1983 YT175 Frustration

[ddiggerr]

Well I am at my wits end!

I have one of those temperamental trikes that does not want to run. It will fire up (only while hitting the throttle), and will not idle. Choke seems to work fine. I have taken everything off the carb and soaked it and made sure every hole was flowing with carb cleaner. I have replaced what was needed with new parts. I have set the float per manual and float needle looks like new.

In order for it to even, somewhat idle, I need to have idle adjustment screw (purchased new) turned in all the way. Adjusting it only stalls out engine. Air mix screw is out 1 1/2 turns.

Today I tore into engine thinking it was a crank seal, however, all is good inside. The only odd thing I found was in the clutch pack. Instead of either 8 or 16 balls, there were 10. I removed 2 as I do not have spares to complete the 16 count.

I have the oil injection hooked up as it is currently working as it should. I had also added premix to tank just to be sure. When running, it is quite the smoke show and there is oil spewing out exhaust making a mess of anything behind me. Will running this much oil be my issue as to why I cannot keep this thing idling????

When I do have it running, it goes like a bat out of hell, until I come to a stop. Then it is like I hit the kill switch, every time.

My compression is approx. 105 and I have lots of nice blue spark. Spark plug is wet and black. Starting is not an issue, idling is.

Just frustrated as I am 2 days away from hitting the trails and cannot rely on this thing to keep running.

Any suggestions would be much appreciated.

Thanks

[John_Neary]

Have you checked for a broken reed petal?

[ddiggerr]

Have you checked for a broken reed petal?

Hmmmm .... that is now at top of my list.

Would this cause a no idle situation?

[John_Neary]

my two stroke tuning skills are a few decades rusty but yeah i believe a broken or worn out reeds that are not snapping shut fully will cause idle issues and stalling

[ddiggerr]

my two stroke tuning skills are a few decades rusty but yeah i believe a broken or worn out reeds that are not snapping shut fully will cause idle issues and stalling

Yes indeed.

It was the reeds. Not by much, but there is lots of light shining through these things.

Funny thing is, when I take out the 2 screws and hold the plates down at the screw holes with my finger, there is no light at all. As soon as I tighten them down, they want to bow and then there wide open. Flipping them is even worse.

Anyways, time for replacements or the entire reed cage.

Thanks

[John_Neary]

@ddiggerr - glad to help, always was a fan of the early Tri-Motos

[ddiggerr]

There was also a tear in the rubber intake boot. All repaired and idling great. Time to ride!

[barnett468]

.

in addition to checking the reeds as John suggested, one big prob is your compression . . it should be at least 140 and around 170 is acceptable for premium gas . . cheap comp gauges can be off by 20 psi.

if someone ported the bejesus out of it this prob would not be uncommon to some degree.

you can not tell if a crank seal is leaking simply by looking at it . . a proper leak test must be performed, however, a leaking flywheel side crank seal will make it rev high . . a leaking seal on the other side may make it idle high but may also suck oil which will sort of reduce the air leak but it will smoke like heck.

too much two stroke oil makes it lean on fuel but the excess oil will carbon up the piston, plug and head . . if you don't mind mixing oil then just shut the pump off.

is your carb stock?

are the jets stock?

is the pipe stock?

has it been ported?

[RubberSalt]

Proper compression on these engines are around 110-120 psi factory. They are a very low comp engine.

[ddiggerr]

.

in addition to checking the reeds as John suggested, one big prob is your compression . . it should be at least 140 and around 170 is acceptable for premium gas . . cheap comp gauges can be off by 20 psi.

if someone ported the bejesus out of it this prob would not be uncommon to some degree.

you can not tell if a crank seal is leaking simply by looking at it . . a proper leak test must be performed, however, a leaking flywheel side crank seal will make it rev high . . a leaking seal on the other side may make it idle high but may also suck oil which will sort of reduce the air leak but it will smoke like heck.

too much two stroke oil makes it lean on fuel but the excess oil will carbon up the piston, plug and head . . if you don't mind mixing oil then just shut the pump off.

is your carb stock?

are the jets stock?

is the pipe stock?

has it been ported?


I don't have the setup to do a leak down test. I never had an issue of it revving high, unless I adjusted the idle screw and then wiggled the carb or throttle cable. It would smoke a lot and bog down.

All of this was a result of a tear in the bottom of the intake boot. Now with this being repaired, there is no more sporadic idling, no more bogging out, and it barely smokes. It idles great now.

Carb is stock
Jets are stock
Pipe is stock
and no it has not been ported.

The entire trike is stock, except for the front tire.

I checked compression again and it is just under 110. Still have tons of blue spark. I don't think either is an issue as it fires up no problem.