workshop. It was pretty 'gummed'. Since cleaning it looked clean.

Now the bike idles. There seems to be a little of idling variation from about 900-1100 rpm.
Two comments here. A KN filter may not be the best thing on this motor, but that is for another debate. Idling variation could be due to a small vacuum leak that interferes with the idle fuel/air mixture.

Have had the fuel pump, fuel filter, fuel lines, fuel pressure regulator replace... However, cold riding for about 3-5 miles is ok, but when the engine temperature gauge reaches about 1/2 mark, it bucks when I open the throttle and pull off. At cruising its ok. Does anybody have any suggestions on what could be the problem here ? Thanks
What rpm is the engine when you open the throttle, and how far do you open the throttle to experience this surging? If this is at small, part throttle, a vacuum leak may still be interfering with the mixture.

So, perhaps a vacuum line was loosened when the last service was done?
 

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Discussion Starter #3
It does this when I start from standstill.
It also does this when I am at speed and open the throttle to accelerate.
What does it mean about the vacuum leaks.
Could you help specify where I should look for these before I have to bring the bike back to the workshop.
They charge at least USD80 just to lay a hand on the bike :(
Thanks for the input, this site is a gem for all the $saving advice. I have been looking at the LT for about a year ever since I found this site :)
 

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krider08,

You will have to remove all the body panels (Some call it the Tupperware) to get to the engine area. You could use the old school method to test for vacuum leaks by mixing dish soap and water in a spray bottle and spray the mixture all around the engine area while the bike is running and see if you get a surge or idle change while spraying around all the hoses. Usually if you have a vacuum leak you will hear a slight change in idle when the soapy mixture hits the area that is leaking. I have a slight idle issue when the bike is at operation temperature and I think that I also may have a hose connection that seems to leak slightly when things begin to warm and swell with heat. One thing that is difficult, is trying to isolate the area since fuel injected systems can correct the fuel mixture to compensate for additional air presented by a vacuum leak.

Hopefully this helps

Cheers,
Tom
 

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Discussion Starter #5
Hi
I'm now a one year 'newbie' .
Still the surging.
Though much better.
Things done so far :
new Platinum plugs
oil/ filter change x 2
valve clearances done
Changed the throttle bodies mounting to the engine (round rubbers)
put in multiple fuel injector cleaners.
removed the canistor
removed the yellow plug for the fuel map

Have been using my Stelvio more as the surging has not gone away
It's barely noticeable above 4000 rpm. But significant on load ie accelerating / going uphill. There's occassional idle hunting. This barely happens when the temp gauge is below the 1/2 point. Have tried looking for vacuum leaks to no avail. Bought a good condition throttle body and had it installed too.

Can anybody suggest what else I can to ?
Thanks.
loke
 

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Discussion Starter #9
Ok thanks
Will try to see if the fuel pump is the issue.
That's something we've not looked into yet.
Loke
 

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I have a 2000 LT watch my video posted...... http://www.youtube.com/watch?v=4t0HpmspTgw ..........is this the problem your having idle surge after spending lots of money with dealer decided to do it myself I found the removing the charcoal canister and vaccum line took care of the problem took the bike for a 280 mile ride to key west and the engine performed like brand new...oh another think if you remove the vacumm line you have to plug the 4 throttle body port auto part sell the rubber vaccum plugs for a couple bucks
 

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oxygen sensor - motor will run rich
 

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Discussion Starter #13
1 half years. finally found the problem.
When I bought the bike at 42k , battery was dead. Mech did not reset throttle position and took out throttle bodies to 'clean' it.
Long story short, the screw holding the fuel rail was installed using a stainless steel one without the original washers. Cold ok, warm surging.
Took long look at the microfiches and realized the washers were missing. Also noticed the microfiche specified Zns screws. Ordered the original washers, screws. Since it was coming out, replaced the rubber grommets.
Problem solved ! I am a happy LT rider now :wave
Hope this does not happen to any other rider.
 

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krider08 said:
1 half years. finally found the problem.
When I bought the bike at 42k , battery was dead. Mech did not reset throttle position and took out throttle bodies to 'clean' it.
Long story short, the screw holding the fuel rail was installed using a stainless steel one without the original washers. Cold ok, warm surging.
Took long look at the microfiches and realized the washers were missing. Also noticed the microfiche specified Zns screws. Ordered the original washers, screws. Since it was coming out, replaced the rubber grommets.
Problem solved ! I am a happy LT rider now :wave
Hope this does not happen to any other rider.
Good for you. Main Issue - problem solved. BUT still this is interesting.... Just Might Be BUT I would still bet on messing around with fuel rail solved the original problem - not the type of bolts or washers.... Perhaps the fuel rail was not properly in place and there was some air leakege bypassing the O-ring(s) in the injector body. So when fixing the original problem with idle another new one was created... Now when new bolts & washers were installed maybe the rail was set on its place properly.

Originally you mentioned that "some cleaning" for the throttle bodies was done. How about injectors?
 

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Dang! BRAVO on following up on the fix for a year and a half! Regardless, this thread will help somebody, someday! :D
 

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Discussion Starter #16
It was good for a good 2 weeks. Then the little niggle started again, not as bad as before.
Replaced the spark plug cables, the acceleration was much better. But the hestitancy still remained.
Decided to change the o-rings on the fuel injectors (replaced 1+ year ago) and this is what I found. 5 plugs, the extreme right one was covered up by the mechanic. The 2nd double green wire was plugged into injector 2 !! Will be doing the right wiring and hope for a good ride thereafter this weekend. sigh......
 

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WIth the age of your bike I would consider replacing all the fuel supply hoses inside and outside of the tank - along with a new fuel filter. I had similar symptoms and the hoses inside my tank were like sponges... completely porous and especially ahead of the fuel filter which was also clogged.
 

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krider08 said:
It was good for a good 2 weeks. Then the little niggle started again, not as bad as before.
Replaced the spark plug cables, the acceleration was much better. But the hestitancy still remained.
Decided to change the o-rings on the fuel injectors (replaced 1+ year ago) and this is what I found. 5 plugs, the extreme right one was covered up by the mechanic. The 2nd double green wire was plugged into injector 2 !! Will be doing the right wiring and hope for a good ride thereafter this weekend. sigh......
That was the plug that was to go to the cannister valve which is opened by the ECU above idle to burn the cannister fumes. So one of your injectors was open above idle. That would explain the rich running. I had one injector plug that was on but not locked and it gave me poor running above 3,00 rpm as it vibrated loose.
 

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Discussion Starter #19
bike now pulls well on 5th gear.
100 km ride running about city / hway gave me an improvement from 12 km/l to 17 km/l.
Guess now I'll need to go on a looong ride to enjoy the bike after 22 months of trials and tribulations.
 
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