Question about 1976 Honda CB 100

3 Answers

Honda cb100 motor sezied can i rebore and fit larger piston and ifso what. Thanks

Posted by on


3 Answers

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 10 achievements.


    An expert that got 5 achievements.

    Vice President:

    An expert whose answer got voted for 100 times.

  • Master
  • 738 Answers

In adition to the above coment, which i must say is spot on, the posability of a used barel and piston if a new piston is not available could be worth considering, other things you may wish to check on that particular engine is camshaft seizure, in a uk bike it runs directly in the machined surface of the cylinder head, oil failure due to blocked oil filter has severe consequenses, located on the l/h side of the engine under a 22 or 24mm spaner head cap just below the gear change lever, this is a washable filter retained by a cap and spring, correct replacment is inperitive. are you located in UK? HOPE THIS HELPS YOU

Posted on Aug 03, 2010

Testimonial: "thanks mate wil look at crank when i manage to get the head off."

  • tomlyth1954 Aug 03, 2010

    sorry mate yes uk res. friend bringing me a compleat motor tomorrow but would like to know if the cb100 engine can be maid any bigger like 125 or more?


  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 20 achievements.


    An expert that got 10 achievements.


    An expert that got 5 achievements.

  • Master
  • 3,567 Answers

That cylinder can be rebored. You would go to 1st oversize, 2nd oversize, 3rd oversize, etc., as needed. You won't know what size will be needed until the cylinder is bored enough to clean up the scoring. The problem will be finding a new piston and rings for the bike. You can try babbit's but no promises on a bike that old. You may be able to take the old piston to a Honda shop and have them match it up to a newer bike. You may get lucky.

Posted on Aug 03, 2010

Testimonial: "thanks for the info mate i will get it rebored i was thinking a 125 piston might be fitted but will see what size they are .Tom"

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 10 achievements.


    An expert that got 5 achievements.

    Vice President:

    An expert whose answer got voted for 100 times.

  • Master
  • 560 Answers

I seized my mx360 up 3 times....Each time...I used a 3 blade hone on a drill to bore it out 1mm at a time until I got rid of the score marks...Then, I used a inside micrometer to measure the top, center, and lower bore diameter's...and bought a piston to match my bore and taper measurements. If you only seized the top end, your crank and cam should be fine. Use new oil, and a new filter and you'll be fine..Also, you might want to re jet the carb power jet itself to make up for your new (larger) bore....from 100cc to 110 or 120cc etc. There is a formula you can access to figure it out when done boring...Also, there is a standard guide you can look up to tell you your NEW engine's cubic centimeter displacement...Good luck...and remember the 500 mile break in on those new rings and piston....

Posted on Aug 03, 2010

Testimonial: "thanks guru or tom i do not have the tools to do the boring so will go to a workshop so it can be done and thanks for the running in info"

1 Suggested Answer

  • 2 Answers

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

Hi there,
Save hours of searching online or wasting money on unnecessary repairs by talking to a 6YA Expert who can help you resolve this 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.

Here's a link to this great service

Good luck!

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%


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



Related Questions:

1 Answer

What is the effects of new pistons especially bigger ones in a daewoo lanos 2000 model, can the sound of the car change compare to the standard pistons?

bigger than standard pistons are measured in .010" increments and will require a rebore of the cylinders to fit them
most people fitting over size pistons to gain more power generally increase the size of the exhaust system and fit extractors as well
that will change the tone of the engine , but pistons alone will not

Dec 19, 2016 | Daewoo Cars & Trucks

2 Answers

How to fix 1982 xs 650 yamaha starter?

it could be your button i know this bike very well
does not matter if it is the xs 1 or the xs2 the same set up applies
there are a few components you need to test first
starter button
starter solenoid
main fuse

i will also tell you some major mods i did to one
when i was dragging the xs650 at super twins
which included a rebore to a 1056cc and having 7 gears
and a turbo

to eliminate the button
with the battery still connected
get a spanner or a screwdriver and not doing it to long
arc out the two polls on your starter solenoid
if you do not know what that looks like follow the main red wire
that goes from your battery
the first stopping point will be the starter solenoid
one poll clamps the main wire from the battery
second poll clamps the main wire to your starter motor
arc out the two polls with a spanner or a screwdriver
to test the motor
if your motor turns the engine then it is not your starter
the problem lies in either your

starter solenoid, (this is a sealed unit replace unit with a new one)
the wiring, (test main wire from your ignition to your switch
also test wire from your switch to your starter solenoid also clean all your wiring connectors)
your starter button, (strip and clean)
main fuse, (replace with a new one)

if the motor does not turn
then you will need to remove the starter motor
before you take the starter motor apart
test it with a multimeter
set on omes test each wire on the body of the starter motor starter
to check if the windings inside are earthing out on the body
if there is a reading on the multi meter
then your windings are earthing out
if there are no reading it may just need a clean up and new brushes fitted
and reassemble your ride


if you play or really want to play there are a few major mods you can do that have been tried and tested

parts needed
slab billet alloy 13in x 8in x 1.5in (for stroker kit)
or a pre brought stroker kit from halco tuning or wisco
get 2 mercedes benz 2.3 pistons ( for rebore)
2 barrel liners
find a good engineer and rebore your barrels and fit new sleeves
fitted with your 2.3 pistons

by fitting the stroker kit you will lose the standard top engine mount
or have more made as you by now should know a good engineer

remove kick starter reduction gears
find a good engineer and have 2 more gears made up
and fit

tried and tested turbo fitting
a mk 1 land rover turbo is small
and can be fitted under the carburettors
with a heat shield fitted between the carbs and the turbo

these are all mods i have done to the xs650
i built and raced i got to 180 mph over the 1/4 mile strip
with a xs650 hardtail chop that looked like a standard engine

have fun

Jun 22, 2014 | Ford 8n,9n,2n, Tractor Starter With Drive

1 Answer

Excessive carbon on spark plugs which causes to fail

carbon on sparkplugs are caused by oil in the combustion chamber.

here are some things to do:
1. replace the sparkplug
2. replace your head gasket
3. check if your ignition timing is correct (timing in the distributor, camshaft, and crankshaft)

if these does not solve your problem, try this:
1. have your cylinder head checked for leaks/cracks
2. replace your piston rings

lastly, if all of these dont work, this is the solution (but quite pricey)
1. have your head rebored. reboring the cylinder head means making your combustion chamber wider so cracks/leaks on the wall will be removed.
2. after rebore.. you have 2 options: resleeve or replace piston rings. Resleeve means inserting sleeves in the bored chamber to replace the removed part. replacing pistong rings is also an alternative since your old one will not fit anymore ot the rebored head.

Aug 12, 2011 | 1992 Nissan Sentra 4 Door

1 Answer

Need piston clearance value on a rebore for a 1964 Honda c105 and can push rods be straightened? Frame# c105-0040778 what year?

Piston clearance is .002. The push rods can be straightened, be careful not to crush them. It's also not critical that they are perfectly straight. Not sure about the year, Honda actually didn't create "model years" until 1972. They used a letter and # designation (for example, 68-71 CB 750's are K1) until the changed something about the bike.Good luck!

Jun 09, 2011 | Honda Honda Passion Plus Motorcycles

1 Answer


replace piston and rings and gudgeon pin and bearing , check condition of con rod for wear also ! check bore for wear and if it can be rebored ! ?? it will fail and cause more damage !!!

Feb 06, 2011 | Sherco 5.1i SM Motorcycles

1 Answer

1998 Honda.Just got cylinder rebored, does the cyl...

Clean all the dirt and grit off the cylinder, coat the cylinder wall with motor oil and install piston,

May 18, 2010 | Motorcycles

1 Answer

Kickstarter lever for a 1971 Honda CB100,

i had one of these and i think one from a honda cb125 - cb250 or even a cg 125 one will fit

Apr 02, 2010 | 1971 Honda CB 100

2 Answers

Oil blowing from breather pipe Honda 250

Take out engine Strip down and replace the Piston rings and check bore if got a ridge in it where the top ring stops then rebore it and fit new oversize rings
If worn bad then also new piston as well thats the only way to stop the oil from coming out of the Breather and give you back the power you lost ..
Easy done so do it and enjoy riding the Buggy

Oct 07, 2009 | Honda CB 250 Motorcycles

1 Answer

93 cr 125 has lack of power and a loud nocking

In a 2 stroke engine there are no valves and thus no adjusting required.The itself acts as a valve too.
Maybe you will have to rebore the cylinder and fit an oversize piston -kit or if the cylinder is to its tolerance thn fit in new setoof piston rings.

Jul 23, 2009 | 2005 Honda CR 125 R

Not finding what you are looking for?
1976 Honda CB 100 Logo

Related Topics:

627 people viewed this question

Ask a Question

Usually answered in minutes!

Top Honda Experts

Arnie Burke
Arnie Burke

Level 3 Expert

5057 Answers


Level 3 Expert

81400 Answers


Level 2 Expert

342 Answers

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

Answer questions

Manuals & User Guides