Author Topic: New cylinders from honda  (Read 3571 times)

mudbogger

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New cylinders from honda
« on: April 25, 2004, 10:36:52 AM »
I was curious, will a A piston fit a B cylinder or vice versa?The reason I ask is this< I was talking to mudbogger last night and he told me Trevor at Hillside Honda says that a new A piston will fit a new B cylinder-I am under the impression thats not true but he(trevor) insists they will meet tolerances aka piston clearances,etc.I know the rings will work, but am I wrong in stating the pistons are not interchangeable?If they were, then why would they sell a-b-c cylinders?Trevor insists the mecanic at Hillside tells him they will, I am not in agreement with him and are losing patience with them over at Hillside.This A cylinder and piston I had ordered was to have been shipped to me weeks ago according to Dan at Hillside, I have come to find out the A cylinders are now on national backorder and just the B cylinders are available at the present from Honda with their limits being low as well.Has anybody here ever had this type of thing happen to them?Why would Trevor at Hillside say the pistons will work when I know the tolerance are totally different?I am in the future not going to use them, they(Hillside) are insistant on the fact the A piston will work in the B cylinder-both being new dont forget.If I am wrong, someone if you would please explain to me why?thanks alot.

ludedude

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New cylinders from honda
« Reply #1 on: April 25, 2004, 10:41:26 AM »
Fit? Probably...correct tolerances? I doubt it...

mudbogger

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New cylinders from honda
« Reply #2 on: April 25, 2004, 11:00:50 AM »
Thats I thought, why would they try to sell it then, don't they have any clue at Hillside?The guy Trevor shouldnt tell guys thats stuff-I for 1 arent going to use them no more, thats not right, it seems to me that they should get their act together over at Hillside, I have used them for parts but get the same product and better services from others and will use them from now on.

ludedude

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New cylinders from honda
« Reply #3 on: April 25, 2004, 11:04:50 AM »
If A is the smallest, then it would fit in a B, it would just have more piston to cylinder clearance, I don't know what the differences between A, B, and C are, you may never notice the difference...Now putting a A in a C cylinder may be too much clearance, again I don't know...just guessing

MonkeyWrench

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will it fit and the tolerances?
« Reply #4 on: April 26, 2004, 01:36:44 PM »
Well when I built my website back in 2001, the piston and head deal were mind meltingly confusing. Honda changes its a b c numbers around like musical chairs.
When the "a" gets the boot then "b" steps in and on down the line. like a good country western song.

I think that Hillside is probably correct.
I dont think they have any reason to steer you wrong.

Monkeywrench

mudbogger

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New cylinders from honda
« Reply #5 on: April 26, 2004, 01:45:04 PM »
Hey Wrench, can you give me some better info perhaps because everybody that I have talked to have told me there is a reason for the A-B-C pistons and cylinders and they are matched from the factory, is this true?I have also heard the pistons must be with the correct cylinders i/e A with an A CYLINDER etc.due to piston/cylinder clearances.Is this a false assumption people make by chance?Do you have any type of link that shows perhaps the clearances by chance?

PilotHawK

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« Reply #6 on: April 26, 2004, 04:52:15 PM »
Alright. enough debate. Here is what I know about the pistons and cylinder business. All mojor bike manufacturers use some sort of labeling system for new parts (this labeling system refers to NEW PARTS ONLY!!!!!!!). Honda uses A, B, and C for their pistons and cylinders. The difference between the parts is a mere.0010 or .0015" between the three. Honda uses very tight tolerances when building parts and when they run off a batch of parts, tool wear is taken into account for the fitment of pistons and cylinders. For example if you are boring 100 cylinders at a time the first cylinder is going to have a slightly larger bore than the 100th cylinder due simply to tool wear. To save time and money on tooling honda simply has 3 different pistons that take into account for the wear on their tooliing. It is a very simple concept. If you look in the pilot manual the tolerances for a stock piston are tight at .0031 inches of piston to cylinder clearance. (this is the difference between the size of the bore and the size of the piston. Meaning that if a cylinder measured 3.1750 inches in order to get the proper tolerances the piston would have to measure 3.1729" inches.) As I understand it the C piston is the smallest available, so it will in fact fit into a B cylinder, but the tolerances will be loose for a NEW piston and Cylinder combination. Monkey wrench never did get that right with an order i placed with him one time. After the first piston has been run through a "lettered cylinder" the lettering system should go out the door period. Any cylinder that has been bored or honed should have the tolerances measured by someone who knows what they are doing, and the cylinder fit to the piston. Using this, the most desireable cylinder would be the "C" cylinder and with wear you could hone the cylinder to the next letter honda piston when needed, taking into account cylinder wear. If you do it this way you can get a lot more uses out of a new cylinder.

If you don't get any of this, all the lettering system is used for is for NEW PARTS. That is when the letters need to match, but do not necessarily have to match. Like I said above any letter piston CAN be run in ANY letter cylinder. It is just a matter of tolerances. You would have to hone a "C" cylinder to accept an "A" piston or you would have to live with a little more piston to cylinder clearance running a "C" piston in an "A" cylinder.

If this isn't clear to anyone let me know and I'll see if I can explain it more clearly.

<EDIT>
Post is fixed...C is the smallest, cylinder and piston combination. And hence the most desired. You could start with a C and C combo then hone out to a B piston, then an A piston, then your first oversize, at whicj point all letters are thrown out the window and mean nothing.

PilotHawK

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« Reply #7 on: April 26, 2004, 04:56:48 PM »
In the above remarks i misstated that the A was the smallest piston. It is in fact the largest of the three standard bore pistons.

ludedude

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« Reply #8 on: April 26, 2004, 04:57:14 PM »
Thanks PH...I just wasn't sure which was the smallest end of things...the A or C...it's all clear to me.

Moskito

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New cylinders from honda
« Reply #9 on: April 27, 2004, 08:07:42 AM »
Quote from: "PilotHawK"
If this isn't clear to anyone let me know and I'll see if I can explain it more clearly.


I'm so confused!!! :shock:

Guess I need to go learn my ABC's again!
Moskito - Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming \'WOW-What a Ride!\'

redrider

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Hey Hawk
« Reply #10 on: April 27, 2004, 05:23:18 PM »
How about going into your long post above and use the edit feature to make it read correct information.  That way if it is reviewed later, the reader will not have to rely on the next post to set it straight!  :)  
And thanks for clearing up the different numbers pistons and cylinder issue.  I wasn't clear on that either, but had decided quite sometime back that you could check the sizes and continue to step up to the larger size if you'd started with the "C" until a bore and oversize was forced.

ludedude

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New cylinders from honda
« Reply #11 on: April 27, 2004, 05:31:49 PM »
I edit the post...PH had mentioned he could not edit it....the permissions were set wrong for that forum...post is fixed, permissions are fixed.

Hope it's all clear now :)

LiveWire

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Back to the first post
« Reply #12 on: April 28, 2004, 07:20:30 AM »
So going back to what Hillside said:

If an A piston is larger than a B piston, a B cylinder will need to be honed to size to use an A piston.

Running a B piston in an A cylinder would just give you a looser fit and may still be within limits.

mudbogger

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New cylinders from honda
« Reply #13 on: April 30, 2004, 02:25:13 PM »
Quote from: "LiveWire"
So going back to what Hillside said:

If an A piston is larger than a B piston, a B cylinder will need to be honed to size to use an A piston.

Running a B piston in an A cylinder would just give you a looser fit and may still be within limits.
I have since had numerous conversations with Trevor at Hillside and he says that Honda is now supercedding the A,B,C cylinders to the A cylinder parts number, they are no longer selling them as A,B,C cylindes, the pistons are also superceded to the A piston part number as well.So I guess you are gonna get a cylinder and piston that will match tolerances from now on.Also, as I stated earlier, the cylinders are getting harder and harder and get from Honda so you may want to stock up on a fresh top end for the future, they may be hard to come by in the later years.