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premix
Posted: Sun Apr 01, 2007 6:29 pm
by Colorado Rider
I have been riding four strokes for the last 4 years and I just got my old (82') CR-250r back from a friend. He left it sitting for the last couple years. Trouble is I don't remember the pre-mix ratio. Anyone help me out , thanks.
Posted: Sun Apr 01, 2007 7:40 pm
by Asmith
40:1 is a safe ratio. If that's too rich drop to 32:1.
Posted: Sun Apr 01, 2007 7:45 pm
by JAWS
It depends on the oil you are using. There are some oils that are formulated to run at 100:1. Which oil are you using?
Joe
Posted: Mon Apr 02, 2007 4:15 am
by Aussiecrf230
I think bikes of that vintage ran anything from 20:1 to 32:1.
A 2001 CR80 runs 20:1 standard. The bike shop keeps telling me it will foul plugs etc.
Plug is clean as a whistle, as is the piston, and piston and rings last.
Don't believe oil makers claims they don't pay for piston seizures and crank replacements.
PM Oldtimer he runs a CR250 not sure what year though, but I would bet he knows.
If you do run different mixture rates remember you will have to adjust fuel amount.
More oil bigger jets, Less oil smaller jets.
You would be surprised.
Posted: Tue Apr 03, 2007 10:05 pm
by Colorado Rider
I am using pro honda GN2 pre mix oil. Anyone have any sources for vintage plastic and seat covers? Thanks.
Posted: Wed Apr 04, 2007 5:29 am
by 124
~ wrote:40:1 is a safe ratio. If that's too LEAN drop to 32:1.
Fixed
Posted: Wed Apr 04, 2007 5:35 am
by Asmith
124 wrote:~ wrote:40:1 is a safe ratio. If that's too LEAN drop to 32:1.
Fixed
I thought increasing the amount of oil to gas will lean the mixture. You are saying that will
richen it???
Posted: Mon Jul 21, 2008 11:37 am
by Praetorian
I would run 32:1 in a 250 as previously suggested. I run 44:1 in my CR500. If I may recommend Maxima 927. Its a great premix!!!! Smells purdy good and is castor based. You cannot beat the protective properties of castor. It has an affinity for hot metal surfaces. Most synthtics burn off well before castor does. When it does burn it leaves a lubricating film.
Posted: Mon Jul 21, 2008 11:43 am
by krisrtch
I run 50:1 full synth either Panolin or Golden Spectra oil in my 06 CR250R Still runs as strong as the day I brought it home new still has orginal piston in it.
Posted: Mon Jul 21, 2008 12:09 pm
by 124
~ wrote:124 wrote:~ wrote:40:1 is a safe ratio. If that's too LEAN drop to 32:1.
Fixed
I thought increasing the amount of oil to gas will lean the mixture. You are saying that will
richen it???
I just realized that I had left an open question AS...and ofcourse you already know the answer.
I think I was responding oil/gas ratio vs air/fuel ratio. There was discussion of both in this thread. Who knows what I was thinking...I don't half the time.
Anyways, 32:1 or 40:1 is close to stock jetting for premix ratios. If it matters anymore...I'm diggin the NO PREMIX! Haha...
Posted: Sat Aug 23, 2008 5:54 pm
by ship_killer6666
40:1 is too lean
I range from 30:1 to 35:1, depend on the oil
also try having your jetting a bit too rich on gaz/air. remember it is a two stroke and your crankshaft life depend on the small amount of oil in the gaz