86 venture backfiring

[kevin-vic-b.c.]

I am kind of new to the motorcycle scene. I have worked with cars since I was a kid. I purchased a totaly perfect '86 Venture last summer. As I use it regular I desided to change plugs and oil over the christmas break. Then wile out riding last week it started to back fire when I get off the gas and some times when I am warming it up it will pop slightly.

 

Have I got a plug loose.... what a bear to change plugs on..... ?

Have I disturbed something...... a carb rubber?

 

The local shops just shake thier heads and say live with it or scrap it.

 

any recommendations from other riders would be helpful

 

Kevin

Victoria BC Canada

[Boody]

Hi Kevin,

 

My '87 started doing the same thing recently after a plug change. My bike had sat for a while before the plug change and I finally decided some trash had accumulated in one of the carbs. I bought some seafoam and put about half a can in a full tank of gas and rode that out, the the other half in the next tank. After this another can adding as specified on the can. It usually disolves anything but the most solid of debris in the fuel system and also gets rid of any moisture that may have accumulated from the bike sitting around. Hope this helps your problem.

[mini-muffin]

Might also want to think about getting your cabs done. I don't know who the closest to you with a carb tune is but you may want to find out. Or you could get your own. You say you've worked with cars so you should have no trouble with the bike. Don't go back to a dealer that tells you to live with it either. Evidently they don't want your business.

 

Good luck.

 

Margaret

[93 venture]

I am kind of new to the motorcycle scene. I have worked with cars since I was a kid. I purchased a totaly perfect '86 Venture last summer. As I use it regular I desided to change plugs and oil over the christmas break. Then wile out riding last week it started to back fire when I get off the gas and some times when I am warming it up it will pop slightly.

 

Have I got a plug loose.... what a bear to change plugs on..... ?

Have I disturbed something...... a carb rubber?

 

The local shops just shake thier heads and say live with it or scrap it.

 

any recommendations from other riders would be helpful

 

Kevin

Victoria BC Canada

 

I hate shops like that, everyone wants to work on nice new stuff,dont want to get their hands dirty anymore.

Anyhow sounds to me like you have a vacume leak at intake boots or a vacume line cracked,Put your bike on the center stand and let it idle take some carb cleaner and spray around the intake boots,if there's a leak should hear the engine change in sound or rpms will pick up.having the carbs sink isnt a bad ideal to have done also.i would just go ahead and replaced all the vacume hoses and vacume plugs you can find.

[Squeeze]

Might also want to think about getting your cabs done. I don't know who the closest to you with a carb tune is but you may want to find out. Or you could get your own. You say you've worked with cars so you should have no trouble with the bike. Don't go back to a dealer that tells you to live with it either. Evidently they don't want your business.

 

Good luck.

 

Margaret

 

Yeah that

 

first checking the Plugs, Vacuum Leaks and Carb Synch, then next Levels Countermeasurements

[mother]

is the popping noise maybe coming from the exhaust. these bikes are known for the exhaust collectors to rust and have holes in it, or the where the pipes go into the collector rust out. my 86 did.

when the bike is cold start it up, lay down on your back put your hand up around the exhaust collector and feel for any exhaust leakage before the exhaust system gets too hot. i have an 86 also, keep in touch.

cheers, Scott

[Guest Bigin]

Had same issue with my 89. Did all the suggestions above, all of which are important to eliminate, but did not help. Then looked deeper into the carbs, solved the issue by opening the pilot jets up. Its easy to do, costs nothing, and it worked in my case. Some bikes need to be open more than the standard turn or two. Mine are now from 3.5 turns to a max of 5.5 on one of the cylinders. Did it by ear adjusting each carb noting where I started at for a baseline. Helps to know the rpm range the popping occurs, then just open each jet to see if it helps until you find the offender. Hope this helps. Be very gentle with bottoming them when you tighten as the jet tip will blunt easily. I was so pumped to end that backfiring racket. Hope this helps.

[bobcat]

I'd also try taking off the covers and checking the diaphrams for holes....

 

About the spark plugs...I use to struggle with the plug socket in the tool kit also until I got a plug socket and universal..I use them in conjunction with a long extention and rachet..Now I can change plugs in about 5 minutes..

[kycaveman]

Hey Kevin,

I truly feel your pain, I have a 85 VR, so far I have rebuilt the carbs, (New Diaphgrams, o rings, dipped and cleaned) shimmed the valves, new plug wires and plugs. The bike is running strong, but the backfiring is driving me nuts, and I have had no luck at all in getting the carbs to sync. But all they are saying makes a lot of since. I am sure I have some holes in my collectors, I have not checked all of my vacuum lines or the plugs that cover the sync ports, and two of my pilot jets are locked tighter then hell and so far not coming loose.

 

If I have learned anything so far about the 1st Gen VR, is it is a labor of love, and this group is the best when it comes to giving great advice... Good luck, and I will continue to read replies to your question in hopes of finding my gremlin.

 

When if I do find my problem, I promise to pass it on to all....

[Boody]

About the spark plugs...I use to struggle with the plug socket in the tool kit also until I got a plug socket and universal..I use them in conjunction with a long extention and rachet..Now I can change plugs in about 5 minutes..

 

AMEN, Bother. The stock spark plug tool in the kit is only for emergencies on the road. Definately use a good socket and universal joint to change the plugs. I also left off the plastic heat shields on top of the cam covers when I changed mine. I've noticed no ill results and it makes changing the plugs so much quicker.

[Venturous Randy]

Even though I don't think your bike has the YICS system, on older 1st gens you need to check the condition of these hoses. I was chasing a carb problem and it ended up being the hose connection near the right rear carb. I pulled them all off and plugged them and the bike runs much better.

As far as the decelleration poping, that is usually an exhaust leak that is pulling in oxygen and firing.

RandyA

[payntor]

Then wile out riding last week it started to back fire when I get off the gas and some times when I am warming it up it will pop slightly.

 

 

 

Kevin

Victoria BC Canada

 

kevin,

i have this problem if my idle is set to high. lower the idle to 950 and see if the problem still exists.

 

jim

[kycaveman]

What exactly is the "YICS system", I have one and yes it has the 4 hoses, properly the original ones, so can I plug it off? I am now beginning to start the process of elimination game, checking exhaust gaskets, rubber plugs on the sync ports, vacuum lines, ect

 

and Kevin please forgive me, I am not trying to hijack your thread, but it looks like we are both fighting the same demons. I promise to report any success and failures I am having so maybe we can come to a group fix

[Tupperj]

YICS is the Yamaha Induction Control System which basically is a balancing system between the various cylinders. Here's a link to the XS1100 site that has a pretty good explanation:

 

www.xs11.com/tips/norm/yics.htm

 

Of course, works a little differently on the XS than the Venture, as one is an inline 4 and the other a V four, but you get the idea. I'm sure you'll find more info here with a search.

 

Paul

 

What exactly is the "YICS system", I have one and yes it has the 4 hoses, properly the original ones, so can I plug it off? I am now beginning to start the process of elimination game, checking exhaust gaskets, rubber plugs on the sync ports, vacuum lines, ect

 

and Kevin please forgive me, I am not trying to hijack your thread, but it looks like we are both fighting the same demons. I promise to report any success and failures I am having so maybe we can come to a group fix

[Venturous Randy]

As I noted, I did plug mine off and the bike runs fine. If you are going to plug your's off, make sure you use pretty good caps. If not, the caps will come apart.

RandyA

[Neil86]

KYCaveman...

 

The YICS uses a 4 chambered plastic reservoir that the hoses go to...the seams on the chambers can fail over time, so as the engine vibrates you get intermittent or continuous vacuum leaks. Yamaha dropped YICS with the 86 1300 update on the Venture.

 

Kevin...

Make sure you got the plug caps tight on the wires and tight on the plug terminal. A very common exhaust leak on a Venture is at the stubs at the rear cylinders....you'll see a ring clamp around the joint.....they use a copper bevelled gasket (looks like a washer).

[Gene-b]

Hey It's old, give it a break, My Grandpa backfires too:rotf::rotf:

[Doug Hare]

Kevin, could be as simple as a bad plug. Maybe the casing ion the plug got cracked during or before installation. Also is the gap correct on the plugs.

Also check the connections of the plug wires. It seems to me if it was running well before this probably has something to do with what has been done to it lately, so check all vacuum lines or anything else that was disturbed during the tune up.

Best of luck!