1985 YTM 225 DXN Carb Questions

[czac]

Ok, some may know the story but here's the condensed version:
When I bought my trike it had an after market Mikuni carb on it, the trike would start one or two pulls, would idol, take the throttle well, but when you tried to ride it, it would stall out. Then, if you went to re start it, it wouldn't start. It didn't matter how it stopped, if it stalled or you shut it off, that was it, it would take almost the better part of 24 hrs. before it would start again.
I thought it was electrical but it wasn't. The carb it seems, was flooding out. So, luckily the trike came with what was left of the original Mikuni carb so I stripped out all the jets and anything else I could and put them in the after market Mikuni. It fired up and ran great....
Recently though, it was starting to do the one start trick again so I figured, "hey, I got this $40.00 stock Mikuni off eBay, let me clean it up and throw it on. so I did, it wont start at all now... lol here's the questions...

there's two lines coming out of it.. one silver and one brass, which is the one for the fuel line? someone said gold is prolly it, im not sure, Chris P, a member here, suggested blowing a small amount of air through it and see if it comes out from the needle valve which I will try if need be but for now I don't want to pull the carb again if I don't need to...lol

Next question: the break down of the carb in the repair manual shows the Pilot screw set as having a spring and what looks like two rubber o rings, mine had a spring and one rubber o ring and one steel washer. what should it have?

Next, it also shows that there is some sort of plastic baffle on the main jet... huh? what? yes.. that's what it shows... none of the three carbs I have had this... is it needed?

Last but not least.. I had recently put a muffler on it from a YZ 250 and it ran good with it on, should I have to re jet the carb/ I say it ran good, maybe it wasn't, I have no clue how its supposed to run, it wasn't popping or bogging down or sluggish... it had plenty of power and speed id say... what's your thoughts on this? Just as a point of reference, the original muffler was wide open with no baffle or anything and it also seemed to run good to me...

Thanks in advanced!!

[barnett468]

wow.

here's some options.

post a photo of the carb fittings.

the brass is tyoicsally the fuel inlet. if it is lower than the other and pointed directly at the bowk this is it.

pull the spark plug and post a very close up photo of it.

install new spark plug.

go up 2 sizes on the main and tell us if it burbles on top end or anywhere during acceleration.

after 30 minutes or more of all around riding, ride it hard the last 10 seconds then wot for around 3 seconds and shut it down immediately and post photo of plug. it should be a lite to medium tan.

MAIN JET BAFFLE - This helps keep fuel around the main when riding over rough terrain. yes it should have one.

[czac]

wow.

here's some options.

post a photo of the carb fittings.

Ask and Ye shall receive... Here's a pic of said Carb with really cool arrows and letters and stuff!:p
http://www.brokenfencephotography.com/Other/Yamaha-225-DXN/i-4LfVmCG/0/L/carb%20lines-L.jpg



the brass is tyoicsally the fuel inlet. if it is lower than the other and pointed directly at the bowk this is it.

MAIN JET BAFFLE - This helps keep fuel around the main when riding over rough terrain. yes it should have one.

So it wont have anything to do with starting the trike then?
Thanks!!!
Ill have to look into the jet thing... should I actually need it if its running ok with out it?

[czac]

so if the main jet is 112.5 what's the size I need? 14.5? or do they run is some strange size range I don't know of? also, how do I find one for my carb? what do I need to have, year, make, mfg, all that stuff?

[Ghostv2]

B is for fuel, A is a vent.

I do not have the plastic piece, none of my 2 dx's had them. It seems to run fine without it. As for the jets, I took them out and took them to my local atv store, they had them on stock. I got the next two sizes up from stock because I was not sure either. Just for an idea, I run a 120 main (112.5 is stock I believe) and 25 pilot (20 is stock). But I have mine bored out, DG exhaust, pod filter. But this is also on a 225dx, so obviously you will differ.

[czac]

B is for fuel, A is a vent.

I do not have the plastic piece, none of my 2 dx's had them. It seems to run fine without it. As for the jets, I took them out and took them to my local atv store, they had them on stock. I got the next two sizes up from stock because I was not sure either. Just for an idea, I run a 120 main (112.5 is stock I believe) and 25 pilot (20 is stock). But I have mine bored out, DG exhaust, pod filter. But this is also on a 225dx, so obviously you will differ.

thanks!

So on the vent one, does it get a hose or does it not need one? if it does, where does the other end of the vent hose go? I never had it with the stock carb on it so its new to me... lol
now to figure out why it wont start, I had the gas line to the silver tube so it should have been getting gas. Hmmm! lol
thanks again.

[Ghostv2]

I have them both vent down the same way as the bowl overflow hose. There is a little hook thing by the back of the engine it goes in. You can't see it in the pic but oh well.

http://i281.photobucket.com/albums/kk237/coloredname1/159803F5-90E7-480E-AF66-8258CF54BDAF_zpskbwqguik.jpg (http://s281.photobucket.com/user/coloredname1/media/159803F5-90E7-480E-AF66-8258CF54BDAF_zpskbwqguik.jpg.html)

[czac]

cool, thanks!
so I went home last night, tore the carb down again and really scrubbed it, I made sure every hole in every nozzle and every nook and cranny was open and clean, I then reassembled it and it still wouldn't start, I then shot a little starting fluid in it and boom, it fired up but....! its stuck on a really high idle and turning the idle screw either way doesn't do anything... Could it be that, when I took off the carb, I also put in a different rod in the carb slide? the one I had was really pointy, the one I put in last night was more blunt and round and a tiny bit thicker as it did not come to a point. other than that, it fires right up now. oh and I tried to see if it could be the throttle cable but I cant adjust it because the adjustments are all rusted up. Im ordering a new one soon though. I think im also gonna just bite the bullet and get a carb rebuild kit as well.

[barnett468]

the pointy rod is called the needle. this should have little affect on your idle unless your slide is open too far.

[czac]

the pointy rod is called the needle. this should have little affect on your idle unless your slide is open too far.

what if the slide is down as far as it can go? would it ten be the main jet?

[muthey]

ok your flooding issue is more than likely the o-ring on the float needle seat. they get one nick or ding in the o-ring and it will flood. also on the pilot jet or air mix screw as I like to call it the order into the carb is rubber o-ring steel washer spring and then the mix screw. your high rev can be caused by a cracked intake boot which will also prevent starting look it over carefully and you might see a nasty crack in it. As far as jetting you should be able to run original jetting to start with to get it running and dial it in from there for the aftermarket exhaust. I made you an offer once to rebuild the carb once before think on it. also your main needle the pointy rod on the throttle body will make a difference on how it runs as well. Your idle screw should be in a couple of turns so that the throttle body is just slightly up from the bottom of the throat, you can adjust it from there. you are also heavily leaning your carb with an open air filter like that as well. The vent hose goes up under the fuel tank and gets stuffed into the hook there that holds the wiring harness and throttle and choke cable.

[czac]

your high rev can be caused by a cracked intake boot which will also prevent starting look it over carefully and you might see a nasty crack in it
Thanks!! I will check the intake. is there any other reason it may be stuck on such a high idle besides a crack or other air leak?


also on the pilot jet or air mix screw as I like to call it the order into the carb is rubber O-ring steel washer spring and then the mix screw.
I have the order of parts wrong for the air mix screw, I have it as washer, o ring, spring, screw going into the carb... ill have to fix that. maybe that's my high idle problem?


I made you an offer once to rebuild the carb once before think on it..
Im sorry, Im too old lol...I don't remember the offer of rebuilding the carb, thanks much!

I had the rebuild kit in my eBay shopping cart since last week and finally went to buy it and someone got it before me. Worse, no one on there has one now, sure there's tons of used parts but I may as well stick with what I got if im going to buy used jets and stuff. there's a guy on there who sells the jet kits for performance and he says to give him the specifics of the trike so he knows what to give you so I did and it took two days to get a reply and he never answered my questions... all he said was I didn't need the plastic cap and that I should re jet the carb because of the YZ 250 muffler... lol


you are also heavily leaning your carb with an open air filter like that as well.
I have a K&N Air filter, I took off the stock air box cause it was broken and also I didn't have the rear cover for it, I have been thinking of getting a new one but they are either way too moch $$$ on eBay or they are all broken where mine was. I want to get one though cause I heard some horror stories of water getting into the carb and stuff, not that I plan on doing any under sea riding but hey, you never know...lol




As far as jetting you should be able to run original jetting to start with to get it running and dial it in from there for the aftermarket exhaust.
Is there some way of figuring out the jet size to use or is it more of a trial and error? If my jets are a #112.5 and a #20, what would the next sizes be? do they go up one whole number or half or two numbers?

Thanks for the tips and reply!

[muthey]

I forgot to tell you that plastic baffle as you called it is a de-atomizer it helps keep the fuel from atomizing in the bowl while you ride not a necessary part but is nice to have I have a few of them. for the jets you are going to want to go up in sizes I would do a couple whole numbers up and if it is almost right but not perfect start playing with halves. if the o-rings on the intake to motor or the carb to intake are shot it can cause a death idle. with my offer to rebuild it was you paid shipping both ways which is roughly 15$ total and 20$ and I will have it set up with a stock machine and from there you can dial it in for your after market parts.

[czac]

I forgot to tell you that plastic baffle as you called it is a de-atomizer it helps keep the fuel from atomizing in the bowl while you ride not a necessary part but is nice to have I have a few of them. for the jets you are going to want to go up in sizes I would do a couple whole numbers up and if it is almost right but not perfect start playing with halves. if the o-rings on the intake to motor or the carb to intake are shot it can cause a death idle. with my offer to rebuild it was you paid shipping both ways which is roughly 15$ total and 20$ and I will have it set up with a stock machine and from there you can dial it in for your after market parts.

cool... I just may take you up on that. how long for turn around?

im gonna look into the carb again just to be sure I didn't forget an o ring or something plus, I know the O-ring, washer, spring combo on the pilot jet is bad from your last post (thanks) so after that, if its still revving I will be in touch!

[Afrothunderkat]

https://scontent-b-iad.xx.fbcdn.net/hvideo-ash2/v/t43.1792-2/1099333_10200309146237252_5_n.mp4?oh=7e05177fe64f2 f7bc2e4fda9ed237124&oe=537D0D55

Had a 32mm off a KX80 on my dx and it worked great

[czac]

https://scontent-b-iad.xx.fbcdn.net/hvideo-ash2/v/t43.1792-2/1099333_10200309146237252_5_n.mp4?oh=7e05177fe64f2 f7bc2e4fda9ed237124&oe=537D0D55

Had a 32mm off a KX80 on my dx and it worked great

lol... nice video!

[barnett468]

hello;

http://t0.gstatic.com/images?q=tbn:ANd9GcTDheK_NT7A9cIdJnV_1Pg7lGbLDWNu5 AVQnY60FToKElt_Wip72n1nHA


great offer by Muthey.

I would also check the actual gas level first by doing the following: If the level is good or can be corrected, and it maintains that level, your float needle is not leaking much if at all.

1. get a small 10” long piece of clear plastic tube.
2. connect it to the float bowl drain fitting.
3. hold it close to the carb with the open end even with the top of the carb.
4. open the gas valve on the tank and drain screw on the carb bowl.
5. the gas in the tube should be around 1/8” plus or minus 1/16th below where the bottom of the main carb body where it meets the float bowl. If it is around 1/16th outside this range it should still work but should be corrected. If it is out of spec by more than that it might cause significant probs.

[czac]

hello;

http://t0.gstatic.com/images?q=tbn:ANd9GcTDheK_NT7A9cIdJnV_1Pg7lGbLDWNu5 AVQnY60FToKElt_Wip72n1nHA


great offer by Muthey.

I would also check the actual gas level first by doing the following: If the level is good or can be corrected, and it maintains that level, your float needle is not leaking much if at all.

1. get a small 10” long piece of clear plastic tube.
2. connect it to the float bowl drain fitting.
3. hold it close to the carb with the open end even with the top of the carb.
4. open the gas valve on the tank and drain screw on the carb bowl.
5. the gas in the tube should be around 1/8” plus or minus 1/16th below where the bottom of the main carb body where it meets the float bowl. If it is around 1/16th outside this range it should still work but should be corrected. If it is out of spec by more than that it might cause significant probs.


Good idea!
ill try it after work (I hope) if it doesn't rain.
thanks!

[czac]

Ok, i may have got it this time. I took off the carb again and re installed the pilot screw in the correct order, then i checked the intake for cracks and didn't see anything, i then put the more pointy needle back into the slide, then i picked the best looking needle valve of the three i have and put it all back together thats when i noticed the slide wasnt going all the way down. I pushed the throttle a few times and the slide would come down but not all the way so i took apart the slide and cable and then i compared the stock carb to the aftermarket one and the slide chamber on the newer carb is about a 1/4" shorter than the original. I messed with the cable some more and got the slide to go all the way down, installed everything and it fired up, i had to mess with the air screw and idle screw to get to run and idle... Now, it starts up, idles and seems to run good, has power and all but when i hit the gas then let off like say, going into a corner, it does the whole pop pop thing when you let off the gas... Should it do that or is that a jetting issue?

[muthey]

that's a jetting and air filter issue, or it could be a exhaust leak somewhere. I'm pretty sure you have already checked the valves but incase you haven't give them a good check.

[Jwmajic]

It could be caused by the 2 stroke muffler you got on there not giving it the right amount of back pressure I know that is often caused by not having proper exhaust back pressure.
" I had recently put a muffler on it from a YZ 250"

[Jwmajic]

Check the exhaust doughnut too.

[czac]

that's a jetting and air filter issue, or it could be a exhaust leak somewhere. I'm pretty sure you have already checked the valves but incase you haven't give them a good check.

No, I haven't dared mess with the valves yet...lol
It wasn't doing the popping thing before, with the after market carb that's why I just figured its a jetting problem or air/fuel mix problem. It seems like it was popping out of the carb, could it still be an Exhaust issue?



It could be caused by the 2 stroke muffler you got on there not giving it the right amount of back pressure I know that is often caused by not having proper exhaust back pressure.
" I had recently put a muffler on it from a YZ 250"

Maybe should I just look for a good used 4 stroke muffler?
What's the difference in 2 stroke vs 4 stroke muffler anyhow? the baffle?
Also, what should I look for, as an example, one from another 225, 200 or 250 4 stroke or does it matter if its from a bigger ATV like 600 or 400 or so? From what I have been reading around the web that others have used, I just figured a muffler was a muffler.

[czac]

that's a jetting and air filter issue, or it could be a exhaust leak somewhere. I'm pretty sure you have already checked the valves but incase you haven't give them a good check.

if I wanna buy a couple new jets to try, what do I look for, does it matter what I buy as long as they are for a Mikuni round slide VM carb? or do I need the exact carb part number and such? do you think I should go bigger on both the #112.5 and #20?
thanks!

[barnett468]

hello

the popping could be a few things especially with a high perf exhaust or straight pipe. it does not automatically mean that it is improperly jetted or your valves are leaking. i guarantee you 110% that all the camel series 1/2 mile bikes as well as many others are perfectly jetted and pop like the dickens upon decel. do not jet to remove the pop. jet it so it runs properly under acceleration and it will do what it wants on decel. if the valves are leaking, it will miss or pop under acceleration also. its quite simple, but do check the things mentioned by others anyway.

[czac]

hello

the popping could be a few things especially with a high perf exhaust or straight pipe. it does not automatically mean that it is improperly jetted or your valves are leaking. i guarantee you 110% that all the camel series 1/2 mile bikes as well as many others are perfectly jetted and pop like the dickens upon decel. do not jet to remove the pop. jet it so it runs properly under acceleration and it will do what it wants on decel. if the valves are leaking, it will miss or pop under acceleration also. its quite simple, but do check the things mentioned by others anyway.

cool, thanks!
I did not notice anything on acceleration only on decal. I will take it up the road tonight and open it up and see what it does. I can only get into third gear in my yard and by that time im hitting the break and down shifting to save my butt...lol but the next door neighbor has about 1200' of dirt road for a driveway and I use it as a test track every now and then. lol :twisted: