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  #1  
Old 20-11-2017
Nutty Nutty is offline
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The KTM 250/300 wet mod: The Ten Basics

The wet mod comprises ten (10) basic areas of attention:
You can do any one of them as a separate job but total reliability will only come from biting the bullet and doing the lot...

The areas to attend to are:
1) 410W Starter
2) Update Bendix
3) Crown wheel lash
4) Bendix end float
5) Update case gasket
6) Alternator case sealing
7) Alternator case venting
8) Earth return strapping
9) Li battery
10) New bendix cover gasket
11) New bearings*

* used bikes only

1) 410W Starter. self explanatory. even new starters should be witness-marked, dismantled and both bearings lightly greased internally

2) Update bendix. There were two levels of update bendix, a) welded and b) welded and re-geared. Either works fine.

3) Crown wheel lash. Should be set at 1/2 tooth of lash. It's adjusted with 8mm-bore suspension shims. Always use a fresh gasket as gasket thickness/compression alters the gear lash. Don't over tighten the cap! A dab of blue Loctite on the cap screws will suffice and the bolts just nipped up.

4) Bendix end float. This setting is often messed up by riders banging the ignition cover in falls/crashes. Machining or replacing the cover is necessary. This setting is THE most critical setting in getting the starter to work well.

After installing fresh bearings...set the end float at 0.6-0.8mm, once again using 8mm-bore suspension shims.

End float GROWS as the bearing faces wear. End float SHRINKS as ham-fisted mechanics crush the bendix cover gasket or crashes indent the case cover. It takes only 0.5mm of deflection to bugger the starter...

Not enough end float doesn't let the bendix get enough 'run-up' to throw out firmly. Too much makes it noisy and clacky and work every second go. Start with a 0.01 shim on the gear side. This stops the bendix gear binding on the alloy bearing face and slowing the start-up of crank rotation.

5) Update case gasket. The original part was green paper, the update part is Black, made of rubberised aluminium.

6) Seal the alternator case. Use Selleys 'Brick and concrete sealer' sticks like nothing else. Lightly coat the new gasket as well.

7) Alternator case venting. Vent them up to the spare vent hole on the rear of the steering head down-tube using an OEM fitting for the fuel cap vent hose. Remove the pulser/AC bus loom and rubber wiring seal, place the seal in a vise and drill it with a sharp butterfly-bit.

Seal the tube passage through the rubber seal with Yamaha bond #3 or similar latex based sealant.

8) Earth return strapping. Here I remove the OEM black positive lead to the starter terminal and re-use it from battery -ve to one of the two bolts fixing the actual starter motor. I then make a new +ve lead using nice red heavy duty speaker cable from the stereo shop.

This part of the wet-mod makes a hell of a difference, especially on Bergs and Huskys (plastic subframe)

9) Li battery. Self expalantory, call Walks at Hollyhock Batteries for a great deal and the correct battery.

10) New bendix cover gasket. New every time!!! This part controls bendix end float and is crucial to the whole caper. DO NOT REUSE. Don't over tighten. Blue Loctite, nip up bolts only.

11) New slipper Teflon bearings. These are cheap as, there's two for the Bendix, one for the crown wheel, etc. Replace them when doing the wet-mod.

Disclaimer: this post was intended in good faith as a checklist only. there's loads of info everywhere on each item.
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Old 20-11-2017
slideshowbob slideshowbob is offline
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Thanks.
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Old 20-11-2017
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RMJay84 RMJay84 is offline
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I did the wet mod to a bog stock 2010 300exc

Worked well lubrication/maintenance wise, brushes in the motor wore out at 160hrs so I replaced them (kit $35 from mototech) and then it worked some more

I found that ideally, the oil needed an overflow reservoir as some of it would bubble out of the vent hose when hot
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Old 20-11-2017
Nutty Nutty is offline
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Quote:
Originally Posted by RMJay84 View Post
I found that ideally, the oil needed an overflow reservoir as some of it would bubble out of the vent hose when hot
This is caused by:
1) vent hose protruding into the alternator cavity
2) too much oil
3) too viscous oil.

70-80ml of synthetic 2.5wt fork oil and make sure the vent hose stops at the rubber seal.

Mine don't push oil, even on 40 degree days in horrendous terrain.
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Old 20-11-2017
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Thank you sir
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It pumps one way and then it pumps the other...
you have to know what you're doing with these machines and wear gloves
Current rides: 125 trially, 200EXC, 2x 250EXCs, XR70
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  #6  
Old 21-11-2017
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This needs to be a sticky. Excellent compilation.
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  #7  
Old 21-11-2017
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quality post. been drummed into me by the professor for years
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  #8  
Old 22-11-2017
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Bushmechanic Bushmechanic is offline
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Interesting Pete. Is there any benefit or opportunity to possibly connecting the ignition cavity to the gearbox with some holes so you can run the same oil ? You might be able to block the vent then
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frame build http://www.husaberg.org/forum/viewtopic.ph...php?f=8&t=13268
Engine http://www.husaberg.org/forum/viewtopic.ph...php?f=5&t=12131

Update http://www.dirtbikeworld.net/forum/s....php?p=1679488
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  #9  
Old 22-11-2017
axel axel is offline
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Disclaimer - do your own research and don't rely on the below as absolute fact.

BENDIX for 300
55140026100 BENDIX 18/27 (2007 - 2014)
55140026200 BENDIX 18/30 (2014 FREERIDE ONLY)
55140026300 BENDIX 18/28 (2015)
55140026400 BENDIX 18/28 (2016) $217.55 Boltons

CROWN for 300
55140022100 CROWN WHEEL 18/41 (2007 - 2014)
55140022200 CROWN WHEEL 15/41 (2014 FREERIDE ONLY)
55140022300 CROWN WHEEL 16/41 (2015) $137.70 Boltons

55130040100 2015-2016 Gasket apparently metal with rubber coating $24.65 Boltons
55130041100 (2007 - 2016) IGN. OUT SIDE COV. GASKET 07 $13.45 Boltons
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  #10  
Old 22-11-2017
axel axel is offline
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From KTMTalk:
Quote:
I believe the 16 bendix is the same as the 15 but the gear is laser welded to the shaft.
There have been some reports of the gear slipping on the the shaft with the 15 parts.
The crown wheel is the same on both 15 and 16.
...the '15 solution is 13% lower ratio that previous yrs that used the 350W starter.
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