Single Massive Backfire

[weehe]

Well I just filled up after a full tank plus 1oz of freering.Ended up getting 49mpg with 50/50 city/highway. So that is pretty amazing. I still have the backfire but it is not nearly as often and I cant repeat it like I could before. So I would say that is a good thing. Next, TB sync when the carb tuner comes in. If that doesn't fix it il start taking apart the exhaust.

 

[TownsendsFJR1300]

It'll take some time for it to work fully. You'll see gradual improvement but in your case, I would easily run 2-3x's the amount recommended. I have ALL the CATs in both my bike and SUV and have run it that heavy W/O issue.

This won't be an on-going thing once everything's cleaned up.

Yamaha Marine recommends running it regularly in the outboard engine (they tend to sit alot (way more than a bike, in general).


As noted, I run in every gas engine I own, bike included..(but at the recommended amount).

Overall, its a whole lot cheaper than valve jobs, partially clogged injectors/carbs, etc..

 

[weehe]

Got my carbtune in today and hooked it up to see where I was at. There were a few problems right away. I get no vacuum from cylinder 2 or 3 and when I adjusted cylinder 4 to match 1 my idle will not go below 1400. I didn't have time to rip into it to see if there is a leak, but I did notice my air filter is only dirty on cylinder 1 and between 3 and 4. Is this a common problem?

As a note, I switched all the lines and fittings to rule out the carbtune, it works fine something is wrong with the bike.

 

[weehe]

Looks like I jumped the gun asking for help. Just took the air box off to find cylinder 2 and 3 vac lines melted. They were basically not attached. It's too late now so don't want to wake the neighbors, but will report back tomorrow once I can check if that fixed it.

 

[FinalImpact]

It looks like you need some hands on time below deck doing some hands on verification.

The RED hoses are the sync ports. They simply look at vacuum below the throttle plates.If plugged or open (cracked, broken, pulled off), they could show no vacuum.

Looking up from the bottom:

Pink Strips are outer cylinders 1 & 4: Do you see evidence of someone being here before? You might pull the airbox and verify!

Also, check the lower clamps. Make sure they are tight. 3mm here. (4mm airbox)

As for exceeding the manufactures recommendations on "cleaning products", those are there to protect hardware. OEM Wide Band sensors can easily be killed by additives... Although it doesn't apply here, its not good practice on modern hardware with O2 sensors and CATs. Sorry, but you can't state its fine when it gets such little use and is never tested (bike). Modern cages use Wide band O2 sensors and can have four sensors and 3 to 5 CATs which can be VERY expense if they fail. I'm just saying, the product may not induce instant failure and it takes more than run down the street to detect an issue.

 

[weehe]

It looks like you need some hands on time below deck doing some hands on verification.

The RED hoses are the sync ports. They simply look at vacuum below the throttle plates.If plugged or open (cracked, broken, pulled off), they could show no vacuum.

Looking up from the bottom:

Pink Strips are outer cylinders 1 & 4: Do you see evidence of someone being here before? You might pull the airbox and verify!

Also, check the lower clamps. Make sure they are tight. 3mm here. (4mm airbox)

As for exceeding the manufactures recommendations on "cleaning products", those are there to protect hardware. OEM Wide Band sensors can easily be killed by additives... Although it doesn't apply here, its not good practice on modern hardware with O2 sensors and CATs. Sorry, but you can't state its fine when it gets such little use and is never tested (bike). Modern cages use Wide band O2 sensors and can have four sensors and 3 to 5 CATs which can be VERY expense if they fail. I'm just saying, the product may not induce instant failure and it takes more than run down the street to detect an issue.

Yup, number 2 and 28 were melted/split open right at the nipple. Just removed the damaged section and reattached the hose for now. I will be looking into all the other vac lines to make sure they are still intact. Do you happen to know the inner diameter so I can buy some more? I am not sure about your last paragraph, if it is referring to the freering. Being a 04 I didn't think I had an O2 sensor to worry about, just the cat which I plan to eventually remove anyways.

 

[FinalImpact]

Nope - don't know ID of hose. Sorry. True, not specifically applicable to "your cause", more of a waning to others.
Glad you found the vacuum leaks. Should help your cause.

 

[TownsendsFJR1300]

If the rubber is still flexible, you may still be able to use it, simply cut it down IF its long enough.

It obviously was put back and laying atop a hot engine part (from someone dinking under there) resulting in a lean running engine..

I think 1/8" is the ID but bring a piece of the old hose down when / if trying to match. I would paint a stripe on the hose just like the pink stripe from the factory for later, easier adjustment.

You want to make sure the NEW hose (if not OEM) DOES not KINK when doing a sync

(I'd replace it with OEM eventually just so there's no issues later)

 

[FinalImpact]

So, I'm curious - did the previous owner try to adjust the sync screws to offset the air leaks? Were all the sync screws within an 1/8 turn of each As Found?

It does explain the higher than usual idle issue... Just make sure that when all is said and done the thumb screw provides HOT ENGINE idle control through the range of say 1000 - 1500 RPM.

If you have trouble getting lower idle values (like 1000 rpm) and the TBs are balanced, you may need to move all 4 sync screws to reduce the idle speed to return some control to main idle thumb screw. Same issue if the idle is too high and the main thumb screw offers limited control of hot idle.

 

[weehe]

So, I'm curious - did the previous owner try to adjust the sync screws to offset the air leaks? Were all the sync screws within an 1/8 turn of each As Found?

It does explain the higher than usual idle issue... Just make sure that when all is said and done the thumb screw provides HOT ENGINE idle control through the range of say 1000 - 1500 RPM.

If you have trouble getting lower idle values (like 1000 rpm) and the TBs are balanced, you may need to move all 4 sync screws to reduce the idle speed to return some control to main idle thumb screw. Same issue if the idle is too high and the main thumb screw offers limited control of hot idle.

Not sure if they were all with in 1/8 turn. They did look about even visually. Someone clearly did a sync before because one of the vac line plugs was broken in half. On a positive note, now that the leak is fixed and tbs are synced I don't think I have the backfire issue. Didn't even burble. Will need to ride more to confirm.

 

[weehe]

Just went on a ride and beat on it pretty hard. No backfires what so ever. Next step actually moding it!