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Message started by rbeathe on 03/31/19 at 06:05:25

Title: carbon fouling
Post by rbeathe on 03/31/19 at 06:05:25

I recently rebuilt my carb and added a pod filter. The bike ran fine for about a week and then started carbon fouling. It seems to get worse every time I clean the plug. Should i put the air box back on? The main jet is a #150 and the pilot jet is adjusted to 2 3/4 turns. Ive read that I should try a spark plug with a higher heat range but Im having trouble finding one: the current plug is an NGK DPR8EA-9. Thanks. Im trying to sell the bike and really need to have it running tight. Its got a custom seat, diamond stitched and new paint on the frame and tank and fenders. Thanks!

Title: Re: carbon fouling
Post by LANCER on 03/31/19 at 06:30:05

What pilot jet are you running ?
Where are you located, and close to sea level or in the mountains ?
You may still have something clogged in the carb. Did you check all passageways in the carb body when you cleaned it ?

Title: Re: carbon fouling
Post by batman on 03/31/19 at 08:10:01

Generally use of a pod filter would tend to make the motor run leaner ,not richer, but we need more information . What pod filter are you using? does the pod filter block any of the openings entering the carb? what petcock do you have ,stock or Raptor? have you done the spacer mod ,if so how ? what is your elevation above sea level ? Did you set the float level after carb rebuild? pilot jet size? and what are you running for exhaust/muffler?
Carbon build up many cause detonation , and ruin the motor ( the carbon buildup on the plug is also building up on the walls of the combustion chamber and piston crown),I wouldn't be running the bike until you solve this problem.

Title: Re: carbon fouling
Post by rbeathe on 03/31/19 at 08:25:21

I don't know the pilot jet size. Im slightly above sea level. I have the carb off so I guess Ill take it apart and check everything again. i spent the morning putting the air box back on (unnecessary step as I now know). The pod does not block anything as it attaches to the air intake just like the air box.the breather hose from the head has no place to attach to the pod though, does that matter? OEM header with a slip on muffler.

Title: Re: carbon fouling
Post by Dave on 03/31/19 at 08:38:42

You should never install a "hotter" plug on a modern engine that is made to run "lean" from the factory.

If you are fouling plugs - you need to fix the problem and not resort to just running a hot plug (which can put a hole in the piston).

What did you do to the vent hose? You need a filter on the end of the house.....and never plug the vent (one forum member did and he blew the rubber cam plug out of the head).

And as ask previously....what petcock is on your bike?

Title: Re: carbon fouling
Post by rbeathe on 03/31/19 at 08:47:48

OEM petcock bolted to the fuel tank.

Title: Re: carbon fouling
Post by ohiomoto on 03/31/19 at 09:41:21

Many pod filters are actually more restrictive than the stock airbox AND they often block air ports in the back of the carb.

Title: Re: carbon fouling
Post by Dave on 03/31/19 at 11:57:06

21313632273B36530 wrote:

OEM petcock bolted to the fuel tank.

Check to see if you have any fuel in the vacuum line....it could be the petcock diaphragm is going bad and allowing fuel to flow down the vacuum line.

Title: Re: carbon fouling
Post by batman on 03/31/19 at 21:17:17

Generally at your elevation you need to run larger jets , 55pilot ,152.5/155 main would not be unheard of, nor 2 to 3 washers on the spacer mod. (air being denser at sea level means you need to add more fuel) . but that doesn't sound like your problem, your flooding the carb ,the extra fuel could be from the stock petcock as Dave said,(and also why I asked) or when you cleaned the carb you may have swapped the the larger air jet from the top of the carb and the main jet from the bowl area (They thread right in we've seen this before) an that will also cause you to run Very rich . The only other thing to check is the float valve leaking by, the O-ring on the outside of the float valve seat, or the float level set to high. good luck!

Title: Re: carbon fouling
Post by rbeathe on 04/09/19 at 03:34:08

The gasket on the pod filter was restricting the port at the top of the air intake on the carburetor. I got a RYCA goose neck and new pod and the carbon fouling has stopped! Thanks. I have noticed that until the engine gets warm I get some back fire trough the air intake. It goes away quickly and then runs fine. I have the air/ fuel mixture needle open 1 1/2 turns and was wondering should I have it open more. Thanks.

Title: Re: carbon fouling
Post by Dave on 04/09/19 at 03:43:09

74646367726E63060 wrote:

I have the air/ fuel mixture needle open 1 1/2 turns and was wondering should I have it open more. Thanks.

That is something that cannot be determined over the internet on a forum.

You need to adjust the idle fuel mix with the bike running.....every engine is different and needs to be adjusted manually. Make sure the bike is nearly vertical when doing the adjustment, and don't take a long time doing it as the low engine speed causes low oil pressure and there is not much oil flowing to the cam and rockers. The engine needs to be fully warmed up before making the adjustment....ride it to warm it up and don't just warm it up in the driveway.

The Savage has a "fuel" mixture screw, and opening it more increases the amount of fuel flow.

Here are some videos that show how to adjust the mixture screw. You need to lower the idle speed so you can hear the adjustment, at 1,100 rpm some of the fuel will be coming from the needle jet - so you need to drop the speed down around 800rpm for the adjustment....then turn it back up to 1,100 rpm when the adjustment is done. If you can turn the screw all the way in and the engine doesn't stumble...the pilot jet is too big - if you need to turn the screw out more than 3 turns...the pilot jet is too small.

https://www.youtube.com/watch?v=zm5mB3R8Ucw

https://www.youtube.com/watch?v=YxpQjDQzX7g&t=287s