Clogged Exhaust?

[jackd]

I just purchased a 1986 Yamaha Vmax all original with 13,500 miles. I had to rebuild the clutch slave and master cylinders before I could ride. There was a mouse nest under the seat and I noticed something coming out of the exhaust that looks like dog food. When I first got it running, it seemed to be very powerful. After about 30 miles, I rolled it on and it fell flat and barely accelerated up to about 85. It seems to fall on its face around 4000 to 5000 rpms. I eased it home and began looking it over. I revved it a few times and noticed sparks and more "dog food" coming out the exhaust. Then it overheated and I had to cut it off. It still runs.
I really like the stock exhaust and it is in good shape so I am trying to save it. It may wind up modded slightly, but I want to use it. I cut a small section out of the crossover so I could see inside. There is nothing there. It is wide open! Now I weld it back up. I still believe there is something clogging this exhaust. I went down the road with open headers. It runs great and the vboost kicks!
Any ideas?
Thanks in advance!

 

[bazwell]

You can't really get inside those mufflers without destroying them.
It can be difficult to get the mufflers off sometimes, but you might be able to see something inside. I doubt it though.

If it doesn't come out by itself, or burn out, I don't know what you can do.

 

[alorio1]

You may want to do this and run the bike a couple hundred miles to blow the rat nest/food out, then replace end caps like the guy did in this video. I have an 85 and did this mod and the bike sounds nice.

http://www.youtube.com/watch?v=bd0r7J1caZs

 

[jackd]

Sounds like you guys have about the same thoughts I have on the exhaust. I guess I am going to mod it some way even though I would prefer to leave it stock. I am one of the few that likes it quiet!

Is it normal for the Vmax to be cold natured? Once it reahes operating temperature it runs great, but until then the first quarter throttle is pretty weak/lean sounding.

 

[alorio1]

If you do the exhaust mod you should see a big difference in performance. If it's been sitting up your carbs may need cleaning and synched. I would start adding something like seafoam or Start your engine fuel treatment in the fuel and maybe clear up some gummed up jets. You say bike is completly stock, does that mean the A/F covers are still in place? Normally a Vmax is not as cold natured as you are experiencing.

 

[m-cman]

Until you are sure the exhaust is not clogged and the carbs are clean, you will not be able to determine what needs to be done. The bike will not run properly with either of those conditions. Rats/mice have a habit of building nests in the strangest places. I once had them eat through an old 1960's 650 Triumph seat and make a nest in the foam. Don't know how to clean out the exhaust though. Maybe someone can come up with some ideas. Removing the end caps only exposed the rivet holes used to attach the cap. :confused2:

 

[tugla]

The bike does need to warm up prior to running down the road. Usually guys will let the temp gauge get to 1/4, before that they do run rough or pop or hav to be on the choke. Now all bikes different yes but let it warm up before flogging it and it will respond better for ya.

 

[[email protected]]

If you want to stay quiet, don't remove the endcaps. Its not going to help you with cleaning out the exhaust.

I would remove the mufflers from the bike and try to poke something thru there. Start and the inlet side and work toward the outlets. A fiberglass fish tape would work pretty good IMO. Not too many people have those sitting around but, I'm sure you can come up with something suitable.

 

[davesax36]

You can have my stock exhaust if you ship it to yourself. It had a couple dents and the connectors are rusty, but I'll clean it up as best I can. Already has the holes drilled and plates bolted back on by the previous owner.

Sent from my Galaxy Nexus using Tapatalk 2

 

[PATMAX]

If you want to bother pulling the muffler section off which I am guessing you did to cut the center section out, I would not be opposed to try flushing them from both ends with large volumes of water. A garden hose may not do it. I might even consider immersing them to soften the obstruction and then blast it out. I have access to firehoses at work and volume of water is more important than pressure. Let her dry real well afterward. Save them old pipes!

 

[95spfldmax]

You definately had critters in the exhaust...might still be bodies in there?...along with the dog food.....you'll prob have to take the exhaust off to empty it from the other side....but I would check the air box!!.....first place I look before starting any bike that's been parked more than a couple months.....

 

[jackd]

Thanks for all the replies. The carbs were rebuilt and the fuel tank replaced about three years ago. They were hoping to ride again. Overall, the bike sat for about 5-6 years other than that. I did change the air filter and the oil and filter. The carb plugs were out and the screws were only backed out about one turn. I backed them out 2-1/2 and that helped the throttle response a lot. I also added some starbright startron fuel treatment and lucas fuel treatment.

I am going to see a friend tomorrow that owns a CNC shop. He has an air compressor with a 1" hose so we can send a lot of air through the pipes! He also may be able to help me with going deep enough to be sure there are no obstructions. I'll let you guys know what I find. I am ready to get on the road.

 

[jackd]

Update. I did get some debris out of the exhaust, but not a lot. I went ahead with the five hole mod and now everything seems fine. I have ridden over 200 miles since this with no more problems! Thanks for all the replies.

 

[Traumahawk]

Good...glad that things are working out.

 

[fltinstructor]

I love a happy ending!! At the massage parlor too!

 

[DMAN999]

Glad to hear it !!!