Author Topic: RZ350 Kenny Roberts  (Read 18111 times)

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Offline rtbmrgl

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Re: RZ350 Kenny Roberts
« Reply #25 on: March 25, 2015, 11:06:55 am »
I just love the smell of 2-strokes in the morning,  8)
thanks, Mark
Roseville, Ca

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1973 CB500 back yard find 1243 orig mi,  http://forums.sohc4.net/index.php?topic=124285.0
1976 CB750 Restoring,        http://forums.sohc4.net/index.php?topic=132997

Offline grcamna2

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Re: RZ350 Kenny Roberts
« Reply #26 on: March 25, 2015, 12:11:26 pm »
Two strokes eat rings faster than 4 strokes so a good peek inside the top end will be a good idea anyways since it already has a problem. How many miles is the odometer showing ?

He mentioned that it had 18,600 showing in a previous post
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline ekpent

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Re: RZ350 Kenny Roberts
« Reply #27 on: March 25, 2015, 02:17:39 pm »
Two strokes eat rings faster than 4 strokes so a good peek inside the top end will be a good idea anyways since it already has a problem. How many miles is the odometer showing ?

He mentioned that it had 18,600 showing in a previous post
Whoops my bad, should have re read.  Worth whatever it takes to make it sing again.

Offline joeyvans

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Re: RZ350 Kenny Roberts
« Reply #28 on: March 25, 2015, 09:00:08 pm »
Awesome find, harisuluv! I need to get my hands on one of these before the price gets driven up even more. I'm diggin on the full fairing with the seat cowl and the Toomey expansions. Can't wait to hear it!
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Offline harisuluv

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Re: RZ350 Kenny Roberts
« Reply #29 on: April 03, 2015, 09:10:35 pm »
Here's an update:  Partial fairing removal (I kinda just like it with the bikini), initial "let's see where we're at" wash complete.  Tranny oil drained (looked brand new).

So engine needs to come out to address this whole stuck thing.

Offline harisuluv

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Re: RZ350 Kenny Roberts
« Reply #30 on: April 03, 2015, 09:11:45 pm »
more pics

Offline Stev-o

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Re: RZ350 Kenny Roberts
« Reply #31 on: April 04, 2015, 05:53:31 am »
Engine look in great shape.  Have you tried rocking it back and forth in 3rd gear trying to free it up?
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Offline grcamna2

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Re: RZ350 Kenny Roberts
« Reply #32 on: April 04, 2015, 07:43:20 am »
AllRight it's up on the rack  ;D ; I hope it'll loosen up easy for you.
Those wheels will shine again if you use a powerful pressure washer to remove that flat black and reveal the oem finish.
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline harisuluv

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Re: RZ350 Kenny Roberts
« Reply #33 on: April 04, 2015, 07:51:45 am »
Engine look in great shape.  Have you tried rocking it back and forth in 3rd gear trying to free it up?

yeah, unfortunately didn't budge :(

Offline grcamna2

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Re: RZ350 Kenny Roberts
« Reply #34 on: April 04, 2015, 07:56:47 am »
How about removing the cyl. head while it's in the frame to brace it? and using some wood & hammer ? it may have that corrosion from water leakage like you mentioned
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline harisuluv

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Re: RZ350 Kenny Roberts
« Reply #35 on: April 04, 2015, 08:03:35 am »
I would be open to that!  I'll try that first.

Offline scottly

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Re: RZ350 Kenny Roberts
« Reply #36 on: April 04, 2015, 01:44:05 pm »
Don't beat on the pistons with a block of wood and a BFH: if a piston is at the bottom of the stroke, it can't go any further down, and you can damage the needle bearings in the rod as well as the crank journal. Rig a couple of pullers that bolt to the top of the cylinders with bolts that thread down onto the piston tops (with suitable padding to protect them), and "pull" the cylinders off the pistons.
Don't fix it if it ain't broke!
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Offline harisuluv

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Re: RZ350 Kenny Roberts
« Reply #37 on: April 04, 2015, 02:46:27 pm »
thanks scottly!  that is definitely good advice, will take it.

Offline grcamna2

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Re: RZ350 Kenny Roberts
« Reply #38 on: April 04, 2015, 04:09:03 pm »
How do those pistons and cylinders look inside harisuluv ?
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline harisuluv

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Re: RZ350 Kenny Roberts
« Reply #39 on: April 04, 2015, 06:49:04 pm »
How do those pistons and cylinders look inside harisuluv ?

Funny you ask, I just got a glimpse!


Offline scottly

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Re: RZ350 Kenny Roberts
« Reply #40 on: April 04, 2015, 06:58:11 pm »
Slugs and jugs look good!?? No evidence of rust or gouges in the cylinder walls from seizing. I wouldn't pull the jugs just yet, without a bit more investigation...
Don't fix it if it ain't broke!
Helmets save brains. Always wear one and ride like everyone is trying to kill you....

Offline harisuluv

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Re: RZ350 Kenny Roberts
« Reply #41 on: April 04, 2015, 07:32:44 pm »
yeah..  not sure where the next logical place to look would be.  PO said that supposedly the bike had a high speed lock up from a bad shift or something, supposedly though it was "fixed"

Offline scottly

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Re: RZ350 Kenny Roberts
« Reply #42 on: April 04, 2015, 07:40:59 pm »
I was wondering about the trans. See if you can get the back wheel to turn backward with the bike in gear. I had a gear tooth break off once, wedging itself between the gears and locking the trans, until I backed the bike up and it fell into the sump.
Don't fix it if it ain't broke!
Helmets save brains. Always wear one and ride like everyone is trying to kill you....

Offline harisuluv

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Re: RZ350 Kenny Roberts
« Reply #43 on: April 04, 2015, 08:24:20 pm »
I did that when I was trying to "unstick" the top end.  Rocked it back and forth to no avail.  =/

Offline grcamna2

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Re: RZ350 Kenny Roberts
« Reply #44 on: April 05, 2015, 05:07:43 am »
The stator cover is off,is the 'flywheel' locked-up ? Will it shift at all?
I look forward to what you find  ;)
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline harisuluv

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Re: RZ350 Kenny Roberts
« Reply #45 on: April 05, 2015, 08:58:28 am »
Shifts through all the gears. I thought I might just lift the jugs to just verify pistons are free, then read Scott's message and didn't. 

Offline grcamna2

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Re: RZ350 Kenny Roberts
« Reply #46 on: April 05, 2015, 09:13:28 am »
I would pull the jugs just to verify that it isn't the pistons;they sure do look nice from the top though..
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline scottly

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Re: RZ350 Kenny Roberts
« Reply #47 on: April 05, 2015, 01:02:03 pm »
Take a peek through the intake and exhaust ports at the pistons. Also, see if there is any tiny movement of the crank at the flywheel: if a piston is stuck, the crank may be able to move a tiny bit from the clearance in the rod bearings.
This link has pictures and info about engine dis-assembly:
http://www.scooterhelp.com/RZ_help/restorations/engine.start.html
Don't fix it if it ain't broke!
Helmets save brains. Always wear one and ride like everyone is trying to kill you....

Offline scottly

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Re: RZ350 Kenny Roberts
« Reply #48 on: April 05, 2015, 05:48:46 pm »
Can you rotate the rear wheel with the clutch pulled in and the bike in gear? If so, you may want to pull the clutch cover off and check the primary drive gears.
Don't fix it if it ain't broke!
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Offline NobleHops

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Re: RZ350 Kenny Roberts
« Reply #49 on: April 05, 2015, 08:22:07 pm »
Yes Scottly, it did rotate like that. So maybe the trouble is all behind the clutch cover. That could be a lot simpler to deal with.
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