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SumpThing kit for all Honda SOHC 750 F & K engines ,


Product ID: 3679 SKU: SU-666. Categories: , . Tag: .


27-5-2020 UPDATE! All back-orders are shipped. We’re on point with production.

20-4-2020 UPDATE! We’ve finally managed to outwork the back-order list. At this point all back-orders have been machined and will be deburred, cleaned, checked, packed and shipped this week. We’re working day and night to get a fresh batch ready and then the kits will finally be in stock again! There is already a fresh batch of AL6082 blocks waiting for you, so you can safely order your kit at any moment, but please keep in mind we are still busy producing the fresh batch. The sooner you order, the sooner you have it!

SumpThing logo is still missing on the side of the kit – most customers ask if they can get the kit without the logo anyway. We’re looking into etching right now as this is a far easier way to get the logos on the kits.

28-3-2020 UPDATE! The “SumpThing” logo on the side is missing on current batches as we need an extra fixture to get the logo’s machined in the kit. Working on it, stay tuned!

26-3-2020 UPDATE! Due to the massive demand (THANKS!) being higher than productionspeed, we are still a tad behind on orders. Current batch is the last one before being completely done with all back-orders and current orders. When you order now, you are on the fresh batch which will start once current batch is done. Complete kit is being CNC machined, deburred, checked and packed in-house and next to being a full-time motorcycle workshop, it takes some time to get them done. Please email us by clicking here for more info about lead-times. General rule of thumb here is; “The sooner you order, the sooner you have the kit”.

23-3-2020 UPDATE! Machine is running smooth and we’re finally working on last batch of back-orders. Kits will be put “in stock” shortly.

14-3-2020 UPDATE! Extended shipping times due to COVID-19. All open orders are being informed via email. If you have an open order but did not receive this email, please let us know by emailing us at the address we sent the orderconformation from.

11-11-2019 UPDATE! Because we’re still learning the CNC machine, orders are piling up. We are very much aware of this, but are in a tight spot. We’re sorry for the delay. Rocking day ‘n night to get the kits ready!

15-6-2019 UPDATE! We’ve invested BIG TIME and got our own CNC machine! All production will be in-house from now on! My friend Luuc is helping with getting it all up and running. Read more about that here!


Update; Temporary out of stock! Please mail for info



The final solution for all SOHC CB750 oil tank haters.

Wait.. What?

Sumpthing is a complete kit that enables you to remove the external oil tank on your SOHC CB750.


Instead of the original system with the external oil tank, SumpThing reroutes the oil internally into a lowered oil pan. Just like all older Honda CB’s it’s making it a wet-sump instead of the dry-sump. Oil capacity stays the same at 3 Quarts /2.8 liters.

Hmm.. any advantages?


  • First of all, the looks. Many SOHC CB750 owners want the oil tank removed. Some companies offer aftermarket solutions, but they all have an external oil tank and bulky hoses. Not anymore!
  • SumpThing lowers the stress on the internal oil pump, as the oil doesn’t need to be pumped up into an external tank.
  • SumpThing makes for better oil cooling in certain circumstances.
  • SumpThing lowers the center of gravity.

Ok,  any disadvantages?

The only thing we could come up with are possible exhaust clearance issues (explained below).

Awesome! What do I get and how much is it?

The kit comes complete with everything you need. Fresh stainless steel hardware, new gaskets, new o-rings and even a fresh oil filter. You could re-use your oil but we strongly recommend giving her fresh blood while you’re at it – it’s gonna get messy anyway.

Sounds good, how much time does it take to get it on my bike?

You will need around 1 to 3 hours to get it all bolted up depending on your skills, tools etc.

Anything I need to check before i purchase this?

You sure do.

  1. Check your exhaust clearance as the kit will lower the oil pan with 50mm.
  2. Check if this fits your machine, simply make sure it’s in the list below. Please email if you’re unsure whether it will fit your bike.
  • Honda Motorcycle 1976 CB750K A – 750 FOUR
  • Honda Motorcycle 1976 CB750F A – 750 SUPER SPORT
  • Honda Motorcycle 1977 CB750K A – 750 FOUR K
  • Honda Motorcycle 1977 CB750F A – 750 SUPER SPORT
  • Honda Motorcycle 1978 CB750K A – 750 FOUR K
  • Honda Motorcycle 1978 CB750F A – 750 SUPER SPORT
  • Honda Motorcycle Models with no year CB750K3 A
  • Honda Motorcycle Models with no year CB750K1 A
  • Honda Motorcycle Models with no year CB750F A
  • Honda Motorcycle Models with no year CB750K5 A
  • Honda Motorcycle Models with no year CB750K2 A
  • Honda Motorcycle Models with no year CB750K4 A
  • Honda Motorcycle Models with no year CB750K A

Anything i need to know before ordering this?

SumpThing took us over two years to develop and a lot of time and cash was invested into the project. SumpThing is an Outsiders Motorcycles product, and we’re running it with no extra funds. Update; Temporary out of stock! Please mail for info

What tools do i need?

It’s possible to get this working with just the basic tools. Hex keys, screwdrivers, ratchet set and such but a great help are the good ol’ impact screwdriver and a >11Nm torque-wrench.

How about warranty?

Please check our terms and conditions. You have to check the box before you can place an order. This page will be getting lots of updates over time, so check back for more info and pictures.

 *We’d appreciate it if you send us pictures of your bike with the SumpThing kit so we can add those to the product photos.

If you have any other questions, please check the FAQ page on the SumpThing website –