1985 YTM 225 DXN Carb Questions

**czac** · 05-19-2014, 03:03 PM

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** · 05-19-2014, 03:31 PM

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** · 05-19-2014, 04:06 PM

Originally Posted by barnett468

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!

Originally Posted by barnett468

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** · 05-19-2014, 04:10 PM

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** · 05-19-2014, 04:20 PM

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** · 05-19-2014, 04:31 PM

Originally Posted by 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.

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** · 05-19-2014, 05:58 PM

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.

**czac** · 05-20-2014, 07:33 AM

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** · 05-20-2014, 08:33 AM

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

**czac** · 05-20-2014, 08:55 AM

Originally Posted by barnett468

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** · 05-21-2014, 01:58 AM

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** · 05-21-2014, 07:41 AM