RXS100 - Leaky Carb and Oil Fouled Plugs.

[johnsmith222]

Hi guys.

A quick question just to ask whether or not a carb which overflows would also cause a sparkplug to become oil fouled?

I am having these two issues, and I have tried to sort the carb multiple times, but I guess maybe it just keeps getting corroded, or stuff blocks the needle valve and causes this problem.

Just making sure that sorting the carb is likely to sort my fouling problem.

Thanks again.

[bladerunner]

if the carb is overflowing then the float valve aint doing its job and the mixture is going to be rich or even pouring fuel straight into the engine.....which at worst can cause mechanical damage should you bump start it....or at least cause it to run rich enough to kill plugs.. try turning off your fuel tap...remove the old plug and kick it over a few times to clear the motor of excess fuel. fit a new plug and take it for a ride. turn the fuel off when you park up and see if a bit of use stops the overflowing issues, if not check your float height and if its right and its clean you possibly have float valve wear or its hardened up with lack of use at some time. most of my 2T bikes do this for a day or 2 if not used for a while..RGV250/KDX200's and the RD125 LC all do this for a while after not being used for a few months! they all come right after a few hours use and are on original float valves and have at some point had a few years in their life not been used for a few years at a time! however if a previous owner has decided to adjust the float height to "remedy" the problem or fitted a cheap after market valve......then your likely to be having issues untill you get that sorted!

get an inline filter fitted and see if you have debris coming from the tank as that wont help the situation either but I'd expect the carb to not overflow whilst the engine is running if the float height is near where its supposed to be!

HTH!
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Current bikes...cbr929, KDX200's, Rd125lc mk2, RGV250's

[johnsmith222]

Thanks bladerunner. I think I've identified the true source of the problem. My tank is far too rusty inside and is transferring that mess down into the carb. I believe this is clogging the float valve and causing problems where it isn't closing correctly.

The carb has been dismantled and cleaned multiple times, but it always gets into a terrible mess.

There is a fuel filter present, but this doesn't seem to prevent the rust from getting to the carb. It is this kind of fuel filter:

https://i.ebayimg.com/00/s/OTYwWDEyODA=/$(KGrHqN,!n8E63WLoHU1BPDfOou-Cw~~60_35.JPG

Tbh part of me thinks the tank is bin fodder, but then it does't leak yet so maybe something can be done to sort the problem.

[N cee thirty]

my tank was an utter pain, if i had a fuel filter on it would stop it from blocking the pilot jet and it would be able to idle, but it wouldnt go over 50 odd because of fuel restriction, remove the filter and it would block the idle yet but go flat out

i think you can get some tank sealer, but tis like £30
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'00 Aprilia RS50 > '92 Honda CG > '99 Yamaha Fazer > '91 Yamaha RXS > '79 Suzuki X5 > 01' Honda Cg > 07' Honda Cg > 82' Kawasaki Z200 > suzuki gsxr 400 gk73a > honda vfr 400 NC30 Mod 2 Passed 09/06/2011

Jewlio Iglesias wrote: I actually did vote BNP once

[johnsmith222]

[bladerunner]

Take the tank off and get rid of as much rust as you can. Plenty of posts about it on bcf about ways to do it. My RD tank was sealed 5 years ago as it was bad enough to leak! But still holding up well! If I'm not mistaken...didn't the rxs also have a filter bowl on the tap? That'll need cleaning out!
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Current bikes...cbr929, KDX200's, Rd125lc mk2, RGV250's

[N cee thirty]

[Robby]

If the tank is rusty, it needs to be de-rusted. Don't use a sealer, get rid of the rust instead. This guide is the one I like to follow, most effective one that I've come across.

https://www.realclassic.co.uk/techfiles/petrol_tank_cleaning_and_rust_removal.html

Just bear in mind that acid will attack aluminium alloy, so don't leave any alloy parts like the fuel tap or cap fitted.

[johnsmith222]

Thanks for the help guys.

I have decided to go ahead and de-rust my tank using caustic soda and electrolysis. I have ordered the stuff that I need and I have the tank off and drained.

Thanks for the tips robby. It's been helpful as your post has made me decide to do this process, although I'm going to give the acids a miss as I don't fancy dealing with the fumes etc.

What are peoples opinion of the fuel filters for the RXS100, as they seem to let the powdered rust through. I will need a new one anyway, but are there more effective ones that I could use which trap all the powdered rust?

The RXS100 uses this filter type:

https://images.wemoto.com/full/FUEL_FILTER/10047598.jpg

But I know my kawasakis use this type (but also know they have a fuel pump)

https://images.wemoto.com/full/FUEL/10003116.jpg

My plan is to do the tank electrolysis and then seal the tank using POR15. I can just buy the POR15 because I read that this method makes a good key for it to seal (in practical sportsbikes magazine).

Hopefully this will solve my problem and get my RXS running reliably.

[Robby]

Use the acid. It costs less than 3 quid from a hardware store. Either do it outside, or do it in the bathroom (like I do) with the window open and a fan on. There are very few fumes, and it does a good job of clearing the drain afterwards.

Electrolysis is a shit way of derusting a tank, I've done a lot of it. Very good for a steel part that can be suspended in a bath of electrolyte and surrounded by sacrificial anodes, but an easy way of getting a load of sludge into a fuel tank.

If you want to use a more gentle acid, get some phosphoric. More expensive and a bit slower (an hour instead of 10 minutes).

Sealers are best avoided because of concerns over how they handle the ethanol content of fuel. The current POR-15 may handle the current fuels, but may get eaten in 5-10 years. It's also far cheaper to just use acid.

[mudcow007]

dont for christ sake use sealer...(i used petseal ultra)

im in the process or removing said sealer from my carbs as it has decided to dissolve an literally gum/ stick everything up - plus it didnt seal my tank its still leaking

try an find a replacement tank