SMC Upgrade

Does anyone know how to read Honda's part codes?
I'm interested in (2) different parts, in which the part number is the same, except for the last (3) digits.
Example:
2005 - 2007 45620-MCS-G03
2008 - 2009 - 2010 - 2011 45620-MCS-R01
does anyone know IF there is a difference between the G03 and the R01?
You can see the parts on Ronayers.com if your curious.
Thanks in advance for any assistance.
Igofar

Discovered the 08 and up ST1300's have a new part number for the smc piston set (4562-MCS-R01). They have changed the way the piston is machined, and made the spring longer and narrower in dia. You can view the pictures of them over further down in this thread. Hope this may help those suffering from SMC issues.

Re: micro fiche codes

The first three digits is the part number, the three letter MCS means ST1300, the last 3 alpha numerics reference the vendor. The parts themselves are the same from different vendors.

Re: micro fiche codes

Conveniently enough: CLICKY

The parts you're looking at (left brake caliper piston set) have some history and are a strange case because they're sets:

• 45620-MCS-G01 was used 2003-2004 and is the original version of the part. This would consist of two 45207-MAJ-G41 (22x35 piston) and one 45107-MAJ-G41 (22x27 piston), which come up as having first been used on the ST1100 in the late 1990s and a whole slew of other bikes thereafter.
• 45620-MCS-G03 was used 2005-2007 and is listed in the fiche has having superseded the -G01 part. Sometimes the difference is just in packaging: at some point they revised the brake pads from a -G01 to a -G02 and the only difference I could find was an insert with warnings about safe installation. The fiche shows the same three pistons as individual parts as in previous years.
• 45620-MCS-R01 appeared in 2008, there were major changes to the brake system, including a new caliper that looks to be lighter than the old one. Again, the pistons themselves are the same ones.

So the bottom line is that all three sets contain compatible parts and should be interchangeable. Honda may have a bunch of the -G03 part in its warehouses and won't mark it as superseded until they run out. But if you're ordering replacements, best to be safe and order the what the fiche specifies for the year of the bike.

dduelin said:

The parts themselves are the same from different vendors.

Click to expand...

That isn't entirely correct. They're the same in the sense that they serve the same purpose, but they're not necessarily compatible. The entire caliper assembly for 2003-2007 shares the same function, component and model codes (45150-MCS) but changed in 2008 (-G01 vs. -R01). The -G01 part was superseded by a -G02 part at some point, and the fiche doesn't show that the -R01 superseded it.

The more I look at it, the more I'm starting to think that the modification process design code may actually be three things and not have anything to do with who manufactured it. The first digit ("modification") is the version of the part itself and the last digit ("design") is the revision of that design. I have no idea what to make of the middle ("process") digit. I'll have to keep an eye out for things that bear that out.

--Mark

Re: micro fiche codes

Also, the Product code ("MCS" for ST1300) shows the motorcycle that the part was first used within. In other words, a part number that includes MCS was either first designed for and used in the ST1300, or it could be a part that was used on another motorcycle but it's design was changed some amount to fit the ST1300.

All that does not preclude using the same part later on another motorcycle. Case in point: the ST1300 oil filler cap is part number "15611-MB0-000". MB0 is the Product code for the 1982 VF750S. Therefore the oil filler cap that we have in the ST1300 today was first used in it's current configuration in the Honda VF750S. The designers chose to use that part, unchanged, in the ST1300, so it retained it's VF750S part number.

Fun.

Re: micro fiche codes

Ok, so we all are in agreement on the product code, the fitment, and the vendor or improvement as far as the part number goes.
Here's why I'm so curious, last night I was examining a SMC piston set from a 2012 model (not even listed on the parts list yet), but it would appear to be the part from a different vender, or an improvement of the part, etc.
Here's what I found. We all know about the dreaded SMC binding, sticking, jamming, etc. I think the RO1 version may be an improved part, heres why...
The older part (G03) that was on the 2007 (my old one), has a metal piston body, and (2) individual rubber parts that slide onto this single part, then a shorter, thicker spring, with less coils, snaps onto the metal piston on a machined surface, the newer part (R01) part uses a completely new designed part!
It uses a smaller piston, same joint, and surface area, however its cut flat on the rear and polished smooth, the spring appears to be a little smaller in dia. and has several more coils, and the spring snaps onto a rubber disk area that simply mates up to the smooth surface of the piston. This would appear to be a much better design in my opinion, because the spring does not look like it can bind or stick, it can't come "off" the surface area and be misplaced, causing it to bind, and the rearward scrubber part does two functions, push fluid, and the piston without having alot of wear forced onto it by being "on" the piston body, instead of behind it pushing it, so there is no way to tilt, slip off, or bind.
The bores of the brackets themselves 05-07 (06454-MCS-G02) and 08-> (45150-MCS-R01) appear to have the same bore dia., mounting points, etc. and other than the caliper itself being an investment cast unit now intead of a two piece clamshell design, the only reason for the vender or improvement code could be for the slot machined in it instead of the drain hole.
The parts do "appear" to be interchangeable, with the R01 part fitting a little looser and working more smoothly.
To get the older version out of the bore, you use to have to use pressure (brake lever & fluid) or air pressure from behind, to force it out, the newer version FALLS out when you tip the SMC caliper over. I think Honda may have finally addressed our brake dragin' issues.
Comments?

Re: micro fiche codes

Pictures of the differences would really help Larry.

Re: micro fiche codes

I took some last night, and will have my CEO help me post them later today.

Re: micro fiche codes

Here are Larry's (Igofar) pictures of two different SMC Piston Sets:
005:
006:
008:
009:

Re: micro fiche codes

That is an interesting discovery. The Ayers fiche is not always up to date - if you go to a dealer and they order the part for you the current revision is the one that Honda order system will have listed currently. Today 5/4/2013 the part number for 2008 to present is 45620-MCS-R02. For my 2005 it is 45620-MC-G03. I guess the R02 parts would retrofit but since I have an 05 and my spares kit includes a G03 I'm sure that one fits if I need it.

Igofar said:

Discovered the 08 and up ST1300's have a new part number for the smc piston set (4562-MCS-R01). They have changed the way the piston is machined, and made the spring longer and narrower in dia. You can view the pictures of them over further down in this thread. Hope this may help those suffering from SMC issues.

Click to expand...

The entire front calipers are different from 2008 moving forward. Not every, if any, part is interchangeable with pre-2008 bikes. Just something to be aware of. If it were me, I would only replace a pre-2008 bike part with the same unless someone does do this and report a positive outcome.

Mine is now work in progress, will let you know of any issues.

Igofar said:

Mine is now work in progress, will let you know of any issues.

Click to expand...

Cool.. did you replace the entire SMC assembly or just the internal piston/spring/etc?

As you said the calipers are different, and use a one piece cast unit instead of the two piece clam shell on the older bikes, the pads are also different, and require longer or wider pads for proper fitment, however, the internal parts of the bore (piston set) appear to be interchangeable, as the bore dia. and depth seem to be the same, the only difference I can see is the way the piston is being made now, and that could be for cheaper machining costs, a simpler way to tool them, or as my quess would be, slightly looser tollerances to prevent the jamming and binding we've seen in the past from poor bleeding maintenance.
What we should do is contact honda and ask if the R01 part will replace the G03 part once the old stock is used up.

Stay on it Larry. Inquiring minds want to know. I know from my Tool and Die days, that automotive guys wanted more clearance on parts to keep things from binding.
Ron

After sitting and looking at the photo's for a few minutes, a thought popped into my head....
With the old style, the spring is forced onto the metal piston, meaning where ever the spring wiggles it pushes the body of the piston in that direction, however slight, this could cause binding....with the new style, smooth bottom, the only mating surfaces are the smooth flat polished end of the piston, and a slippery plastic cap, that will center itself when moved. The new design may work better by allowing the piston and the pad on the spring to work together, yet not be connected to each other, allowing room to find the path of least resistance.
Comments?

Larry can the whole SMC be swapped out, or is it just the piston and spring that will fit?
Ron

It could be that if corrosion was considered the root cause of problems that they wanted to separate the metal parts and did so by putting one of the seals in between them. This would prevent any galvanic corrosion.

Not likely, because the corrosion happens towards the front of the unit, where the metal disc with the rubber surface attempts to seal the unit.
The corrosion usually starts on the ball end of the rod, then works its way down the shaft, then the plating appears to become damaged, allowing moisture
through the hole that the shaft goes through.
Another thought may be, when the kits are sold, its up to the person installing the rubber parts, to make sure they are facing the correct way, and stretched over the
piston and placed in their groove correctly. I've seen one that was rebuilt incorrectly so far (backwards).
I don't think there would be much corrosion where the spring pushes onto the base of the piston, but I guess it could happen there as well.
As far as the caliper itself goes, I'll have to get my hands on a newer one again and measure it next to my 2007. I'm sure the bracket is probably the same, even though the calipers were redesigned with the slot and for fitment to the once piece design.
I would recommend that nobody try and use parts that were not intended for your bikes fitment, without further testing, and any such testing should be done at your own risk. Brake systems are very important and should not be modified in anyway other than factory fitment, and to do so, you may be putting yourself at risk-dislclaimer.

Igofar said:

Not likely, because the corrosion happens towards the front of the unit, where the metal disc with the rubber surface attempts to seal the unit.
The corrosion usually starts on the ball end of the rod, then works its way down the shaft, then the plating appears to become damaged, allowing moisture
through the hole that the shaft goes through.
Another thought may be, when the kits are sold, its up to the person installing the rubber parts, to make sure they are facing the correct way, and stretched over the
piston and placed in their groove correctly. I've seen one that was rebuilt incorrectly so far (backwards).
I don't think there would be much corrosion where the spring pushes onto the base of the piston, but I guess it could happen there as well.
As far as the caliper itself goes, I'll have to get my hands on a newer one again and measure it next to my 2007. I'm sure the bracket is probably the same, even though the calipers were redesigned with the slot and for fitment to the once piece design.
I would recommend that nobody try and use parts that were not intended for your bikes fitment, without further testing, and any such testing should be done at your own risk. Brake systems are very important and should not be modified in anyway other than factory fitment, and to do so, you may be putting yourself at risk-dislclaimer.

Click to expand...

I can take some pics of my 08 w/measurements if you wish.. post a pic with some lines and measurements and I can try to match that using my caliper.

My thought is, I would probably not venture into a fitment either way, but if my SMC goes out again, and I have to replace it, I would consider a 2009 SMC if that is an option.
Ron