Bridgestone Motorcycle Parts Discussion Board
Bridgestone Tech Talk => 175 & 200 Talk => Topic started by: ajf on November 15, 2017, 10:15:01 AM
-
Hi, I posted awhile ago that my rs200 race replica was smoking bad after I replaced 1 broken ring. I pulled the heads for sandblasting, and noticed the PO had installed the pistons backwards. I don't know how I missed it when I changed the ring the first time. Fortunately the ring was not cracked or bore scored, so I just reinstalled the piston the correct way around.
As I understand it, this probably has no change on the burning oil problem I have. However the crankcase had oil in the bottom of it and the transmission was empty. I originally didn't think it was a trans leak because it was smoking evenly from both cylinders. Is there a particular seal to change in the transmission that may be the culprit?
Ill try to attach a pic of the ongoing project. Thanks for all of the info on the site!!
-
Hi ajf,
A couple of questions :-
How much oil did you find in the crankcase. There will always be some which drains down from the cylinders / pistons etc when the engine is static.
Presumably, the transmission had been filled before you ran it. Daft question I know but have to ask.
-
A fresh assembly will smoke excessively for the first 5-10 miles just on the oil used to lube the bearings and pistons, etc. during assembly. It can also continue for quite some time if someone applied grease to the crank bearings during assembly.
Excess smoke from both cylinders is either an oil pump or oil pump control malfunction, defective both left and right rotary valve center seals or it is pulling transmission oil into the crankcase through the crankcase splitline. Double check that the oil pump has the brass check valves on both outputs. Transmission oil getting into the crankcase is a possibility due to improper cleaning of the crankcase splitline surfaces before assembly or something like the crankshaft being installed without lining up the hole in the center bearing race to the locating pin in the lower crankcase half, which holds the crankcases apart slightly. If the issue is the splitline leaking or two bad seals, you should be able to make at least a slight difference in the idle speed by plugging the transmission vent or by removing the transmission fill cap while it is running. If the splitline or the seals are leaking, it also should be somewhat difficult to start.
-
Thanks all,- I may have made a mistake in my description. The oil level I checked had the filler next to the kickstart. My brain said transmission, but it could have been the clutch/ primary ? I'm at work now and don't remember!!
When I had the cylinders off, I rotated the crank, and the flywheel came around with a coating of yellow/gold oil on it. The injector lube I use is red, so I thought it may be transmission oil. I unscrewed the oil level screw on the sidecase (no dribble of oil), so I dipped a piece of wire as a dipstick into the primary. It came up dry. I hadn't seen any leaks on my garage floor.
The original pump had some problems, so I purchased a new one, cleaned out the check valves and installed. I have only idled it for 15 mins 2-3 times, but it starts right up and idles fine, no excessive smoke. If I then rev it in neutral, it will rev cleanly 2 or 3 times and then start to fog out the neighborhood. Kind of like the cylinders are loading up, but its pure white smoke. It smells a little different from my injector oil- the reason I am thinking transmission or primary.
-
The transmission and primary drive share the same oil supply, so you were right.
From what you tell us, it certainly sounds as if she is pulling oil from the transmission. Most likely cause is worn or hardened seals on the crankshaft. These are the ones that fit in the centre of the disc valve covers. Time consuming but easy to replace.
If that doesn't cure the issue, you will have to consider a leak on the crankcase split line as Karl Swartout suggests. A pressure test on the crankcase would help to diagnose a leak, if you are able to do that.
-
Brian is right. It's probably transmission oil accumulated in the crankcase through the rotary valve seals. You likely haven't burned it all out yet, so don't get too excited about it; you won't know how bad a leak you have until you've run it for a reasonable distance.
Check the transmission/primary oil level using the screw on the lower right side of the clutch cover in front of the kickstarter. It is shown on page 36 of the owners manual downloadable from this site, but the pictures are pretty bad.
-
Brian/ Carl, thanks for the direction. I will try to take a look at the rotary valve seals, it may be just as easy as setting up for a pressure test. This is an engine that had been rebuilt 5-10 years ago but not many miles were put on. When I bought the bike 2 yrs ago, the transmission was locked, so I only disassembled/ inspected and reassembled the motor- not changing any seals, only the necessary gaskets and the piston ring I broke on disassembly. Most of the rubber was hard as a rock now that I think of it.
I am almost embarrassed to say this is going to be a display bike, but I want to know if I want to hop on it and go, it will work as expected.
Tony