Motorcycle

Motorcycle Questions? Ask a Mechanic.

Ask an Expert,
Get an Answer ASAP!

Motorcycle

Backfires thur throttle bodies and exhaust all new parts

Customer Question
all JA: How many miles are...
backfires thur throttle bodies and exhaust all new parts all
JA: How many miles are on the car? How has your mileage been lately?
Customer: brand new 06 gzxr 1000 will idle will reav up but backfires
JA: What is the model/year of your motorcycle?
Customer: motor is in mini sprint
JA: What year is your Sprint?
Customer: new wireharness
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: new seneors ecu comp test leak down all is spot on
JA: Anything else you think the mechanic should know?
Customer: did not check cam timming but guy that rebuit it benn doing it for 30 yyears
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Motorcycle Mechanic about your situation and then connect you two.
Submitted: 1 year ago.Category: Motorcycle
Show More
Show Less
Ask Your Own Motorcycle Question
Answered in 1 hour by:
6/19/2016
Motorcycle Mechanic: Matt, Engineer replied 1 year ago
Matt
Matt, Engineer
Category: Motorcycle
Satisfied Customers: 22,460
Experience: Honors degree in Mechanical Engineering, worked 8 years as a Formula 1 engine engineer.
Verified

hello

to get a backfire when running, either the coils are connected on the wrong cylinders ( so wrong firing order) or there's a lack of compression or the engine is running extremely lean

I'd start by double checking your coil wiring and if you're sure this is OK then I'd repeat the compression test with a squirt of oil in all the cylinders to see if the reading flies up - as this will show if the bores are worn

and if thats OK then check for any leaks after the throttles as any air dragged in here isn't 'seen' by the ECU and so not compensated for and can lean the engine out and can also allow the engine to rev up when not desired causing rough running.

As its a mechanical fault it tends not to turn on the fault light and you can sometimes hear a 'hissing' noise with the engine running.

Check the hose clips for tightness and inspect the trunking for any cracks or splits and also all the vacuum system, the small bore pipes and fittings for cracks and missing parts.

The best way to locate a leak is to have the engine running and warm and then spray lighter gas /propane around each joint in turn. If the engine rev's up you've found your leak.

Now you might think that spraying lighter gas around a hot engine isn’t wise, however the flash /ignition point of gas is about 400°C so you need a naked flame or spark to set it off and I’ve used this method for many years without incident.

Work your way through each possible joint one at a time and you should find it. I use a slightly flattenedpiece of brake pipe and some rubber hose from the can of lighter gas to provide a spraying 'wand' and allow a direct blast of gas into each area, especially those difficult to reach with large implements.

It’s also worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a poorly pump will all result in insufficient fuel being delivered to the engine

Ask Your Own Motorcycle Question
Ask Matt Your Own Question
Matt
Matt
Matt, Engineer
Category: Motorcycle
Satisfied Customers: 22,460
22,460 Satisfied Customers
Experience: Honors degree in Mechanical Engineering, worked 8 years as a Formula 1 engine engineer.

Matt is online now

A new question is answered every 9 seconds

How JustAnswer works:

  • Ask an ExpertExperts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional AnswerVia email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction GuaranteeRate the answer you receive.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

I would (and have) recommend your site to others I was quite satisfied with the quality of the information received, the professional with whom I interacted, and the quick response time. Thanks, and be sure that I'll be back whenever I need a question answered in a hurry.

Stephanie PElm City, NC

used your service this weekend with "Trecers" help. thank you ,thank you, thank you. replaced an A/C fan motor. Local Auto Zone had part. $15.00 "tracer" fee and $40.00 for parts, I saved several hundreds of dollers at a shop. i will recommend you and use you in the future.

David L.Richmond, TX

9 dollars, 2 hours of my time, and I drove away. Your diagnosis was right on the mark. Thank you so much.

PhilMarysville, CA

Lurch. Thank you very much. I had real doubts about this website but your promptness of response, quick followup and to the point answer with picture was incredible.

CharlesWalnut Creek, CA

As a single woman, I really appreciate an excellent and affordable opinion.
Thank you Geordie, I will not hesitate to contact justanswer in the future!

SueCharleston, WV

Another great insight to what may be the problem. I will have my mechanic take a look at it tomorrow. Thanks again, Frank...you do indeed know your stuff.

JimCastleberry, FL

Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help.

Mary C.Freshfield, Liverpool, UK

< Previous | Next >

Meet the Experts:

Jeff Policky

Jeff Policky

Motorcycle Mechanic

2,425 satisfied customers

Yamaha Gold, Suzuki Gold, Honda Bronze, Polaris Bronze, BRP

Louie

Louie

Technician

1,281 satisfied customers

25+ yrs. experience

TIMOTO

TIMOTO

Motorcycle Mechanic

1,233 satisfied customers

Honda registered technician, silver level award, former Kawasaki/Suzuki tech, 40+ years exp.

Andre Pilon

Andre Pilon

Motorcycle Mechanic

1,032 satisfied customers

Over 25 years experience, ICS, MMI, Owned shop for 12 years, worked tech-support for Harley Davidson

Kenny O.

Kenny O.

Motorcycle, ATV, Mules, Side by Side's Product Specialist. All Brands

619 satisfied customers

Worked for Kawasaki Motors as a Product Support Specialist (Factory Support) for 24 years

asphaltcycles

asphaltcycles

Motorcycle Mechanic

458 satisfied customers

I operate a motorcycle dealership and CCS Ducati Race team.

Glenn Adams II

Glenn Adams II

Motorcycle/ATV Technician

393 satisfied customers

6 years Motorcycle/ATV/Water Craft; 4 years auto; 18 years carpenter

< Previous | Next >

Related Motorcycle Questions
Honda Nss250S Headlights fine, but when I switch to dip,
Honda Nss250S Headlights fine, but when I switch to dip, nothing happens and the headlights stay on. Their are only 2 wires into the switch. Surely their should be 3 ? Any advice would be most welcome… read more
Louie
Louie
Technician
Associate Degree
1,281 satisfied customers
I have a 1991 vmax yamaha 1200. So there is no power on the
I have a 1991 vmax yamaha 1200. So there is no power on the spark plug. But it turn over normally. … read more
Louie
Louie
Technician
Associate Degree
1,281 satisfied customers
I replaced the starter & now no spark. It wasd running finr
I replaced the starter & now no spark. It wasd running finr before. … read more
Steve
Steve
I&C technician
Vocational, Technical or Trade Scho
6,997 satisfied customers
Got a 96 Fxdwg that I am doing a ground up resto on it has
Got a 96 Fxdwg that I am doing a ground up resto on it has the stock tranny but when I built the motor i had to replace to lowerend with S&S cases and oil pump question is where do all the oil lines g… read more
Steve
Steve
I&C technician
Vocational, Technical or Trade Scho
6,997 satisfied customers
I'm looking the new 2018 Kymco xcting 400i scooter. I'm 5'6"
I'm looking the new 2018 Kymco xcting 400i scooter. I'm 5'6" tall so I need to lower it. Can it be done, and what Shocks and how can I go. Thanks,Dane … read more
Pete
Pete
Independent Auto Technician
Vocational, Technical or Trade Scho
138 satisfied customers
I have a 1970 Rupp Sprint and have to replace the track.
I have a 1970 Rupp Sprint and have to replace the track. What is the proceedure? … read more
Pete
Pete
Independent Auto Technician
Vocational, Technical or Trade Scho
138 satisfied customers
How to open a jam seat when the does not work. It is a 2016
No the brakes have not been squeaking and I have check the fluid level … read more
Pete
Pete
Independent Auto Technician
Vocational, Technical or Trade Scho
138 satisfied customers
For 2004 harley night train the turn signals on left not
Hello, for 2004 harley night train the turn signals on left not working,left side rear was working., now its not working, front running lights are working.only turn signal on front left side working. … read more
Steve
Steve
I&C technician
Vocational, Technical or Trade Scho
6,997 satisfied customers
The check engine light is on. How can I find out what is
The check engine light is on. How can I find out what is wrong without taking it to a dealership? … read more
Kavey
Kavey
86 satisfied customers
How can I open the seat of my 2014 Yamaha Zuma without a
How can I open the seat of my 2014 Yamaha Zuma without a key. The key is locked in the seat! … read more
Kavey
Kavey
86 satisfied customers
I own a 2009 fatbob dyna and I have just put 14 inch bars,
my name is ***** ***** I own a 2009 fatbob dyna and I have just put 14 inch bars , new wiring , switches , hand controls , braided throttle and clutch cables but when it was time to fire it up I had n… read more
Steve
Steve
I&C technician
Vocational, Technical or Trade Scho
6,997 satisfied customers
I have a 2006 Honda Rancher TE and wanted to see if someone
I have a 2006 Honda Rancher TE and wanted to see if someone could answer a question regarding lining up the cam shaft marks on crankshaft lobes ( that may not be what they are called exactly. Accordin… read more
Pete
Pete
Independent Auto Technician
Vocational, Technical or Trade Scho
138 satisfied customers
My son's LT50 started giving starting problems. I removed
Hi, my son's LT50 started giving starting problems. I removed the carb, cleaned it out. Was very dirty. New sparkplug etc. Now I can't get itstarted at all. Tried the priming and flooded piston. It's … read more
Louie
Louie
Technician
Associate Degree
1,281 satisfied customers
I have a 1985 h-d fxsb headlights dim when throttled up an
I have a 1985 h-d fxsb headlights dim when throttled up an brighten when I let off throttle… read more
Steve
Steve
I&C technician
Vocational, Technical or Trade Scho
6,997 satisfied customers
MY1998KALASAKI VOLCAN 1500 IS GITING BAD GAS MILEAGE. A
MY1998KALASAKI VOLCAN 1500 IS GITING BAD GAS MILEAGE … read more
Pete
Pete
Mechanic
Construction, Plant Fitter
57 satisfied customers
Will a 1995 GL 1500 Gold Wing engine that didn't come with
Will a 1995 GL 1500 Gold Wing engine that didn't come with reverse, be able to swap out to a 1995 GL 1500 Gold Wing that has reverse?… read more
Eric
Eric
technician
Vocational, Technical or Trade Scho
1,566 satisfied customers
I was having some issues regarding the start up on my Suzuki
Hello pearl , I was having some issues regarding the start up on my Suzuki SV650 2008. … read more
Louie
Louie
Technician
Associate Degree
1,281 satisfied customers
I changed the rear pads on a '08 sportster 1200 nightster. I
Hello. I changed the rear pads on a '08 sportster 1200 nightster. I don't know what the break pedal felt like before but now I can't get a firm pedal. I have bled and bled with no good results. … read more
kwiggins29059
kwiggins29059
Associate Degree
219 satisfied customers
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Show MoreShow Less

Ask Your Question

x