`99 KTM LC4 hard cold start?

Discussion in 'Thumpers' started by Jerrykap, Feb 13, 2015.

  1. Jerrykap

    Jerrykap Motorbike mishugana

    Joined:
    Dec 6, 2003
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    234
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    Davis, CA
    Someone suggested I start over here... So here goes:

    Hi all,

    I'm an experienced mechanic that's been working on bikes forever.

    The last couple of years it's been almost impossible to coax the bike into a normal start when cold, either on the starter motor or the kickstart. If I do finally get it to catch and run she warms up beautifully and runs and starts perfectly until it's left to sit and cool down again.

    All the obvious things have been checked, valves, battery, carb overhauled & starter cleaned & working properly. The cranking speed seems fine and it should start with just a touch of choke. But no joy. The local dealer has looked it over several times and I always authorized the work they wanted to do but the problem remains.

    There seems to be a lack of feedback as the bike will only crank with not even a fart. Pulling the plug reveals a hot spark and correct mixture? Hard to tell if it's too rich or too lean to start? Finally with a lot of patience she will begin to catch and die briefly and then eventually get going properly. Even starting fluid doesn't help.

    I always crank in small bursts and I've never had much luck with the kickstarter. It's gotten so I can no longer rely on this bike to get me out of the garage, I'm losing my patience and getting annoyed with this whole process. Please share your ideas with me as I really don't want to give up on a bike I enjoy riding.

    Thanks,
    '
    Jerrykap
    Davis, CA
    #1
  2. gunnerbuck

    gunnerbuck Island Hopper

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    Have you visually looked at the condition of the stator and pickup coil? I have found that the LC 4s are very hard to start cold if there is any kind of deficiency in the ignition output even if a spark is being produced... This really shows when you combine cooler weather and a sub par battery, the power it takes to crank the engine robs from what is needed to produce a hot spark... Though once you do get them running they seem to be fine until the next cold start..

    By what your describing, you have lots of cranking power so the battery is ok, so it is worth investigating the stator and pickup coil faces for scoring... I worked on one bike a few yrs back that had similar issues to yours and it proved to be this very issue..
    #2
  3. bmwktmbill

    bmwktmbill Traveler

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    Jerry,
    Read the details on the other thread. Sounds like you have done all the common sense things and have run out of easy stuff, Derek's suggestions were good ones and Gunner's.

    Seems like a leak down test and checking the pick are next logical steps.

    The starter fluid failure to get things going makes me think it must be electrical.

    You have our sympathy and understanding. We have all been there.

    bill
    #3
  4. Grreatdog

    Grreatdog Long timer Supporter

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    32,600
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    Annapolis, MD
    I will throw you a curve, my 2000 has an electrical problem that only happens on cold starts. If you get it to come alive and start it will be good for the rest of the day. It drove me crazy. I thought maybe an issue with the tip over switch, ground, battery, carb, etc.

    But I have finally isolated it to something in the ignition switch not making contact or something on cold starts. I wont know until I take it apart. But I know the switch is causing the problem. The intermittent nature and having everything always check threw me.

    Maybe not your issue. But it sure sounds like what mine does. Once the weather warms up a little I will either rebuild the ignition switch or ditch it altogether since I could care less about a fork lock.
    #4
  5. McBoab

    McBoab Fast side of farty

    Joined:
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    Oddometer:
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    Blighty
    If the bike has the Dellorto carb read on, if its the Mikuni CV carb then its probably of no use.
    My old '98 LC4 Duke was a right royal pain in the harris to start when temps dropped below 10degC from new. I too had it at the dealer and they weren't of any help either. I ended up jetting down the idle mixture jet by quite a margin from stock ( it often used to flood after many failed start attempts, using the choke only made it worse) and it became quite a decent starter after that with the choke becoming useful for extreme cold starts. it had the additional benefit of perking up the low rev oomph so much it would hoike the front at a hint of throttle :) .
    #5
  6. Jerrykap

    Jerrykap Motorbike mishugana

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    Davis, CA
    You guys rock...we're really getting down into the obscure, niggling little faults that can make for a hard cold start. As they say, God is in the details.

    I'm generally a very patient wrench, with some of your new tips in mind I'll hang in there until the fault is isolated.

    Thanks to all, C-ya, Jer:norton
    #6
  7. tallbob

    tallbob Been here awhile

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    Butt Mt. VA
    I have a 99 640 that has always been hard to start when cold then fires right up after it has been ridden a bit. I've had it about 8 years and it has always been this way. It's pretty much stock except for a SXC silencer and a 45 pilot jet. I totally rebuilt the carb a couple of years ago and it didn't change the cold starts.

    When I first got it and it wouldn't start sometimes I would pull the plug and crank the engine to check spark then the bike would start when I put the same plug back in???

    I've had luck laying the bike over with the gas on to flood the carb and sometimes I tap on float bowl with a screw driver handle and it would start up like the float was sticking. It almost always starts after this but I always have to let the starter crank MUCH longer than normal when starting cold for the first time.

    I had a 39mm FCR carb on it for awhile and it didn't do cold starts any better with it.

    It's worse when the weather is colder, several times it wouldn't start in the morning and I rode my other bike, then the KTM started in the afternoon when the ambient temperature had gotten warmer.
    #7
  8. slackmeyer

    slackmeyer Don't mean sheeit. .

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    My bike is usually tough to start with the e-start when cold, but it kicks over fine, and then will usually start fine on e-start the rest of the day. My hunch is that the sprague clutch spring is a little bit off- it was getting loose and the starter was beginning to not catch, so I snipped about 3/4" of that spring off and rethreaded it into itself. Now I think it's a little too tight, and won't let the engine freewheel quite as easily as it should.

    Try this kickstarting procedure, it usually works for me to start the bike in one or two kicks even after sitting for a couple weeks

    With the key set to off, set choke/enrichener to about 1/2 way.
    Kick the bike over about 1/2 dozen times, don't be shy with the decomp lever, you don't need a ton of compression, just a little air flow.
    Turn the key on. Set choke a little lower, like 1/4-1/3 on.
    Set the kickstarter to just after TDC and give it a good smooth kick. It's definitely easiest to do with the bike on the centerstand. After much practice, I can often kick it over when the bike is down on it's wheels, but it's hard to get a really good kick. (I'm about 5'10", can't flatfoot the bike).

    Hope that helps.
    #8
  9. VanFitz

    VanFitz Adventurer

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    Apr 20, 2013
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    Location:
    Vancouver BC Canada
    I'm having the exact same issue with my '03 LC4 Adventure. I'll try to start the bike with the starter and it just spins, doesn't seem to catch at all, and this depletes the battery enough that it won't even crank over after a few tries. Then it takes about a dozen to 20 kicks to get it to start. With regard to the Dell Orto carbs, (sorry if this is a dumb question) but when you say "jetting down the idle mixture", do you mean make it leaner?
    #9
  10. bmwktmbill

    bmwktmbill Traveler

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    Hey Van,
    Are you saying the starter doesn't engage or that the engine turns over but won't start.

    I'm not clear on that.

    bill
    #10
  11. hajoktejnSI

    hajoktejnSI Been here awhile

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    I have a 99 adventure with dellorto carb. It starts with full choke, no problem. After couple of seconds it wants to die and I dissengage the choke and give it a little gas so it starts running nicely; I did 3 services of the carbie (new needlejet, needle, mainjet, new float valve, and did a proper float height adjustment) and it didn't make no difference in cold starting.
    Actually the only time the bike started and ran fine (without me giving it gas) when it was cold, was when I've put a smaller size mainjet and droped the needle one notch; but then it was running lean.
    #11
  12. McBoab

    McBoab Fast side of farty

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    Blighty
    yup made the fueling leaner by quite a margin . Don' t have the jet sizes to hand but supplier questioned the amount of change ( maybe halved the jet number?)
    #12