[JC173]

Greetings all,
I'm an owner of a 2006 Bullet Military with 3,000 miles. It was modified by a dealer, Speed Motorsports in Union, Washington, to include electronic ignition, Mikuni Carb, disc brake, K&N air filter, and a less restrictive exhaust. Up till now it's run great and I'm delighted by my Enfield. I am a new member of this forum. I'm glad there's a group such as this to talk to because I'm having a problem.

Initially I noticed a backfire "pop" between shifts and then extensive popping on decelleration, particularly down steep hills. Then, within a few days, I was unable to kickstart the motor. I'm not getting any resistance when kicking-I think that the sudden loss of compression might be the decompressor valve not closing all the way. Possibly there's a buildup of carbon. All this occurred over a few days. I'd like to decarbonize the valve but the classic manual I bought doesn't get specific about how to do it. Otherwise, the machine had been running great. Does anyone have any ideas? I have a trained mechanic willing to help; I'd rather do it then trailer it across the state to the dealer.

Thanks!

JC 173

[The Garbone]

For decarbonizing you could get the engine warm,  remove the air filter and spritz a mist of water into the carb of the bike as it idles,  just enough for it not to stall..  The steam should loosen the carbon.

I would check your valve clearances, sounds like you might just need to adjust one as it might be too tight.

I imagine if your decomp valve was goofed up you could feel the blowby with your hand above it.  To be safe I would spritz it and the cable with some lube to make sure its not hung up.

[Blltrdr]

I would rotate the decomp valve , twisting around in it's seat may knock off anything that might be hanging it up. After a round of twisting it push it up and down as you twist it around in different positions. Check your cable connection and operation.

Possibly try some SeaFoam gas and oil additive mixed with your fuel, one can will give you 2-3 treatments and remove most carbon deposits in combustion chamber. The water spritz is also an effective way to loosen up deposits.

[JC173]

Thanks to Blltrdr and The Garbone. I'll get started on that. Re: Sea Foam-awesome product. I've been using it lately in older auto motors and a chain saw. That stuff really works. Cheers.

[cyrusb]

When you try to start  it do you hear the air rushing out the carb or exhaust?  Try pulling up and rotating the decomp to seat it. The decomp relieves out the exhaust pipe so it would indicate there as well as an out of adjustment exhaust valve. You did not mention a valve adjustment in 3000 miles and you may need one, especially if its the first 3000.

[Ice]

 Welcome aboard JC173 congrats on your military and welcome to the club.

 Water spray in the carb and Sea Foam in the gas tank are two popular methods of periodic de carb. Several threads on them as well as de comp valves.

[JC173]

Thanks Cyrusb and Ice. I appreciate the response. Re: valve adjustment, The dealer mechanic showed me how to do it and I adjust the valves about every 1,000 miles.

[nisonov]

Hi,

I had similar problems with my bike last month. The compression just suddenly disappeared. I ripped off the cylinder head and thanks to the advice of couple of experts in this forum, i took the head to the machinist. They did a real valve job and and yesterday i finally got my bullet back together.

Now everything works perfectly again!

The bike is from year 2008 and it had 5800 km when this occurred, so i guess this might be the case with your bike as well.

[JC173]

Thank you nisonov; I appreciate the information. I'll definitely look into that if the previously mentioned fixes don't work. If it does go that far, what do you recommend I do for the valve job? Can you direct me to a previously published forum topic that dealt with that?  Thanks again.
-JC

[Ice]

 Removing the petrol tank and rocker boxes is simple.

The thing to watch for is the washers under the head nuts.

The factory washers are quite soft and can squish, sometimes enough to grip the threads of the head stud making removal of the head a challenge.

[RBHoge]

With the Carburettor and exhaust modifications that you mentioned in your first posting,  and the popping you mentioned, I am prone to believe that you have been running too lean... By all means, check the valves, and decompressor to restore your compression first. If all else fails, remove the decomp and screw a second spark plug into the head to replace it. (CMW sells a decompressor blanking plug to accomplish the same goal.)

Now to diagnose the popping and lean running issue. Remove the spark plug.  By reading the tip of the plug you can learn a great deal about the operation of your engine. The tip of the plug should be off white, to a reddish tan in colour. If it is black, or sooty looking you are running with a richer than needed fuel/air mixture.  From the symptoms that you mentioned, I think that you will find the plug tip to be ash white. ( A sign of running  leaner than needed Fuel/air Mixture.)  If that is the case the easiest fix would be a larger than stock set of Carburettor jets. My old Iron Jug has the K&N cone air filter and Classic exhaust. Very similar to your set up. I am running well with a .135 Main Jet and a .27.5 pilot jet. If Ace Picks up this thread he will be able to give you a much more detailed explanation than I ever could.

Hope this helps,

[JC173]

RBHoge,
Thanks for taking the time to write. I appreciate the useful advice.

-JC

[neil]

CMW sells a manual decompressor, nifty little screw in device about the size of a spark plug, which I have on my bike. I got ride of the original with the cable attahced to the decompressor, It didn't work very welll anyway. With the manual decomp,you press the button on top and it opens. As soon as the bike starts, the button pops up with a snap and compression is fine. I'd try something simple like that before going into all of the trouble of removing the head etc. Try the simple and work your way up to the complex.

[single]

You mite remove the decompressor and inspect it.It does sound like a tappet check is in order.My valve springs were both broken at about that mileage.To have a valve burned so badly as to not seal at all is pretty extreme.Need to be sure valves are closing,could just be a piece of carbon on a seat,but not likely if you are lean.Check the exhaust system joints when it starts up.Good luck.As stated go thru the simple stuff first.Let us know how it goes.

[cyrusb]

Does your decompressor lever snap back or do you have to push it ?On mine the heat dried up all the oil on the cable and it would hang up. In fact it never snapped back until I oiled the cable at 5000 miles. Just my 2 cents.