[TomSL]

Hello All,

I've been reading the great forum posts here for the last few months in order to educate myself. I have to say, the wealth of knowledge and experience here is amazing, and has really helped to make things easier for me so far. So thank you all for everything you share on the site!

When it finally started getting cooler here last weekend, I decided to get the engine out of my SL350. This is the only motorcycle I've owned, and I've never had it running, though I've owned it for a bit over two years now. Just been spending time acquiring missing parts and chasing electrical gremlins. Anyways, since my wife was out of town for the weekend, I hauled the engine into the living room, and broke open pandora's box to find:

1) Shredded tensioner wheels - I expected this, and have already purchased a KA Slipper, have not yet ordered a Tsubaki chain, but it's on the list.
1a) Improperly-installed timing chain guide opposite the shredded tensioner
2) Aluminum particles in the oil, a lot of aluminum - more on that later
3) Silicone gasket sealer had been used on pretty much every surface, including inside some oil passageways.
4) Some metric, some imperial hardware
5) Mildly rusty bores
6) Top end obviously starved of oil at some point in its life

I found that the camshaft had some heat discoloration, the tach-side bearing block is completely shot, and the tach-end of the cam has some really nice deep grooves in it (Improves oil retention?!?! ) I have yet to crack the case halves apart, on account of having found too many atrocities and now being fearful of what it might hold.

The big picture: I'd like to restore the bike and have it as a daily rider. I don't ever plan to use it on a race track, but it will be used on the occasional forest road tour up in the white or green mountains. Realistically, it won't often (if ever) see 10k RPM, or a jump, or speeds in excess of 70 mph. However, I'm not bound to sticking with stock stuff everywhere either, as long as the overall look is maintained. Primary goal is an engine for around town and in the woods that is as close as possible to infinitely reliable. I don't care much about weight or high HP/TQ or high revs.

My plan: Convert the cam to needle bearings, install Tsubaki chain and KA Slipper, have Bore Tech re-do the cylinders for me, new 65.5mm cast pistons, new gaskets, seals, and wear items, and then throw this all back together.

My Question: If the cam bearings on either end of the cam box are worn so badly that they wobble, can they still be converted to needle bearings? Or will this not-round-ness make it impossible for a machinist to correctly mount and line up the end pieces for machining? Do I need to buy new (NOS or lightly used) points and tach housings to supply for a machinist? Is anyone here on HondaTwins doing the machining for this conversion? I know RRR posted a little while back that he does it, but I'm on the wrong side of the pond. Captb seems to have done it for himself, but isn't in business for it.

I've read all the great posts from Outobie, RRR, and captb about needle bearing conversions, but I have limited knowledge of the processes, and no equipment, so I'll be farming it out to someone else. Thanks for all the info!

 

[J-T]

Welcome to the group.

Got any pictures?~

 

[captb]

I have my Roller Fat Cam (286) complete assembly I want to sell, it needs sent to Delta Cam for regrind and some rockers refinish, I'm running a 312 Roller until I finish building my #2 motor. I had to adj. valves about 4 times in 5k city miles, due to pitting. It ran cooler and revved nice with the roller bearings, engine was strong, it had pitting when I installed it but I figured I'd run it and send it another time and have Delta do a race grind.
Machined Roller bearings are perfect and are high grade with machined inner races and oil feed hole matching inner races on cam. I started with mint cam bearing ends, polished perfect and no leaks, tach drive has a new seal, cam runs true, cam end play .008 with no shims with oem gaskets, sprocket is mint. It has hardened thrust washers that run against the machined roller bearing cases no wear or end play change.
$185 shipped in the US for everything in the pics.
They're large pics click on them.

 

[TomSL]

J-T,
I do have pictures somewhere, but I believe they're on my other computer. Happy to upload them sometime over the weekend. Was planning to do a new member intro post prior to posting here, but couldn't track down the pictures I wanted to include.

captb,
That sounds great! If I understand correctly from the little bit of research I did this morning: My SL has the "skinny" cam box. A fat cam will fit in a skinny box without machining, but a skinny cam will not fit in a fat box without some reduction. If this is correct, I'd love to move forward with this. It would be great to be able to say parts of my engine were machined by a bunch vintage Honda nuts I met on the internet!!

 

[dtsmjr8dan]

Welcome to the forum.

 

[captb]

PM sent.

 

[captb]

Cam/rockers/bearing housings and sprocket ships Monday morning. Thanks

 

[TomSL]

Okay, That problem is resolved for the most part, just waiting for the mail man. Thanks captb! Here's some photos
The bike on its way to Boston from the Midwest:

In this photo, you can see the exhaust system I hacked together using the factory headers and some cheap black ebay mufflers. The previous owner had crappy, baffle-less mufflers right under the engine oil drain plug. I cut them off, and had a local shop weld these on. They should work for now, but my eventual plan is to get rid of them. I'll either replace them with a factory-type reproduction setup, or do a custom high-mount, scrambler style exhaust.

Engine Removed:

Disassembled:

Round one of cleaning done, as well as mating surface clean-up with 220-, then 320-, then 600-grit wet/dry sandpaper and a dribble of Rotella T.

and the pistons that came out:

The oil rings on both pistons broke when I tried to remove them.

Next question
Last time I had the side covers off, I checked the measurements of the oil pump orifice and piston. They did not match up with the factory manual that I have on hand. Perhaps this is because the factory manual references the older, narrower pump? What should the measurements be in these later SLs? This thread talks about the importance of correct clearances, and mentions "the manual" but he must be talking about a different manual, or mine has been altered.

Also
In this picture, you can see the difference between the two combustion chambers in the head. Any thoughts on whether I should have these machined out, or just replace the whole head? They appear to be pretty deep. This picture was taken after spending some time trying to sand the chamfer and clean it up. I'm wondering at this point if the right cylinder was run on water instead of fuel. The whole right side of this engine is TERRIBLE!!

 

[captb]

Your SL looks pretty good overall, looks like it all there.
The one piece oil rings suck, I would never run anything but the newer 3 piece.
The oil pump I just check for wear signs/scoring if it looks good I bench test it, just submerge the screen in oil and pump it, should pump pretty quick, after engine assembly remove oil test bolt rt side of points housing, start bike sitting upright, mine usually starts pulsing oil with a blip of the throttle, mine takes about 4 seconds, makes a mess. Use assembly lube on all cam parts incase it takes longer than about 10 seconds.
If you need a head I have a CB head (larger intake ports than SL K1/K2 it's what I run, ideal if you want to run VM30 carbs, the stock SL carbs are pretty much impossible to find needles/nozzles and other jetting parts for, not to help you spend money but if it's a keeper the VM30 carbs are gold once jetted in. I found my VM30 set on sale on Amazon for $150 shipped. All jetting stuff is easy to find. You can look thru my build pics for my set up.
You can have the bare head cheap $25 plus shipping.
Here's some head pics, I media blasted it, guides feel good, 1 side valve seats look very nice the other side some pits may need refaced/may be ok with valve grinding compound, threads all good, gasket surfaces good all CB/CL/SL head parts are the same.

 

[TomSL]

Thanks for the offer captb. I think I'll stick with mine for now and see if I can get things machined at school (Currently a grad student at BU). They have a really nice machining and rapid prototyping center here. 3D printers, all kinds of CNC goodies, just don't know what I can use and what it'll cost yet. I'd also like to keep the original carbs if possible, but I'm not sure how much of a displacement increase I can do without having problems with inadequate carbs. 65.5 mm pistons should add less than 20cc. 325.6cc to 341 cc is only a 4.73% displacement increase.

***This should be able to be handled with carb tuning, not replacement, right??***

I'm looking forward to getting the three-piece rings and new pistons. I have no idea how those rings would have gone on originally without fracture. Seemed to snap fairly easily.

I think for now, my plan is to have the intake and exhaust ports cleaned up. Overnight leakdown test was good, so just some valve clean up and lapping. Also, there was pretty significant pitting in the cylinders, especially on the right, and the cold, dry compression showed both cylinders at 120 psi +/- 3 each time it was tested. To me, all these symptoms point to good valves, bad cylinders. Feel free to chime in if you disagree, happy to have outside input.

At this time, given my budget and project goals, the most I'll do to the valve train is bronze guides and new seals. No desire to go to a kibblewhite system with 5mm stems and Ti bits . . . . yet Valves look ok, tops of valve stems don't seem overly worn, etc.

***Another question - I like the idea of better heat transfer and increased re-usability of copper gaskets. Bore-Tech offers one for the cam box, which I'll buy, but the head gasket they have is for a 67.5 mm forged piston. Can I use this with the 65.5 mm ones? it won't overhang obviously, but there will be a 1 mm gap all around.***

If you plan to follow this thread, many of my questions will be similar to the above. I've rebuilt car engines in the past, most frequently on my old SAAB, but never rebuilt a motorcycle engine, and never done any tuning or upgrades to engine internals, so I'm learning as I go.

Last question for today - Anybody know a good small engine machine shop in New England? Willing to travel to nearby states.

Thanks

 

[peejay]

One of the things I have learned about Japanese car and motorcycle engines (this probably applies to outboards, snowmobiles, generators and other power equipment, but don't know for sure) is that the valves have a hardened surface where they contact the valve seats and these valves should NEVER have any type of resurfacing or the layer of hardening can easily be penetrated or even removed rendering their effectiveness to zero. This will most likely lead to an extremely short life of the rebuild. Seats can be resurfaced, but if valves have issues, then best if you replace, best with new, but if unavailable, then what other option other than hoping for a GOOD used set.

 

[captb]

Thanks for the offer captb. I think I'll stick with mine for now and see if I can get things machined at school (Currently a grad student at BU). They have a really nice machining and rapid prototyping center here. 3D printers, all kinds of CNC goodies, just don't know what I can use and what it'll cost yet. I'd also like to keep the original carbs if possible, but I'm not sure how much of a displacement increase I can do without having problems with inadequate carbs. 65.5 mm pistons should add less than 20cc. 325.6cc to 341 cc is only a 4.73% displacement increase.

***This should be able to be handled with carb tuning, not replacement, right??***

I'm looking forward to getting the three-piece rings and new pistons. I have no idea how those rings would have gone on originally without fracture. Seemed to snap fairly easily.

I think for now, my plan is to have the intake and exhaust ports cleaned up. Overnight leakdown test was good, so just some valve clean up and lapping. Also, there was pretty significant pitting in the cylinders, especially on the right, and the cold, dry compression showed both cylinders at 120 psi +/- 3 each time it was tested. To me, all these symptoms point to good valves, bad cylinders. Feel free to chime in if you disagree, happy to have outside input.

At this time, given my budget and project goals, the most I'll do to the valve train is bronze guides and new seals. No desire to go to a kibblewhite system with 5mm stems and Ti bits . . . . yet Valves look ok, tops of valve stems don't seem overly worn, etc.

***Another question - I like the idea of better heat transfer and increased re-usability of copper gaskets. Bore-Tech offers one for the cam box, which I'll buy, but the head gasket they have is for a 67.5 mm forged piston. Can I use this with the 65.5 mm ones? it won't overhang obviously, but there will be a 1 mm gap all around.***

If you plan to follow this thread, many of my questions will be similar to the above. I've rebuilt car engines in the past, most frequently on my old SAAB, but never rebuilt a motorcycle engine, and never done any tuning or upgrades to engine internals, so I'm learning as I go.

Last question for today - Anybody know a good small engine machine shop in New England? Willing to travel to nearby states.

Thanks

You can find main jets, needle options no, I think I saw pilot jets when I was shopping around, probably go down one size on the mains, do some plug chops lean is not good.
The new 3 piece rings seal so much better, my engine runs clean.
If your running stock valve guides don't use valve stem seals they will wear guides quicker, as long as they're in spec they don't leak.
If the valves pass leak down test you should be good if no funny wear on seats or valves.
Cylinders sound pretty rough use Bore Tech recommendations for boring with they're pistons.
Ask bore Tech for head gasket recommendations for you, intended use of the bike.
Don't worry about splitting cases it's not bad but follow reassembly directions, it's more time checking stuff than work...other than cleaning the gunk out of the bottom.
Best of luck!

 

[TomSL]

Peejay,
Thanks for the input. I was not aware of that, but while on the phone with BoreTech today, he said the same thing without me even bringing it up. I suppose I'll be picking up some new Kibblewhite valves (stock size) when it's time to do the head work.

Here are some comparative photos of the combustion chambers in the head. Any thoughts from other HondaTwins members? I don't know how much machining I can get away with in these heads before I start having problems.

Left Chamber:


Right Chamber:


Did a bunch of calling around today to various machine shops. All the smaller local shops won't touch it because they're afraid of having to find parts. Looks like BoreTech will be getting more of my money than I planned! I had never looked into it before, but I learned today that BoreTech will do valve jobs and head work too. That works out well.

Thanks for the motivation, captb. I'll get into it over the coming weeks. Also, I've heard of inspecting the plugs, but I never really knew what a "plug chop" was. Google is a great teacher. Just added this beauty to my SL350 bookmarks: http://kawtriple.com/mraxl/carb/plugchop.htm So thanks for that as well.

 

[TomSL]

After talking with some people locally as well as with captb, I've decided to go with captb's head. I did some measuring and found out I actually have a CB head on this thing already. Now that I have a fat cam that needs a re-grind, a nice clean CB head, and some 0.75-over pistons, I think I'm pretty much stuck with upgrading the carbs. I'm a little sad to have to see the carbs go, just because I spent so much time getting them in order, but oh well! More cleaning, dremel tooling, and disassembly over the coming days or weeks. Will try to keep up with posting pictures.

 

[captb]

0.75 Pistons

 

[TomSL]

All the goodies from captb have arrived. They look great, and were packaged really well. Thanks!

Found this business in Pawtucket, RI (sorry, no website, just a Facebook page)

His name is Dmitry and he's been doing vapor blasting for a while it sounds like. He's on the North East Street Riders forum, of which I'm not a member, but that's how I found him. Anybody else have any experience with him? Regardless, I'm going with him to save shipping costs. That money can perhaps go to having the piston tops and skirts coated at Swaintech. Some cool photos and videos of vapor blasting process, as well as before and after, on the Facebook page.

After things are all apart, degreased, and vapor blasted, I'll get the necessary machining done, and then it's back together. Hopefully in time for spring riding.

While waiting for some tools and parts to arrive, I've been playing with the Dremel tool on various bits to clean up factory casting marks, and open up some air passageways between and around the cooling fins a little. Also altering some slopes of the factory casting to minimize gunk trapping and hopefully make cleaning easier. I'll post photos shortly.

Anyone seen this set-up before? HHMMMMMMmmmmm......

EDIT - clarified location of air flow modifications. Not on intake tract, just air passageways on the external cooling fins.

 

[outobie]

While waiting for some tools and parts to arrive, I've been playing with the Dremel tool on various bits to clean up factory casting marks, and open up some air passageways a little. Also altering some slopes of the factory casting to minimize gunk trapping and hopefully make cleaning easier. I'll post photos shortly.

not sure what you are dremmeling but changes to the intake can have dramatic effects on performance and not necessarily for the better.

that oil cooler kit looks very cool...

 

[TomSL]

Outobie, see edits.

Re: oil cooler - although I live at such a high latitude in Boston, and we don't see overly high temps, having a switchable oil cooler that I can use based on ambient temp or how bad I'm flogging the bike would be a pretty nifty experiment if nothing more. I'll be pondering on it a bit more, but I think it would be more beneficial from an engine durability standpoint (assuming proper engineering) than some of the other minor things I was considering upgrading, like coatings and whatnot.

 

[outobie]

Outobie, see edits.

Re: oil cooler - although I live at such a high latitude in Boston, and we don't see overly high temps, having a switchable oil cooler that I can use based on ambient temp or how bad I'm flogging the bike would be a pretty nifty experiment if nothing more. I'll be pondering on it a bit more, but I think it would be more beneficial from an engine durability standpoint (assuming proper engineering) than some of the other minor things I was considering upgrading, like coatings and whatnot.

Ahh external casting slag...

while ambient air temp in your riding environment does play a role; your use of the throttle can dump enough heat into the motor to overcome the cooling capacity of the cooling fins and cause premature deterioration of your oil. although in my opinion just adding the extra capacity to the oil sump is worth it alone...stock, these motors only hold about 3 quarts...more is always good

 

[TomSL]

Thanks for the input Outobie. I've been looking into it a bit more, and the costs seem to be pretty reasonable to design and build something that should help.

I've also been exploring the factory oiling system just to get a better idea of how things work, and to find points where I could make improvements. Today, I found this (see pic) inside of the clutch cover. The slinger cover is lined up with the bolt holes. Shouldn't the output port of the slinger (slinger to clutch case, bottom in photo) line up more like its input port (clutch case to slinger, top in photo)??? Maybe the PO put in a replacement slinger cover that's for a different bike? It is substantially shinier and newer looking than many of the other parts on the bike... Either way, flow testing (me blowing through holes) reveals substantial blockage of the output tract compared to input.