Topic: CB750 K ENGINE REFINISHING

[steviewonder]

My CB750 KO die cast engine/gearbox is being totally rebuilt aiming to make the insides perfect, but what about the outside?

The lower and upper crankcase are painted silver, as are the barrels and cylinder head - were they when new? If so what is the correct paint?

Can anyone advise on blasting/ coating options that have proven to be durable? I'm told just blasting Japanese engines doesn't come up as well as Italian engines and I doubt this would be durable. What coating experience might you have?

I have had the carbs and oil filter case restored by vapourworx and am delighted with the finish, so may well go back to Ben there if he is able to help with the big stuff.

All good and more importantly bad experiences much appreciated.

[bryanj]

Whatever you do clean, clean and clean again all oil paths or you will be fitting a new cam etc

[Stev-o]

Welcome from Texas Steviewonder!

The cases, cylinder and head were painted silver. Here in the U.S. most of us use high temp paint such as VHT Univ Aluminum...

https://www.amazon.com/VHT-SP127-Engine-Universal-Aluminum/dp/B000CPIMVW

I had my Kawasaki engine vapor blasted as those were not painted from the factory and it looks amazing and has held up nicely.

I believe you blokes call it wet blasting over there?

[Doobie]

I use this: https://marblesmotors.com/product/honda-engine-cover-paint-matched-color-silver/

[steviewonder]

Thank you for the feedback folks.

Yep, for sure the insides will be cleaner than an Andrex puppy! US translation = bathroom paper.

Thanks to both our UK and American friends for confirming they were originally painted and the links to suitable products.

Anyone out there refinished with other coatings?

[Progas]

Dupli-Color part number #1615 is an exact match and less than half the price! It's all I use on my restorations. You can get it at an Auto parts store.

[BenelliSEI]

Dupli-Color part number #1615 is an exact match and less than half the price! It's all I use on my restorations. You can get it at an Auto parts store.

+1. On all my restorations, very close to original and durable.

[Ujeni]

Ive used Duplicolor 1615 Aluminum engine paint for years...good stuff. That is until I tries the stuff I use now: POR15 Aluminum engine enamel. Exact same color as the original and duplicolor. You can spray it with a gun, which means you can get much more even coats. Out of curiosity, I painted two oil pans from cb750 sandcasts; one with duplicolor 1615 and one with POR15 engine enamel. I followed the directions for both products to fully cure them and then scraped a key across them to see which would stand up better. The duplicolor help up well. The key scratches could be seen, but were not bad. The POR15 engine enamel simply show ZERO scratches. I could not believe it. Significantly stronger. The POR15 does not require a primer either. But like others have said, it really comes down to cleaning a lot!

[Nurse Julie]

As you are in UK, you need Simoniz SIMVHT31D Engine Enamel. We have done many, many engines for customers and our own engines and its the closest we have ever found. Get it off ebay, it's aboy £7 a can at the moment and you will need 2 cans. Read instruction carefully.

[steviewonder]

Thanks Julie, I'll get some of that as the US recommendations are not available here.