Forums/Tips & Tricks

KTM 300 XC/XC-W/EXC Bendix Damage

Jamin
posted this on September 02, 2010 10:23

 

Examination of electric starter operation and specifically returned Bendix revealed that approx. 80% of
the parts were fully functional.
These examinations also revealed that poor starting performance is often caused by inadequate ground
connection of the electric starter motor.
While replacing the part with a new electric starter motor eliminates the problem, this is usually because
the ground connection is simply reconnected.
In case of starting problems, we recommend checking that the ground connection of the electric starter
motor is properly connected before replacing the part.
It is then advisable to re-cut the M6 threads indicated by the red arrows
used to fasten the ignition cover in the engine case.

Examination of electric starter operation and specifically returned Bendix revealed that approx. 80% of the parts were fully functional.These examinations also revealed that poor starting performance is often caused by inadequate ground connection of the electric starter motor. While replacing the part with a new electric starter motor eliminates the problem, this is usually because the ground connection is simply reconnected. In case of starting problems, we recommend checking that the ground connection of the electric starter motor is properly connected before replacing the part. It is then advisable to re-cut the M6 threads indicated by the red arrows used to fasten the ignition cover in the engine case.

 

300Bendix.jpg

 

 

A further step to improve functionality of the electric starter motor is to carefully adjust the play between the crown wheel and the starter motor gearing. This can greatly reduce the frictional loss between the two components.

This procedure is described in the repair manual KTM 250/300 Item Code 3206088.

Excerpt from repair manual KTM 250/300 Art. No. 3206088.

RM3206088.jpg

 

 

Comments

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Dwayne Ross

Is it your recommendation to go with a wet system as many have done? I have used Red Line synthetic gear oil for a couple years now. I just can't seem to get much more than about 1 seasons riding in before my brushes wear out. Do you offer a brush kit for this starter?

September 08, 2010 22:01
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Jamin
KTM Parts

What do you mean by 'wet system'?

This is the latest Brush Set:

55140002044 BRUSH SET FOR STARTER
September 09, 2010 11:37
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Dwayne Ross
It seems many are opting for the wet system for the troublesome 300 starter, as it requires much less maintenance & generally just works better. It involves cleaning/removing all the old waxy grease that KTM uses, sealing up the sidecover weep hole, shimming the starter correctly(as previously mentioned), some folks add a breather tube/hose vent to the electrical grommet, then adding a few ounces of oil for lubrication. I personally use Red Line Synthetic gear oil as the crown wheel/starter shaft spline is basically a differential, and the synthetic gear oil works well & remains fairly thin, even though it is an 85w/90 oil. Red Line synthetic gear oil, awesome stuff as anyone who has used it knows. I have modified the plastic cover so that can be easily removed to access the crown wheel so I can add a couple ounces of oil every month or so, as it does seep/weep oil a bit. At the end of the season take it apart and it's clean as a whistle in there. No wear, no corrosion, much less hassle than taking it apart every month to relube. It is also necessary to get a decent battery(7series or Turn Tech). The only issue is the fact that I can only get 1 season out of a set of brushes. My bet is that KTM changes the design soon as other 2 strokes spool up with a more troublefree estate system. Do your brush sets come with a new brushholder? and are the bushings available for the sidecover separately?
September 09, 2010 16:00
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John Copley
Where can i purchase new needle bearing and oil seal for my starter motor?
January 31, 2012 05:43
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Dwayne Ross

the newly available bushing for the side cover/case/bendix shaft is 55140030100.

The bevel gear, or intermediate shaft coupling as KTM call it, also uses this bushing, and they can easily drop out when reassembling the case if you’re not careful. There are 4 in total.

I understand that you can get the shaft bushing & seal. Google "KTM starter parts" and check Rick. He may have them. 

January 31, 2012 07:13
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Dwayne Ross

select a year and go from there…. it seems a full rebuild kit including the bearing & seal can be had.

January 31, 2012 07:26
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Andrew Cooper
Hi, dumb question I guess to those in the know, however what effect does the wet system (oil smothering the electrics) have on the performance/quality of the spark?
April 24, 2012 15:26
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Jamin
KTM Parts

That's a good question, I'd also love to know the answer. I had actually never seen that setup before it showed up on these KTMs. I was like, wet ignition? That can't be good!?!?

April 24, 2012 15:52
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Andrew Cooper
Why doesn't ktm provide a reliable site to get your hands on a full workshop manual. I have looked for ages and found zip. Can anyone direct me to a site where I could download a PDF version or buy a DVD or hard copy of a full 2008 ktm 300 exc e workshop manual. Help.....
April 24, 2012 17:09
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Dwayne Ross

This is the KTM shop manual CD. I bought one and printed a hard copy for ease of use.

There is absolutely no problem whatsoever with running wet. Every four stroke electric start out there runs oil under the cover. No problem. Much cleaner under there with oil & a  sealed cover, and way less mtce.

April 24, 2012 18:03
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Andrew Cooper
Thanks heaps. Took my starter motor apart, adjusted seized brush springs and brim brim.....back into life....and saved $700 nz dollars. Will try the oil. It was pretty dry and a bit rusty around the flywheel. Cheers. Can you give me the link to the CD manual so I can purchase. Will need to be in English.
April 24, 2012 21:04
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Jamin
KTM Parts

This is the most current manual from KTM and covers all 2-strokes 125-300 1998-2012

http://www.ktm-parts.com/3206106.html

 

3206106.jpg

April 25, 2012 17:01
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David Kendrick

Also if you check out Slaven Racing you will find some great videos on rebuilding the starters in case anyone is a newbie trying to take it on.

June 29, 2012 11:40
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Linds
Hi guys just a quick question I need answered I had and 2010 exc 300 and am about to replace a set of brushes in my starter but I need the black plastic ring that holds the brushes in (brush holder) but ktm won't sell it to me in a kit. I found someone selling a kit on eBay but said it was listed for an xc-w 250 300 not exc but I didnt think there was any difference betweent the to when it comes to starter motors if someone can confirm this that would be great thanks as I would love to get this sorted, thanks
July 06, 2012 18:33
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David Kendrick

@ Linds, pretty sure they are the same but easy enough to check, go online and open the repair/parts manual for each and check part numbers ;O) Little bit of research on your part but you should find out what you need.

I do online part number compares at times through various sites with online manuals or shops that support stock oem part orders.

Good luck...

July 06, 2012 19:11
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Linds
Thanks for your help David, will be sure to check it out from what ive compared in pictures the parts look the same But if they have a part number I will have a look
July 07, 2012 05:14
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Sandro SANCHEZ

what I had found out , regarding starting problem, is the axle on the starter , gets rusted and the bearing locks up , solution take cover  out , grease up with water proof grease ,  where the roller bearing is , change the o´ring every time  , and it works forever.

December 07, 2012 21:53
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Jamin
KTM Parts

Here's a link to the shims described in the original post:

http://www.ktm-parts.com/search.html?q=098808140&x=-1055&y=-83

May 31, 2013 12:22
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denis oven

exc 300, 2012

I've renewed starter motor completely (rotor, brushes, springs, orings, bearings), battery charged up, and for exclusion also had fully operable battery from exc 450, that started the 450 flawlessly.

Motor itself, when NOT connected to crown through gears, rotated fast and strong.

 

Cleaned all the old grease, applied new grease to the 4 bushings (idler gear and bendix). Lubed all gear teeth with thin 5W oil.

 

When starter connected to gears, it turns the engine like this:

http://www.youtube.com/watch?v=blRNBXMaGuo&feature=youtu.be

Turns in the same corrupt manner as prior to renewal.

 

No major wear, other than normal rotation marks, is seen on any gear teeth: starter, idler-(rad&ax) and bendix.

Next step will be replacing the bushings and shimming the idler gear, although power transfer seems OK, no jumping through teeth.

If that won't do the trick, what next?

Bendix is, like everything else, cleaned, degreased and thin oil lubed. It works OK, when rotated in hand and also it locks, when rotated quickly in its seating.

I will do the oil mod, when problem solved, but for now I only lubed the gear teeth, to avoid constant oil spillage while removing the starter side engine cover.

 

 

 

June 24, 2013 07:14