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SL350s

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Well if you don't want to spend a bunch of money - which is not necessarily. (I agree with your buddy)

Clean the carbon off combustion chamber of heads (scotch bright soft wire brush etc.) - with the head right side up, spray some WD40 in the ports (intake and exhaust) to slightly puddle on top of the valves - let sit for 15min (do not turn over) then raise it up and look under it at the combustion side (with out turning it over - so the WD doesn't spill out)
If the valves are not leaking through then leave alone.

Run a hone through the cylinders to scuff up the walls (so new rings will seat correctly) clean any carbon from piston ring grooves and install new rings.

Then ride it.
Save the money toward your higher taxes in 2013!
Or invest in ammo as it's values are rising faster than gold these days :eek2:
 
I would clean the carbon off, check the ring end gap and check all the valves for minor leakage. As long as you have it apart you may as well freshen it up. It's getting pretty close to min spec on compression.
 
When I first bought this engine in April I poured a little Marvel Mystery oil into the cylinder. Now that it is apart and time to de-carbon the piston, the carbon wipes right off. The MMO did its job.
 
Another bump in the road. I am removing the pistons and the first came out easily after I removed one clip. On the second piston I took off both clips but can not slide the piston pin out. I want to take the cylinder and BOTH pistons to the shop.

To add a little to my curiousity, the pistons are different. One has ART stenciled into the side. It also has what looks like a ding in the top of it. That one came out easily. I used the piston pin that came out easily to drive out the other - no dice. Plus, the slide I can't get out does move about a 1/2". Any ideas - use a punch? I don't want lateral force on the crankshaft, it is not made for that.



The problem is #5 in the following fiche:

http://www.bikebandit.com/houseofmotorcycles/1971-honda-motosport-350-sl350k1/o/m151892#sch397158
 
A short section of pipe slightly longer and with slightly larger I.D. than the pin's O.D., A section of allthread rod that will slip through the pin, and about 3x as long as the pin, a pair of nuts for the allthread rod, one small and one large flat washers.

Slip allthread through the pin, slip on the small washer and a nut.

Slip the pipe over the other end, with the large washer and the other nut.

start tightening the nut at the large washer, and it should draw the pin out of the piston and into the pipe.
 
Thanks grandpaul. I got anxious and used a center punch. Not too much whacking since it was not frozen. I first sprayed it with penetrating oil (L. Wrench) and the diameter allowed it to slide into the wrist pin and get snug but not too large at the end to block it.

I had tried a socket and that failed. Having a nice set of different sized punches is nice. One thing about being an old fart is that I have accumulated SOME tools!

Thanks for the help.

Taking these apart is a bit of detective work. Once removed, I found BOTH pistons have ART on them. At the bottom of one piston are vertical scratches. Same for along the inside of the camchain slot in the block. Since the camchain appears in good but not new shape, and that one of the piston has a kick on top, I am betting this already had catastrophic failure on the camchain and that the tensioner has been replaced. The valves are on the bench testing for leakdown and I have the block and both pistons, rings attached, ready for the machine shop (after the hangovers).

Happy New Year!
 
Today I am having problems with getting an old gasket off a head. I have been using a blade from an exacto knife.

8338528525_98a37115fa_n.jpg


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I need to take it to the shop since it failed a leakdown test, do I need to even bother with the razor if they are going to do a valve job anyway? Should I de-carbon these myself if they are going to have it anyway? What should I do BEFORE taking it in tomorrow?
 
Took the block to Plano Power equipment and he suggested going + .5 over (+2). There were some scratches in the bottom of the cylinder.

Time to order pistons and rings.

I am still trying to get the old gasket off the head. Instead of taking it in today, I let it soak in goo-gone overnight. Today I will try a little heat and then use the exacto razor blades. Still looking for suggestions (see photo above).
 
SL350 said:
Took the block to Plano Power equipment and he suggested going + .5 over (+2). There were some scratches in the bottom of the cylinder.

Time to order pistons and rings.

I am still trying to get the old gasket off the head. Instead of taking it in today, I let it soak in goo-gone overnight. Today I will try a little heat and then use the exacto razor blades. Still looking for suggestions (see photo above).
Click to expand...

A stiff putty knife,a dremil tool with small wire wheel but you have to be really careful not to cut into the aluminum. I have used WD40 to soak gaskets in to make them softer and easier to remove. Even a pocket knife or screw driver with a wide blade just extra caution needs to be taken so no nicks are put in the gasket surface. If you use a something to soften it may be the best advice. Drew
 
plastic brush wheels for die grinder work well without removing metal material.
if your real careful you can use scotch brite wheels, but it will remove metal
 
I have just about decided to give up on cleaning the head. There are too many knicks where I have gouged the head with the razor and my knife. Going any further just looks like more damage and more oil leaks in the future. I tried a hair dryer and a different knife but it looks like money is the best tool.
 
Just spend an hour driving from hardware store to hardware store looking for allen heads to complete the sets ordered from eBay. The last two kits were missing and other just plain the wrong size. Both sets missed on the hardest to find, the m6.0X75 1.0. Nor can I find it at the hardware stores. Crud. Half and Half on the side covers and that long one is critical cause it holds the clutch mechanism. Either way, I put some anti-seize on the old phillips and back in they go. I used to get good kits from Burks but he disappeared about 3 years ago.

Pistons and rings are here. Time to drive to PLano and drop off the head and check on the valves.
 
I just bought the permatex copper gasket sealer. Looks like another run to the store!

Another problem, I just can't get the seal behind the sprocket off. With 2 of 3 seals complete, it is just killing me to get this off.

8366541424_0aa7c3b5b9_n.jpg
 
The seal should never have been touched. It will need the cases split to replace the oil seal that was only damaged because I tried to remove it. Cases splitting adds another whole can of worms to what was originally a camchain tensioner replacement. Now it is camchain tensioner, new valve job, bore and hone + pistons and rings, AND complete disassembly.

I am already looking for more table space. The lower unit is also dirty so I will have to do that too.

This was engine #2. Earlier in the thread I spoke about working on another sl350 engine with a stuck piston. It is still there on the garage floor. I might try to learn with it before I open the bottom of this one. I tried everything but max heat on it to free the stuck piston. I tried every concoction of oils, acetone, and penetrating solutions along with a hefty amount of beating on it with no success. The only thing I have found left to try after scouring the internet is to fill the cylinder with kerosene or diesel and some MMO and set it on fire.

If you see smoke coming from North Mesquite, think stuck piston.
 
A follow up on the two sl350 engines being overhauled.

The bum sprocket seal is ready to split the cases. All case screws, clutch and oil filter, shift shaft and other do-dads are all removed. Tomorrow I will try to separate the top case from the bottom. No clue what to do even with the manual.

The other 350 engine with the stuck piston - well it was used as a bbq for a fellow TWT member and I. We filled the cylinder with a little MMO and the rest with kerosene. The we let it burn. I had read several threads about doing this to unstick a rusted in place piston. Here it is:

8394335964_cb2b7b98bc_m.jpg


hot dog was um um good. piston still stuck.
 
Three more fires later, it is still 100% seized. It has soaked for 9 months, hammered 1000 times, and been set on fire 4 times. What next? Another fire of course.
 
The seal should never have been touched. It will need the cases split to replace the oil seal that was only damaged because I tried to remove it. Cases splitting adds another whole can of worms to what was originally a camchain tensioner replacement. Now it is camchain tensioner, new valve job, bore and hone + pistons and rings, AND complete disassembly.


I have seen seals removed by drilling a couple of small holes in the seal and installing long screws then using a slide hammer action to pull the seal using the screws to pull it out. This only works if you have enough room between the housing and the shaft to drill the holes. Not sure if explanation is clear but it might be worth a try.
 
LPDOIN said:
I have seen seals removed by drilling a couple of small holes in the seal and installing long screws then using a slide hammer action to pull the seal using the screws to pull it out. This only works if you have enough room between the housing and the shaft to drill the holes. Not sure if explanation is clear but it might be worth a try.
Click to expand...

I have done that method. Used it for the one on the clutch rod. The one on the 350 behind the sprocket is different than any I have ever done. It has a "bump' on the diameter and that makes it larger than the hole so it can't slide out.

The cases are open today and I have already replaced the oil seal. Tomorrow I will look it over and then seal it with Suzuki bond.
 
A bit of success today. The seized motor is free. After 9 month of soaking, 5 fires, and numerous hammer blows, she came free this morning. I had mixed coleman fuel and MMO and burned it until it went out and then burned the same again immediately. Before it cooled down I hammered on a wood 2x2 and eventually used the hammer itself, striking and damaging the jugs multiple times and probably destroying it (if it was any good anyway, who knows). Now the crankshaft, gears and case will live on either as a rebuilt motor with another jug or as needed parts for someone else's SL. Really, this is a hobby and if someone needs a crank, you missed buying them from Honda 20 years ago at $800 each.

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The other engine that I am rebuilding is ready for drop off with new pistons at Plano Equipment.
 
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SL350 said:
A follow up on the two sl350 engines being overhauled.

The bum sprocket seal is ready to split the cases. All case screws, clutch and oil filter, shift shaft and other do-dads are all removed. Tomorrow I will try to separate the top case from the bottom. No clue what to do even with the manual.

The other 350 engine with the stuck piston - well it was used as a bbq for a fellow TWT member and I. We filled the cylinder with a little MMO and the rest with kerosene. The we let it burn. I had read several threads about doing this to unstick a rusted in place piston. Here it is:

8394335964_cb2b7b98bc_m.jpg


hot dog was um um good. piston still stuck.
Click to expand...

Thats the funniest thing I've seen on here in awhile. Have you tried to cook sausage or hamburgers yet on it? Could be a new type BBQ pit for motorcyclists. You may have to patent it before the idea gets away. Remember me when you do your info-mercial for the new MC BBQ pit. Drew
 
The formerly seized engine is abandoned for now. It is for parts if needed and it looks like that is not needed.

The engine being rebuilt is coming along. Over the weekend I put the upper and lower cases back together. They took a real long time until someone told me that you have to do it upside down. That tip was not in any manual and not in dozens of internet "here is how I did it". Once the suzuki bond was applied, I managed to get the two cases back together.

After that it was time to assemble all the gizmos that I had to take off before I could split the cases to replace the seal behind the sprocket. That include the shift shaft, clutch, oil pump, generator and both side cases. The lower unit is done and I await the call from PLano Power Equipment with my bored cylinders and valve job.

I did steal the generator from the siezed engine since it had a good connector.

Still have not decided on whether to use the engine in my original SL350 or to put it back in its frame and make a bike with a single seat and a big luggage rack like my ct90. I need a single seat and some kind of bracket to mount that on my frame.
 
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