Planet Minis

xr100man · 08-06-2008, 07:14 PM

I HAVE A QUICK QUESTION. I AM IN THE PROCESS OF PUTTING IN NEW RINGS IN A 1979 RM 125. I'M JUST WONDERING I CHANGED THE TRANS OIL ON THE BIKE TODAY WITH RED HONDA TRANS OIL. IM JUST WONDERING WHEN I WAS LOOKING AT THE CRANK IT IS FULL OF THE NEW RED TRANS OIL. IS THAT NORMAL? I PUT THE CYLINDER BACK ON AND THE PISTON IS NOT DRAGGING ANY TRANS OIL UP. JUST WONDERING IF THIS IS NORMAL FOR THE TRANS OIL TO BE ON THE CRANK OR IF THERE IS A PROBLEM. ANY INPUT WOULD BE APPRECIATED. THANKS

firepower354 · 08-06-2008, 07:20 PM

Sounds like bad crank seal, or center case gasket. Not surprising, given it's age. Cheap and easy to replace.

Sweet old scoot. I'd almost forgot about the funky "N" model fenders. Looks like the front got swapped for a later one? I had a 78 with the cobbled looking aluminum banana arm.

xr1million · 08-06-2008, 07:23 PM

Yea, you have either a bowl right crank seal, leak between center cases or a hole in the cases into the crank area!

xr100man · 08-06-2008, 07:52 PM

Can I run it like this?

SUZUKIRM12594 · 08-06-2008, 07:57 PM

Quote:

Originally Posted by xr100man

Can I run it like this?

Maybe for a while if you run engine oil in the tranny but I REALLY DO NOT RECOMMEND IT!!!

50-50 · 08-06-2008, 08:02 PM

Quote:

Originally Posted by xr100man

Can I run it like this?

They're right - it's probably a crank seal. If you're smart you won't run it like this because you'll fix it while you have it apart. You can wait for a $2.00 part and put it in now or you'll have to tear down the whole engine again just to put this $2.00 part in. Think it through. It's not a hard choice.

xr100man · 08-06-2008, 08:03 PM

Is it that hard do i have to split the cases? So it is suppose to be dry on the crank?

xr100man · 08-07-2008, 06:18 AM

Any more opinions?

TheCRKid · 08-07-2008, 06:37 AM

Quote:

Originally Posted by xr100man

Any more opinions?

opinions ?

you never have tranny oil in the crank case on a 2 stroke
period

pull the motor
replace the crank seals and center case gaskets
no choice

xr100man · 08-07-2008, 07:35 AM

How hard is that to do? Do I have to take out the transmission gear by gear?

stevec · 08-07-2008, 08:09 AM

This site may give you an idea of what's involved. New Page 1 There are sections on splitting and assembling the case. If you leave it like that, it'll run rich and foul plugs.

BTW. look at this Mini. He ain't the mad scientist for nothing.

index.gif

xr100man · 08-07-2008, 03:36 PM

I hope that I can just get away with crank seals how hard are those?

xr1million · 08-07-2008, 05:00 PM

I doubt its the crank seal because they usually only leak when the engine is running or when you pressure test the bottom end. (if you can find a way to seal the ports then you can pressure check it at no more than 6 PSI)

If I were you I would buy a manual and pull the whole thing apart! The worst part on bottom ends is the tranny, but if your careful to not let the gears fall off the shafts then you wont have a problem with it.

Also tranny fluid will cause scuffing between the piston and cyl. ... dont know why, as oil is a lubricant and the tranny oil is oil.

ANd that little mini bike with the 80 motor is bad ass!!!!!

keith42 · 08-07-2008, 06:04 PM

firepower like this one? it's a 78 1/2 C2

keith42 · 08-07-2008, 06:06 PM

Quote:

Originally Posted by xr100man

Can I run it like this?

No throw some seals in it and you'll be good to go.

firepower354 · 08-07-2008, 07:43 PM

Quote:

Originally Posted by keith42

firepower like this one? it's a 78 1/2 C2

Yup. There was no C2 125 or 400, though. The 250 C came out early with a steel arm and aluminum tank, and the 125/400 were intro'd at the regular time with the 250 C2 plastic tank and alloy arm. If my memory serves me better than some of my other functions

Good call on the rerouted resivour lines. Mine wore in to my boots before I figured how to run them different. I was 12, so improvements came in small steps.

Dig the 81 YZ80 too! I was on a 465 by then, but little bro had one I'd steal for a few laps. I'd tell him we'd swap, kill the 465 with the choke and roost off on his, while his 115lbs tried to start the flooded big bore. He'd have killed himself if it ever fired up.

keith42 · 08-07-2008, 07:57 PM

your correct, Suzuki only had this swingarm and plastic style for 1 year. I had a 1980 RM400 back in 80. in my profile I have pictures of my 79 yz80 and my MR50's.

firepower354 · 08-07-2008, 08:06 PM

Sweet rides, too!

TheCRKid · 08-07-2008, 08:46 PM

1978 1/2 RM 250 C-2
my first real MX bike !!

CJsDad · 08-07-2008, 08:49 PM

Are you sure its trans fluid? Is the oil you mix in the gas red? It could be the oil from your gas. Usually a crank seal on the clutch side will smoke real bad and when you change the clutch oil, there will be a lot missing.

08-06-2008, 07:14 PM	#1 (permalink)
xr100man 3rd Gear Member Join Date: Feb 2007 Location: Chicago Burbs Posts: 1,138	2 stroke engine question please look I HAVE A QUICK QUESTION. I AM IN THE PROCESS OF PUTTING IN NEW RINGS IN A 1979 RM 125. I'M JUST WONDERING I CHANGED THE TRANS OIL ON THE BIKE TODAY WITH RED HONDA TRANS OIL. IM JUST WONDERING WHEN I WAS LOOKING AT THE CRANK IT IS FULL OF THE NEW RED TRANS OIL. IS THAT NORMAL? I PUT THE CYLINDER BACK ON AND THE PISTON IS NOT DRAGGING ANY TRANS OIL UP. JUST WONDERING IF THIS IS NORMAL FOR THE TRANS OIL TO BE ON THE CRANK OR IF THERE IS A PROBLEM. ANY INPUT WOULD BE APPRECIATED. THANKS

08-06-2008, 07:20 PM	#2 (permalink)
firepower354 3rd Gear Member Join Date: Oct 2006 Location: Flint MI Posts: 5,187	Re: 2 stroke engine question please look Sounds like bad crank seal, or center case gasket. Not surprising, given it's age. Cheap and easy to replace. Sweet old scoot. I'd almost forgot about the funky "N" model fenders. Looks like the front got swapped for a later one? I had a 78 with the cobbled looking aluminum banana arm.

08-06-2008, 07:23 PM	#3 (permalink)
xr1million 3rd Gear Member Join Date: Dec 2005 Location: Just south of hell, FL Posts: 4,555	Re: 2 stroke engine question please look Yea, you have either a bowl right crank seal, leak between center cases or a hole in the cases into the crank area!

08-06-2008, 07:52 PM	#4 (permalink)
xr100man 3rd Gear Member Join Date: Feb 2007 Location: Chicago Burbs Posts: 1,138	Re: 2 stroke engine question please look Can I run it like this?

08-06-2008, 08:03 PM	#7 (permalink)
xr100man 3rd Gear Member Join Date: Feb 2007 Location: Chicago Burbs Posts: 1,138	Re: 2 stroke engine question please look Is it that hard do i have to split the cases? So it is suppose to be dry on the crank?

08-07-2008, 06:18 AM	#8 (permalink)
xr100man 3rd Gear Member Join Date: Feb 2007 Location: Chicago Burbs Posts: 1,138	Re: 2 stroke engine question please look Any more opinions?

08-07-2008, 07:35 AM	#10 (permalink)
xr100man 3rd Gear Member Join Date: Feb 2007 Location: Chicago Burbs Posts: 1,138	Re: 2 stroke engine question please look How hard is that to do? Do I have to take out the transmission gear by gear?

08-07-2008, 08:09 AM	#11 (permalink)
stevec 1st Gear Member Join Date: Sep 2007 Posts: 140	Re: 2 stroke engine question please look This site may give you an idea of what's involved. New Page 1 There are sections on splitting and assembling the case. If you leave it like that, it'll run rich and foul plugs. BTW. look at this Mini. He ain't the mad scientist for nothing. index.gif

08-07-2008, 03:36 PM	#12 (permalink)
xr100man 3rd Gear Member Join Date: Feb 2007 Location: Chicago Burbs Posts: 1,138	Re: 2 stroke engine question please look I hope that I can just get away with crank seals how hard are those?

08-07-2008, 05:00 PM	#13 (permalink)
xr1million 3rd Gear Member Join Date: Dec 2005 Location: Just south of hell, FL Posts: 4,555	Re: 2 stroke engine question please look I doubt its the crank seal because they usually only leak when the engine is running or when you pressure test the bottom end. (if you can find a way to seal the ports then you can pressure check it at no more than 6 PSI) If I were you I would buy a manual and pull the whole thing apart! The worst part on bottom ends is the tranny, but if your careful to not let the gears fall off the shafts then you wont have a problem with it. Also tranny fluid will cause scuffing between the piston and cyl. ... dont know why, as oil is a lubricant and the tranny oil is oil. ANd that little mini bike with the 80 motor is bad ass!!!!!

08-07-2008, 06:04 PM	#14 (permalink)
keith42 2nd Gear Member Join Date: Nov 2007 Location: sumner, wa Posts: 466	Re: 2 stroke engine question please look firepower like this one? it's a 78 1/2 C2

08-07-2008, 07:57 PM	#17 (permalink)
keith42 2nd Gear Member Join Date: Nov 2007 Location: sumner, wa Posts: 466	Re: 2 stroke engine question please look your correct, Suzuki only had this swingarm and plastic style for 1 year. I had a 1980 RM400 back in 80. in my profile I have pictures of my 79 yz80 and my MR50's.

08-07-2008, 08:06 PM	#18 (permalink)
firepower354 3rd Gear Member Join Date: Oct 2006 Location: Flint MI Posts: 5,187	Re: 2 stroke engine question please look Sweet rides, too!

08-07-2008, 08:46 PM	#19 (permalink)
TheCRKid Advertiser Join Date: Jan 2005 Posts: 3,371	Re: 2 stroke engine question please look 1978 1/2 RM 250 C-2 my first real MX bike !! __________________ T Bolt USA ALL top Pitbikes ,Engines and Parts for Pitbikes & Minis Website Contact THECRKID@TBOLTUSA.COM or Call 215-630-3554

08-07-2008, 08:49 PM	#20 (permalink)
CJsDad 2nd Gear Member Join Date: Jan 2007 Location: BrookPark, Ohio Posts: 952	Re: 2 stroke engine question please look Are you sure its trans fluid? Is the oil you mix in the gas red? It could be the oil from your gas. Usually a crank seal on the clutch side will smoke real bad and when you change the clutch oil, there will be a lot missing.

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