RG150 Premix - What jets?

[Jase W]

Have search but couldn't find an answer...

I'm in the process of converting my RG150 to premix and want to know from the guys out there that have done this what I should be looking at changing jet wise? I have been told that I shouldn't need to change the jets as the oil would only make up 2% of the mixture (50:1 Ratio), but I'm fairly sure I will need to.

Also does 50:1 sound about right for the fuelil ratio? Or should I go for somewhere around 40:1? Does it pay to run it at say 25:1 for a tank while running in a new piston?

Thanks for any help.

[Str8 Jacket]

Well, Malcolm is in Upper Hutt working on converting mine to pre mix now. Can't remember what ratio and jets were decided on but if you have his number give him a call. If you don't PM me and i'll give it to you.....

[Racey Rider]

Adding oil to the fuel makes the fuel slightly heavier, so less fuel/oil is sucked up through your main jet than when running straight petrol and oil injection.
Less fuel sucked through your main jet means your running the motor on a Leaner fueloil/air mix.
Does it pay to run it at say 25:1 for a tank while running in a new piston? Given that a 25:1 mix would make your mix leaner - It's not what I would do.
But I know nothing.

Racey.

[ajturbo]

your on the money (in my books) RR.. but Jase, i suggest you PM "oyster" what he doesn't know about the RG's is not worth knowing....

[Jase W]

Cheers for the replies.

RR = Would it only be the main jet that I would need to worry about? If I were to run 25:1 when running in I would jet bigger again to compensate. Any idea on a good place to start with standard jetting as a base?

Will email Pete also, cheers.

[xr-rider]

if you convert to premix there is something you have to drill a hole in. can't remember what it i off the top of my head, could be a bearing. make sure you get that checked

[ajturbo]

you could also ask "Billy" here on KB...

[Racey Rider]

In a Perfect world one might do needle jet as well, but nobody does it seems. For a race bike it's just the main jet that matters.
I have no idea what # jet to suggest as I work on Kawasaki KR's not RG's.

[Jase W]

Well Pete has strongly recommended I don't convert it (apparently its nothing but trouble...), so I will leave it as is for the moment. Cheers for the help though.

[CookMySock]

Interesting. A lot of people don't get, that if you run your fuel/oil ratio leaner - you actually get a richer fuel/air ratio. Conversely, too much oil will lean(A/F) your engine out.

Steve

[Jase W]

That's why I thought I would have to jet bigger - the oil is taking up a portion of the volume of fuel.

[Racey Rider]

There has been talk before about having more oil in your fueloil/air mix (and ajusting main jet to suit), as a good thing. They say, the oil is a combustable fuel in itself, and benefits compression by helping to seal around rings more. I have run injection and premix together at the same time before (with a rich MJ ofcouse), for a good resuilt.

I hope to test the idea of premix 2/ oil (with rich jets) in the GT250 four stroke soon.

[F5 Dave]

if you convert to premix there is something you have to drill a hole in. can't remember what it i off the top of my head, could be a bearing. make sure you get that checked

Well Pete has strongly recommended I don't convert it (apparently its nothing but trouble...), so I will leave it as is for the moment. Cheers for the help though.

Perhaps his reason is for the above.
Obviously Premix has been used on all proper race bikes since Christendom.

Some bikes, are all ready for it, just blank off inlet, pour in oil & adjust jetting - job done. Yams usually have one inlet for the oil in the carb. But older designs often have the extra feed to the main bearing on the left hand side, (sometimes right as well). You need to drill a hole from the transfers down to the bearing, just as it is on the RHS. Had to do this on my RGV150, not sure if it is like RG150.

[xr-rider]

Perhaps his reason is for the above.
Obviously Premix has been used on all proper race bikes since Christendom.

Some bikes, are all ready for it, just blank off inlet, pour in oil & adjust jetting - job done. Yams usually have one inlet for the oil in the carb. But older designs often have the extra feed to the main bearing on the left hand side, (sometimes right as well). You need to drill a hole from the transfers down to the bearing, just as it is on the RHS. Had to do this on my RGV150, not sure if it is like RG150.

that is what needs to be done on the rg150

[CookMySock]

They say, the oil is a combustable fuel in itself

Can you quote your sources? I submit, the oil should not burn whatsoever, but should part company from the fuel during the combustion process and then proceed to do its' job lubricating the piston and rings.

Steve