Question about Motorcycles

1 Answer

Misfires and interrupted idle in low rpm

Hello folks, I have problems with my bike and don't know what I should do further. The problem actually came from one day to the other. I start the bike and it sounds great till it gets a little bit warm. What happens ? When I have the bike running and standing, the idle goes up and down it isn't constantly. The sound of the bike is not good at all, I can hear that the flow is interrupted. When I accelerate it seams like the bike won't get enough fuel. This problem exists till about 3 000 rpm, at higher rpm it seems to run great. In the lower rpm when i pull the throttle it tries to suck fuel, goes slower and faster all the sudden. Sometimes the bike even just goes off on me during acceleration. Now I thought it might be the carbs. Took them off, cleaned the carbs, put in a new air filter and the carbs back on. I synchronized the carbs to, but the problem is still the same. I checked the bike for leaks a cant find any. I think the valves are still adjusted good, because the bike starts up without problems. I don't think the piston or the rings are bad, I do not have any smoke in the exhaust. Does anybody have some similar problems or experience with ? I would be very thankful for help. Jason

Posted by on

1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    Top Expert:

    An expert who has finished #1 on the weekly Top 10 Fixya Experts Leaderboard.


    An expert that got 20 achievements.


    An expert that got 10 achievements.

  • Motorcycles Master
  • 40,800 Answers

Sounds like you have a vacuum leak
check manifold gasket, any vacuum lines to carby or vent hole for the tankcap

Posted on Mar 03, 2017

6 Suggested Answers

  • 2 Answers

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

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.

Posted on Jan 02, 2017

  • 9 Answers

SOURCE: 2005 yamaha yzf 250-unstable idle

I had the same problem, Turns out that my shims were finished, replace the chims and check clearences.

Posted on Mar 12, 2009

  • 3567 Answers

SOURCE: carb or manifold or exhaust problem hellllppppppppp

You have an air leak on the intake side of the motor. Get new carb and carb manifold gaskets. Tighten the bolts down evenly in three stages. For the exhaust, try the link below. It is a high temp silicone sealer.

high temp silicone (red)

Posted on Apr 08, 2009

  • 1 Answer

SOURCE: Backfiring

Hi, maybe its the same problem i had, i have a 1200 goldwing where your spark plug are there are holes if these become clogged the water stays there and causes backfiring, get a metal welding rod or steel coat hanger and push through the hole to clear the water, hope this helps good luck.
regards Mark

Posted on May 11, 2009

  • 3567 Answers

SOURCE: high idle on start up with choke off.

This sounds like an air leak is making the fuel/air mixture too lean. Any air leaks between the carb and the head will lean the mixture. Old, hard and cracked rubber manifold parts are the usual culprits. Old gaskets and "O" ring seals can leak air also. A bad head gasket seal happens at times also, as does an exhaust valve not fully seating. Air leaks are the idle speed problem.

A different problem is likely present in the carbs and that is what is causing the rich fuel smell. The carbs must be balanced. Example > If three of four carbs are perfectly balanced and one carb is not, then the 3 are "driving" the 4th carb. This will cause gas to spit into the air cleaner from the "bad" carb and can cause a backfire or two. Special vacuum gauges are needed to balance the carbs. Also be aware the carbs must be scycronizsed as well. The slides on all four carbs must lift at exactly the same time when the throttle is cracked.

Go to the site below where you can see a parts diagram for your specific bike. You will select the actual brand, year, model, etc., once you go to the site. Part numbers and prices are also shown. You can order parts from this site. In the event no price is shown on a particular part, the part is not in stock.

I don't get paid for my answers but I do take pride in them, and I am only trying to help. So if you will, > > A “very helpful” rating for these answers? Thanks!

Posted on Jun 14, 2009

  • 375 Answers

SOURCE: I need tuning specs for my 1982 suzuki gs 750.

You need to fix the fueling first - without fuel it won't run!
Your other problem sounds like an air leak - either the manifold or the carb. Check by spraying WD-40 or CRC at the manifold and carb join while the bike is running - if the revs change (either up or down) you have a leak.

Posted on Jun 29, 2009

Add Your Answer

Uploading: 0%


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



Related Questions:

1 Answer

Feels like miss firing at higher speeds

Your caption says misfires at high, then you say low? You have a 95. Lots of miles I assume. So there are several things that would cause misfires at high and low. First is timing chain/belt, sloppy. Second, would be the valves and rings. Valves worn or bent, not seating right. rings just worn out, not holding compression. Do a compression test and see. Low speed or idle misfires can be from vacuum leaks. check hoses. Low and high rpm misfires can be from ignition problems. Wiring, coil/s, ignition modules.

Apr 04, 2014 | 1995 Chevrolet Tahoe

1 Answer

Misfires and interrupted idle in low rpm under 3000 rpm


Apr 18, 2013 | Yamaha XV 535 Virago DX Motorcycles

1 Answer

My 2000 nissan sentra misfires when gas is applied to the mix but idles well and runs well at low rpm's.what could be causing this problem

You probably have a weak spark plug or injector.
You should get a check engine light and if you have the computer scanned you should have a code telling you which cylinder is not firing.
The problem is there at idle but not as serious as when you put a load on the engine.

Jan 12, 2013 | 2000 Nissan Sentra

1 Answer

The bike was out of use for about 4 months .it stards perfectly but when it is running in low rpm the engine begins to fail but does not stall in high rev it goes well I cleaned up the carb it improved a...

When you cleaned up the carbs did you also clean out the low speed idle jets? They are the first thing to plug up when your bike sits with out gas stabilizer in the tank. The bike runs great at speed but will not idle properly.

Jun 03, 2011 | 1995 Suzuki RF 600 R

1 Answer

I have a 2004 CR125R that i baught in 2006 brand new it has less than 20 hours on it. ever since i've got it, it hasn't liked anything other than high rpm/powerband...if im just riding along at...

Reason is pretty common as these 2 stokes and all 2 strokes they really only designed for one thing - Wide open throttle ! Race track performance. short bursts of flat out to clear all fuel and oil enough to idle through tight corner then straight into wide open throttle again.
Some alternatives for you to try would be lean out the fuel air screw just tiny amount 1 / 8th off a turn in. See if bit leaner setting helps your low RPM a bit also you could consider less oil in the fuel mix 32:1 is pretty high on oil. Most would run these at around 40:1 at the track you don't need to make big changes just adjust to 36:1 first just to check the results - you will soon know if is improvement or not ?
Only change one thing at a time then test ride or you will never know the right direction if the change helps then great but if no change or worse, put it back to original setting and try something else until you find the right direction If the bike is at its best flat out then there cannot be to much wrong thats actually perfect really! so just some very fine tuning should get you where you want to be - Good luck! regards Jamie

May 27, 2011 | 2004 Honda CR 125 R

2 Answers

Misfiring 2007 Honda VFR 800

I would say that your bike may be running a little lean. I usually replace the jets on all my bikes as soon as I get them as the emissions requirements mandate that the manufacturers pass stringent emissions tests prior to the dealer selling them. Some bikes wont even idle or run, especially off road bikes from places like California. and in these cases you must re jet it is a must! I even throw away or drill larger holes into my air cleaner cover.

Good Luck!

Sep 22, 2009 | Honda VFR 800 Motorcycles

1 Answer

Misfiring 2007 Honda VFR 800

try new plugs also maybe a different plug also check air filter is clean

Sep 22, 2009 | 2005 Honda VFR 800

1 Answer

Runs rough at idle and low rpm. misfires. gets better @ high rpm

sounds to me you have a emissions problem check your EGR valve and MAP senser

Dec 28, 2008 | 2004 Chevrolet Malibu

1 Answer

Runs rough at low rpms. Misfires but goes away at about 2000 rpm.

Sounds to me like it could be a Mass Airflow Sensor issue. Or Air fuel mixture problem. Is the harness to the MAF and Trottle control sensors hooked up right? These are just simple solutions that may work. Check all of your fuses as well. One could be blown causeing you DLC not to operate. DLC =DATA LINK CONNECTOR. Find the fuse... read the code.... solve them problem! GOOD LUCK! hope this helps.

Dec 28, 2008 | 2004 Chevrolet Malibu

Not finding what you are looking for?
Motorcycles Logo

Related Topics:

23 people viewed this question

Ask a Question

Usually answered in minutes!

Top Motorcycles Experts

Arnie Burke
Arnie Burke

Level 3 Expert

4514 Answers


Level 3 Expert

75117 Answers


Level 3 Expert

102366 Answers

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

Answer questions

Manuals & User Guides