Question about Honda CB 750 Motorcycles

3 Answers

I have a 1982 CB750 Dohc Frame RC041023283 eng RC013201156 My Sons bought it for me as at 75 I cannot Kick Start my Triumphs which I gave to my sons. The prev owner sold it as he had problems with it . It never ran properly for me it would start missing after a few miles and replaceing the wet plugs it would run ok for a while. I carried out a compression test and 4 cyls were 125 to 150 psi.I replaced the Ign coils and several sets of Plugs.all no good Itried to check how the eng was running using a colortune and found no4 rich which I adjusted.I could not shift any of the other pilot screws and found on removeing the carbs that they were seized and 2 carb bodies damaged beyond repair where pilot jet is fitted.The Carbs on the bike are VB52A With Prim jet 68 and Secondry 75 I have been given a set of VB42A Carbs with Prim jet 68 and Sec 102 and fitted with an acc pump (not on 52A and they Supposedly came off a running bike) I fitted them as is and the bike ran very erratic spitting and backfireing. I would like to Know (1) Can I rejet the VB42A with the Jets from the 52A P68 Sec 75. Or can I split the 42A and use the bodies to rebuild the 52A . Please help as I am missing out on some good runs

Posted by on

  • 1 more comment 
  • pateli Apr 29, 2010

    The Bike does not have points it has electronic Ign and the Timing is spot on

  • pateli Apr 29, 2010

    This guy does not know hie Hondas

  • pateli Apr 29, 2010

    Dont want replies from this subscriber

×

3 Answers

  • Level 2:

    An expert who has achieved level 2 by getting 100 points

    MVP:

    An expert that got 5 achievements.

    Novelist:

    An expert who has written 50 answers of more than 400 characters.

    Governor:

    An expert whose answer got voted for 20 times.

  • Expert
  • 164 Answers

Memories of my mis spent youth came flooding back when I red C.B750now that ive wiped the tears from my eyes I will try to help you catch up on those missed runs I would be inclined to try rejetting before you go down the road of attempting to fit vb52a inards into th52 bodies if my memoryserves me correctlythe 52a is physicly smaller than the 42 let me know how you get on as there are other alternatives Ican advise you on. Regards Geoff

Posted on Apr 30, 2010

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

    Brigadier General:

    An expert that has over 10,000 points.

  • Master
  • 3,917 Answers

Hi,

Thanks for writing to Fixya.com.

It sounds like your observation about not getting enough gas may be right on target.
Is there fuel in the tank? Are the fuel taps open? Is the tank cap vent plugged?
Verify the fuel flow to the carb to make certain that isn't the problem. This sounds like the fuel taps are plugged or restricted. What are you doing with the throttle while trying to start? Nothing is probably best but some setups start best with a slight throttle opening.


Thanks for contacting Fixya and please accept the solution if it has helped you.

Posted on Apr 29, 2010

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

    Genius:

    An expert who has answered 1,000 questions.

  • Master
  • 1,341 Answers

Sorry I thought the bike was a 1975 when in fact it is a 1982. I would suggest you check the points and make sure it is clean and adjusted properly. Regarding the carb, you can make 2 become 1 but if the parts will fit and bear in mind that air mixture will require careful tuning since it will not be the same as manufactured default. Back firing is often caused by faulty spark, plugs, coil or even bad ground to engine.Also before you consider doing any work on the carb, try to swap the points to a new one.(I assume it has a points engine due to the year of manufacture)

Posted on Apr 29, 2010

  • heeman mohun Apr 29, 2010

    Ok if it is electronic it makes things much easier. After you swap the parts, you will need proper tuning for air intake, gas inlet screws etc which may need changing in order to get to the right combustion mixture. I would advise you seek professional advice on this bit as it is impossible to explain the steps for air mixture over this text.

  • Michael Hansen
    Michael Hansen Apr 19, 2014

    You should also make sure that the rubber-mounts, between the carbs and top-end (engine) is not old and cracked, as this will cause both backfiring, plug discoloration and poor running. If you start engine and let it idle, spray some diesel-start on the rubbers.If engine revs while you do this, the rubbers should be replaced, before you do anything else. And make sure the valve settings (clearance and timing) are correct too. The camchain can "jump" one tooth on either sprocket and still run, but will run bad...

×

1 Suggested Answer

6ya6ya
  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi,
a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
goodluck!

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

Need to remove flywheel on cb750 1981 model to repair starter clutch Any ideas on how to remove


Hi, Stephen for this scenario you will need your service/owners manual if you can't find the first and best tool you ever bought for your Yamaha, despair not, for a mere $0 you can download another one. For more information about your issue and valuable "FREE" downloads that you will need please click on the links below. Good luck and have a nice day.
1980 Honda CB750 Alternator Rotor Replacement
Pulling Honda Stator Rotors Without Having To Fight Them
http://dicky-pickles.org/d/sites/default/files/Honda-1979-1983-CB750-DOHC-Service-Manual.pdf
http://www.partsfish.com/page/oem-parts-for-honda
http://dicky-pickles.org/d/sites/default/files/1982-CB750C-owners-manual.pdf

Oct 20, 2016 | Honda CB 750 Motorcycles

1 Answer

Where can I find my starter clutch om my 1992 CB 750?


Hi, Gerrit for this scenario you will need your service/owners manual if you can't find the first and best tool you ever bought for your Honda, despair not, for a mere $0 you can download another one. For more information about your issue and valuable "FREE" downloads that you will need please click on the links below. Good luck and have a nice day.
Dohc cb750 starter clutch issue
Starter clutch rebuild for CB 750 DOHC
Nighthawk 750 starter issueissue http://motorhead.jactup.com/CB750F2/Honda%20CB750F2%20Service%20Manual%20(1992).pdf


Jul 31, 2016 | Motorcycles

1 Answer

Dirtbike kick star


this happened with my sons pw50 where the piston ring had snapped and when it locked it was stuck bewteen the piston & bore

i would seek a shop or mechaninc to look at the top end and isnpect the piston & rings for wear or damage

dont keep kicking as this could result in further damage

Mar 20, 2014 | 2003 Yamaha YZ 125

1 Answer

Cb750 dohc free manual


http://www.sohc4.net/cb750k-manuals/ has the shop manual for CB750 K1 thru K8

Feb 03, 2014 | Motorcycles

1 Answer

1982 cb750 S I can't see how to remove the seat to access the battery.


Most likely a catch under the left side of the seat, towards the front.

Jun 16, 2011 | 1982 Honda VF 750 S

1 Answer

I just bought Microsoft points but I want them on my sons account


Did you already buy them under your account through the xbox? Or did you buy a card? If you bought a card you just need to redeem them. If you bought them on your account it can be a little more difficult. Is your sons account and yours together on a family plan? I would contact microsoft directly 1800-4MY-XBOX
Thanks,
Lee

Feb 02, 2011 | Microsoft Xbox 360 Console

1 Answer

Iphone


Try cleaning the sim. If that doesn't work try doing a restore in itunes

Aug 01, 2009 | Nokia N73 Cellular Phone

Not finding what you are looking for?
Motorcycles Logo

Related Topics:

448 people viewed this question

Ask a Question

Usually answered in minutes!

Top Honda Experts

Arnie Burke
Arnie Burke

Level 3 Expert

4514 Answers

yadayada
yadayada

Level 3 Expert

75822 Answers

Mike

Level 3 Expert

4336 Answers

Are you a Honda Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...