Help! Did the oil mix ruin my CR250 engine?
sla...@hotmail.com
I'm new to the 2-stroke dirt bike stuff - always had 4-strokes
previously. About 6 months ago, I bought an 86 CR250.
The Haynes manual (specifically for an 86 CR250) stated
that the correct mix was 20:1 for that bike. I rode the bike
a few times and now it is very hard starting. I took it to the
local dealership and had them look at it. They told me the
engine needed a complete rebuild. Since then, a guy at a
local cycle parts counter told me that 2-strokes need 40:1 ratios.
Did I ruin the engine running a 20:1 mix? Should I sue the
Haynes manual people (just kidding...)?
Steve
Wudsracer
--
Too much oil would gum, or spooge, everything up, but wouldn't hurt anything,
unless your jetting was now too lean and you ran wide open for too long at a
time. Probably, if the bike needs a complete rebuild, it needed it when you
purchased it.
Jim Cook - Wudsracer
Gas Gas EC250 - SMS Racing - Team LAGNAF
Smackover Motor Sports
(870)725-3966 www.smackovermotorsports.com
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Scott Aldrich
: I have a question about the oil/gas mix for an 86 CR 250.
: I'm new to the 2-stroke dirt bike stuff - always had 4-strokes
: previously. About 6 months ago, I bought an 86 CR250.
: The Haynes manual (specifically for an 86 CR250) stated
: that the correct mix was 20:1 for that bike. I rode the bike
: a few times and now it is very hard starting. I took it to the
: local dealership and had them look at it. They told me the
: engine needed a complete rebuild. Since then, a guy at a
: local cycle parts counter told me that 2-strokes need 40:1 ratios.
: Did I ruin the engine running a 20:1 mix?
No. My Honda Shop manual for my '85 CR125R also states to use a
20:1 ratio. I've used that ratio for quite awhile up until a few
years ago. After my last top-end, I switched to a 32:1 ratio, but I
really haven't noticed any difference. Two-strokes do not "need" a
40:1 ratio.
The hard starting could be due to quite a few things. It may need a
rebuild, but I think I'd start with just a top-end (piston and rings).
Make sure your carb and air filter are clean and there are no air
leaks. Use a new spark plug. Check the cylinder for scores when you
take it apart.
Sometimes mine won't spark at all. I've tracked it down to either a
bad stator or rotor (or both). Very expensive part$$$. I have to
pull the rotor off, and then by simply putting it back on the spark is
good again. Go figure.
--
Scott Aldrich / UN*X System Administrator
Paul
had an 87 cr250 and now have a 93 cr250. Initially i ran the 87 w/ 32:1.
Then I read in Dirt Bike magazine how they ran tests using all of the
synthetic oils at different ratios from 20:1 to 50:1. They found no
difference in wear. I believe the manuals say 20:1 to protect the
engine.
For the last 6 years I've run 48:1 with Maxima Super M. I've had good
success. I used to rebuild the top end twice a year (When I raced) I
haven't had to rebuild since switching to 48:1. I don't attribute that
to the ratio but to the fact that I really pay attention to the fuel/air
mixture (jetting, needle position) it took me awhile to learn proper
jetting but it paid off. My bike always runs great, easy starting, same
plug for 4 years.
For info on jetting check out http://www.ecmx.com/bike_tips/jetting.html
If I would had read this years ago I would have had more fun and more
trophies.
In regard to the rebuild, ask the dealership how far out of specs it is.
Consider that a rebuild is better than a blown engine. Hopefully it only
needs a new top end or a new plug.
I agree with Wudsracer and Scott about what to do, I think they hit the
nail on the head. I just wanted to add my 2 cents in about jetting and
not to be afraid to go lean on the oil.
Happy riding,
Paul
sla...@hotmail.com wrote:
>
> I have a question about the oil/gas mix for an 86 CR 250.
> I'm new to the 2-stroke dirt bike stuff - always had 4-strokes
> previously. About 6 months ago, I bought an 86 CR250.
> The Haynes manual (specifically for an 86 CR250) stated
> that the correct mix was 20:1 for that bike. I rode the bike
> a few times and now it is very hard starting. I took it to the
> local dealership and had them look at it. They told me the
> engine needed a complete rebuild. Since then, a guy at a
> local cycle parts counter told me that 2-strokes need 40:1 ratios.
>
Peter Patton
used, it was more likely in need of a rebuild anyway. 20:1 is a little
lean. 40:1 is a bit rich, which you want at first when you get your bike
back and break it in. I use 32:1.
Peter
sla...@hotmail.com wrote:
> I have a question about the oil/gas mix for an 86 CR 250.
> I'm new to the 2-stroke dirt bike stuff - always had 4-strokes
> previously. About 6 months ago, I bought an 86 CR250.
> The Haynes manual (specifically for an 86 CR250) stated
> that the correct mix was 20:1 for that bike. I rode the bike
> a few times and now it is very hard starting. I took it to the
> local dealership and had them look at it. They told me the
> engine needed a complete rebuild. Since then, a guy at a
> local cycle parts counter told me that 2-strokes need 40:1 ratios.
>
> Did I ruin the engine running a 20:1 mix? Should I sue the
> Haynes manual people (just kidding...)?
>
> Steve
--
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