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Motorcycle Discussions => Japanese Bikes => Topic started by: emmettemmett on July 10, 2010, 01:03:14 PM

Title: Honda 400/4 -> 750/4
Post by: emmettemmett on July 10, 2010, 01:03:14 PM
Hello i'm a beginner in regards to fixing and doing up old motocycles. However i took the challenge in buying a 400/4 a month ago.
I've started replacing worn parts and buying original details for the bike. I heard from a repairman the transformation for a 400/4 engine into the 750 is the easiest he's ever done. I'm interested to know some more details about the matter.
-Is it like he says 'just drops in'
-What else would you suggest changing on the bike to deal with the new engine
-How can i spot a good engine for the transfer
-What is the worst case scenario

Many Thanks
Emmett
(http://i52.photobucket.com/albums/g34/m8inlondon/cb400four0029.jpg)
Title: Re: Honda 400/4 -> 750/4
Post by: rogerwilko on July 11, 2010, 01:40:37 AM
He's talking through his sphincter! Why would you want to change it anyway???
Title: Re: Honda 400/4 -> 750/4
Post by: L.A.B. on July 11, 2010, 10:32:30 AM
Quote from: emmettemmett on July 10, 2010, 01:03:14 PM
I heard from a repairman the transformation for a 400/4 engine into the 750 is the easiest he's ever done. I'm interested to know some more details about the matter.

So why not go back and ask him exactly how it's done if it's that easy?

Which "750/4" (presumbly Honda?) engine is he talking about? Did he mean a "top end" conversion rather than swapping the complete engine?

There are different Honda 750/4 engines, and I seriously doubt an early single overhead cam CB750K or F engine would fit in a 400/4 frame at least not without some serious work? The SOHC CB750 engines are also "dry sump" so you'd need to fit an oil tank to the bike.

If you wanted a 750, then why didn't you buy one in the first place?    
Title: Re: Honda 400/4 -> 750/4
Post by: bobber on July 13, 2010, 08:32:21 PM
what does this repairman fix, vaccuum cleaners?
Title: Re: Honda 400/4 -> 750/4
Post by: esometisse on July 13, 2010, 09:51:19 PM
complete rubbish!
no way will a 750 go in the 400/4 frame!
Title: Re: Honda 400/4 -> 750/4
Post by: dunboyneroadracing on November 05, 2010, 11:34:48 PM
not a hope , engine simply wouldnt fit, top end wouldnt go on either , notings interchangable between the 2 engines
Title: Re: Honda 400/4 -> 750/4
Post by: craignation on December 04, 2010, 11:03:08 AM
Quote from: rogerwilko on July 11, 2010, 01:40:37 AM
He's talking through his sphincter! Why would you want to change it anyway???
correct , even the 550 does not fit , frame is tottaly differant  your mate is winding you up