wont run

[yam175]

hello everyone, i have a 82-84? yamaha tri-moto 175. it wont run, cleaned the carb out, has spark, has compression, messed with carb adjustments. nothing seems to work, and ideas of any sort will be appreciated, thanks. steve :confused:

[Fuzzy]

Does it try to fire at all?.

When you say it has compression have you done a compression test on it?. If so what was the reading you got?.

Have you tried to pull start it to get it spinning over faster?.

[yam175]

well, since i dont have a comptression gauge i put my thumb over the spark plug hole, and cranked i over, and it pushed my thumb up. i found out to do that if you dont have a gauge. and as for pulling it, i dont have the rear sprocket on and i dont have a chain yet. when i tried to put the rear sprocket on i couldnt get the hub off so i just gave up since that was the least of my worries at first, i just wanted to get it running.

[Fuzzy]

Have you tried putting a few drops of gas down the cylinder it self?. On two strokes when the side seals on the engine go bad they suck air in and cant pull air and duel from the carb. And i was just wondering if that might be the problem.

So pull the spark plug out and put a couple of drops of gas down the hole. And put the plug back in and try it. It should fire or at least try to run for a few secounds. That will at least tell you if your electricals are ok and that you have enough compression.

Let me know what it does when you try it and we can go from there and try to narrow down the problem.

[yam175]

i tried the gas, and it didnt run. so i tried a small bit of starting fluid and that didnt help either, but i heard a noise tthat sounded like air, then some smoke came out of the exhaust each time i cranked it over.

[Fuzzy]

Wow even starter fluid wouldnt fire in there. My guess would be maybe it is out of time and firing at the wrong time.


Can you give me a little more history on it. Did it ever run while you had it. Or was it not running when you got it. What other work has been done to it?. Has the engine been apart before, Like new top end or anything?.

[YamaChuck]

There is no adjustment on either the YT125 or the YT175 so you can scratch that. By priming the motor with straight gas and it still doesn't fire I would suspect a weak spark. No reason for that to not fire. What do you think Fuzz?

[yam175]

hey, when i got it it didnt run. i bought it planning to get it to run just to mess around on. im pretty sure it has been sitting for a period of time in a barn. you said there might be weak spark, how much would that run to fix? thanks, steve

[200x_Basket]

where there is smoke there is fire. what shape is the plug in? i could not get my 250r to start, i wokred on it for hours. then i swapped the plug, it fired right up:doh:

[yam175]

well the plug i used was brand new, ngk bp7es. i havnt taken it out since then though, so i will see tomorrow what shape the plug is in now.

[Fuzzy]

Yea i would say it has to be in the spark somewhere. Maybe the stator is rusted up from not being run in a while.

[yam175]

hey, i looked at the stator before, and everything didnt look that bad, but ill check again today more throughly.

[yam175]

hey, i checked out the stator, and everything looked clean. still confused on what could be the problem

[mudfreak99]

After readin this post I can honestly say that I don't think it is spark problem. you say it ahs compression but putting your thumb over the spark plug whole dosenn't give you an accuarte reading, I would get a dial and check it. also go buy a new plug but buy a hotter one. if you need help just ask a local dealer they can give you the numbers for a hotter plug for that model. and keep us posted.... and I would suggest getting the sproket and all on and trying to roll start it. I had to pull my 200x around the yard like 4 times before it started when i first got it.... and it ain't no fun if you can't ride it when you get it running anyway

[yam175]

i will try to get the sprocket on this weekend, but i still need to get a chain and the shifter linkage so i can put it into gear. i almost got one off ebay but some guy outbid me by 50 %#$*!%cents!. i tried putting on the shifter off my cr125 but the shaft on the trike is smaller then the bike.

[yam175]

also, i already have a plug that is one hotter, i will try using that one

[IronX]

I had that problem timing was incorrect and valves were a little to
tight..
Iron

[yam175]

hey, still no luck. im gonna have a friend over to check it out sometime, but in the meantime what should i do from start 2 finish to try and diagnose this problem. i know it cant be a valve related problem because its a 2 stroke. thanks

[YamaChuck]

I guess I would get that shifter fixed and pull start that thing. It has to fire if it is getting fuel and the spark is good. If still no luck, I'd replace the CDI coil . The problem has to be electrical if you can't get it to fire after priming it.

[yam175]

hey...ive decided that m gonna rebuld the entire trike and make it look nice n stuff...for something to do over winter....ill also try and diagnose any problems i see that way. ill try and take pictures if i get to. everyone who replied with tips, thanks. ill keep ya updated. steve

[yam175]

now, i have the trike apart. i took off the top end...and the piston and rings seem to be brand new so i figure that the rings arent bad. i also tried to shift the gears but it wont seem to want to move. it wiggles a little bit up and down but it wont go into gear, but that shouldnt effect the fact if it runs or not would it? its stuck in neutral as far as i know. i can spin the sprocket and it wont turn over the piston so thats how i figure its in neutral..but im not sure since the trike does have an automatic clutch. the next thing i have to do now its get the screws for the side cover off...which will probably be a pain in the a$$ since i can tell they will strip like on every motor ive taken the side covers off of. if there is anyone who has any experience with workin on the tri moto 175 please reply with any problems youve had to fix on yours...thanks, steve

[ATCnut]

If the side cover screws are philips (like the older Hondas) get a manual impact driver. It is a thing that you hit with a hand sledge and it breaks the screws loose. the replace them with hex head bolts

[trike250cc]

maybe its not in neutral? just a thought ;)