Topic: Standard pistons - Honda or aftermarket?

[TheVet]

Currently have the top end of my 550 project apart for rebuilding, found the #4 piston pretty thrashed and am trying to decide what to replace them with.  I'm not looking to put a lot of money into forged high-comp pistons and the requisite machine work to install them, rather just keep things fairly simple and straight-forward on this front.  Since I still have to pick up a top-end rebuild kit anyway, can anyone speak to the quality of the aftermarket pistons from places like 4into1?  Or should I steer away and stick with NOS Honda parts? 

[drumstyx]

If it's apart for a rebuild anyway, consider measuring the bores and pistons to make sure the clearances are still within spec. If the piston is thrashed, what other mayhem might have been going on in that cylinder?

Bore gauges were pretty pricey when I did mine, but they've come down in price (and that was only 5 years ago or so!). Transfer gauges are cheap, just make sure you use a micrometer, not verniers to measure them.

[Stev-o]

Drums gave good advice up there, you need to check the jugs before you go ordering anything.

If you luck out, you will be able to hone and re-ring, but may need at least one piston?

I've found that rebuilding an engine correctly is never cheap!  Good luck.

[TheVet]

Yeah, #4 cylinder was decently scored.  Honed it out to the service limit for stock piston size hoping it would clean up, but the damage was deeper than it first appeared.  Figured it would be cheaper to snag a nice set of cylinders off EBay and clean those up; worst case I'm only out $80 and have a better piece to work with anyway (since my original has several broken fins).  Either way, original question still stands:  Are the inexpensive piston kits (stock of oversize) available from 4into1 and the likes good to go, or should I be looking elsewhere?

[bryanj]

Cruzinimage are what a respected builder in the UK uses

[drumstyx]

IMO, if you're only replacing one piston, stick with the same piston that's on the other 3 rods -- probably OEM Honda. It's not terribly expensive for a single piston.

[Nicklopic]

the cruizinimage pistons are actually pretty nice. They seem super sketchy because theyre cheap and like only available on ebay but they're solid quality and ship from japan for a little piece of mind. Used 1mm over pistons in my 650 from them, mike from jmr said that that despite them being number for their hole, the tolerances were so close it really didnt matter where i tossed what piston. He said they were maybe .0001" difference between the set.
I do think you should just bite the bullet and send the jugs to a machine shop even if you have a wait a little and do a full set of whatever size you decide/need but do what you can afford and want to deal with.

[dave500]

ive used the david silvers 550 over size piston kit,been thrashing the #$%* out of it for years no trouble,i had a good proper rebore done with bores honed to match each piston,im not kidding ive truely thrashed the #$%* out of it and no problem.

[MauiK3]

Hondaman sourced mine.
Yamiya has pistons too.
I would study Hondaman's observations about a one or two over bore on cylinders due to the bores not all being parallel. I know this is more than you are expecting but it's good information.

[PeWe]

I was surprised that cruzinimage pistons were all very equal when measure them before install.

Good value for a complete kit of 4 pistons with rings that cost like a set of rings.


I have not seen the life time yet.

[HughL]

Doing my top end and need standard 61mm pistons for my K6 750K.

I reached out to cruisinimage yesterday and they now get their parts from Taiwan, per their customer support. OEM pistons are about $60/piece without rings and pins. 4into1 sells a set for ~$100.

Any recommendations for aftermarket 61mm pistons that may be worth looking into?

[jaytee-nz]

Cruzinimage is still your best bet. Many people here (including me) use their pistons and rings and they give no problems at all.

[Tracksnblades1]

I’m not a 550 or a cruizin image guy…

That said, I’ve read repeatedly on here that 550’s and smaller sohcs’ need the tighter fit so they’re not oil burners and mosquitoe foggers..

You are right there, at least do the 1st oversize. To at least straighten and square up any bore/core shifts that might have occurred over time from Honda’s green cylinder block or just from normal cylinder wear…you’ll never be any closer than right now..🤞🤞

[PeWe]

+3 of above
Do not order 61mm pistons unless you have new tight sleeves. Used bores will end up in a clearance of 0.04-0.05mm which is double than these pistons need. It WILL smoke.

Use the +0.50mm pistons and make sure that total clearance is max 0.02mm

[HughL]

+3 of above
Do not order 61mm pistons unless you have new tight sleeves. Used bores will end up in a clearance of 0.04-0.05mm which is double than these pistons need. It WILL smoke.

Use the +0.50mm pistons and make sure that total clearance is max 0.02mm

I've already had my cylinders honed and properly measured and they are still within manual specs.

But my original question was about branding rather than sizing as I have that figured out.

[HughL]

I’m not a 550 or a cruizin image guy…

That said, I’ve read repeatedly on here that 550’s and smaller sohcs’ need the tighter fit so they’re not oil burners and mosquitoe foggers..

You are right there, at least do the 1st oversize. To at least straighten and square up any bore/core shifts that might have occurred over time from Honda’s green cylinder block or just from normal cylinder wear…you’ll never be any closer than right now..🤞🤞

I know this started as a 550 thread but my specific question was about 750 piston brands if you have any suggestions for those

[Stev-o]

Any recommendations for aftermarket 61mm pistons that may be worth looking into?

Not a budget piston but I've used Wiseco's on at least 3 of my engine rebuilds, they are forged, not cast. My machinist highly recommended them and have no regrets.

EDIT: they are 65mm, not what you are looking for.

https://www.ebay.com/itm/364745529580?fits=Make%3AHonda&_skw=wiseco++piston++honda+836&epid=220642904&itmmeta=01JJ79W071X8PK0VG04RAFJDAG&hash=item54ec8718ec:g:WNAAAOSwTVFmfsH8&itmprp=enc%3AAQAJAAAA4HoV3kP08IDx%2BKZ9MfhVJKlY0xofSJyJIoKfKjd1Rc3NKuQG2gnK%2B%2Frr0t9OV6WRo8FggQ4tjoOPuAg%2FNesMamNGUCUwXvpPvTrgYq7ehqIL0POBaDeyb4R3tNbaXNDVnP5761bD%2FS7j64v64gLFIbeDX918RIuS%2F1SIt6%2Bext9of8zoJQt55NkDhsPoYm1uv6ROPcTn0vkrh9zQ1ffyxrmaxbzBOkRANRwBZozFLa67uHMZO3Ld8UPyPMEmAbaQlu%2FdOGsjQaZRD9gxFWd2LaaAbRSkZ8jg25Qwb8yFOEsu%7Ctkp%3ABk9SR9aD8OmRZQ

[newday777]

Any recommendations for aftermarket 61mm pistons that may be worth looking into?

Not a budget piston but I've used Wiseco's on at least 3 of my engine rebuilds, they are forged, not cast. My machinist highly recommended them and have no regrets.

https://www.ebay.com/itm/174138579061?chn=ps&mkevt=1&mkcid=28&google_free_listing_action=view_item&srsltid=AfmBOopIb0sgV_T5WnVCLup0ZyEkybkFofQLBfNzdprXZnj0gQHm14WFUTw&gQT=2

Steve
Those are Wiseco??
The link doesn't show they are.

[Stev-o]

Any recommendations for aftermarket 61mm pistons that may be worth looking into?

Not a budget piston but I've used Wiseco's on at least 3 of my engine rebuilds, they are forged, not cast. My machinist highly recommended them and have no regrets.

https://www.ebay.com/itm/174138579061?chn=ps&mkevt=1&mkcid=28&google_free_listing_action=view_item&srsltid=AfmBOopIb0sgV_T5WnVCLup0ZyEkybkFofQLBfNzdprXZnj0gQHm14WFUTw&gQT=2

Steve
Those are Wiseco??
The link doesn't show they are.

Sorry wrong link, here are the ones I used, but they are 65mm  [836]

https://www.ebay.com/itm/364745529580?fits=Make%3AHonda&_skw=wiseco++piston++honda+836&epid=220642904&itmmeta=01JJ79W071X8PK0VG04RAFJDAG&hash=item54ec8718ec:g:WNAAAOSwTVFmfsH8&itmprp=enc%3AAQAJAAAA4HoV3kP08IDx%2BKZ9MfhVJKlY0xofSJyJIoKfKjd1Rc3NKuQG2gnK%2B%2Frr0t9OV6WRo8FggQ4tjoOPuAg%2FNesMamNGUCUwXvpPvTrgYq7ehqIL0POBaDeyb4R3tNbaXNDVnP5761bD%2FS7j64v64gLFIbeDX918RIuS%2F1SIt6%2Bext9of8zoJQt55NkDhsPoYm1uv6ROPcTn0vkrh9zQ1ffyxrmaxbzBOkRANRwBZozFLa67uHMZO3Ld8UPyPMEmAbaQlu%2FdOGsjQaZRD9gxFWd2LaaAbRSkZ8jg25Qwb8yFOEsu%7Ctkp%3ABk9SR9aD8OmRZQ

[Tracksnblades1]

I’m not a 550 or a cruizin image guy…

That said, I’ve read repeatedly on here that 550’s and smaller sohcs’ need the tighter fit so they’re not oil burners and mosquitoe foggers..

You are right there, at least do the 1st oversize. To at least straighten and square up any bore/core shifts that might have occurred over time from Honda’s green cylinder block or just from normal cylinder wear…you’ll never be any closer than right now..🤞🤞

I know this started as a 550 thread but my specific question was about 750 piston brands if you have any suggestions for those

First, you have provided nothing except my block has been honed and it’s within specs.?
But, we must/may infer your pistons are not within specs because you want information on new pistons..

Unable to read your mind, my thoughts wonder. Is he trying to get his pistons to wall clearance in spec or
tighter because his OEM pistons are worn excessively? Or my cylinders are at the lower spec and my pistons
were reusable and now there not..or one of them is damaged etc.

Without knowing your cylinders’ actual size and taper you have blindfolded all of us.
If you’re determined to use your honed cylinders I would at least know the actual taper and size of each
bore and record that information. When you decide on your pistons and type, measure each piston and record it size
 to the ten thousands. Put the biggest piston in the biggest hole. Continue ending with the smallest measured piston in the smallest hole.

What piston would I recommend? I don’t know your actual bore size or taper. What type of hone or glazed breaker honed it or what the finish is for your desired ring pack..However if your cylinders are perfect and are on the smaller bore size you maybe able to consider new cast pistons and you may still have a good piston to cylinder wall clearance. But if you’re on the largest bore size Honda allows which I think you’re at. I would use a forged wiseco piston. Why, because forged pistons generally require more clearance to operate normally than cast pistons do..Why, the forge pistons generally expand more at normal temps than cast piston do.. so your worn cylinders may have a closer to an ideal new piston to wall clearance than a cast piston will.

So if your clearances are already tight you may be able to use a new Honda (cast) piston. Or you may be able to stiff hone a little more to remove any taper while achieving the larger desired piston to cylinder wall clearance most forge pistons require.

If your clearances are already big then provided that your cylinders have little or no taper then I would use forged pistons only if any type of of boring wasn’t in the plans..Just because forge pistons generally require more clearance so you’ll be closer to ideal even when it’s excessive for a cast piston requirements.

Attached is a better description of piston to cylinder wall clearance and block material and the whys, better explained than I can articulate.. But, in short your cylinders’ housed in aluminum will have an expansion rate similar to your aluminum pistons expansion rate is. As compared to the same piston type in a cast iron/water cooled cylinder bore,as an extreme. Basically your cylinders will expand as your pistons expand as the temperature rises. So if you start out with too big of clearance it stays too big as it gets hot..

https://www.wiseco.com/auto/wiseco-auto-tech/piston-to-wall-clearance-myths-mysteries-and-misconceptions-explained/?srsltid=AfmBOooIH8YMXEF8aPVHTZ7zPlcUNzmKdSzIt2DF3QHRcLtZLHz5z8Ve

Wiseco and Honda has so tight of quality control it may be hard to measure accurately enough to determine if there is any difference. But, a good Starett or Mitutoyo micrometer will measure easily to the ten thousandth’s for the cheaper pistons.. wear gloves..😇

Since your already honed and have an unknown bore finish grit and crosshatch you might see whose rings (chrome, cast, moly, etc) works best with your current finish..you know the cart and the horse thing.

[bryanj]

Over the past few years i have found that rarely do the 500 and 550 clean at first oversize and need to go to 0.5mm due to the cylinder going barrel shaped, only has to go a few thou to not clean

[HughL]

I’m not a 550 or a cruizin image guy…

That said, I’ve read repeatedly on here that 550’s and smaller sohcs’ need the tighter fit so they’re not oil burners and mosquitoe foggers..

You are right there, at least do the 1st oversize. To at least straighten and square up any bore/core shifts that might have occurred over time from Honda’s green cylinder block or just from normal cylinder wear…you’ll never be any closer than right now..🤞🤞

I know this started as a 550 thread but my specific question was about 750 piston brands if you have any suggestions for those

First, you have provided nothing except my block has been honed and it’s within specs.?
But, we must/may infer your pistons are not within specs because you want information on new pistons..

Unable to read your mind, my thoughts wonder. Is he trying to get his pistons to wall clearance in spec or
tighter because his OEM pistons are worn excessively? Or my cylinders are at the lower spec and my pistons
were reusable and now there not..or one of them is damaged etc.

Without knowing your cylinders’ actual size and taper you have blindfolded all of us.
If you’re determined to use your honed cylinders I would at least know the actual taper and size of each
bore and record that information. When you decide on your pistons and type, measure each piston and record it size
 to the ten thousands. Put the biggest piston in the biggest hole. Continue ending with the smallest measured piston in the smallest hole.

What piston would I recommend? I don’t know your actual bore size or taper. What type of hone or glazed breaker honed it or what the finish is for your desired ring pack..However if your cylinders are perfect and are on the smaller bore size you maybe able to consider new cast pistons and you may still have a good piston to cylinder wall clearance. But if you’re on the largest bore size Honda allows which I think you’re at. I would use a forged wiseco piston. Why, because forged pistons generally require more clearance to operate normally than cast pistons do..Why, the forge pistons generally expand more at normal temps than cast piston do.. so your worn cylinders may have a closer to an ideal new piston to wall clearance than a cast piston will.

So if your clearances are already tight you may be able to use a new Honda (cast) piston. Or you may be able to stiff hone a little more to remove any taper while achieving the larger desired piston to cylinder wall clearance most forge pistons require.

If your clearances are already big then provided that your cylinders have little or no taper then I would use forged pistons only if any type of of boring wasn’t in the plans..Just because forge pistons generally require more clearance so you’ll be closer to ideal even when it’s excessive for a cast piston requirements.

Attached is a better description of piston to cylinder wall clearance and block material and the whys, better explained than I can articulate.. But, in short your cylinders’ housed in aluminum will have an expansion rate similar to your aluminum pistons expansion rate is. As compared to the same piston type in a cast iron/water cooled cylinder bore,as an extreme. Basically your cylinders will expand as your pistons expand as the temperature rises. So if you start out with too big of clearance it stays too big as it gets hot..

https://www.wiseco.com/auto/wiseco-auto-tech/piston-to-wall-clearance-myths-mysteries-and-misconceptions-explained/?srsltid=AfmBOooIH8YMXEF8aPVHTZ7zPlcUNzmKdSzIt2DF3QHRcLtZLHz5z8Ve

Wiseco and Honda has so tight of quality control it may be hard to measure accurately enough to determine if there is any difference. But, a good Starett or Mitutoyo micrometer will measure easily to the ten thousandth’s for the cheaper pistons.. wear gloves..😇

Since your already honed and have an unknown bore finish grit and crosshatch you might see whose rings (chrome, cast, moly, etc) works best with your current finish..you know the cart and the horse thing.

I thought 61mm would've been understood as the sizing to be used. Yes my pistons need to be replaced hence why I'm asking. I've already ordered some new pistons since, thank you for the suggestions and information.

[Tracksnblades1]

I’m not a 550 or a cruizin image guy…

That said, I’ve read repeatedly on here that 550’s and smaller sohcs’ need the tighter fit so they’re not oil burners and mosquitoe foggers..

You are right there, at least do the 1st oversize. To at least straighten and square up any bore/core shifts that might have occurred over time from Honda’s green cylinder block or just from normal cylinder wear…you’ll never be any closer than right now..🤞🤞

I know this started as a 550 thread but my specific question was about 750 piston brands if you have any suggestions for those

First, you have provided nothing except my block has been honed and it’s within specs.?
But, we must/may infer your pistons are not within specs because you want information on new pistons..

Unable to read your mind, my thoughts wonder. Is he trying to get his pistons to wall clearance in spec or
tighter because his OEM pistons are worn excessively? Or my cylinders are at the lower spec and my pistons
were reusable and now there not..or one of them is damaged etc.

Without knowing your cylinders’ actual size and taper you have blindfolded all of us.
If you’re determined to use your honed cylinders I would at least know the actual taper and size of each
bore and record that information. When you decide on your pistons and type, measure each piston and record it size
 to the ten thousands. Put the biggest piston in the biggest hole. Continue ending with the smallest measured piston in the smallest hole.

What piston would I recommend? I don’t know your actual bore size or taper. What type of hone or glazed breaker honed it or what the finish is for your desired ring pack..However if your cylinders are perfect and are on the smaller bore size you maybe able to consider new cast pistons and you may still have a good piston to cylinder wall clearance. But if you’re on the largest bore size Honda allows which I think you’re at. I would use a forged wiseco piston. Why, because forged pistons generally require more clearance to operate normally than cast pistons do..Why, the forge pistons generally expand more at normal temps than cast piston do.. so your worn cylinders may have a closer to an ideal new piston to wall clearance than a cast piston will.

So if your clearances are already tight you may be able to use a new Honda (cast) piston. Or you may be able to stiff hone a little more to remove any taper while achieving the larger desired piston to cylinder wall clearance most forge pistons require.

If your clearances are already big then provided that your cylinders have little or no taper then I would use forged pistons only if any type of of boring wasn’t in the plans..Just because forge pistons generally require more clearance so you’ll be closer to ideal even when it’s excessive for a cast piston requirements.

Attached is a better description of piston to cylinder wall clearance and block material and the whys, better explained than I can articulate.. But, in short your cylinders’ housed in aluminum will have an expansion rate similar to your aluminum pistons expansion rate is. As compared to the same piston type in a cast iron/water cooled cylinder bore,as an extreme. Basically your cylinders will expand as your pistons expand as the temperature rises. So if you start out with too big of clearance it stays too big as it gets hot..

https://www.wiseco.com/auto/wiseco-auto-tech/piston-to-wall-clearance-myths-mysteries-and-misconceptions-explained/?srsltid=AfmBOooIH8YMXEF8aPVHTZ7zPlcUNzmKdSzIt2DF3QHRcLtZLHz5z8Ve

Wiseco and Honda has so tight of quality control it may be hard to measure accurately enough to determine if there is any difference. But, a good Starett or Mitutoyo micrometer will measure easily to the ten thousandth’s for the cheaper pistons.. wear gloves..😇

Since your already honed and have an unknown bore finish grit and crosshatch you might see whose rings (chrome, cast, moly, etc) works best with your current finish..you know the cart and the horse thing.

I thought 61mm would've been understood as the sizing to be used. Yes my pistons need to be replaced hence why I'm asking. I've already ordered some new pistons since, thank you for the suggestions and information.

Sounds great, good luck..
Sorry you didn’t understand the advantages as conveyed of using a 61mm forged pistol in place of a 61mm cast piston..
It would still be interesting to know the actual taper and bore size of your cylinder bores..?

[Tracksnblades1]

Over the past few years i have found that rarely do the 500 and 550 clean at first oversize and need to go to 0.5mm due to the cylinder going barrel shaped, only has to go a few thou to not clean

Brian,
It’s a 750 now…if I read it right…

[HughL]

I’m not a 550 or a cruizin image guy…

That said, I’ve read repeatedly on here that 550’s and smaller sohcs’ need the tighter fit so they’re not oil burners and mosquitoe foggers..

You are right there, at least do the 1st oversize. To at least straighten and square up any bore/core shifts that might have occurred over time from Honda’s green cylinder block or just from normal cylinder wear…you’ll never be any closer than right now..🤞🤞

I know this started as a 550 thread but my specific question was about 750 piston brands if you have any suggestions for those

First, you have provided nothing except my block has been honed and it’s within specs.?
But, we must/may infer your pistons are not within specs because you want information on new pistons..

Unable to read your mind, my thoughts wonder. Is he trying to get his pistons to wall clearance in spec or
tighter because his OEM pistons are worn excessively? Or my cylinders are at the lower spec and my pistons
were reusable and now there not..or one of them is damaged etc.

Without knowing your cylinders’ actual size and taper you have blindfolded all of us.
If you’re determined to use your honed cylinders I would at least know the actual taper and size of each
bore and record that information. When you decide on your pistons and type, measure each piston and record it size
 to the ten thousands. Put the biggest piston in the biggest hole. Continue ending with the smallest measured piston in the smallest hole.

What piston would I recommend? I don’t know your actual bore size or taper. What type of hone or glazed breaker honed it or what the finish is for your desired ring pack..However if your cylinders are perfect and are on the smaller bore size you maybe able to consider new cast pistons and you may still have a good piston to cylinder wall clearance. But if you’re on the largest bore size Honda allows which I think you’re at. I would use a forged wiseco piston. Why, because forged pistons generally require more clearance to operate normally than cast pistons do..Why, the forge pistons generally expand more at normal temps than cast piston do.. so your worn cylinders may have a closer to an ideal new piston to wall clearance than a cast piston will.

So if your clearances are already tight you may be able to use a new Honda (cast) piston. Or you may be able to stiff hone a little more to remove any taper while achieving the larger desired piston to cylinder wall clearance most forge pistons require.

If your clearances are already big then provided that your cylinders have little or no taper then I would use forged pistons only if any type of of boring wasn’t in the plans..Just because forge pistons generally require more clearance so you’ll be closer to ideal even when it’s excessive for a cast piston requirements.

Attached is a better description of piston to cylinder wall clearance and block material and the whys, better explained than I can articulate.. But, in short your cylinders’ housed in aluminum will have an expansion rate similar to your aluminum pistons expansion rate is. As compared to the same piston type in a cast iron/water cooled cylinder bore,as an extreme. Basically your cylinders will expand as your pistons expand as the temperature rises. So if you start out with too big of clearance it stays too big as it gets hot..

https://www.wiseco.com/auto/wiseco-auto-tech/piston-to-wall-clearance-myths-mysteries-and-misconceptions-explained/?srsltid=AfmBOooIH8YMXEF8aPVHTZ7zPlcUNzmKdSzIt2DF3QHRcLtZLHz5z8Ve

Wiseco and Honda has so tight of quality control it may be hard to measure accurately enough to determine if there is any difference. But, a good Starett or Mitutoyo micrometer will measure easily to the ten thousandth’s for the cheaper pistons.. wear gloves..😇

Since your already honed and have an unknown bore finish grit and crosshatch you might see whose rings (chrome, cast, moly, etc) works best with your current finish..you know the cart and the horse thing.

I thought 61mm would've been understood as the sizing to be used. Yes my pistons need to be replaced hence why I'm asking. I've already ordered some new pistons since, thank you for the suggestions and information.

Sounds great, good luck..
Sorry you didn’t understand the advantages as conveyed of using a 61mm forged pistol in place of a 61mm cast piston..
It would still be interesting to know the actual taper and bore size of your cylinder bores..?

1: top is +0.0005 2: top +0.0015 3: top  -0.0005 4: top +0.0005

Measurements in inches of difference.

1 2 and 4 were wider at the top measuring the lateral widths. The thrust sides were similar.