CB750A carburation - anyone worked on this?

[CB750A]

Having had, worked on and restored CB750s (since 1969!) I took up the challenge of a Hondamatic. Bought a bike, unseen, but it turns out someone has removed the anti-stall device (and associated solenoid and airbox). Has anyone run one of these without the anti-stall? The carbs are 28mm, not the usual 30mm as per the manual version.
I don't want to waste a year minting the bike if I can't get it to run right. The parts required seem to be hard to find - also there doesn't seem to be the parts on the linkage to connect to, in any event.
If anyone else has one of these, I would appreciate having a look to see exactly what is required. I have even considered manufacturing the parts, if that is the only way out. Any help much appreciated.

[AshimotoK0]

You need to talk to Hondaking on here (Ron Thorn) but he doesn't come on here now. I will Facebook message him for you. Ron restored one a couple of years back.
Welcome BTW

[CB750A]

Many thanks. I don't do Facebook but hope Hondaking and I can get together on this.

[Green1]

Can't get my head around an auto but welcome anyway 

Mick

[AshimotoK0]

Please don't put this guy off ... not so sure that's what happened to Ron and he went over to FB instead. A really lovely guy, who no longer joins us on here. Not everyone's bag I know  but this new member is telling us he has a long history with Cb750's so probably knows his onions. I  too am not really part of the FB generation but  mark my words it is definitely worth joining a model related closed group ... If you don't believe me ask JamesH

[Green1]

Not trying to put anyone off there are members on here that have superdreams I still talk to them. 
There are many bikes I don't like or understand why people like them all that matters is the owners like them

[AshimotoK0]

Will PM Ron's email address .. he say's he's always keen to talk Honda's .. he's done some awesome restorations and I think doing them is really good therapy for him as he's suffered poor health over the last few years. his latest bike is an awesome CBX1000.

[hondaking]

Hi CB750A

Ash has just mailed me about your problem. Like he has said i do have one restored and even though i have three other cb750's from k2 to f2 i so enjoy the Hondamatic  please send me a message to my email address Ash has it and i have sent him a message for him to send it to you. And dont take any nonsense of some people on here the Hondamatic is a work of art and dont put something down till you have tried one   

[hondaking]

Thanks Ash your a star yourself and have helped me loads in the past. And yes i have been unwell and lucky to still be alive and kicking

[K2-K6]

I'd like to haven't a ride on one of these, could be interesting around here in London as it's so crowded with many interruptions to traffic flow.

Don't know if car stuff has any relevance to this installation, guess Ron will known more. Auto cars of past era used a bypass air valve going from the filter side of throttle body to engine side and bled air in to vary the tickover. The type I'm most familiar with (Rover V8) has the coil low tension pulse monitored to give rpm check and a small cone moved by a stepper motor to open and close the air supply and hence pull rpm up and down.

The valves are not car specific and often fairly common even across different manufactures that use the same supplier. Often called IACV or something similar,  meaning "idle air control valve".

It'll be interesting to see a renovation of the bike,  after all it is a SOHC.

[SteveD CB500K0]

Most modern fuel injected bikes use IACV.  My 955 Sprint used one valve with a stepper motor and three rubber pipes to the injectors. The pipes rotted - if you find a 20 year old fuel injected Triumph that won't tickover, that's usually the problem.

[CB750A]

This is the crazy new member that has a Hondamatic. Thanks for all the interest and involvement. As one of you hinted at, I do know a thing or two about CB750s. I bought my first in 1969 from Elite Motors in South London. I went in to buy a mirror for my 6 month old Trident, and came out with a red CB750! I let a friend have a go about three weeks later and he proceeded to write it off trying to round a bend at 100 MPH. He survived, but the bike did not.
There were no more red ones in the UK so I ended up with a blue one (the insurance in those days seemed to cover the bike, rather than who was riding it).
Since then I have had a host of bikes and restored many classics. I thought I would have a go at the Auto, as it was so quirky. So - I am not a complete lunatic, but I do need some help with this one, due to some of the bike not being there.
If someone could forward Hondaking's email address to me, that would be greatly appreciated. Thank you all for your input and interest.

[hairygit]

I did have a 40 mile ride on a 750A about 20 years ago, it was a nice ride once I'd got used to using the brakes much more than I was used to due to the lack of engine braking. Also the engines are seriously de- rated from the regular 750's, not sure why Honda did that, maybe they thought the transmission would not handle the full power engine, or more likely they didn't want huge law suits against them if people started crashing them because they were so easy to ride quickly, but scary having to rely totally on the brakes. Don't think I'd buy one, only because the parts are really scarce today, but I would like to ride one for a week or so for the experience again. Good luck with it.

Sent from my X6pro using Tapatalk

[AshimotoK0]

Hi I PM'D you the day you posted As below :-


"Hi and welcome .. would love to hear stories of you 1st CB750. Mine is 1010382 from the 1st batch of UK imported bikes.

Ron's email is ronthorn@yahoo.co.uk and he's keen to talk Honda's anytime.

Best wishes .... Ash    ashimoto750@gmail.com"

[Green1]

keep us posted with your progress.
Just because I don't get an auto motorcycle it doesn't mean I'm not interested 

Mick