[HeWhoAteTheCaviar]

Ive been having a difficult time with my 17' 250x starting up off of a cold start. The bike will fire right up after a brief warm-up period, but when its cold it back fires and struggles hard. Any suggestions? possible carburetor issue? Im lost.

[JimDirt]

My first thought is Check the Valves ..... that is where I would start first , If you have done the "check the bowl for dirt in the bottom plug" , "Put in Fresh Gas" thing , then I would tend to think the Intakes have tightened up

[HeWhoAteTheCaviar]

My first thought is Check the Valves ..... that is where I would start first , If you have done the "check the bowl for dirt in the bottom plug" , "Put in Fresh Gas" thing , then I would tend to think the Intakes have tightened up

I haven't taken the carb apart yet. Ill give that a shot and see if I've got any dirt in it. Thanks for the feedback!

[HeWhoAteTheCaviar]

UPDATE
Carb was clean. replaced a rusted out spark plug which i thought was the issue. looks like the 250 is going to get her first valve adjustment. My buddies want to go for a ride this weekend but I am hesitant to go ride with my bike having these issues.

[JimDirt]

If the valves are just going out , then you have a couple rides left , so I would adjust them , go for the ride with your friends , and then as soon as you can schedule it , have the valves done ........ OR , you could buy a already done head (not sure of your budget) from Ken (the owner here) , and swap it out in a evening , and not have any down time , and be back on the trails without missing any ride days , then you have a backup for later on , if you decide to have that one redone ...The options are endless (depending on your budget)

https://www.crfsonly.com/catalog/index.php/cPath/258

[HeWhoAteTheCaviar]

If the valves are just going out , then you have a couple rides left , so I would adjust them , go for the ride with your friends , and then as soon as you can schedule it , have the valves done ........ OR , you could buy a already done head (not sure of your budget) from Ken (the owner here) , and swap it out in a evening , and not have any down time , and be back on the trails without missing any ride days , then you have a backup for later on , if you decide to have that one redone ...The options are endless (depending on your budget)

I went for my ride and the bike ran fine, aside from the starting issues. Got the Valves adjusted. Intake valve had 0 clearance! needed to be shimmed twice 195mm to 170mm, according to mechanic's notes. Exhaust was still within speck. Is this unusual or a year old bike?

[JimDirt]

For a 2 year old bike , yes/no , ..... If dirt got past the air filter , then yes that is normal , ...... If for any other reason , then no

Generally what takes out the valves (Intakes mainly) is dirt getting to the valve seats and hammering the valve face to death (kind of like sandblasting it non stop) , the valve face usually cups , which lessens the clearance , so you need a smaller shim , till you get to the smallest size and , no more shimming , and its time for new valves , also , even when shimmed , if it hits 0 , then its going to go fast again to 0 , so your time is minimal at best before the next adjustment or the need for the valve job ..this is inevitable ...... it could happen after only 1 ride , or 3 or 10

The next most likely candidate is hitting the rev limiter over and over , this will literally beat the valves to death , again , causing the same symptoms and end result .... Since its a X , I doubt it was ridden on the limiter , so I am guessing dirt is the culprit here , so you might want to look closely at where the filter seals with the airboot in the airbox , if you see dust/dirt beyond the filter and in that snorkel area , then you have found the cause .... The next issue (after a valve job or replacement head) is to find WHY the dirt got past , is it getting thru the filter itself ?? (not enough filter oil) , or is it getting past the seal surface (not enough oil on the filter or a improperly installed filter) , or not greasing (most people do this) the filter lip where it meets the airbox seal

I learned this lesson with my 06 450X the hard way , within a few months of brand new , I had the Intakes zero out , and had to replace the valves .... I went with Stainless instead of Titanium (harder and last longer) , and have not had to adjust them since (yes from 2006 to 2019 , I have not had to adjust the valves since switching to Stainless) .... I highly recommend going that route when you do decide to do the valves (or replace the head)

This is what dirt looks like getting past the filter (I put a J in the area where the dirt is , and not supposed to be) As you can see , the seal area looks clean , so the dirt got in thru the filter ...

[HeWhoAteTheCaviar]

For a 2 year old bike , yes/no , ..... If dirt got past the air filter , then yes that is normal , ...... If for any other reason , then no

Generally what takes out the valves (Intakes mainly) is dirt getting to the valve seats and hammering the valve face to death (kind of like sandblasting it non stop) , the valve face usually cups , which lessens the clearance , so you need a smaller shim , till you get to the smallest size and , no more shimming , and its time for new valves , also , even when shimmed , if it hits 0 , then its going to go fast again to 0 , so your time is minimal at best before the next adjustment or the need for the valve job ..this is inevitable ...... it could happen after only 1 ride , or 3 or 10

The next most likely candidate is hitting the rev limiter over and over , this will literally beat the valves to death , again , causing the same symptoms and end result .... Since its a X , I doubt it was ridden on the limiter , so I am guessing dirt is the culprit here , so you might want to look closely at where the filter seals with the airboot in the airbox , if you see dust/dirt beyond the filter and in that snorkel area , then you have found the cause .... The next issue (after a valve job or replacement head) is to find WHY the dirt got past , is it getting thru the filter itself ?? (not enough filter oil) , or is it getting past the seal surface (not enough oil on the filter or a improperly installed filter) , or not greasing (most people do this) the filter lip where it meets the airbox seal

I learned this lesson with my 06 450X the hard way , within a few months of brand new , I had the Intakes zero out , and had to replace the valves .... I went with Stainless instead of Titanium (harder and last longer) , and have not had to adjust them since (yes from 2006 to 2019 , I have not had to adjust the valves since switching to Stainless) .... I highly recommend going that route when you do decide to do the valves (or replace the head)

This is what dirt looks like getting past the filter (I put a J in the area where the dirt is , and not supposed to be) As you can see , the seal area looks clean , so the dirt got in thru the filter ...

Thanks for the feedback! Everyone I have spoken to also agrees that dirt most likely caused the valve to go out of speck. I have a hard time believing this because of how frequently I change my filter. Because of my dusty area, its almost mandatory to swap out a filter every ride. Every filter swap I check the boot to make sure nothing has gotten past the filter. I have lost count of how many times I've changed my filter, and the airboot still looks just as clean as it did when I picked the bike up still in its crate, which was exactly one year ago today lol. This is somewhat disheartening considering how well I've maintained the bike. However, I also have between 400 and 500 miles worth of desert and trial riding on the bike in just one year. I'm also a relatively conservative rider. The bike has maybe hit limiter twice in it's short lifetime.

[JimDirt]

Is the area damp/wet with filter oil (inside the snorkel area ??) as that would hide any indication of dirt even though dirt is getting past ..... They can wear just from use , but its not common to zero out unless they had not been checked since new and you did not notice a change in spec

1 other thing .... check the carb ,.... Take the 17mm drain bolt out on the bottom of the bowl , do not tip it , just hold it level and pull it out from under the carb , look down inside and see if there is any sand/dirt in it , that is a sure sign dirt is getting thru/past the filter , if you find ANY dirt in it ......

[HeWhoAteTheCaviar]

Is the area damp/wet with filter oil (inside the snorkel area ??) as that would hide any indication of dirt even though dirt is getting past ..... They can wear just from use , but its not common to zero out unless they had not been checked since new and you did not notice a change in spec

1 other thing .... check the carb ,.... Take the 17mm drain bolt out on the bottom of the bowl , do not tip it , just hold it level and pull it out from under the carb , look down inside and see if there is any sand/dirt in it , that is a sure sign dirt is getting thru/past the filter , if you find ANY dirt in it ......

The airboot has a little bit of moisture in the bottom of it, but doesn't look like any dirt has accumulated in it as well. I'll take a look at the carb bowl for any dirt. If you do find dirt in the carb, how do you go about (1. cleaning it out and (2. preventing dirt from getting in there again?

[JimDirt]

I "think" I see a slight bit of dirt/dust in the snorkel in your picture , similar in place to the picture of mine , it looks to be damp with filter oil , but still present , so I think dirt IS getting thru the filter , remember , even a trace amount will still beat on the valve face , because whether you are putting in a bag of sand/dirt , or sprinkling it in 1 grain at a time , its still sand/dirt getting to the valves and getting hammered into them

As far as cleaning the carb , if you are not struggling with idling/low throttle bogging/stalling then chances are , it has not clogged the jets yet....however ..... I recently took my carb apart (fighting the same issue) , and found in the middle section (where the carb body splits) dirt to be present , as well as lots of it under the top cap where you access the slide and needle and all thru that part of the carb and all over the slide itself , I had to completely clean EVERY part of the carb , due to dirt/sand ...... Make sure you do not use carb cleaner on any parts that have O-Rings , including the fuel screw O-Ring , so make sure when you remove the carb for a thorough cleaning , to take care in removing ALL rubber parts , including the seal on the Slide Plate , and take note of its orientation , and how the slide plate sits on the carb (where the hole is in relation to the slide top/bottom)

I also found slight traces of dirt/sand in my gas tank , so after flushing it out , I now strain my gas with a coffee filter when pouring from one jug to another (I mix Non Ethanol with Av Gas , so I pour 2 different cans into one (smaller can) (I use Tuff Jugs , because of the gravity fill , it's just like a race can , no need to try not to spill using the typical hose type can when you can just tip the can upside down into the gas cap opening and when the tank is full the gas stops flowing and you remove it)

Anyway , you might look into the way you are oiling your filters , or possibly think about changing filter brands or filter oil brands/type .... I have tried them all (seriously all of them) and currently prefer No-Toil filters and oil ...and their customer service is second to none ..... and the best part .... I clean my filters with warm water (you can use cold if warm is not available) and Oxyclean , as the oil is water soluble , so no stinky gas or solvent cleaning , and you can literally stick your bare hands on the filter while cleaning it and then rinsing it , no bulky gloves , or mess to clean up , when you are done , you simply dump the dirty oil on the ground , as its enviro friendly , so no worry about disposal of used solvent , it won't harm anything in the ground ......... ok sales pitch over .....

Seriously , you need to look at why the dirt is getting past , as from what I can see in that picture , there is dirt getting thru ..... even the slightest trace amounts over time cause damage , and that is what I think you are finding , its not dirt dumping into the engine ..... its just being fed dirt constantly , like throwing powder into a fan , and that will cause the same damage as running no filter at all , it just takes longer to accomplish this ....

[HeWhoAteTheCaviar]

I "think" I see a slight bit of dirt/dust in the snorkel in your picture , similar in place to the picture of mine , it looks to be damp with filter oil , but still present , so I think dirt IS getting thru the filter , remember , even a trace amount will still beat on the valve face , because whether you are putting in a bag of sand/dirt , or sprinkling it in 1 grain at a time , its still sand/dirt getting to the valves and getting hammered into them

As far as cleaning the carb , if you are not struggling with idling/low throttle bogging/stalling then chances are , it has not clogged the jets yet....however ..... I recently took my carb apart (fighting the same issue) , and found in the middle section (where the carb body splits) dirt to be present , as well as lots of it under the top cap where you access the slide and needle and all thru that part of the carb and all over the slide itself , I had to completely clean EVERY part of the carb , due to dirt/sand ...... Make sure you do not use carb cleaner on any parts that have O-Rings , including the fuel screw O-Ring , so make sure when you remove the carb for a thorough cleaning , to take care in removing ALL rubber parts , including the seal on the Slide Plate , and take note of its orientation , and how the slide plate sits on the carb (where the hole is in relation to the slide top/bottom)

I also found slight traces of dirt/sand in my gas tank , so after flushing it out , I now strain my gas with a coffee filter when pouring from one jug to another (I mix Non Ethanol with Av Gas , so I pour 2 different cans into one (smaller can) (I use Tuff Jugs , because of the gravity fill , it's just like a race can , no need to try not to spill using the typical hose type can when you can just tip the can upside down into the gas cap opening and when the tank is full the gas stops flowing and you remove it)

Anyway , you might look into the way you are oiling your filters , or possibly think about changing filter brands or filter oil brands/type .... I have tried them all (seriously all of them) and currently prefer No-Toil filters and oil ...and their customer service is second to none ..... and the best part .... I clean my filters with warm water (you can use cold if warm is not available) and Oxyclean , as the oil is water soluble , so no stinky gas or solvent cleaning , and you can literally stick your bare hands on the filter while cleaning it and then rinsing it , no bulky gloves , or mess to clean up , when you are done , you simply dump the dirty oil on the ground , as its enviro friendly , so no worry about disposal of used solvent , it won't harm anything in the ground ......... ok sales pitch over .....

Seriously , you need to look at why the dirt is getting past , as from what I can see in that picture , there is dirt getting thru ..... even the slightest trace amounts over time cause damage , and that is what I think you are finding , its not dirt dumping into the engine ..... its just being fed dirt constantly , like throwing powder into a fan , and that will cause the same damage as running no filter at all , it just takes longer to accomplish this ....

Hmmm... I use maxima filter oil. I have a bucket that i poor the oil into and i then dip my clean filter into the oil bucket and then massage the filter to make sure that it is completely soaked in oil. as far as cleaning is concerned, I use twin-air filter cleaner to wash out the old filter-oil then i rinse the filter out with hot water and dish-soap. I let the filter dry then I will re-oil it and replace. I just got a brand new Honda OEM air filter and re-oiled it to make sure (it doesn't come very oiled from the factory). When I replace the filter, I always make sure the foam seal on the filter is well oiled and seats right with the airboot seal. I have noticed that when I re-oil the filter, a lot of excess filter-oil will drain out of a small plug located at the bottom of the airboot. Am I over-oiling? using the wrong cleaner? Thanks again for the knowledge

[JimDirt]

That is basically the same process as the No-Toil , so I think your good , on what your using , and it "sounds" like you are applying it correctly , the only way you would be "over oiling" the filter is if it affected the running/starting of the bike , in other words , if it runs rich or like the choke was left on (blubbering) then I would say you were over oiling , though with the fact that there is dampness inside the snorkel , means the engine is sucking hard , so the air is somewhat restricted , and it is sucking the oil thru the filter into the snorkel , so there is that , as shown by your picture which does indicate dirt is getting past , and possibly sucking in the dirt inadvertently due to too much oil and it really sucking the air thru , bringing the dirt along with the air .... , but ,

I would not lessen the amount of oil you are using , or at least not by much ...... maybe let the filter sit for a hour or so before installing to let it breath and the oil "set" (not sit , but set , so its not so prone to flowing) , before confining it into the airbox ..... if you want to eliminate the "drip" just cut a 2-1/2"x3" chunk of foam and place it in the little recess at the bottom of the airbox , and it will stop the drip , and act as another "filter" to aid in keeping dirt to a minimum ......

What I would suggest after reading what you have done , is get a PC Racing filter seal (it goes on the face of the airboot where the filter seats) , I had to do this on my 450X to keep the dirt out , even though I was greasing the filter edge , it still did not seal completely and was the source of my 450X valve issues , which were somewhat different , yet the same from my 450R valve issues caused by dirt getting thru the filter itself as well as the boot not sealing , which I ended up (just recently) replacing the 02 airbox for a better sealing 03 airbox .....The extra thickness of the PC Racing seal , seems to seal the filter itself better , which is why they put it on the market , because this is a known issue with the Honda airboxes and valve failure related issues .... It is not the ONLY fix , but it is used in conjunction with the other methods to keep the dirt to a minimum if not eliminate it when all things are applied together to combat the dirt from entering the intake tract

I have not put one on my R yet as it was not available for the 02 as its airbox is different than the 03-04 , so they did not make a seal for the 1 year , but the 03-08 take the same filter (same one as the X) so they are readily available , but I am also still in the testing phase with the 03 airbox , as the weather is still wet here so I have not been riding in the normally severe dust I ride in ....but so far the airbox swap , has eliminated (at least under current weather/dust conditions) dirt getting thru/past the filter on my 02 , as that picture I posted was of just a month ago , and for now , my snorkel is free from dirt/dust , where under the same conditions with the 02 airbox , it was as shown in the picture i posted ... so a major 100% improvement .... So I am right there with you on this issue , and have tried most every remedy known , to resolve it and keep my valves from self destructing ... What knowledge I do have on the subject is completely from actual experience using the products and "fixes" to try to resolve it

https://www.crfsonly.com/catalog/produc ... ts_id/3205

[HeWhoAteTheCaviar]

That is basically the same process as the No-Toil , so I think your good , on what your using , and it "sounds" like you are applying it correctly , the only way you would be "over oiling" the filter is if it affected the running/starting of the bike , in other words , if it runs rich or like the choke was left on (blubbering) then I would say you were over oiling , though with the fact that there is dampness inside the snorkel , means the engine is sucking hard , so the air is somewhat restricted , and it is sucking the oil thru the filter into the snorkel , so there is that , as shown by your picture which does indicate dirt is getting past , and possibly sucking in the dirt inadvertently due to too much oil and it really sucking the air thru , bringing the dirt along with the air .... , but ,

I would not lessen the amount of oil you are using , or at least not by much ...... maybe let the filter sit for a hour or so before installing to let it breath and the oil "set" (not sit , but set , so its not so prone to flowing) , before confining it into the airbox ..... if you want to eliminate the "drip" just cut a 2-1/2"x3" chunk of foam and place it in the little recess at the bottom of the airbox , and it will stop the drip , and act as another "filter" to aid in keeping dirt to a minimum ......

What I would suggest after reading what you have done , is get a PC Racing filter seal (it goes on the face of the airboot where the filter seats) , I had to do this on my 450X to keep the dirt out , even though I was greasing the filter edge , it still did not seal completely and was the source of my 450X valve issues , which were somewhat different , yet the same from my 450R valve issues caused by dirt getting thru the filter itself as well as the boot not sealing , which I ended up (just recently) replacing the 02 airbox for a better sealing 03 airbox .....The extra thickness of the PC Racing seal , seems to seal the filter itself better , which is why they put it on the market , because this is a known issue with the Honda airboxes and valve failure related issues .... It is not the ONLY fix , but it is used in conjunction with the other methods to keep the dirt to a minimum if not eliminate it when all things are applied together to combat the dirt from entering the intake tract

I have not put one on my R yet as it was not available for the 02 as its airbox is different than the 03-04 , so they did not make a seal for the 1 year , but the 03-08 take the same filter (same one as the X) so they are readily available , but I am also still in the testing phase with the 03 airbox , as the weather is still wet here so I have not been riding in the normally severe dust I ride in ....but so far the airbox swap , has eliminated (at least under current weather/dust conditions) dirt getting thru/past the filter on my 02 , as that picture I posted was of just a month ago , and for now , my snorkel is free from dirt/dust , where under the same conditions with the 02 airbox , it was as shown in the picture i posted ... so a major 100% improvement .... So I am right there with you on this issue , and have tried most every remedy known , to resolve it and keep my valves from self destructing ... What knowledge I do have on the subject is completely from actual experience using the products and "fixes" to try to resolve it

https://www.crfsonly.com/catalog/produc ... ts_id/3205

Upon re-oil and install of the clean filter, I always start the bike up. With a freshly-oiled filter, the bike doesn't like to idle until it is done draining all of the excess oil. maybe this is a good indicator of over-oiling? I try not to completely submerge the filter in oil. I typically dip the three corners of the filter and then lightly massage it (while lightly re-applying oil where needed) until the outside is completely covered in oil, then I will ensure the foam seal is well-oiled. I went for another ride post valve adjustment and still ended up with a very small amount of dirt and dampness in the airboot. I don't think I am doing anything wrong as far as oiling and cleaning is concerned, and yet dirt is still getting past, but I've been wrong before. However, the bike had a significant jump in power and throttle response after the valves were re-shimmed. I will try the racing seal and "setting the filter before install" method for sure. Hopefully that will solve this issue. I also learned how to check valve clearance (much easier than I initially thought) so ill be keeping an eye on that as well.

[JimDirt]

I think you are actually under oiling the filter by the sounds of it .... as mentioned , submerging the entire filter is the key to making sure the filter is adequately oiled , I completely submerge mine and have to squeeze it out (not wring it out , but squeeze from top to bottom , kind of like how you would milk a cow) till the excess oil is removed but the filter is still saturated , then as mentioned , let it set for at least 1 hour or even overnight before installing , letting it air dry will help with the dripping . but still allow the oil to be abundant in the filter , when I use the No-Toil Red oil , I let it set overnight , when I use the Green oil I let it set for at least 1 hour (the green does not have Alcohol to dissipate)

Try as I mentioned above , along with the PC racing seal (which I just picked up one for my R today , even though so far I have not had dirt since switching to a 03 airbox) , and see what it does , you can saturate the filter completely , just start squeezing from the top where the rubber ring is , and work your way to the seal , then find a nice clean spot and put a paper or shop towel down , and let it sit in the sun (away from any wind that might blow it into the dirt , like sitting on your workbench) , then after you notice it is tacky (should be minimum 1 hour) then install it , and see if you notice any difference in dirt getting THRU the filter.........Report back with findings ...