Waterproofing my KDX

Got questions? We got answers....
Post Reply
Otoko Retoro
Member
Posts: 29
Joined: 05:13 pm Sep 20 2015
Country:

Waterproofing my KDX

Post by Otoko Retoro »

Firstly just a shout out to say you guys are awesome and insanely helpful!
Skip to the bit in bold for the short story

Anybody following my posts knows I have a recurring problem with rain and my kdx cutting out.

After reading all the responses this is where I am at:
Tidied up all the wiring and re loomed it.
Silicon'd up any areas in the wiring water may get in ie spark plug cap and stator wiring grommet.
Replaced the HT lead plug and cap.
Rewired the crappy excuse for an indicator kit.
Reseated the exhaust and engine as the exhaust kept blowing or forcing the mounts to snap.

So... I am still getting trouble when it rains.
I believe water is getting in through the exhaust gasket. I deduced this because the bike has to be moving to incur the problem, runs happily stood in the rain, only cuts out when moving.
There was also rust on the spark plug.

To remedy this, I removed the exhaust, replaced the seals and copper washer and used the copper silicone as advised to seal the gasket. This worked perfectly for a couple of weeks (lets say 300 miles) and I rode in some horrendous rain no problemo, but the exhaust has started blowing again and guess what, it cut out in the rain :(

I checked the gasket and you can clearly see the remains of one of the rubber o rings sticking out, the silicone has let go of the exhaust and is clinging on for dear life.

Why oh why did it not stay sealed? :wah:

SO the question is.. how the hell do you keep the exhaust sealed?
the rubber rings perish in a couple of weeks, the copper gasket is a wafer thin scrap of foil now. Even when new, whilst fitting the exhaust it never really felt like it was in all the way but just wouldnt go on/in any further. It didnt even feel like it married up to the hole in the barrel very well, I tired to find a sweet spot where it held itself in without springs but that wasnt gonna happen. Am I doing something wrong?
User avatar
Tioli
Supporting Member I
Supporting Member I
Posts: 267
Joined: 06:57 am Jul 19 2014
Country: Tasmania AUS

Waterproofing my KDX

Post by Tioli »

I think you may have more than one problem as I don’t know that it is possible for a motor to suck water in through the exhaust flange and extinguish the motor.

So one is electrical and the other is an issue with the exhaust.

If you want to suspect sparkplug and heavy rain is the go then have a look how loose the plug cap is. It may be rusted enough already and need replacing. If it’s loose up the sides of the plug put a zip tie on it to seal it better, put one on the lead side also. Use silicon grease to help seal. Talk to it and let it tell you what the problem is by looking at it very closely and noting every aspect.

The exhaust is not lining up properly. I know you say it is but it seems it’s not so you are not listening to what it is telling you. We are not there so it’s up to you to look closer ie, you say it’s not going in far enough? Have you measured the depth, marked it on the exhaust and put it in and see where is goes in to? Is the silencer blocked or restricted, your pipe is not happy and is telling you that so take all the covers off, remove the silencer and exhaust mounts and line it up. If it doesn’t then why not.

When you get the exhaust lined up the end that joins with the silencer should both sit naturally in the same spot without putting any pressure on each other. If not why not.

The answers are infront of you just keep looking till they appear.

I was just thinking about this on my bycicle ride home and where I would look for a rain issue. For starters I think the kill switch is pretty pours. As a test to eliminate that from the list you could take the throttle off. Cut the ends off a small tube clear plastic zip lock bag and slide it over the kill switch. Fold the throttle side of the bag over and tape it up with electrical or nylon tape. Then tape the tape to the handle bars to seal it. The cable side fold some tape between the two and seal each op and against the handle bars. It it fogs up in there then you never dried it out or its leaking. If that's not it move on.
2001 KX125 with a 1997 KDX Tioli Hp motor

My KDX journey starts at the bottom of this page:
http://www.trials.com.au/forum/viewtopi ... &start=160

Trials.com.au / Forum / All about...me! / My long time friend the prancing horse / page 9
ohgood
Supporting Member II
Supporting Member II
Posts: 925
Joined: 10:00 am Jan 04 2014
Country:

Waterproofing my KDX

Post by ohgood »

Otoko Retoro wrote:Firstly just a shout out to say you guys are awesome and insanely helpful!
Skip to the bit in bold for the short story

Anybody following my posts knows I have a recurring problem with rain and my kdx cutting out.

After reading all the responses this is where I am at:
Tidied up all the wiring and re loomed it.
Silicon'd up any areas in the wiring water may get in ie spark plug cap and stator wiring grommet.
Replaced the HT lead plug and cap.
Rewired the crappy excuse for an indicator kit.
Reseated the exhaust and engine as the exhaust kept blowing or forcing the mounts to snap.

So... I am still getting trouble when it rains.
I believe water is getting in through the exhaust gasket. I deduced this because the bike has to be moving to incur the problem, runs happily stood in the rain, only cuts out when moving.
There was also rust on the spark plug.

To remedy this, I removed the exhaust, replaced the seals and copper washer and used the copper silicone as advised to seal the gasket. This worked perfectly for a couple of weeks (lets say 300 miles) and I rode in some horrendous rain no problemo, but the exhaust has started blowing again and guess what, it cut out in the rain :(

I checked the gasket and you can clearly see the remains of one of the rubber o rings sticking out, the silicone has let go of the exhaust and is clinging on for dear life.

Why oh why did it not stay sealed? :wah:

SO the question is.. how the hell do you keep the exhaust sealed?
the rubber rings perish in a couple of weeks, the copper gasket is a wafer thin scrap of foil now. Even when new, whilst fitting the exhaust it never really felt like it was in all the way but just wouldnt go on/in any further. It didnt even feel like it married up to the hole in the barrel very well, I tired to find a sweet spot where it held itself in without springs but that wasnt gonna happen. Am I doing something wrong?
i think you have an electrical problem. spray from the front tire can easily find it's way onto the coil, hi lead, and spark plug cap. a crack anywhere along there will jump to ground and prevent the bike from running properly.

water getting into the pipe isn't likely, and the pressures from combustion would keep out 99.9% of water unless the entire engine were underwater, then, it MIGHT get some through, but i would imagine the speed of the cycles would prevent any appreciable amount.

i would spray everything with silicon, grease all the connection points (waterproof or vaseline) and try a rain ride again.

post up what you find. :)
User avatar
Jaguar
Supporting Member
Posts: 590
Joined: 01:32 am Jul 03 2013
Country: Paraguay
Location: Paraguay
Contact:

Re: Waterproofing my KDX

Post by Jaguar »

there is a moment of reverse flow toward the cylinder due to the return baffle wave. that is what causes the return to the cylinder of fuel mixture that had escaped into the exhaust. so it is possible some water can be delivered into the combustion chamber.
make sure the pipe and cylinder are flush so that no part of the pipe is closer. if the match is uneven then that can cause it to squeeze out the rubber o-ring. bend the pipe till it matches the cylinder.
Performance CDI -- KDX motocross mods -- the SR KDX -- expansion chamber analysis---> http://www.dragonfly75.com/moto/
Otoko Retoro
Member
Posts: 29
Joined: 05:13 pm Sep 20 2015
Country:

Re: Waterproofing my KDX

Post by Otoko Retoro »

UPDATE Many thanks for the replies and concise information, I swapped out the plug and HT lead and now I think I can cross the channel without an issue. Spot on advice :)

With regards the exhaust, I'm going to get new seals and copper o ring before I investigate that, from memory, the exhaust bracket nearest the tank mount is crooked as hell making me think its pulling the exhaust to one side. Ideally the exhaust needs replacing as its rusty and had many repairs. Would like an fmf fatty but trying to get one in the uk is hard!!
Post Reply