Crankcase seals?

[sbraatz3]

Ok, so I've posted in the past week about my Super Rat (98) that I recently bought from my uncle. The bike probably sat for at least 20-30 years without being started. Not sure what kind of issues it would of had when it was still being used. I did get the bike to start up relatively easy after cleaning the carb and adding a fuel filter. I did have to drill through one of the petcocks plastic inserts because it was siezed closed. I added gear lube too. After further inspecting and starting the bike here and there without running it for very long...10-15 seconds at the most I've noticed a few things:

1. The exhaust spit oil. Took out the flame arrestor and the packing was saturated with oil. I'm sure it had been that way. Cleaned and repacked.

2. Was getting fuel out of the air vent tube. Calibrated float and will be ordering new valve and seat.

3. Gear lube must of gotten fuel and air that could have been from fuel getting into crankcase from valve not working correctly or shutting off petcock. Lube is now sudsy with a lighter color.

Guess my question is if fuel/air got into the gear case would that indicate that I need to replace some seals? Would it only be a problem if I had gotten fuel in my crank from faulty float valve and or petcock not being closed? Once it does get by the seal is it a done deal? Dale D. had previously given me some good information on how the float system works. Just wondering if I have bigger issues then I realize. Thanks in advance.

[viclioce]

Pretty good indicator. Seals that old can't be anything but dry and possibly cracking by now! If it's your intent to ride it regularly, I would replace the seals, bearings and bushings. ; D Victor

[Dale]

Shaun,
I will give my 2 cents. Hopefully others will offer advice too. Generally speaking, seals as old as these should be changed out regardless as they will have hardened. The issue with fuel in the oil will not hurt the seals however. You just need an oil change. The bike holds 20 ounces but you can only get about 16oz out via the drain plug. Removal of the clutch cover will allow the remaining oil to be drained. Use a good motorcycle gear lube rated for wet clutches. There are many choices. Many use Bel-Ray 80W Gear Saver.

Regarding the seals, there is only one that is critical to the survival of the motor. That is the left side crank seal. Failure of this seal typically means piston siezure. Other seals mean excessive oil and will let you know when they have failed by either excessive smoke or an oil leak
And the good news is that the left crank seal can be changed without splitting the cases. You would need a puller but it is a job no tougher than the carburetor work that you have already performed.
Dale

[thrownchain]

I wouldn't get any deeper at this point than to change to fresh oil. Oil over time will gather water and when run gets that "milky" look to it. Change it and then run it for a while, if it milkys up again, then look to other issues.

[hodakamax]

Gear lube contamination by fuel probably would be the right side seal, but lighter foamy gear oil sounds more like water in the oil. After long periods of storage condensation can build up in the gearbox and cause the light colored foam you are talking about. I would change the gear lube and see if it persists. As for the seals they probably do need to be changed after 20-30 years. Changing the seals requires splitting the cases but Is not rocket science stuff and seals aren't that expensive. Also a good time to check bearings and such. As I always say "It's part of the Hodaka experience."

Max

PS--I guess I type too slow, I see that others have responded while I was typing/thinking. Looks like we all agree which is par for the course.

[socalhodaka]

From your local bearing shop

Seals PC type Dubl lip
R-crank 47mm/25/7
L-crank 30mm/20/7
Counter 38mm/25/5

Bearings C-3 type
6304 - 1
6204 - 2
6203 - 1

[sbraatz3]

Hey guys,

As far as the gear lube goes, I had taken the cover off originally and emptied it all before I filled back up. So everything in there was new. I will repeat the process once I get the petcock fixed and new float valve assy. So I'm pretty sure any intrusion would have been fuel since I haven't had it outside or rode on it yet.

I did do a compression test or what I thought was a compression test. Would that indicate a bad seal that were talking about? Also when I did it, I got a reading of about 155 - 170 after kicking it like 10 - 15 times. Not sure if that is the right way. How many times do you want to kick it? Does the it matter?

Other then that I'm enjoying the "Hodaka experience" My wife thinks I've left her though. Thanks for all the imput!

[thrownchain]

Did the oil you drain out smell like gas? You'd have to flow a lot of fuel to contaminate the gear case oil. Your poundages look good for compression. Kick multiple times with the throttle full open? You can do a complete motor freshen in a weekend, but I don't see the need at the moment.

[sbraatz3]

I did perform a smell test but I don't have the greatest olfactory system. I will hold off on any motor work until I get the carb parts and petcock, then refill gear lube. I could have had enough fuel get by the carb if he float valve wasn't working good. I didn't have a ton of fuel in the tank but I also didn't have it shutoff completely because of that broken petcock.

I know this could be a loaded question also, but what fuel mixture would I use for conservative to moderate riding? The manual says 16:1, gas cap says 20:1. I know guys run them leaner then that now.

[Dale]

Yes, it is a loaded question... but I am not afraid to give what I run. Especially since it was a recommendation from Harry Taylor. Yamalube 2R mixed at 32:1.

There are a ton of good choices, but I think this choice is a good one.
Dale

P.S. Any chance that your wife can ride a motorcycle? If so, let her take it for a spin and she will be hooked too. Worked for me...

[sbraatz3]

My wife riding a motorized bike.....that would be like Obama flying air force one. . Not getting political though!

[Bullfrog]

You have completed a compression test, and the results sound fine. But that test doesn't tell you anything about the condition of the crankshaft seals.

It is important to know that a two-stroke engine MUST be air-tight. The only acceptable ways for air to enter or leave the engine are 1) through the carburetor or 2) out the exhaust. Doing a pressure test is the diagnostic test which will identify air leaks if they exist.

You can read up on doing a pressure test of your engine on this site. Go to the home page (see the menu option "Return to Strictly Hodaka") and search around for the Hot Tips. Then click on the one titled (inexplicably ) something like, "Build Your Own Mini-Buff". The first page concerns a Fuji engine . . . but the remaining pages tell you everything you wanted know about pressure testing but were afraid to ask.

Ed

[sbraatz3]

I just looked around for some different set ups for pressure testing. I think I'll invest in those parts so do this periodically. Thanks for guiding me in the right direction.

[sbraatz3]

So I hooked up a pressure tester that I made tonight and my results were that at about 6psi the air started come through some sort of stud looking vent off of the crank cast I believe. Then between 5-4 psi it would hold pretty steady. Is this what I should expect to see?

[dcooke007]

If air is coming out the crankcase breather that is not normal and indicates an air leak. The right crank seal may be leaking or the sealer applied between the two cases may have failed.....also a cracked engine case is possible.

Item 19 pictured in the link below is the breather I think you are referring to.

http://www.strictlyhodaka.com/Parts-List-B-s/2142.htm

Danny

[thrownchain]

How much pressure does it take to overflow a seal? He says it'll hold at 5 lbs, but leak at 6. Where is the limit? ED?

[sbraatz3]

Yes, that is the breather I was referring to. So any ideas to where I should go from here? Is this a red light not to run the bike?

[Bullfrog]

Start the test at 6 psi. Leakage must be less than 1 psi per minute. So if it takes less than 60 seconds for the pressure to drop from 6 to 5psi . . . that would be a failed test.

NOTE: There are Hodaka tuners/engine builders who won't accept anything less than 9psi with NO leakage for 10 minutes. But I'm comfortable with the published specification (6 psi, less than 1psi pressure loss in 1 minute). However, I also like to do a vacuum test. Unfortunately, I can't remember the specification for the vacuum test. The purpose of the vacuum test is to ASSURE that the crank seals actually "seal" in the "other" direction too.
Ed

[sbraatz3]

As soon as it gets to six it leaks out the breather until 5. Then from there it takes about 2-3 minutes to drop from 5-4 psi. I guess I need to replace some seals? Which ones is the question. Is it going to hurt the bike to run it the way it is?

[Bullfrog]

If you lay the bike on its side, you can remove the clutch cover and clutch. Then you can watch for bubbles coming up thru the oil in the main bearing. Bubbles there would confirm that the crank seal is not holding the required pressure - and needs to be replaced.

Your test results yell out for finding the leak and fixing it. It is my strong belief that the clutch side crank seal is at fault, since a leak between the cases is unlikely to "seal up" a bit at lower pressures - whereas a bit of remaining flexibility in a seal lip might do that.

Complete failure of the seal is coming soon, diagnostic starts in the shop (to check clutch operation for example) aren't likely to cause damage. But the engine is not going to run well till the leak is fixed. While the risk of seizure is lower with a clutch side seal failure than with a magneto side seal failure, there still IS that risk . . . so I would surely recommend that you bite bullet and fix it now.
Ed

[sbraatz3]

Sounds like I'll be splitting the case if that is the problem. Once I do that is there anything else I should replace while it's apart? Uggghhh!

[sbraatz3]

That probably also explains why when I would run it for a few seconds the gear lube would look very aerated for a lack of a better way put it. Probably not so much fuel getting into it but air. It's all starting to make sense now.

[taber hodaka]

The use of some gear oil in the old days would foam. But if you changed the oil to a good standard it should not be foaming.
Clarence

[Bullfrog]

sbraatz3,
I forgot to mention how impressed I was that you read up on pressure testing, threw together the necessary items to do a proper pressure test and did the test in about a day! I have all the stuff needed to do a pressure test . . . but probably couldn't pull the stuff together in one place in a week. It seems apparent that you can pull off a complete re-build on a Hodie engine quite well. While I can understand the lack of excitement about the mechanical issues which are getting in the way of actually riding your scooter, you'll find the re-build to be interesting (and actually, pretty easy) . . . and you will KNOW the condition of the engine when you get done. Hang in there, things will work out fine.
Ed
PS: Replace all seals and ball bearings - also O-rings (they are just as old as the seals).

[sbraatz3]

Thanks Ed, when I put my mind to something I can easily become obsessed. Did I mention I like to fish! Lol. Quick question though, after looking at the schematic the breather is located on the inside of the crank where the crank seal is also. So if it's hissing out that breather then the crank seal wouldn't be the problem? After doing some reading, it seems that hissing out the crankcase breather is indicative of bad ring(s). WHICH RINGS? Cylinder? Does this make sense to you? Either way it looks like I have a project.