Question about Honda CR 125 R Motorcycles

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I have a 2000 cr125 that is making a bad knocking noise when i start it up. i was adjusting the throttle cable and when i started the bike up it was throttled way up probably at redline and didnt have a killswitch hooked up so i turned the gas off to run it down. But, when i started it back up it started fine but the motor was making a bad knocking noise. I replaced the piston, the piston ring and the wrist pin bearing but the noise still did not go away. ANY THOUGHTS??

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Thanks for using FixYa.

The problem is not with the piston. Its the bore of the cylinder. You might want to put an over-sized piston ring in there. If that doesn't help, you probably need to replace the cylinder block already. Ouch..

I hope this helps. Thanks and good day.

Posted on May 15, 2010


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Hi, Radhika I would love to help you with your engine or chassis noise but I just loaned my brand new pair of listening ears to your local dealer's chief technician so he could take your bike for a test ride and give you his professional opinion and estimate about your noise and repair cost. If you are a little short on "DRACHMA" and a Dealership is not on your list of fun places to visit then perhaps the list below will help soothe your worried mind so you can make an informed decision.
1. Bearings---SCREECH
2. Belts---CHIRP
3. Brake Rotors---BUZZ
4. Chains---RATTLE
5. Clutches---CHATTER
6. Shifting Trans---CLUNK
7. Gears---WHINE
8. Front Forks---PLUNK
9. Rear Shocks---SQUEAK
10. Starters---CLICK
11. Solid Lifters---TICK
12. Hydraulic Lifters---TAP
13. Pistons---SLAP
14. Connecting Rods Go---KNOCK-KNOCK---who's there, it's me "*****"
If your scooter is hard to start then the usual suspects are:
1. Spark plugs in bad condition or have an improper gap or are partially fouled.
2. Spark plug cables in bad condition.
3. Battery damaged or nearly discharged, should have 12.5 volts.
4. Check battery terminals for damage or corrosion, check the battery cables at "BOTH" ends for loose, corroded, or broken connectors, "INSIDE" and outside the cable harness, perform connector wiggle test and check cables with an ohmmeter if necessary.
5. Throttle controls not adjusted correctly.
6. Water or dirt in the fuel system.
7. Water or dirt in the carburetor.
8. Intake air leak.
9. Fuel tank vent hose and vapor valve plugged, or fuel line closed off, restricting fuel flow.
10. Enricher valve inoperative.
11. Engine lubricant to heavy (winter operation).
12. Ignition is not functioning properly (possible sensor failure).
13. Faulty ignition coil.
14. Valves sticking.
For more information about your issue and valuable "FREE" downloads that you will need please visit the websites below. Good luck and have a nice day.
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Nov 19, 2016 | Honda Activa Motorcycles

2 Answers

Cleaned carbs on 1989 Radian 600, now idles at 6-8K RPM. Please help.

Please check the following:
- Throttle control cable adjustment.
- Foreign matter in throttle plate.
- Fuel line clogged.
- Water contamination in fuel.
- Vacuum leaks in the intake manifold or at the carburetor.
- Carburetor base gasket or seal.
- Air/ fuel mixture adjustment.
- PCV valve.
- Valve clearance.

May 08, 2014 | 1989 Yamaha YX 600 Radian

1 Answer

2004 Honda CR 125 R very high idle

Hi, Anonymous and the usual suspects are:
1. Throttle cables improperly adjusted, pinched or need lubrication.
2. Idle adjusting screw needs to be backed off.
4. Air fuel mixture adjusted too lean start with 2 full turns.
5. Intake system air leak.
6. Fast idle choke ramp is not releasing.
7. Broken throttle return spring.
8. Damaged diaphragm or slide.
9. Faulty MAP, TPS, ATS, O2, sensors or wiring/connector.
10. Multiple carburetors not in sync.
For more information about your issue and valuable "FREE" downloads that you will need please click on the blue links below. Good luck and have a wonderful day.
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Apr 17, 2014 | 2004 Honda CR 125 R

1 Answer

What is the float level on a cr125 2003

Special Requirements
  • Motocross bikes like the 1994 CR125 have a few special needs. If a motorcycle takes jumps, its orientation changes, so it has to have a carburetor sympathetic to that need. Otherwise, you may find yourself airborne with no fuel to make adjust the position of the bike by blipping the throttle or to make a smooth transition by rolling the throttle on when you land. Another consideration is that motocross bikes fall over more often the street bikes. So, they need a carburetor that can withstand a little abuse. The Keihin PJ 36 has a vertical plunger-choke, smaller and more protected than tab-chokes often found on street bikes, making less apt to get damaged if you tip the bike over, or pick up debris.

Jan 15, 2013 | 2003 Honda CR 125 R

1 Answer

How do you lower the idle on a 2004 cr125?

There should be a screw in the carb body turning this in raises the tick over turning out lowers it normally. Check the throttle cable[s] adjuster is set correctly. Also check that the throttle action is free running if the cable is not well lubed this can prevent the carb slide from seating at the proper level inside the carb. Some bike have adjusters on the carb top make sure this is not keeping the slide from seating. If you get somewhere fairly quiet open the throttle about half way and let go you should hear a metallic clink as the slide seats on the stop.

Aug 01, 2012 | 2004 Honda CR 125 R

2 Answers

I have a 2000 r1150gs and when i take off in first gear, i get this spring and knock noise like the kickstand is automatically coming up kinda sound. 23k on the motor.

I've always gotten the same type of noise you describe after I take off in first gear after starting the bike. This is my ABS brake system setting up and is totally normal.

May 07, 2012 | 2000 BMW R 1150 GS

1 Answer

Knocking noise on idle

Most likely the rocker shaft end float that needs to be adjusted.

Apr 16, 2012 | BMW R 1200 GS Adventure Motorcycles

1 Answer

How do you reset the throttle body limiter screw ( the one preset by factory). The previous owner has altered it and I need to reset it. 2000 R850R

Do you have a vacuum comparison guage? You need some kind of guage setup to work on the TB sync.

Here is what I would do:
-perform a valve clearance check/adjustment to ensure everything is in spec. (this does make a difference!)
-Ride bike for 10-15 minutes, make sure it is fully warmed up.
-connect your vacuum guages to each throttle body.
-ensure that there is throttle cable slack on each throttle body. You don't want the cables holding the throttle plates open at this stage.
-set the brass air screws out equal turns on each side. Start with one and a half turns from bottomed.
-start engine (it may not want to idle, so open brass screws another half turn till it idles)and check vacuum guages.... see how far out things are at this stage.
-adjust throttle stop screw(s) so that each throttle body is set-up exactly the same.
-Once the throttle bodies are adjusted so that the vacuum is exactly the same at idle, start to remove slack from the throttle cables so that vacuum stays the same on each side as the throttle is opened.
-above all, you want the throttle plates to rest on the stops at idle and the cables adjusted with enough slack to allow this to happen. DO NOT tighten the cables too much as this causes the throttle plates to "bounce" at idle and wears out the throttle plate shaft bores quickly.

I think that about covers it, Post back if you have questions.

Nov 17, 2010 | 2005 BMW R 850 R

2 Answers

Start and..

Could be your timing chains are very loose, they will make a noise on start up. Also, when was the last time you adjusted the valves? If they are way out of adjustment, ( on the lose side) they will make some noise.

Nov 20, 2008 | 2000 BMW R 1100 RT (ABS)

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