Topic: 78 cb750 intake boots for CR29

[sazaver]

Hi there,

I have been draining my sleeping hours in order to find a solid solution on this issue.

For my 836cc engine, I want to buy a set of CR29 carbs for my k8 cb750. As you may know, the intake boots for 77-78 years are NLA at honda and other suppliers. Since I am dedicated to run this overbored engine without any idling or performance issues because of the air leaks, I want to change the intake boots with brand new ones.

Buzz from DYNOMAN suggested that the mounting spigots of the carbs, can be changed with the early 36mm ID ones, rather than the 40mm ID 77-78 spigots and mount the carbs with the rotated/flipped 71-76 intake boots.

Which path should I take? Should I try to get custom boots for CR29s? Will running smaller intake boots mess up the performance on cylinders #2-#3?

OR, does anyone know a source for brand new NOS 78 boots?


thanks.

[bytio]

http://www.partsnmore.com/parts/honda/cb750/?filters

[MRieck]

The early intake manifolds are a straight bolt on for the 78K head...it is the F2 head that is different. I have done this several times to fit early style carbs on the 77/78K head. You may have to change your throttle cable(s) but other than that get some sleep.

[wiskey]

http://www.partsnmore.com/parts/honda/cb750/?filters

Whatt!?
anyone use these?

[MRieck]

http://www.partsnmore.com/parts/honda/cb750/?filters

Whatt!?
anyone use these?

One of the guys I know on the board got a set of F2 boots and said they appeared to be OK from a material stand point. Other reproductions haven't worked out because of the ethanol.

[Retro Rocket]

http://www.partsnmore.com/parts/honda/cb750/?filters

Whatt!?
anyone use these?

One of the guys I know on the board got a set of F2 boots and said they appeared to be OK from a material stand point. Other reproductions haven't worked out because of the ethanol.

Hi Mike, is it possible to put the F2 spigots into a k8 head.?  Is there any advantage in doing this to a hypo K8  head ?