1971 SL350

Scootman said:
Completely unjustifiable for bikes that don't even cost $1100 to obtain!!
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Absolutely agree, but until people stop paying their prices they will continue to charge them. I'd be curious to know how much NOS prices went up during the last 2 years, considering the prices on practically everything else in our world went up significantly. Wouldn't surprise me they saw the opportunity and did the same thing for parts they already had money in long before.
 
It's a bit discouraging for sure, especially when your just looking to fix what you can afford and trying not to sweat the rest. Truthfully, what aggravates me more than the cost of a NOS camshaft is the half dozen or so used camshafts on ebay that are either pitted and scored or you just can't tell the condition at all.

Anyway, for the time being, I've got the cylinder head off to Schumann's to get some attention. I've also ordered new pistons and rings, and can get the boring done locally. I'm thinking my next step for me is to mic the existing cam and the rocker pins and take some time to figure out just how much I want to invest in the top end work considering all the other needs. There is lots of time to do some research while I'm cleaning up parts.
 
Juneaudave said:
Anyway, for the time being, I've got the cylinder head off to Schumann's to get some attention. I've also ordered new pistons and rings, and can get the boring done locally. I'm thinking my next step for me is to mic the existing cam and the rocker pins and take some time to figure out just how much I want to invest in the top end work considering all the other needs. There is lots of time to do some research while I'm cleaning up parts.
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At least there are still some decent values out there, like getting the head professionally done by a very competent guy at a fair price. The struggle to find affordable new or used parts will continue, that's for sure.
 
Idler gear day...I pulled the clutch and odds and ends to take a look at the idler gear. The video shows the movement, while the pictures show the visul condition of the bushing. The bushings don't look too bad to me, but obviously there is quite a bit of movement on the shaft.

I was talking online to another hobyist/mechanic and he indicated that even with a new bushing, you should see some movement. (Hummm) He indicated that he liked to use shims to reduce the amount of lateral movement, and was sending me some of the correct shims to use.

What's the thought on this...rebush such that the idler gear is tighter on the shaft? try the shims and see how that looks?

Is there a way to measure such that you can say this amount movement is ok, this amount of movement isn't?

Thoughts....


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Rebushing is one way to go but you might PM Jays100 and ask about the gears he's getting made.
The actual problem IMO is the keyway in the shaft. The end of it aligns with the oiling port on the other side so any pressure built there is bled off. My solution is to fill the keyway leaving just enough room that the keyed thrust washer will fit with the circlip. Polished on the bearing surface and now the pressure should be as good as it will ever be.
 
Juneaudave said:
. . . Is there a way to measure such that you can say this amount movement is ok, this amount of movement isn't?

Thoughts....
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I don't have an FSM that covers your bike, but you probably do have. The manual is usually good about providing inspection data, such as the min/max diameter specs for when the shaft was produced, and the same for the bush in the gear center. Then they will typically tell the minimum size for the shaft before it should be
replaced, and the maximum size for the bushing bore before it should be replaced. In my FSM, they don't give inspection data for the kickstart shaft (which is different from yours). All they say is to inspect it and replace parts if they are too worn. However, they do provide inspection data for similar parts in the transmission.

The best way to inspect your parts to see if there is too much wear is to measure the bushing's internal diameter and the shaft's outside diameter and subtract the difference. The FSM will have data like this for transmission shafts and gears.

One precaution is that you should see if your kickstart shaft is necked down in the spot where the gear was running. If so, you may need to rework (or replace) both the shaft and the gear bush. Otherwise, if you redo the bush to make it fit the reduced diameter of the shaft, you may not be able to slide it over the larger end of the shaft. Hope that makes sense.

Another thing to keep in mind is that as you press fit a new bush into the gear, the inner bore will close in a couple of thousandths of an inch. You should probably wait to finish size the inner bore diameter until the bush is pressed into the gear.

BTW: LDR, you can add the SL350 K0 camshaft to the group of those that have the groove. I don't have a picture for you yet, but you can take my word for it for now.

Ray
 
LongDistanceRider said:
Rebushing is one way to go but you might PM Jays100 and ask about the gears he's getting made.
The actual problem IMO is the keyway in the shaft. The end of it aligns with the oiling port on the other side so any pressure built there is bled off. My solution is to fill the keyway leaving just enough room that the keyed thrust washer will fit with the circlip. Polished on the bearing surface and now the pressure should be as good as it will ever be.
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I PM'd Jay....Sounds promising, maybe this spring for production. Meanwhile, pending any new information, I think I will see what those shims do for me and get some costs locally to rebush the one I have.
 
fxray said:
I don't have an FSM that covers your bike, but you probably do have. The manual is usually good about providing inspection data, such as the min/max diameter specs for when the shaft was produced, and the same for the bush in the gear center. Then they will typically tell the minimum size for the shaft before it should be
replaced, and the maximum size for the bushing bore before it should be replaced. In my FSM, they don't give inspection data for the kickstart shaft (which is different from yours). All they say is to inspect it and replace parts if they are too worn. However, they do provide inspection data for similar parts in the transmission.

The best way to inspect your parts to see if there is too much wear is to measure the bushing's internal diameter and the shaft's outside diameter and subtract the difference. The FSM will have data like this for transmission shafts and gears.

One precaution is that you should see if your kickstart shaft is necked down in the spot where the gear was running. If so, you may need to rework (or replace) both the shaft and the gear bush. Otherwise, if you redo the bush to make it fit the reduced diameter of the shaft, you may not be able to slide it over the larger end of the shaft. Hope that makes sense.

Another thing to keep in mind is that as you press fit a new bush into the gear, the inner bore will close in a couple of thousandths of an inch. You should probably wait to finish size the inner bore diameter until the bush is pressed into the gear.

BTW: LDR, you can add the SL350 K0 camshaft to the group of those that have the groove. I don't have a picture for you yet, but you can take my word for it for now.

Ray
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I've looked thru the SL350K1/2 Shop Manual and it doesn't have any specs for the idler gear. Refers you back to the FSM for 350's.
Ray: the K1/2 uses a different kickstarter system, you can kick start in gear since it engages the clutch basket, unlike the SL350K0 which is essentially a CB/CL350 engine.
The K0 also uses the same identical cam as the CB/CL engines so I think a PO swapped cams on your engine.
 
LongDistanceRider said:
I've looked thru the SL350K1/2 Shop Manual and it doesn't have any specs for the idler gear. Refers you back to the FSM for 350's.
Ray: the K1/2 uses a different kickstarter system, you can kick start in gear since it engages the clutch basket, unlike the SL350K0 which is essentially a CB/CL350 engine.
The K0 also uses the same identical cam as the CB/CL engines so I think a PO swapped cams on your engine.
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Jim, I understand the differences in the kick starters from the SL350K0 to the K1/2. If your FSM that extends through the K1/K2 bikes simply refers the user back to the regular CB/CL350, we may be looking at the same book.

My point was that, absent the usability guidelines for the kick starter idler and its shaft, Dave could still measure his parts, calculate the diametral difference, and look at the usability guidelines that are provided for transmission gears. Honda would have had similar engineering standards for those, which are simply gears freewheeling and/or sliding on a shaft. For example:



They designed fourth and top gears to have ,0008" to .002" clearance. Although they did not provide the maximum clearance before replacement, it would be safe to say that if it exceeds 1 1/2 times the standard, it needs work.

Similarly, they called out ,0008" to .002" clearance for low gear, and a range of .0016" to .003" for second and third gear.

I realize that these are not specs for the K1/K2 kick start idler fit-up to its shaft, but it gives an idea of what Honda thought was acceptable for similar applications. It is probably better than a wild guess.

You could say I am comparing apples to oranges, but I think I am zeroed in closer than that -- maybe more like oranges to tangerines.
:lol:

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In regard to my K0 camshaft with the groove on the end, I would not swear in court that it has never been changed out, but I will say that I am at least 95% sure it is original. A friend of mine bought this bike as a complete but very rough barn find. He tore it down and put it into boxes, but lost interest before he ever went so far as to buy any replacements, whether new or used. I inherited the contents of those boxes.

The FSM I am using is the CB250-CL250-CB350-CL350 FSM, which also includes a supplement to cover the newly released (back then) SL350 K0 model. I think I got this manual from you about 10 years ago, so you probably know the book I am talking about. The SL350 supplement lists nothing specific about the camshaft. It refers the user to the data in the main CB/CL section. My cam agrees closely with the base circle and lift dimensions provided for the CB/CL camshaft, yet my cam does have the groove on the end. Here is a picture for you:

 
The above ^^^ pic looks the same as a fat boy groove cam from my collection.

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I swear we're going to figure this stuff out on all the camshafts:lol:
Partzilla and CMSNL both agree that the KO used the 050 cam up to engine # 1026008 and then the 060 or 070 from 1026009. Here's the picture of the 050 and 070 cams
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Your picture is showing a fat cam which makes it and 040 or earlier. Damien, aka ausman1000, posted a picture of the odd ball cam he has that has a groove and an almost fat cam body which I think is a K1/2.
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I will be getting more info in a few days, Dave just bought an NOS K1 cam that he's going to send me so I can get a master made at Oregon Cam. We'll know then what's what I think.

@10 years ago? Wow, I didn't realize I've been collecting FSM's and such for that long. Time flies when you're having fun.
 
LongDistanceRider said:
. . . Partzilla and CMSNL both agree that the KO used the 050 cam up to engine # 1026008 and then the 060 or 070 from 1026009.
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With apologies to Juneaudave as we continue to trample on his thread, and Merry Christmas to you all, here is some more SL350 K0 cam information.

My S/N is more than 8,600 units below the 1026008 break point mentioned by Partzilla and CMSNL. The picture I posted earlier of my camshaft was only intended to show the groove that you have been discussing. Here are some pictures of the whole thing:









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A question for Dave: As you are making your decision on how to proceed with your rockers, and perhaps your cam, with your SL350 K1, how did you handle that on your CL350 K4?

As I look back to when I was working on my CL350 K3, I remember all the things I was cautioned about that I decided to ignore. Things like:


  • That cam has some pits, and those lifters have some wear. They will fail in no time.
  • Those cylinder head covers (cam bearing blocks) are right at their wear limit and should be replaced.
  • Piston rings are cheap and they are wear items that really should be replaced, not reused.

At this point, my CL350 has run up close to 12,000 miles since I reused the old parts and is still going strong. The valves never go out of adjustment; the engine doesn't smoke or use oil; it starts and runs great. I'm happy with it, especially after reading about all the woes with the cam and rocker regrinders.
 
fxray said:
A question for Dave: As you are making your decision on how to proceed with your rockers, and perhaps your cam, with your SL350 K1, how did you handle that on your CL350 K4?

As I look back to when I was working on my CL350 K3, I remember all the things I was cautioned about that I decided to ignore. Things like:


  • That cam has some pits, and those lifters have some wear. They will fail in no time.
  • Those cylinder head covers (cam bearing blocks) are right at their wear limit and should be replaced.
  • Piston rings are cheap and they are wear items that really should be replaced, not reused.

At this point, my CL350 has run up close to 12,000 miles since I reused the old parts and is still going strong. The valves never go out of adjustment; the engine doesn't smoke or use oil; it starts and runs great. I'm happy with it, especially after reading about all the woes with the cam and rocker regrinders.
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The CL350 K4 only had 3.5 K on it and had been sitting 30 years. It had compression issues related to frozen rings. On that bike, the cam, rockers and valves were in great shape so it only got a cylinder honing, new rings and a new cam chain tensioner. I also replaced seals and such on the engine as I went through it getting it cleaned up. I won't tear into the engine again unless compression drops or something breaks.

On the CL this winter, I changed the oil, pulled the battery, and put on new sprockets and a chain when I parked it. I still intend to pull the exhaust so I can replace the air filters and clean the carbs when I get to it. Hopefully it will be ready to go even if I don't fininh the SL.

I have received a lot of help and sound advice from everyone on the board.
 
I've been spending the last couple days cleaning the upper and lower cases, along with the hated clutch/front sprocket area. On this bike, the upper case was clear coated from the factory but half of the clear was missing and the rest was yellowed and nasty so I stripped it off. The lower case was not cleared. As you can see, there is still a lot of elbow work to do.....

Anyway, the plan for this bike is to paint the cases that were originally painted silver, and leave the crank cases and cam covers in bare aluminum. Any thoughts on clear coating that top case like it was originally? Or should I just leave it.... Part of me thinks clear is the way to go, but I would think the bare aluminum would be fine and easy to clean...

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If you clear coat then you need an epoxy type clear so when the cabs leak the gas doesn't ruin the clear.
If you leave it raw then you need to clean/power wash the engine on a regular basis to wash off anything that will set up corrosion.
Kind of a damned if you do and damned if you don't
 
Looks like it is coming up nicely. I'm not a fan of clear coating aluminum. In my experience it just doesn't corrode nearly as fast as some people think. An occasional light polish keeps it looking good.

For the lower crankcase, I once read that the alloy used there responds well to a steel wire brush. I found that to be true. Here is the lower case from my SL350 that I did this summer with a variety of steel wire brushes in a hand drill. It is fairly quick and easy. You can wail on it with no damage.

The drain plug and all the case hardware I bead blasted and replated with zinc.



 
There were a couple of thoughts and questions earlier, I thought I'd jump into the fray.

-Hardface weld repair rods are Stellite - or should be! That facing is better than the hard chrome from OEM. However, Stellite is not quite as hard as the chrome but an excellent wear coupling to the cam. If you need exact numbers, let me know. But for me, I'd have followers reworked rather than finding NOS as the rework is a definite improvement. I'm looking for a hardness difference of 15-20 pts on the Rockwell "C" scale as minimum for good wear characteristics. My opinion anyway.

-SL350 kickstart idler gears have been designed and detailed, i just have some other/additional gears to buy and was waiting to stack up orders for a better pricing. both for production and shipping. Lately shipping is a horrible impact so am working towards a best way. Ideally i'd like to find a domestic supplier but so far, one gear locally is more than the target retail price so finding a cost v. quality supplier has been difficult. The new gears will be through hardened SAE4140 with a bronze bushing, as is OEM. Core toughness will be better than the OEM cast gears. as noted above, looking for late 1Q23 availability.
 
Long time between posts but I have been working. I'm planning on this bike having minimal polish, with the cases painted and/or clean aluminum and just the oil filter and stator covers polished. But it's got alot of patina to clean up...here's before and after...

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I found a crack on the chain protector while getting it ready for paint. I drilled a hole at the end of the crack before welding but I'm afraid the crack has extended too far at this point. Hopefully the repair will last but the chain protector must have had some stress to on it to crack like that so I'm not so sure.

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It's a stress cracked caused by being unsupported and hanging free. Poor design. If Honda had extended the 2 stress reliefs further down the plate it wouldn't do that but then again they didn't figure that 50 years later thee would still be around.
 
I was cleaning the swing arm this morning and found one of the collars deeply scored. Im thinking it might be a good idea to replace both the bushings and the collars. Any luck with the bronze ones sold on ebay? Can't imagine reusing this collar....


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Looks like the CBX pricing is good so I'll go ahead and order the bushings! Still hard to believe that collar scored like that but it eems par for the course with this bike though...
 
Working on rims and tires today amd have a question about SL350 rim locks.... The parts diagrams from CMS shows a part (#13) but doesn't list anything in the part listing. https://images.cmsnl.com/img/partslists/honda-sl350k1-usa-f-13-rear-wheel_big3IMG01172154_9aab.gif


Is part #13 a rubber grommet that originally went on the rim lock to seal out water? If so, I'm guessing I could substitute a neoprene washer. Anyway, this bike did not have rubber grommets on the rim locks...and the back rim has more rust inside than I would have expected...
 
Actually, it looks like #12 is the one not listed and may be a sealing grommet or washer. I've dealt with rim locks a few times during my days at the shops and honestly don't recall any sealing washer or grommet, just the stud of the rim lock through the hole in the rim with a lock washer and nut on it. Unless you're really concerned about legitimacy in this build, save yourself the trouble and just leave out the rim lock. It's only necessary for when you want to lower the tire pressure to less than 10 lbs for traction purposes and I'm pretty sure you don't plan to run any muddy enduros.
 
ancientdad said:
Actually, it looks like #12 is the one not listed and may be a sealing grommet or washer. I've dealt with rim locks a few times during my days at the shops and honestly don't recall any sealing washer or grommet, just the stud of the rim lock through the hole in the rim with a lock washer and nut on it. Unless you're really concerned about legitimacy in this build, save yourself the trouble and just leave out the rim lock. It's only necessary for when you want to lower the tire pressure to less than 10 lbs for traction purposes and I'm pretty sure you don't plan to run any muddy enduros.
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I got the tire off pretty easy so I'm going to try to put them back in (at least till I ruin the first innertube and scratch up the rim wrestling with it). Would I need to plug the holes in the rim if I left the rim locks out?
 
Juneaudave said:
Would I need to plug the holes in the rim if I left the rim locks out?
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I've removed them when I was younger and didn't put anything over the hole other than the rim strip, but I suppose it wouldn't hurt to clean the rim and maybe put a strip of duct tape over the holes before the rim strip.
 
If I skip the rim locks, maybe that's a good wheel to put one of those self adhesive Motion Pro Rim Strips on. I've got it pretty much cleaned up from the rust but its not the finest rim in the world at this point. I did put a good coat of paste wax on the inside to try to protect it some.

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Are you kidding?? That rim looks like NOS compared to my 450 rims. :) I wire-brushed mine and used that rubberized spray flex-seal on the inside to help keep the rust at bay, yours looks great and you shouldn't have any problems.
 
I agree with AD - inside of the rim looks good!
I asked a question about the rim locks in the rebuild of my SL350K1…..in the end I left them out (taped up, internally, the holes).
Cheers
Mike
 
It took me awhile to get that rim cleaned up....wire brushed, then a round file to get in the corner, more wire brush (different size), dunk in Evaporust, scotchbrite pad, wire brush, nylon abrasive brush, wash and finally a coat of paste wax. I would skip the evaporust if I did it again as it turned the spokes black and I had to take Fritz polish to them individually to get them back to shiny. Whew... about a day and a half. I wasn't foolin...that rim was a mess but I did finally get it cleaned up.
 
I finally got the rear wheel together. I skipped putting the twin rim locks back on and used the rim hole plugs mentioned above. The plugs seemed to work great. I ended up getting the plugs off Amazon for around $8 and also a Motion Pro Rim Strip to fit. Everything went well except I initially put the tire on backwards after being real careful to mark the rotation of the tire with a grease pencil and checking it twice so that wouldn't happen. Then I took the tire off, reversed it and poked a hole in the tube while remounting. After getting a new tube, third time putting the tire on was the charm. You can see the plugs in the picture. Getting a little tired of this tire!

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Looks good. I can relate to getting absorbed in one thing only to double-check something else and still do it wrong. Stuff happens, and it's done right now (and without all the additional pain and suffering of rim lock exposure).
 
Story of the week: I was planning on painting my covers last week. I had a can of Duplicolor Caliper Silver (BCP103) that I had used on a previous bike that had worked well and looked nice, but because it was on the shelf for a couple years, I tossed it and bought a new can. After prepping the covers, I started to spray, and the paint simply separated and looked really blotchy. Darn....so I shook it up some more and tried another cover....same blotchy result. The only thing I could figure out was that maybe the paint can had frozen in a warehouse somewhere.

It took awhile to clean off the new old paint, and in the meantime, I ordered a can of Marbles Motors cover paint to give that a try. Marbles has such a strong following with the SL350 crowd, I figured "What could go wrong?"

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After the paint arrived, and looking at the can...the instructions threw me "Clear coat is optional but required" How could that be?

After a quick email and call....Chris from Marbles Motors promptly gave me a call back. Apparently the can was misprinted, and clear is not required.

They were real nice and were busy trying to find out how many cans they had sent out with misprinted lables. I'm looking forward to seeing the result.
 
I picked up the frame and swing arm from the blaster today. $120 total was the going rate locally @ $100/hour (seems like that has gone up too)... I'm hoping to to get some paint on it this weekend with Omni 170 epoxy primer, a coat of Marbles Cloud Silver frame paint and a coat of two part clear. The frame looks pretty good but for a couple areas I would like to do a little work on.

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Just a follow up on the Marbles Engine Cover Paint. It does spray very nicely, and is well pigmented. I used two very light coats on the case in the pictures and looking at it, thought that two light coats were sufficient. I think the color looks right also...

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Happy Days! I got my cylinder head back from Schumann Motor Works and it looks like new! And....LongDistanceRider got my cam back from Oregon Cam Grinding where Jim was having a master made. This will give us another shop to get SL350 K1 and K2 cams reconditioned. Thanks Jim for gettting that done and for the tee!

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