Fouled plugs

[MrMelon]

My plugs keep fouling up.

I've had the bike in and out of the shop over the last 2 months getting the head and base gaskets replaced, and that seems to have stopped the coolant leaking into the engine, but I've been through 4 sets of plugs within about the last 6 tanks of gas.

This morning i started the bike, it didn't really want to idle so I gave it a bit of throttle to bring it up to 3k or so, and it backfired pretty loudly out 1 exhaust a few times, then felt like it was only running on 1 cylinder when I rode it for the next 10 mins.. after I tried to really open it up for a bit, it came back to normal, stopped backfiring, and started running on both cylinders again.

If i stick a new set of plugs in, the bike will usually feel fine for the first 150km or so, but then it'll slowly start to misfire at the top of the rev range (8k+) and run on 1 cylinder when I first start it up. :/

It's got some heat range 8 plugs in it now.. the factory ones were heat range 9's.. The 8's should be hotter though, so it shouldn't foul up so easily should it?

I've also changed from using elf 2 stroke oil a couple of months ago to shell vxs lately, but I don't know if this is having any effect on it.

I just need to figure out what's wrong with it so I can ride it to auckland, and not have to change my plugs every few hundred km's.

[marty]

now i'm no 2 stroke expert, so shoot me down if you know better....

i had trouble with my plugs fouling, and once i had put the correct ones in, i discovered that on the older RS250's, the leads had a resistor on them, so the plugs were non resistored, but on the later models (post 99) the plugs needed to be resistored, as the leads were not.

i dunno if the tzr is resistored or not, but it may pay to have a look - if you are running resistor plugs, and the leads are likewise, you might be taking too much power out of them, and they don't spark hard enough, resulting in them oiling.

likewise, if the timing is out, it will be causing the spark to go bang at the wrong time, and fuel not being burnt properly.

you should be able to run it on lawn mower oil without fouling the plugs if it's all working properly

[MrMelon]

OK sweet, all the stuff I can find says that tzr's use resistor plugs, and that's what i've been using the whole time.

It's just recently that my plugs are fouling up all the time.

Is there a way to check that the timing's all good, or reset it?

The weird thing is it seems fine for a few hundred km's before having any problems.

[marty]

browsed google - can't find ANYTHING on how to set up the timing on the TZR. that would be my best bet

[Motu]

I'd look at the carbs,I'd say one side is rich or flooding,this is fouling the plug.Don't go hotter than standard on a 2 smoke to stop foulling,makes nice holes in pistons.

[MrMelon]

Do you think running some carb cleaner in the gas would be a good, or very bad idea?

I might go and try and get another set of heat range 9 plugs tomorrow.

[MrMelon]

Do leaky/blocked carbs cause anything like this?

[marty]

yes. did you change the jet sizes recently?

[MrMelon]

I haven't touched the carbs or jetting or anything ever :P
But it's only been like this since I got it back from the mechanic where it's been in and out of for the last couple of months.

It's booked into motomart tomorrow to go on the dyno and get checked out.. they seem to know a bit more about what they're talking about by the sound of it.

[Hoon]

Yeah I'd check the carbs too.

Is it just happening on one cylinder or both?

Are your dead plugs oiled up or still cleanish looking?

Is it hard to start?

You may be leaking fuel into the cylinders while parked up - you could try turning the gas tap off when you park for say a week and see if it makes any difference.

[MrMelon]

I might try and pull things apart tonight and take a look.
It feels like it's only happening on 1 cylinder.
It's not usually hard to start, just takes 1 or 2 kicks, but when it does start, it doesn't want to idle.. it need to be revved to 3k or so, or else it feels like it's going to die.
That's when I get a few loud backfires out 1 exhaust, and after a bit it feels like the 2nd cylinder kicks in again.

All the dead plugs I've taken out have been oiled up. Usually 1 more than the other.

Edit: The fuel tap is always turned off when I park the bike.

[Oscar]

Try changing the plug caps. On TZ's the carbon element in the cap wore out and caused a resistance problem.

[MrMelon]

Well I just went down and pulled the plugs out to take a look at them.. the top one is a nice tan colour, and the bottom one is soaked in oil with a bit of burnt on green crap around the end of it.. it better not be leaking coolant again..

[bungbung]

Hey MrMelon, how is that TZR going now? have you had any joy from Motomart?

[MrMelon]

Long story.. but i've got all night so here it goes :P

I took it into motomart because It was leaking coolant into the right hand cylinder.. he pressurised the cooling system, and half the coolant leaked into that cylinder.

This is less than 200km's after I got the bike back from richards motorcycle services, where he charged me $800, spent 10 hours in total in labour over 2 months to first of all replace the head gaskets and tell me the problem was fixed, but it wasn't so I took it back to him.
He pulled it all apart again, took the heads off and said that they weren't leaking, then proceeded to pull the left hand barrel off to find the base gasket was leaking.
He ordered a left and right hand side base gasket from japan, so a couple of weeks later, he put the left hand base gasket in, put the whole thing back together, including gluing the used head gaskets back on.
He said that he tested it, and that it was completely fixed and gave it back to me. He didn't check the right hand base gasket at all while it was all apart.

So I got it back, and surprise surprise it's still fucked, this is where it's still leaking the coolant into the right hand cylinder.

So the dude at motomart (who actually sounds like he's pretty onto it) pulled it apart again. So far he's found that the heads weren't planed before putting them back on, he said it looks more like they were sanded by this guy by using a piece of sand paper in his hand, so the edges are rounded off where they shouldn't be.
So i'm going to need to get the heads re-planed properly, both head gaskets replaced again (they've got to be ordered from japan again), and I've taken the spare right hand base gasket that the monkey at richards ordered in, but didn't bother to check or use, since that's going to need to be replaced too.

They're just waiting on the gaskets to come in now, so hopefully I'll have it back with in a week or so.

just got all the MTA complaint forms to take some action against richards motorcycle services for doing such a shoddy job the first 2 times.. so hopefully I can get some money back out of him for the job that he completely messed up. There's no way I'm ever letting him touch my bike again.