HELP!!! Need Yammie 225 DXN starting help.

[czac]

Hey guys, long time....
Was riding my DXN a few weeks ago, went down into the woods to look at a tree that fell in a storm recently, to get there I had to cross
a tiny mud bog about 3 or 4 foot wide.
I had no rear plastics on so I didn't want to fly through it and get mud all over myself so I basically tried to crawl through it. the trike got almost all the way through and suddenly just died, cut right off like I had hit the kill switch.

It would not start at all. so I towed it home with the tractor after pushing it out to the road, and have been messing with it since. It wont start with the starter or by pulling it. its got compression, its got spark and it seems to be getting gas. I took the carb off twice and cleaned it, made sure the floats weren't hanging up and all that... nothing.
I tried squirting a bit of starting fluid into the spark plug hole and it just sort of "puffed" once...
yester day I was messing with it again and got it to back fire really loud one time.

what do you all think could have happened? did mud maybe get in someplace its not supposed to be?
I have the stock air box and cleaner on it so I don't think anything got into the carb, im getting spark so I don't think anything shorted. that last time this happened was in the snow and it turned out to be the neutral safety switch went bad but I have already disconnected it and grounded the wire, still not starting.
One thing I did notice but don't think it makes a huge difference, I couldn't tighten the two nuts / studs that hold the carb on because the threads for the studs are stripping and if I try to tighten the nuts, it starts to pull the stud out of the carb. could it be that because the carb isn't tight enough there's an air leak? its tight but not like, Spec tight.
im going to re tap the carb and use new studs.
I cannot figure this out. there's gas in the carb when I take it off... how do I measure the spark to see if its hot enough?
there's def. a spark when I crank it over, it looks good to me but maybe its really not?

[czac]

Anyone? Ideas?

I just picked up another 225 DXL the guy I got it from said it was just running, his kids were riding it just before last winter but it started leaking gas from the overflow so they took off the carb and tried to adjust the floats but snapped off the tang so they threw a tarp over it and hadn't messed with it all winter or this summer... So i took the CDI off it and the Coil and put them on my trikes and it still wont start... I think its a carb deal but cant figure it out. Yesterday, for like the 5th time in two months, I took off the carb and made sure it was perfectly clean, all the jets were clean, no junk in the bowl, the needle valve looks great, seat looks great as well, the floats seem to be fine, not filled with gas, hang good... i put it all back together and it still wont start. i tried taking the air cleaner off and still nothing. What the heck is it? even with starting fluid right into the cylinder it wont kick. Its got great compression... how big a spark should it have? the spark it has doesnt look any different than it has since Ive had it. It was running great until it just died that day. it didn't bog or anything when it died, it just stopped running like it was shut off!.

[DohcBikes]

Good to see you posting! This is going to be a tough one craig. I was going to suggest trying a known working CDI. The next suspect would be the source coil. I highly doubt it's a carb issue because you said it wont run on ether, either.

[redsox]

did you check the decompression lever? Don't mean to insult, but i only mention it because it got me once. I've hd three of these 225dx's. One that is solid and has always run, and two that i got a a package deal on a trade. Those two have now been combined to make one decent runner, but thats not really important to the story. What is important is that with one of the engines i had a similar experience. had been a good starter/runner and then one day i shut it off and couldn't get it going again. After much checking and frustration, (AND FOR REASONS I CANT EXPLAIN OR UNDERSTAND) I got it to start and run. But i have to just barely crack the decomp lever at startup. All the way open and it won't start. All the way closed and it won't start and you'll break your hand. You can pick the thing up by the pull chord. Anyway,, worth a try and it don't cost nuthin'. Let me know if it works, i'll feel like a genius. Just a little crack of the lever. Probably has something to do with sucking fuel into the chamber, because i had fits with the carb and the spark and everything else being good as well.

[El Camexican]

Remove the air box cover take the filter off and make sure it's dry and that there is no water in the box. Remove the plug, pull the engine over a bunch of times and put everything back together make sure it's got good gas in it and try starting it. I'm guessing you got water on your filter.

[czac]

Remove the air box cover take the filter off and make sure it's dry and that there is no water in the box. Remove the plug, pull the engine over a bunch of times and put everything back together make sure it's got good gas in it and try starting it. I'm guessing you got water on your filter.

I took off the the cover and pulled the filter, everything looked good and dry except for some mice started storing food in the air box, Don't know how they got in it though, possibly over the last month or so, While its been sitting.. maybe when I had the carb off it they went in through the intake...lol anyhow i vacuumed it out, all's good there now. No water, corn or, bird seeds (or mouse pee..lol)

did you check the decompression lever? After much checking and frustration, (AND FOR REASONS I CANT EXPLAIN OR UNDERSTAND) I got it to start and run. But i have to just barely crack the decomp lever at startup. All the way open and it won't start. All the way closed and it won't start and you'll break your hand. You can pick the thing up by the pull chord. Anyway,, worth a try and it don't cost nuthin'. Let me know if it works, i'll feel like a genius. Just a little crack of the lever. Probably has something to do with sucking fuel into the chamber, because i had fits with the carb and the spark and everything else being good as well.

Thanks! I will check that. What could it hurt? lol if that's it im going to cry... lol

Good to see you posting! This is going to be a tough one craig. I was going to suggest trying a known working CDI. The next suspect would be the source coil. I highly doubt it's a carb issue because you said it wont run on ether, either.

Yeah it sure is a tough one... cant figure it out. all the usual suspects are fine... gas, compression, spar (i think)... I did order a new Coil, maybe the spark isn't healthy enough... Not sure but its about all i can think it could be. it was running and then it stopped! the last time i had a problem it was a clogged fuel filter. but even running it with no filter she wont fire. and shooting starting fluid in the spark plug hole didn't make it fire either. I dug through all mt parts last night and found another CDI im going to try as well. Hopefully something is going to work...lol Don't know what could have happened, like I said, i went through the mud hole at like 1 mph! so it wouldn't splash all over as i had the rear plastics off.

[czac]

arggggh! i typed up a lengthy reply and then hit "Reply to thread" instead of Post quick reply!!!! that button is so aggravating!!! lol.
anyhow... i think the timing may be off like it might have jumped a tooth ... I checked the top gear and it looks good though, not worn and the chain is nice and tight.. not loose or sloppy... I did put in a brand new spark plug and a brand new coil and the spark is much nicer now but it still wont start...it will pop and backfire some times but not start.
How do I check the timing if it wont start though? any suggestions? is there a way to set the timing up like you would if you rebuilt the motor?

[85burbanator]

I have a similar issue with one of my dx's. Saved it from a field and the top of the cylinder was rusty. Turned over but had a slight groove. Would pop on starting fluid and/or run for a few seconds. Honed the cylinder and replaced the piston. Dropped an oring in the engine and had to pull it out of the frame to get the o ring. Put it all back in and now no spark. Lots of low electrical connectors. I'd check there first. Can't remember how I set the timing (that part was over 6 years ago) but it's right. I'd check for crummy connections down low

[czac]

I have a great spark now, im just not convinced its firing at the right time though. im just wondering if there's a way to check the timing is OK without starting it up... its frustrating when you do all that you can think of doing and everything needed to run is there yet it wont start... lol

[czac]

ok so looking at the repair manual it showed how to put the head back together and in that, how to set up the timing... in a hole , under a large screw (plug) in the crank case you can look in and see the flywheel (at least that's what I am going to cal it..lol) you turn the engine over untill you see a "T" thats engraved on it... when that "T" is lined up with a notch in the case, the piston is at Top Dead Center or TDC. then you take off the top cover on the head to see the cam shaft gear, there's a line engraved in the gear and a sort of "Pointer" at the 12 o'clock position of the round access hole to get at the gear / chain... with the crank gear on "T", the mark in the cam gear has to be at the 12o'clock mark for the timing to be set... mine was at the 9 o'clock position. now f i remove the gear and re set the crank to the "T" and the cam to the 12o'clock position the motor should be timed right.... my question is, as mine is at the 9 o'clock position, does it mean it jumped timing or maybe the chain is worn? everything looks good, the chain looks good, its tight, the gear looks ok, not too worn , no missing of chipped teeth.. but... it does look like someones been in there messing with things before. the bolt that holds the gear on was definitely removed or some had tried to remove it at least because you can see the corners of it are a little worn like a wrench had been on it. and the plug to look in the crank is made to be removed with a big slotted screwdriver and you can see that someone tried to remove it with a smaller screwdriver and sort of messed up the slot. I had to use a vise grip to loosen it. anyone ever do the timing on these things before?

[RubberSalt]

Valve lash. What your clearance?

[czac]

Valve lash. What your clearance?

haven't gotten that far yet.
I did re set the timing last night but got nowhere. it still wont start. I have to check to see if i have a bent valve and also check to see if I have a sheared Key on the flywheel.
I have no clue what the issue is, the timing was so off it seemed like it may have jumped but it seems like a BIG jump to go from the 12 O'clock Position to the 9 O'clock on the cam gear! lol
also given that the chain and gear look to be still in great shape...its a real mystery! also, when a motor jumps the timing, doesnt it back fire or pop really load? mine did none of that, it just shut down like I turned off the key...

[RubberSalt]

It doesn't always. It'll jump if there's slack in the chain. Post a few pictures of the gear and the chain guides if you can.

As for replacing the chain, I'd review the guides and the chain tensioner set up first. If the guides are worn, the tensioner may not be able to help. If the guides are not worn, then the tension may be all soft and squishy. If that's not it, stretched chain and worn gears.

The tensioner pushes on one guide. The guide has direct contact with the chain, the chain just slides over it. groves form in the guide, the tensioner pushes the guides more so they make contact with the chain. When the guides are worn out, the tensioner can't help. It can only push so far. The guides are typically made of a magical plastic that is hard. (I'm thinking nylon? fiber glass fill? anyone?)

The chain could be perfectly fine! Things don't jump time without reason, finding the reason is important and focusing on repairing that. Also, check that valve lash!

To replace those guides, you'll likely have to pull the head. If you pull it, be sure to use new gaskets and check the head for flatness!

Fortunately enough, these parts are available and fit a zillion machines.
http://www.partzilla.com/parts/searc...AIN/parts.html

[czac]

Well I think the problem was solved. I went to Harbor Freight at lunch yesterday and picked up a Flywheel puller set, when I got home from work I pulled the flywheel and there it was, a sheared Key! Half was in the crankshaft and the other part was in the flywheel! so im going to order one today along with all the new gaskets and o-rings and I'll probably replace the timing chain as well just because I can. the guides and cam gear still look good, no issues that can be seen, I'm wondering if this was already fixed once because the bolt on the cam gear shows signs of being wrenched on before as does the screw you take out of the case to look in and set the "T" on the flywheel to the timing mark on the case. anyhow, the crank gear looks great as well so i may just throw a new chain on her and a new key and try it out. It would explain how it went from 12 pm to 9 pm and then wouldn't start when i reset the timing... when I set it to the timing mark the piston should have been at TDC but since it was the sheared key the piston was probably half way through the down stroke...lol Once that's set i will re adjust the valves they seem to be a bit sloppy but i haven measured anything yet. Thanks everyone for all your suggestions and help!

[RubberSalt]

That'd do it! These are held on with friction, that key is simply to line it up. Either that bolt loosened just enough for the flywheel to back off a hair, it was torqued right, or just to many starts/stops caused it to slip.

Had this happen to my brothers 250r at the dunes. Damn thing would ran, but man it ran bad!!