CRF450R Jetting problems (Hawaiian Islands)

[Shawn_Mc]

Just now, island style thumper!!! said:

1 hour ago, Shawn_Mc said:

I never noticed the jet number. A 168 is too damn lean, WAY too lean. I bet the plug is glazed, and shiny. Ive ridden in dunes with 14-45 gearing in 100 degree heat at or below sea level and never had a problem (but I'm never going slow either) with heating or anything. To give you an idea, I get about 25 minutes of hard riding on the stock tank of gas, topped clear to the cap.

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Ok will a 180 or 182 be better ?

I think if you put a 180 in there, it'd run a lot better. Whether or not that cures the running hard for 5-6 minutes, Im unsure. You may be in a situation where it's so lean that it's on the edge of burning itself down and that's why it's nosing over. If that's an R, and not an X, that 168 should have never gotten in there to begin with. You should be running a 42 pilot too.

[mrdsee]

What is the general temp and humidity level where you ride in Hawaii? Also, if you can, you might be able to send that carb back.

Edited September 8, 2018 by mrdsee

[island style thumper!!!]

I never noticed the jet number. A 168 is too damn lean, WAY too lean. I bet the plug is glazed, and shiny. Ive ridden in dunes with 14-45 gearing in 100 degree heat at or below sea level and never had a problem (but I'm never going slow either) with heating or anything. To give you an idea, I get about 25 minutes of hard riding on the stock tank of gas, topped clear to the cap.

My gearing is 13-52 its average temp is 80 degrees 80 to 90 percent humidity .

[island style thumper!!!]

Ok will a 180 or 182 be better ?

My new carb just arrived !! I'm going up on the main jet 1 step and will check plug !

[mrdsee]

Since your humidity is high(water displaces air) and temp is warm(stock jetting level) normally you can get by with slightly leaner jetting. But given that your riding in the sand with a paddle tire I'd start out with a 182(Better rich(safe) than lean(sorry)). BTW, what size main jet is in there currently?

Edited September 8, 2018 by mrdsee

[Shawn_Mc]

12 hours ago, mrdsee said:

Since your humidity is high(water displaces air) and temp is warm(stock jetting level) normally you can get by with slightly leaner jetting. But given that your riding in the sand with a paddle tire I'd start out with a 182(Better rich(safe) than lean(sorry)). BTW, what size main jet is in there currently?

The stock jetting for an 07 is a 178 main and a 42 pilot. With that much humidity, it'll already be rich. A 182 would have it blowing black smoke and running lazy as hell on the top end.

[mrdsee]

Personally, when I jet I start rich and work down. Given that it takes a whopping 10 min to switch mains on a CRF it's no big deal to me. But then again that's the way I approach it, and I also prefer to be rich in high load situations in the interest of motor longevity over squeezing out that extra 1-2%  peak power. I'm still curious what size MJ he's currently running. Plus the pipe?, backfire screen in or out?

Edited September 8, 2018 by mrdsee

[island style thumper!!!]

Personally, when I jet I start rich and work down. Given that it takes a whopping 10 min to switch mains on a CRF it's no big deal to me. But then again that's the way I approach it, and I also prefer to be rich in high load situations in the interest of motor longevity over squeezing out that extra 1-2%  peak power. I'm still curious what size MJ he's currently running. Plus the pipe?, backfire screen in or out?

182 it is !!! Thanks there is a 178 in there now I just pulled it ! The only motorcycle shop on the island are out of the sizes I wanted ! I have to order on line could take a few days

[mrdsee]

Humm 178, that's interesting. The new carb should eliminate any internal fuel flow issues. Check to see that your petcock is flowing well also as they can get restricted.

You might want to check with the company/web site that made your pipe and see what jetting they recommend as a baseline. Also is the backfire screen on your air filter cage still there? Get a 180 and a 175, 172 also. Always good to have a range of jets.

[island style thumper!!!]

There is no screen. And I am going to get 182 to 172 do you know of a cooling fan that will work on this 450 ?

[mrdsee]

59 minutes ago, island style thumper!!! said:

There is no screen. And I am going to get 182 to 172 do you know of a cooling fan that will work on this 450 ?

No I sure don't. Plus pop in a new stock spark plug.

[island style thumper!!!]

No I sure don't. Plus pop in a new stock spark plug.

I will thanks for your help !!! As soon as I get all this out together and run it I will let you know !! Big , big mahalos to yo braddah!!!! For your help !!!!

[Shawn_Mc]

22 hours ago, mrdsee said:

Personally, when I jet I start rich and work down. Given that it takes a whopping 10 min to switch mains on a CRF it's no big deal to me. But then again that's the way I approach it, and I also prefer to be rich in high load situations in the interest of motor longevity over squeezing out that extra 1-2%  peak power. I'm still curious what size MJ he's currently running. Plus the pipe?, backfire screen in or out?

Some bikes are more sensitive to the back fire screen and pipe than others. My personal CRF, with no backfire screen and a practically wide open Thunder Alley exhaust only wanted a 40 pilot and the stock main was just a tad rich. I've yet to see a CRF, unless it had a higher compression piston, need more jet. I dont disagree with your method at all. I do the same, on an unknown combination. But this, this a well known setup. I'm hoping it was a fat fingered typo that put 168 in what he previously told us. One other thing, what he's describing as far a running fine for 5-6 minutes then struggling is also a sign of debris collecting on the stator pick ups or a stator that's failing. Ive found stators that measured fine when they were cold, then went to hell at 180-200 degrees.

The debris on the stator pick ups is a symptom of the left side main bearing wearing the roller cage. That left side bearing is a weak spot. Makes it easy to assemble the cases, but the bearing itself is under sized for that application. Ive found more left side main bearing problems on customer bikes than you can imagine. One other thing about that left side main bearing, they'll run fine with the crank jumping around in there like jumping bean. A side problem is, it's jerking on the cam chain. Eventually, the cam chain tensioner will break loose and reset itself, usually allowing the cam timing to get retarded a tooth or two, leaving you with a "How the F did that happen" rattling around in your head. After you've seen it 10-15 times, it sticks out like a sore thumb.

[mrdsee]

45 minutes ago, Shawn_Mc said:

Some bikes are more sensitive to the back fire screen and pipe than others. My personal CRF, with no backfire screen and a practically wide open Thunder Alley exhaust only wanted a 40 pilot and the stock main was just a tad rich. I've yet to see a CRF, unless it had a higher compression piston, need more jet. I dont disagree with your method at all. I do the same, on an unknown combination. But this, this a well known setup. I'm hoping it was a fat fingered typo that put 168 in what he previously told us. One other thing, what he's describing as far a running fine for 5-6 minutes then struggling is also a sign of debris collecting on the stator pick ups or a stator that's failing. Ive found stators that measured fine when they were cold, then went to hell at 180-200 degrees.

The debris on the stator pick ups is a symptom of the left side main bearing wearing the roller cage. That left side bearing is a weak spot. Makes it easy to assemble the cases, but the bearing itself is under sized for that application. Ive found more left side main bearing problems on customer bikes than you can imagine. One other thing about that left side main bearing, they'll run fine with the crank jumping around in there like jumping bean. A side problem is, it's jerking on the cam chain. Eventually, the cam chain tensioner will break loose and reset itself, usually allowing the cam timing to get retarded a tooth or two, leaving you with a "How the F did that happen" rattling around in your head. After you've seen it 10-15 times, it sticks out like a sore thumb.

Yeah, I hear ya. If it's jetting it may well end up in the 172-175 range due to the high humidity and temps in the 80-90 range. My first thought also was fuel starvation, due to a clogged tank vent, petcock, or something like that (if it had been running OK previously) and had also been already mentioned by yourself earlier. But when that 168 came up, like it was going to go "up to 168" I thought otherwise. More like WTF actually, but now that we know it's a 178 in there it's a new ball game. Hopefully it's not a major mechanical issue as that can get pretty darn expensive when that can of worms is opened. Plus it reminded me again why I went back to my old 2 stroke roots. At least it's a '07 model which I still think was the best of the carb'ed CRF450's.

Edited September 9, 2018 by mrdsee

[island style thumper!!!]

Ok, I finally had time to tear into carb ! Pilot jet is a 42 the main is a 178 and the floats were not set properly and not letting very much fuel in the bowl !! Also the fuel tank cap seems to be clogged ! Took the cap off and and sucked on the hose no air would pass through !!

[island style thumper!!!]

Ok will a 180 or 182 be better ?

Shawn the floats were not set right and the gas cap seems to be clogged no air passes through also it has a 42 pilot ! Should I go with a 40 ?

[Sweet tooth sensation]

I got stranded out in the inland waterways in Port O'Connor ,Tx. Due to a non venting gas cap on a new jet ski. Also glad to see you checked the float height from my post on page one. Riding in sand = full throttle most of the time,  tank needs optimum venting and correct float bowl height. When I put an FCR 41MX on my DRZ434 it would suck the bowl dry at full throttle in a 1/2 mile. Changed the height and it runs flawless.

[mrdsee]

2 hours ago, island style thumper!!! said:

 Took the cap off and and sucked on the hose no air would pass through !!

Remember that the cap assembly acts like a one way valve. It lets air into the tank to prevent a vacuum , and keeps fuel from coming out.

Can you blow through the hose?

[island style thumper!!!]

42 minutes ago, mrdsee said:

Remember that the cap assembly acts like a one way valve. It lets air into the tank to prevent a vacuum , and keeps fuel from coming out.
Can you blow through the hose?

Very small amount of air passes through .
I have a older cap that I found at the track and I tried it and alot more air passed through. But still not alot on that one either ! I'm buying a new one ! Not taking a chance ! I want this to scream without issues!!

Edited September 10, 2018 by island style thumper!!!

[Shawn_Mc]

4 hours ago, island style thumper!!! said:

On 9/7/2018 at 7:17 PM, island style thumper!!! said:

Ok will a 180 or 182 be better ?

Shawn the floats were not set right and the gas cap seems to be clogged no air passes through also it has a 42 pilot ! Should I go with a 40 ?

No, the 42 is fine. Just get the fuel screw set correctly and it'll start first kick, hot or cold.

When you set the float level, remember, you cant hold the carb upside down. The weight of the float will collapse the preload spring and the level will end up too low. The float level is supposed to be 6mm from the flange of the bowl mount on the body.