Topic: 750a motor, can I turn it into a manual?!

[PhotoGeek]

Hey there,

Tomorrow I'm going to pick up a motor out of a '77 750a for really cheap, I want to build a stroker/46mm bore motor, is there anyway I can use this motor as a core for the build? If it's even good, haha.

I understand that is has a torque converter instead of a clutch, but can I convert it over? I'm without any technical details so basically I'm clueless at this point.

Be gentle, I'm still learning about these bikes, and I have no experience with auto bikes.

Thanks a lot, all the best, 
-peter

[eldar]

Well having never looked at an auto in person up close, I may be wrong here. I do not think you can convert it. I think the case is molded different to house the converter. However, it has parts you should be able to use I think. The Hi-Vo primary chain is very strong and the block and such can be used I think.

[Dave L]

Hi
I would think no, as i recall the whole motor is in a diiferent state of tune , the cost even if it could be done would not make it worth whle
There may be some merit in trying to sell it on, there must be someone who needs a replacement for there bike .
I should be noted that you would also need the parking brake lever fitted for it to pass any roadwothy test or mot as its called in the UK ,
THIS WAS STANDARD ON ALL THE 750A AND 400A BIKES .
Dave

[PhotoGeek]

Thanks guys!

Looks like I'll be taking what I need from it and parting out the rest.

Was hoping that I had some easy way out, haha

Thanks again, the quick replies are appreciated,
-peter

[LoopsAndLogic]

I believe the 750a has only a 2 speed trans...... Cause I personally owned the 400a version.

 I might be wrong!  I knew a friend that bored out his 750a, with a mega cam, HD cam chain, and he did some one-off modifications to his trans.

It was amazing

[oldfart]

The 750 Auto is a really interesting animal.  Two clutches, if you don't count the torque converter, one for each "speed."  Actual gears too, but only a few, to facilitate the two speeds.  In reality the trans is an overgrown version of the trailbike type semi auto trans.  I got very familiar with this transmission when a Honda tech back in the 70s because most folks couldn't manage to keep the engine full of oil and therefore burned out the clutches.  That is all that ever went wrong with them, if you don't count the wiring problems (bad enough to warrant a recall).   

[Big Jay]

Don't even try. There are guys looking for those. They drag race them in big money bracket races. With the auto, it can't spin the tire, so it turns the exact ET every single pass. That makes then virtually impossible to beat.

Jay

[PhotoGeek]

So would it be a safe bet to say that I could use the cylinder and head portions of the motor to begin my build?

Thanks again for all of the info, I had no idea they would make a good drag motor, although I suppose that autos throughout the ages have dominated on the strip, aka hydramatic etc.
-peter

[Kamal]

I rode a 750 Auto for a while.

Bottom end is not interchangeable.  You may want to check on the valve sizes and compression ratio.  It is very possible that the motor has dished pistons (lower compression) or smaller valves (more torque), or a bigger combustion chamber (lower compression)...this may lead you to motor that has nothing you are looking for, save some bolts and hardware. 

If you are building a motor, I would skip this, or sell it to someone who needs it.  The regular CB750 motors are a dime a dozen.

Incidentally, the torque converter on the 750A is actually off an early honda civic.  I purchased an extra thinking I was gonna work on increasing the stall speed, but it never happened of course.

Good Luck!

[Sam Green Racing]

When we refer to these bikes as automatics, is it the clutch or gearbox that is automatic ?

I remember the auto 50s and 90s from the early 60s, they had no clutch leaver to let out but, they did have a gearbox that was shifted manualy.

Most of the modern twist and go scooters are fully automatic, electric start, twist the grip and you're gone

How did the 750A drive ?

Sam.

[xtalon]

When we refer to these bikes as automatics, is it the clutch or gearbox that is automatic ?

I remember the auto 50s and 90s from the early 60s, they had no clutch leaver to let out but, they did have a gearbox that was shifted manualy.

Most of the modern twist and go scooters are fully automatic, electric start, twist the grip and you're gone

How did the 750A drive ?

Sam.

Someone can correct me if I'm wrong (because I haven't ridden one since I was about 16 -17 yrs. old and that was a good while ago  ), but if I remember correctly, there was no clutch and two gears.  I want to say one of the gears was like an overdrive, but again.... it's been a long time.

--xTalon

[Sam Green Racing]

When we refer to these bikes as automatics, is it the clutch or gearbox that is automatic ?

I remember the auto 50s and 90s from the early 60s, they had no clutch leaver to let out but, they did have a gearbox that was shifted manualy.

Most of the modern twist and go scooters are fully automatic, electric start, twist the grip and you're gone

How did the 750A drive ?

Sam.

Someone can correct me if I'm wrong (because I haven't ridden one since I was about 16 -17 yrs. old and that was a good while ago  ), but if I remember correctly, there was no clutch and two gears.  I want to say one of the gears was like an overdrive, but again.... it's been a long time.

--xTalon

Thanks --X,  Once started up, do you have to manualy engage the gear and do you have to manualy change to the higher overdrive as you call it, or dose it do it automaticaly ?

Sam.

[merc2dogs]

 On the speedometer are two lines, L is marked from 0 to 60, and H is marked 0 to 100 (1976) so you choose gear for speed you're planning to be in the most, for in town with a lot of stop and go, choose low, if you plan to go faster than plain town driving, or don't have a lot of stop and go use high range, once moving there is no need to change gears.

Ken.

[Sam Green Racing]

Thanks Ken.

Sam.

[Sam Green Racing]

Don't even try. There are guys looking for those. They drag race them in big money bracket races. With the auto, it can't spin the tire, so it turns the exact ET every single pass. That makes then virtually impossible to beat.

Jay

What sort of power will these trannies stand up to Jay ?

Sam. 

[Kamal]

The bike has Neutral, Low and High gears.  There is no "clutch" in the sense of a manual transmission type of clutch.

Basically, the bike rides like an automatic car does, but the automatic function of shifting doesn't exist.  So, you start the motor, put the brake on, and click into low...and THUD, it goes into gear.  Let off the brake, and you are rolling...then click into high, and THUD, it goes into high.  Just like setting the shifter to 1 and then 2 in an Automatic transmission car, never using "Drive", which is programmed to automatically shift from 1 to 2 to 3, etc.

Quite interesting, for sure!

 

[Sam Green Racing]

bump

[nteek754]

PhotoG like someone else said sell it and  get yourself a good K standard five speed engine then start biulding  where they only made these two years they are getting scarce and  yes I garrentee there is someone looking for an extra engine and then the fact of the  racers  that use the 750A  prob find a good swap engine for engine good luck have fun seven fifty four ever Craig in Maine

[eldar]

Well there were actually 3 years made. 76-78 but they are still scarce anyways. Supposedly up in canada they had one in 75 as well but I cant verify that.

[dusterdude]

put that sucker on dragbike.com,someone will buy it.

[Big Jay]

I don't have a clue

[Sam Green Racing]

This guys user name is Honda3303 on dragbike.com. the bike runs low 13s with a 915cc motor, weighs in at the usual 500lbs 

Sam.