Question about 1988 Honda CBR 400

1 Answer

Engine missing threw full rev range and rpm fluctuating at idle

The engine missing al the time under any revs, leads and plugs fine. and at idle 3it jumps between 1000 and 3000 rpm

Posted by on

  • Anonymous Mar 30, 2014

    sounds like missing at idle clears up at 2000 rpm

×

1 Answer

  • Level 2:

    An expert who has achieved level 2 by getting 100 points

    MVP:

    An expert that gotĀ 5 achievements.

    Novelist:

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

    Governor:

    An expert whose answer gotĀ voted for 20 times.

  • Expert
  • 83 Answers

Sounds like you definitely need to do a major tune up, that being you need to adjust the valves and cam chain. You most likely have very tight valves which will cause the erratic idle and misfiring. I'd also check to make sure you don't have any air leaks in the intake manifold. A cracked manifold will certainly cause a problem like this. One last thing would be to make sure the carbs are synchronized. If they are out of synch you will never get the bike to idle smoothly.
Let me know if these recommendations help or not. I'll advise after you post your findings.

Posted on Dec 08, 2008

Add Your Answer

Uploading: 0%

my-video-file.mp4

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

×

Loading...
Loading...

Related Questions:

1 Answer

Yamaha yp 400 2005 majesty will not go faster than 50 mph and revs no higher than 4500 rpm what is the problem?


Fuel starvation? Twisted or kinked fuel line? Some may be getting through to run the engine but not enough under load. Throttle adjusted properly? Only enough movement for low rev range.

Oct 11, 2015 | Yamaha Motorcycles

1 Answer

Tgb 101s pinging and missing at medium to high revs


maybe it went to low revs cos the plug was fouling, if so upping the idle will just make the problem get worse quicker

Feb 14, 2013 | 2011 TGB 101S 50

1 Answer

My aprila rs50 starts fine and runs fine cold but if it heats up abit you pull the throttle and it sounds like its dieng


Instructions
    • 1 Park your RSV 1000R on a well-ventilated, level area, using its kickstand.
    • 2 Start the engine and let it idle in place until the temperature gauge built into the instrument cluster indicates a minimum internal temperature of 180 degrees Fahrenheit. This is the motorcycle's ideal operating temperature.
    • 3 Take note of the engine idle speed, using the tachometer needle, while the engine is running. Ideally, the engine should idle steadily at 1,250 rpm.
    • 4 Adjust the engine idle speed to 1,250 rpm, using the idle adjuster screw hidden between the lower right edge of the fuel tank and the upper edge of the right middle fairing panel. Turn the idle adjuster screw clockwise to increase the engine idle speed, or counterclockwise to decrease the engine idle speed, using a small flat screwdriver if your RSV 1000R's frame (VIN number) precedes ZD4MEE009YS000292. A plastic knob allows the engine idle speed to adjusted by hand on RSV 1000R models with a frame (VIN) numbers starting from ZD4MEE009YS000293.
    • 5 Rev the engine two to three times and observe the tachometer. The engine should return to a 1,250 rpm idle. Adjust the engine idle speed as needed, using the method described, then rev the engine again. Problems may exist within the throttle control, fuel-injection system or engine, if the engine idle speed will not hold steady at 1,250 rpm. Contact your local Aprilia service facility for assistance.
    • 6 Stop the engine, once you have obtained a steady 1,250 rpm idle speed.

Jan 17, 2013 | Aprilia Motorcycles

1 Answer

Just bought a 1993 suzuki gsxr 750. has been sitting in a garage for 2 years. we took the carbs off and cleaned them really well, changed the oil, and air filter and we added new gas. bike starts up and...


If is runs better with full choke, then the bike is lean, check for air leaks at the carb manifold, vacumn cracked hoses, non standard exhausts, perhaps the mufflers have rusted out while sitting

Apr 24, 2011 | 1993 Suzuki GSX-R 750 WP

1 Answer

Vmax will start and barely run only under full choke


If it can idle then still hope to help out else need to rebuild/clean carb out (cost a lot). If can idle then get yourself 2 bottles of fuel injector cleaners, pour 30ml to 5L fuel, let engine idle for 15 minutes, give some spur high3000 - 5000 RPM revs followed by a constant 3500 RPM rev for 15 sec then repeat process again another 3 times. Ride itnormally as if you are breaking it in until next time refuelling, add another 30ml and do the same process before riding it again. Do the same thing for the next 500 km.

Apr 15, 2010 | 2002 Yamaha V-Max

1 Answer

How to tell if the rectifier is bad rode for a couple of hours and started fine the last time when we started it, it was dead so its either stater or rectifier


hi,this might help,if you have a digital volt meter,take a reading across the battery at rest(key off)should be about 12.8-13.2v.start the bike and take a reding across the battery if the bike is charging properly the meter should read between 13.8-14.2-14.4v.to check if the regulater is working correctly,connect the meter across the battery and slowly lift the rpm from idle up to about 3-3500rpm,the reading on the meter shouldnt vary much more than 1-1.5v across the rev range,if the reading fluctuates up and down with the rpm(more than about 1-1.5v)then the regulater is faulty,and obviously if the battery is showing no difference from rest to high rpm then the stator is probably at fault..hope this helps..cheers

Mar 21, 2010 | 1981 Suzuki GS 750 L

1 Answer

My fzr400 starts fine but misfires under load and wont rev past 10000 rpm


check your timing and plugs and make sure there are no signs of ware in the HT leads

Dec 17, 2009 | 1989 Yamaha FZR 1000

1 Answer

02 GSXR Limits to 4800rpm, drops to idle, when warm not cold.


If you have the stock computer replace the power commander with the stock computer then see if the problem still remains. If it goes you can be sure the problem lies within your commander and it will need to be remapped or replaced...Good luck

Nov 02, 2009 | 2005 Suzuki GSX-R 1000

1 Answer

CBR 400 NC29 not pulling through rev range


The carb has serveral jets for different Rpm ranges. If you have a problem with one range, that specific jet is probably blocked. Idle jet, low jet, intermediate jet, high jet. some bikes have more. Sounds like a jet problem to me Run Seafoam cleaner in a couple tanks.

Apr 30, 2009 | Honda CBR 400 Motorcycles

3 Answers

Engine stutters when turned on


Try it with the fuel tank on reserve

Jan 18, 2009 | 2000 Yamaha XJ 900 S Diversion

Not finding what you are looking for?
1988 Honda CBR 400 Logo

364 people viewed this question

Ask a Question

Usually answered in minutes!

Top Honda Experts

Arnie Burke
Arnie Burke

Level 3 Expert

4481 Answers

yadayada
yadayada

Level 3 Expert

61249 Answers

Gino Cussen
Gino Cussen

Level 2 Expert

216 Answers

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

Answer questions

Manuals & User Guides

Loading...