Its a long time since I've had a two stroke and they were always autolube.

Can anyone advise premix ratio for a 98 TX270?

Road use between off road sections

Previous owner said 33:1 but I wasn't convinced (more my nagging doubt than any concern about previous owner)

Thanks

Thats way way too rich. For trial only 1:100 works. If you use high gears (so longer ''speed'' parts) 1:70/60 or so.

 

Also depends on where you live, temp etc.

Edited August 24, 201511 yr by crazybond700

Thanks for that. I hadn't thought about it being too rich. I was more worried about not putting enough oil in it.

 

Consequence of too rich? Smokey exhaust, Fouled plug, poor starting. Can being too rich do it damage?

 

Consequence of to not enough oil? Bottom end wear/seizure?

 

I live in Glasgow in Scotland. A good summers day is 20oC, a very good summers day is 25oC. Winter could be 0 - 5oC.

 

I plan on 2-3 mile road sections in urban areas at 30mph limits, linking up industrial waste land tracks/trails where I'll be pottering about. Bike could run for an hour at a time without stopping.

I agree with above (60 70 or even 75:1) but remember this is with a good quality synthetic, as for damage its worth bearing in mind a rich oil mix means less petrol so the engine can actually run weak with associated problems

 

Why go past the manufacturers recommendation of 50:1? 100:1 was never heard of in 98 and frankly you would have been laughed at then if you said you were running 100:1 or even 70:1. Just the same way you would have been laughed at in the 70s if you said you were running 50:1. 

 

On top of that you have a 17 year old bike with no doubt a worn piston and bore and you want to do road work. I wouldn't entertain anything less than 50:1, possibly a bit more given the bikes age.

 

As you rightly say, the worst consequence of too much oil is a fouled plug (even though thats as much due to your carburation), too little and you have something expensive to fix. 

 

 its worth bearing in mind a rich oil mix means less petrol so the engine can actually run weak

 

No, its means the same volume of a marginally thicker petrol

Edited August 25, 201511 yr by faussy

We have a lot of those bikes (30+), all running 100:1. More oil causes piston rings to stick, your exhaust clogging up etc. I must say those are not used to speed. On trial location used only, low revs. Hence the comment to use more when you are driving it on roads or trails.

 

I use 1:40 on my CR250, which is way way way more maintances needy, and has a lot more power.

 

 

We have a lot of those bikes (30+), all running 100:1. More oil causes piston rings to stick, your exhaust clogging up etc. I must say those are not used to speed. On trial location used only, low revs. Hence the comment to use more when you are driving it on roads or trails.

 

I use 1:40 on my CR250, which is way way way more maintances needy, and has a lot more power.

 

And i run my mx'r at 20:1 and in 5 years have yet to have a piston ring stick.

 

Each to their own.

Thanks for your thoughts guys. All useful stuff for a returnee.

 

Faussy - I didn't know what the manufacturers recommendation was, so thats hugely helpful.

 

It all kind of stacks up. I collected it in the car, by pulling the front end off and rolling it back into the hatchback. In doing so about half a litre of unburnt oil tricked out the silencer/front pipe joint. If he's been running it at 33:1, that's likely a touch too much.

 

I also recognise its an old one likely with a bit of wear in the bore.

 

I'll start off at 50:1, take it gently for a while, and see how it pans out. Fingers crossed.

 

Insurance and tax now all sorted out. Working away from home this weekend, so looking forward to getting back for a play!!

 

 

Why go past the manufacturers recommendation of 50:1? 100:1 was never heard of in 98 and frankly you would have been laughed at then if you said you were running 100:1 or even 70:1. Just the same way you would have been laughed at in the 70s if you said you were running 50:1. 

 

On top of that you have a 17 year old bike with no doubt a worn piston and bore and you want to do road work. I wouldn't entertain anything less than 50:1, possibly a bit more given the bikes age.

 

As you rightly say, the worst consequence of too much oil is a fouled plug (even though thats as much due to your carburation), too little and you have something expensive to fix. 

 

 

No, its means the same volume of a marginally thicker petrol

same amount through jets,petrol vaporised  and most oil deposited on bearings in crankcase, thats what its for, then smaller amount of petrol vapour up transfer ports to combustion chamber, thats what I have been told 

Don't know about the 98 but in 95 GG factory recommended 128-1. My 95 350 has been run on that ratio since new and has never had the head off. It still runs strong. 

Don't know about the 98 but in 95 GG factory recommended 128-1. My 95 350 has been run on that ratio since new and has never had the head off. It still runs strong. 

All the GG manuals I have all recommend 66:1 (1.5%)

 

I wouldn't go any leaner than 50:1 and I've never had a problem with GG

 

I run my air cooled bikes at 40:1 (or more) and never had a problem 

Thanks everyone for the advice.

 

Decided in the end to go 50:1. With 4ltrs of petrol I carefully poured out the 80ml of oil, then let it trickle out to 100ml - just for luck!

 

Got out for a few miles and caught a few tracks before it got dark.

 

 

Wonder how long it'll be before she realises the jug is missing from the kitchen - LOL  !!!!