2002 cr250 surging?

[nmitcheff]

I just picked up a 2002 cr250 and rejetted it according to the manual for winter conditions. The main 400, needle 6bey31-73 in the 3rd clip position, and a 35 slow jet with the screw 1 1/2 out. The bike is mainly stock except for pro circuit pipe and silencer. After running wide open and rolling off the throttle I pull the clutch in and the bike surges. Any help would be greatly appreciated.

[Mecrazyperson]

Originally posted by nmitcheff
I just picked up a 2002 cr250 and rejetted it according to the manual for winter conditions. The main 400, needle 6bey31-73 in the 3rd clip position, and a 35 slow jet with the screw 1 1/2 out. The bike is mainly stock except for pro circuit pipe and silencer. After running wide open and rolling off the throttle I pull the clutch in and the bike surges. Any help would be greatly appreciated.

FIRST OFF WELCOME TO ATM.

I also have an 02 CR250, everytime my bike surges its because you either need to adjust the throttle cable or because the throttle cable is rapd around the petcock. I seem to always do that.

Faded should awnser you question he also has an 02 and is better with jetting then I am. best of luck to you.

[Faded]

Did you happen to check the float level while you were in there? It needs to be set @ 15mm otherwise you're chasing your tail. If you've verified this then I'd try going in (clockwise) 1/2 turn on your air screw to see if this helps.

[Mecrazyperson]

Originally posted by Faded
Did you happen to check the float level while you were in there? It needs to be set @ 15mm otherwise you're chasing your tail. If you've verified this then I'd try going in (clockwise) 1/2 turn on your air screw to see if this helps.

Faded is the man of CR Carbs!! Honda For Life!

[dodgeaspen]

I have an 02 with the same exact problem. I am currently running an s-8 nozzle, 35 pilot, 1.5 AS, 430 main. I always blamed the s-8 nozzle because it really leans out the bottom end. I'm going to try richer needles (straight section) to combat the problem.

[Faded]

dodgeaspen,

I know what your problem is. Hopefully you haven't bought a new needle yet, yours should be fine. The ignition side crank seal is to blame. Mine did the same thing right before I left and it was the seal leaking (air leak). When you pull the clutch in it lets air down through the cable. You can get both seals for $13. The ignition side is easy to change, let me know if you need a breakdown on how to get it out. Good luck.

[dodgeaspen]

I tried to spray carb cleaner behind the flywheel while running to see if it would suck it in through the crank seal and it didn't......I dunno...

[Faded]

Originally posted by nmitcheff
I pull the clutch in and the bike surges.

There's the hint, I can almost guarntee that's the problem if this is what it's doing. It's only $13 for both seals (you'll only need the one) and it can be changed in 20-30 minutes (if you have a flywheel puller). It made a world of difference on mine. Let me know if you need help.

[tomnelsonii]

I also have an '02 CR250 that does the same thing! I ride the bike hard for a couple seconds and pull in the clutch and the bike has a hanging idle (doesn't want to settle back down to idle rpms). However, if I rev the bike on the stand it comes right back down to proper idle rpm immediately. I've tried playing with the jetting and nothing seems to help. The bike did the same thing even with stock jetting(with some minor spooge from the exhaust). Is this the problem that you guys are experiencing?

Anybody else besides us have this problem? Faded, how did you determine that the crank seal was leaking? Is there any sort of a 'leak down' test that can be performed before replacing the seal to verify that there is actually an air leak? Has anybody else had any luck fixing the surging problem?

[tomnelsonii]

Faded,

Could you post some instructions/directions on changing the seal. I can get a flywheel puller, but how do you go about getting the old seal out and driving the new seal without damaging anything. Do I need to lube the new seal w/ 2 cycle oil or assembly lube? Do I need a seal driver or can I use an appropriately sized deep well socket? Any help would be GREATLY appreciated.

Thanks!

Tom

[Faded]

There is this to check for leaks:

Leak Tester

I had plenty of luck fixing my surging problem. The thing to remeber when the bike is on the stand is that it's in nuetral. When you're riding it and you pull in the clutch cable air will leak down the cable into the ignition cavity in the case. Try wriggling the clutch cable where it enters the case with the bike running on the stand. The R's should go up if you can get air around the cable. Sure sign the seal is leaking.

If you have the puller then you're set. Start by removing the four 8mm bolts that hold the ignition cover on and remove the cover. Hopefully you have an impact gun at your disposal. Use it to remove the 17mm nut that holds the flywheel on. After you've removed the nut (and the washer behind it) you can thread your flywheel puller on. Pop the flywheel off.

Next remove the two 10mm bolts that hold the stator on and gently pull the stator off. When removing your stator you'll notice a mark on the bottom and one on the cases. These are timing marks and need to be lined up when reinstalling the stator. Don't worry though, unless you've notched the bottom mounting hole and played with the timing prior to this then you should have nothing to worry about. You can either set the stator off to the side or disconnect it and remove it, what ever you want to do.

Now you can see the seal. Grab yourself a smallish (1-1/2" or so) wood screw and screw it into the seal. You can use more than one if you'd like (another on the opposite side work well) just make sure you work slowly when getting the screw to grab. After this I heated the case a little with the propane torch and then grabbed the screws with a pair of pliers and pulled the old seal out.

I installed the new seal with a dab of grease and a 7/8" (I think) deep well socket, taking care to make sure that it went in straight and to the proper depth outlined in your manual. After the seal is in the it's just a matter of putting everything back together.

If you have any more questions let me know. Good luck.

[tomnelsonii]

Thanks Faded!

Here's my plan... I'm going to start/warm the bike up to operating temps. Next, I'm going to remove the ignition cover while the bike is running. If I have a leak, the rpms should rise slightly as soon as I loosen the cover and air can leak in! Don't worry, I'll be carefull not to get my fingers/hair/shoelaces/toes wound up in the flywheel!

Does this sound correct? Anyone have any other advice/input?

Anyhow, I'll probably try this over the weekend. I'll post the results on Monday. I'm also going to build the leak down tester to rule out any other possibilities.

I'm running the V-Force reed cage and I'd like to verify that there are no leaks there as well.

[tomnelsonii]

One more question for you, Faded! Did you make your leak down tester for your '02 CR250? Can I use the same size plug and fitting as in your directions? I wouldn't want to have to measure and do any work myself. Man, I'm getting lazy these days!

[Faded]

Originally posted by tomnelsonii
I'm running the V-Force reed cage and I'd like to verify that there are no leaks there as well.

That's a good idea. They tend to leak...

[Faded]

Originally posted by tomnelsonii
One more question for you, Faded! Did you make your leak down tester for your '02 CR250? Can I use the same size plug and fitting as in your directions? I wouldn't want to have to measure and do any work myself. Man, I'm getting lazy these days!

Yep! Don't worry, I did all the work for you. The exhaust plug is a tight fit but works great.

[Woody_KDub]

Once you guys are done here, we need to move this to the knowledge base. This is some awesome info. Faded, you never cease to amaze me.

[dodgeaspen]

Although I really wish my problem was my crank seal I'm 99% sure it's not. The reason I say that is isn't is that If I remove the ignition cover the RPMs do not increase and and If I spray carb cleaner behind the flywheel while running nothing is getting sucked in and killing the engine. With that said I will probably replace the seal anyway and see what happens (faded- thanks for the replacing info!). I'm stumped with this problem and I can't rule out an air leak elsewhere or even jetting. The reason I say jetting is that the surging gets worse with colder temperatures. But on the other side of the coin the surging doesn't happen until the enging gets warm????? This sucks!

[Faded]

Originally posted by dodgeaspen
I have an 02 with the same exact problem.

dodgeaspen,

Just going off what you said here I figured that you were having the same problems (i.e. surging w/clutch action). If you don't think that it's your seal and that it might be jetting then we can tackle it from that aspect too.
Just a few questions;
[list=1][*]Can you ride right now? (No snow)[*]What is your elevation and current temps?[*]What needle/clip position are you running? (Stock needle = 6BEY30-74 or 6BEY30-73, need to find out which one it is.)[*]What gas and premix ratio do you run?[*]When was the last time you checked your float level?[/list=1]

I notice a couple things that don't quite seem right w/your above specs mentioned earlier but I'm going to wait until you answer these questions first.

Thanks,
Andrew

[dodgeaspen]

I've got some snow but I'm still able to ride.

I'm at around 700 ft and 25 degrees. I'm running a s-8 nozzle, 430 main, 6BEY30-71/3rd Clip, 35 pilot, AS 1.25 turns. I'm running 92 octane with Yamalube R at 40:1.

I checked the float level about 6 months ago...right on at 15mm.

I'm pretty sure that the problem would go away if I changed the pilot to a 37.5 but then closed throttle would load up rather fast.


Thanks for the help!,

Eric

[Faded]

Originally posted by dodgeaspen
6BEY30-71/3rd Clip

Eric,

This isn't an optional needle. The richest needle that you can get from Honda is a 6BEY30-72. Could you double check your needle?

Also, I'm sorry but there is something wrong...you are really rich. How do your reeds look? If they're okay then I think you need to start checking for airleaks else where.