Author Topic: RZ350 Kenny Roberts (Read 18502 times)

NobleHops · « **Reply #76 on:** April 23, 2015, 05:39:12 PM »

Quote from: Stev-o on April 23, 2015, 05:29:36 PM

Good news!

Ya, and pretty much everything else looks perfectly fine, with the exception of some good scuffing on one piston skirt and the piston wrist pins do not want to come all the way out of the piston. James was able to get them out far enough to remove them, but they are good and stuck on one end.

The crank bearings loosened up some almost immediately after a dunk and rinse in the solvent tank, but they're far from free and of course we have all those crank lubrication passages to think about. What would you guys suggest as the best possible course of action to get that crank clean? Hot tank?

More photos:

scottly · « **Reply #77 on:** April 23, 2015, 06:06:01 PM »

Wow!!!! I've never seen a two-stroke get stuck by gas varnish in the crank-case before!!??
I wouldn't hot tank the crank. Use whatever solvent James used to clean the carbs, but I wouldn't put the assembly in an ultrasonic cleaner as it may damage the bearings. Are there lubrication passages in the crank? I've never seen them on a two stroke..

NobleHops · « **Reply #78 on:** April 23, 2015, 06:14:03 PM »

Quote from: scottly on April 23, 2015, 06:06:01 PM

Wow!!!! I've never seen a two-stroke get stuck by gas varnish in the crank-case before!!??
I wouldn't hot tank the crank. Use whatever solvent James used to clean the carbs, but I wouldn't put the assembly in an ultrasonic cleaner as it may damage the bearings. Are there lubrication passages in the crank? I've never seen them on a two stroke..

Don't know? I confess I assumed there are, but it's too gummy to examine closely at the moment.

We will see what the morning brings.

Stev-o · « **Reply #79 on:** April 23, 2015, 06:19:40 PM »

Quote from: scottly on April 23, 2015, 06:06:01 PM

Wow!!!! I've never seen a two-stroke get stuck by gas varnish in the crank-case before!!??

+1. Something weird happened, petcock left on and gas filled the crankcase? You should consider rebuilding that crank with new bearings and seals.

scottly · « **Reply #80 on:** April 23, 2015, 06:20:52 PM »

I think that once you get it cleaned up you will see the exposed rolling elements in the crank bearings. Normally the bearings are lubed by the oil/fuel mist in the case, but I've never dealt with an RZ...

scottly · « **Reply #81 on:** April 23, 2015, 06:34:40 PM »

Quote from: Stev-o on April 23, 2015, 06:19:40 PM

Quote from: scottly on April 23, 2015, 06:06:01 PM
Wow!!!! I've never seen a two-stroke get stuck by gas varnish in the crank-case before!!??

+1. Something weird happened, petcock left on and gas filled the crankcase? You should consider rebuilding that crank with new bearings and seals.

Yeah, it looks like 3 gallons of gas were condensed in the crankcase. The good part is that it probably protected the parts from corrosion just like cosmoline.

grcamna2 · « **Reply #82 on:** April 23, 2015, 09:28:29 PM »

That may take some time to flush all that old %*#& out of those bearings,rods,etc.
I'd like to know what's good safe stuff to soak'em all in also...you might be able to just clean everything up enough w/o replacing the parts.I believe those holes in the lower case where the bearings ride are for locating dowels for your mains rather than oil holes;that's nice that the engine wasn't seized hard under power but a shame nonetheless having that crap in there.

NobleHops · « **Reply #83 on:** April 23, 2015, 10:15:26 PM »

Quote from: grcamna2 on April 23, 2015, 09:28:29 PM

That may take some time to flush all that old %*#& out of those bearings,rods,etc.
I'd like to know what's good safe stuff to soak'em all in also...you might be able to just clean everything up enough w/o replacing the parts.I believe those holes in the lower case where the bearings ride are for locating dowels for your mains rather than oil holes;that's nice that the engine wasn't seized hard under power but a shame nonetheless having that crap in there.

I just gave it a little scrub and the worst of the goo in the crankcase is gone, but the crank bearings are still pretty solid. If we can't free them up tomorrow then we may dunk them in Berryman's.

Retro Rocket · « **Reply #84 on:** April 23, 2015, 11:58:24 PM »

Quote from: NobleHops on April 23, 2015, 10:15:26 PM

Quote from: grcamna2 on April 23, 2015, 09:28:29 PM
That may take some time to flush all that old %*#& out of those bearings,rods,etc.
I'd like to know what's good safe stuff to soak'em all in also...you might be able to just clean everything up enough w/o replacing the parts.I believe those holes in the lower case where the bearings ride are for locating dowels for your mains rather than oil holes;that's nice that the engine wasn't seized hard under power but a shame nonetheless having that crap in there.

I just gave it a little scrub and the worst of the goo in the crankcase is gone, but the crank bearings are still pretty solid. If we can't free them up tomorrow then we may dunk them in Berryman's.

Try heating it up a bit, nothing extreme but get some heat through everything...

grcamna2 · « **Reply #85 on:** April 24, 2015, 10:37:18 AM »

Quote from: Stev-o on April 23, 2015, 06:19:40 PM

Quote from: scottly on April 23, 2015, 06:06:01 PM
Wow!!!! I've never seen a two-stroke get stuck by gas varnish in the crank-case before!!??

+1. Something weird happened, petcock left on and gas filled the crankcase? You should consider rebuilding that crank with new bearings and seals.

I think you'll have to at least break the crank down and replace the main bearings and seals.

harisuluv · « **Reply #86 on:** April 24, 2015, 10:56:44 AM »

Quote from: grcamna2 on April 24, 2015, 10:37:18 AM

I think you'll have to at least break the crank down and replace the main bearings and seals.

scottly · « **Reply #87 on:** April 24, 2015, 12:21:28 PM »

Quote from: grcamna2 on April 24, 2015, 10:37:18 AM

I think you'll have to at least break the crank down and replace the main bearings and seals.

Why?

grcamna2 · « **Reply #88 on:** April 24, 2015, 04:21:10 PM »

Quote from: scottly on April 24, 2015, 12:21:28 PM

Quote from: grcamna2 on April 24, 2015, 10:37:18 AM

I think you'll have to at least break the crank down and replace the main bearings and seals.
Why?

Well,after you get done soaking it in strong solvents the seals may need replacing;I would do it to install the new crank seals and check/scrub down the other parts while it's apart.

rtbmrgl · « **Reply #89 on:** April 25, 2015, 11:26:43 AM »

Quote from: grcamna2 on April 24, 2015, 04:21:10 PM

Quote from: scottly on April 24, 2015, 12:21:28 PM
Quote from: grcamna2 on April 24, 2015, 10:37:18 AM

I think you'll have to at least break the crank down and replace the main bearings and seals.
Why?

Well,after you get done soaking it in strong solvents the seals may need replacing;I would do it to install the new crank seals and check/scrub down the other parts while it's apart.

I also say splitting crank, it would be a shame to find out after back together and the center seal not working like it should. It is a labyrinth seal and I guess it could get clogged and loose it sealing capability.

harisuluv · « **Reply #90 on:** April 25, 2015, 01:08:13 PM »

never split a crank, so have no idea what it entails, is it something i can do myself? or need a press or something.

I've seen rebuild prices for it around 400, but looks like i can get a brand new one for around that

Stev-o · « **Reply #91 on:** April 25, 2015, 01:32:36 PM »

Quote from: harisuluv on April 25, 2015, 01:08:13 PM

never split a crank, so have no idea what it entails, is it something i can do myself? or need a press or something.

I've seen rebuild prices for it around 400, but looks like i can get a brand new one for around that

Yes, you would need a press among other special tools [that I don't currently have]. I recently had my H1's crank rebuilt.

From 2strokeworld.com:

There are a few different ways you can rebuild them, build two rebuilt sides then press the two sides together to build whole or build from center out to the ends.

If you go here and look through my a build of a RD350 crank will help you understand.
Not extremely hard but need measurement tools, press, fixtures, truing stand, dial indicators and learn the pitfalls that get you into trouble.

http://imageevent.com/supertune/rd350enginebuildpics

Chuck
Team Scream Racing

scottly · « **Reply #92 on:** April 25, 2015, 05:47:27 PM »

How is the crank cleaning going?

bwaller · « **Reply #93 on:** April 26, 2015, 04:48:00 AM »

Get a rebuilt crank, it'll be cheaper than doing it yourself, especially if you haven't balanced a crank before. If the bearings are filled with that goop the seals will have hardened and possibly leak air.

I have an RZ crank here that is really good out of a running engine if you're interested.

scottly · « **Reply #94 on:** April 26, 2015, 07:43:35 PM »

Outside seals that prevent air leaks can be replaced without splitting the crank. If the inside seal is a zero-contact labyrinth seal, it has no rubber parts.

grcamna2 · « **Reply #95 on:** May 03, 2015, 04:43:15 AM »

How's the RZ ? ?

harisuluv · « **Reply #96 on:** May 22, 2015, 06:23:54 PM »

Well boys, I have had a minor setback. Went to clean the tank with a vinegar soak and promptly noticed I had a little row of pinhole leaks near the bottom. I soldered them up to hold the vinegar soak and they seem to be holding up enough to clean the tank.

Usually I don't line/seal tanks but I think I would prefer it in this case, there is a section of metal that is obviously thinned.

Any recommendations for a sealer? Caswell or Por-15 (creme sux). I will try to get some pics up soon.

Stev-o · « **Reply #97 on:** May 22, 2015, 06:59:05 PM »

Sorry to hear. Caswell all the way. I had to do my RD tank as well and used it.

grcamna2 · « **Reply #98 on:** May 22, 2015, 07:27:49 PM »

How's the crankshaft Haris ?

harisuluv · « **Reply #99 on:** May 23, 2015, 12:06:54 AM »

Got a new crank. New pistons one .010 over. Old timer in town already bored and honed them for me. waiting on some seals and bearings and I think I can start putting it back together.

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Author Topic: RZ350 Kenny Roberts (Read 18502 times)