2006 DRZ400SM running badly

I'm a new member but I've been snooping around for a couple years without an account. Anyway, I searched and searched for a similar issue but I wasn't successful so if there is another thread out there then I apologize.

 

The bike:

2006, Full Yoshi, 39 mil FCR, 3x3, stock cams(I think). The bike came from Kansas but is in Montana now, so it was definitely running rich when I got it up here. I took it to a shop to have it rejetted because of lack of time. They said they hard did anything except mess with the fuel screw on the bottom. It was a little better but nothing drastic.

 

The issue:

It all started when I went to do routine maintenance (i.e oil change, spark plug, air filter). The bike ran GREAT before messing with it. I warmed the bike up for about 5 minutes to see where the oil level was. I went to change the spark plug and once I put everything back together it had a hard start-up and then a very high idle and then quit. With the choke on it was fine but it eventually died when it warmed up. Then it wouldn't start at all. So I switched to the old plug to make sure nothing was wrong, both plugs had spark. Nothing was adjusted on the carb since last running it.

 

The next day myself and a knowledgeable buddy rebuilt the carb, nothing was dirty, and everything worked. He did put a 42 PJ in, down from 45 PJ. And on the needle he went from the second highest notch to the highest one. I wasn't too sure on how carbs worked so I trusted his judgement on it. I have no idea what other jets are in it as of now though. We started the bike, and it would run great (well, better) but we could not get it to idle at all. Then it would hardly start without giving it full throttle.

 

Yesterday I had a second, more reliable source/friend take a look at it. He did some adjusting to the idle screw and the fuel screw at the bottom. He got it to idle good, but once you rev it it had a high idle once again and it took a while to come back down. There was a little black smoke, and the radiator fan did come on as well, plus it started back firing out of the tail pipe.

 

Today it starts up fine with no choke and little gas, it barely idles without gas input, but has no smoke or oil residue coming out of the exhaust. However it does backfire still.

 

The compression is good. The vacuum line is on and working. I'm hoping the rings aren't bad. But what could change the bikes attitude so quickly with just a change of the spark plug??  It can't just magically go out of tune.

 

Now that my head hurts from so much pondering, my question is what do you think is wrong, what can I do to fix it, and what is the preferable jetting for an altitude of 3500 feet?

 

 

Thank you so much in advance. I tried to put as much info as possible.  Again, if this is a redundant I apologize!

Edited by durtbikefool

Check your spark plug gap


Or.. are you using the old one?

45 PJ is way to big :banghead:

^ Oh duh, that

I'm a new member but I've been snooping around for a couple years without an account. Anyway, I searched and searched for a similar issue but I wasn't successful so if there is another thread out there then I apologize.

 

The bike:

2006, Full Yoshi, 39 mil FCR, 3x3, stock cams(I think). The bike came from Kansas but is in Montana now, so it was definitely running rich when I got it up here. I took it to a shop to have it rejetted because of lack of time. They said they hard did anything except mess with the fuel screw on the bottom. It was a little better but nothing drastic.

 

The issue:

It all started when I went to do routine maintenance (i.e oil change, spark plug, air filter). The bike ran GREAT before messing with it. I warmed the bike up for about 5 minutes to see where the oil level was. I went to change the spark plug and once I put everything back together it had a hard start-up and then a very high idle and then quit. With the choke on it was fine but it eventually died when it warmed up. Then it wouldn't start at all. So I switched to the old plug to make sure nothing was wrong, both plugs had spark. Nothing was adjusted on the carb since last running it.

 

The next day myself and a knowledgeable buddy rebuilt the carb, nothing was dirty, and everything worked. He did put a 42 PJ in, down from 45 PJ. And on the needle he went from the second highest notch to the highest one. I wasn't too sure on how carbs worked so I trusted his judgement on it. I have no idea what other jets are in it as of now though. We started the bike, and it would run great (well, better) but we could not get it to idle at all. Then it would hardly start without giving it full throttle.

 

Yesterday I had a second, more reliable source/friend take a look at it. He did some adjusting to the idle screw and the fuel screw at the bottom. He got it to idle good, but once you rev it it had a high idle once again and it took a while to come back down. There was a little black smoke, and the radiator fan did come on as well, plus it started back firing out of the tail pipe.

 

Today it starts up fine with no choke and little gas, it barely idles without gas input, but has no smoke or oil residue coming out of the exhaust. However it does backfire still.

 

The compression is good. The vacuum line is on and working. I'm hoping the rings aren't bad. But what could change the bikes attitude so quickly with just a change of the spark plug??  It can't just magically go out of tune.

 

Now that my head hurts from so much pondering, my question is what do you think is wrong, what can I do to fix it, and what is the preferable jetting for an altitude of 3500 feet?

 

 

Thank you so much in advance. I tried to put as much info as possible.  Again, if this is a redundant I apologize!

 

 

Which model fcr is installed.....any idea what needle and clip position ....and main jet is in there.???

Khein 39mm FCR. As for the needle, I wrote down "ocemn". No idea what that means but it was the only number I found. Clip position is at the very top, I just went with my buddies advice who said the higher you go the leaner it gets. PJ was changed to a 42. I have no clue what main jet is in there but just assume its a bigger one. 

 

Spark plug gap on the new one is the same as the old one. New one is installed. 

Use an OCEMP needle , clip 3

155 main jet

45 pilot jet

2 turns fuel screw

 

If its the E model carb remove the coast enrichener...http://www.thumperta...e/#entry9891817

Is you gas good? 

Before I would do anything else I would pull the inspection plugs and cam cover and check the cam and chain timing. Could just be a freak that it jumped time when you were messing with the sp/plug and oil change. If it checks out I would go check compression next. Start with the mechanical basics first and isolate from there. Then move on to the charging system/carb-fuel delivery. Alot of electrical issues can appear to be a carb/fuel problem with drivability issues. I learned this lesson when I owned my Ducati.

Fuel and spark would rate equally as far as basics go....

with the crap fuel you guys have in the States ,most ,but of course not all issues are pilot circuit blockage related ...

I know you have changed out the pilot jet but there still could be some partial blockage in the passage ways...

As described per initial post I guessimate fuel is more likely to be the issue here

Fuel and spark would rate equally as far as basics go....

with the crap fuel you guys have in the States ,most ,but of course not all issues are pilot circuit blockage related ...

I know you have changed out the pilot jet but there still could be some partial blockage in the passage ways...

As described per initial post I guessimate fuel is more likely to be the issue here

Thanks very much Craigo!!

You still want me to go back to the 45 PJ even though I'm at 3500 feet of elevation? Just for educations sake on my part.

I'll definitely put in the order for the new jet and needle, and while the carb is all apart I'll verify that all the passageways are clean.

make sure your mixture screw isn't about to fall out, the pilot jet isn't loose, and the air boot/intake boots are all in good shape. i smell an air leak with a way to rich condition. 

Thanks very much Craigo!!

You still want me to go back to the 45 PJ even though I'm at 3500 feet of elevation? Just for educations sake on my part.

I'll definitely put in the order for the new jet and needle, and while the carb is all apart I'll verify that all the passageways are clean.

 

tune the pilot circuit after you install the new needle with this procedure....http://www.thumperta...ad.php?t=327405

the 45 pj should work out ok

And remove the coast enrichener

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