85' Tecate Carb Still having problems running

[smoknrv4]

Ok, the saga continues. I am loosing my mind with frustration on this one trying to get it to run below 3/4 throttle. One day it doesn't run too bad, (mind you still won't idle, with lots of throttle slack and idle screw all the way in with out Spring), but it just bogs out. It'll run good at 3/4 to full, I believe I have it jetted nice actually, but below that it wants to just die. Every combination of needle height tried and pilot jet setting. I can ride it if I manage to get it in gear without stalling and it works good through the gears as long as I don't let it die. Could this be a stator/Cdi/coil problem at all?? Am I chasing the wrong thing?? I bought the PWK carb used, in awesome condition and rebuilt it boiling it out and everything. Could it have the wrong needle or slide maybe???
Looking for some answers that I haven't already tried.

[smoknrv4]

Doing a little reading I'm now wondering if the crank seal(s) need replacing, at least the flywheel side, hence not wanting to run at lower throttle ranges.

[fieldy]

What was the original thread's name on this problem?

[smoknrv4]

What was the original thread's name on this problem?

Wasn't getting any action on the "85' Tecate Saga" thread so I started another.

[fieldy]

I read the thread. At this point you need to build a pressure tester. There is a thread on that here. An inexpensive tester. You have to know if you do have a leak. I am sure you dont want to ruin a piston and possibly cost yourself alot of money on a cylinder. Saftey is another reason that puts a scare in me. What if the motor goes full throttle by itself, hurts you, then fries the top end? If they are origional seals, 30 years old, you may do yourself a great one by replacing crank seals. It would be worth paying someone with experience to do that.
If the pressure test is good then the jetting can begin. I would get a new adjustment screw that " seems to be shortend."
When you say boiled the carburetor do you mean you stripped all rubber/plastic parts out and soaked or boiled the carburetor body? Maybe you pulled dirt in somehow after cleaning and running?


Sounds like the pilot circuit is dirty or way off. As where to start on jetting once you blow air through and spray carburetor cleaner in every micro pinhole in that carburetor, then go by the symptoms to make changes. Carefully poke through all holes in the carburetor venturi with a thin wire. Symptoms may change once again. If it does the same thing again, start jetting by symptom. Just making sure you are.clean and see if the symptoms are the same before you jet anymore. If you were a neighbor we would put a stock carburetor and cable on that thing and see what happens!

[yaegerb]

Have you pressure tested the motor yet? Your air screw should be between 1 and 2 turns out. Why do you have your air screw fully seated? In that position you aren't allowing any air into the motor through the carb.

[smoknrv4]

Air screw is about 1 1/2 turns out, its the idle screw that's all the way in.

Haven't done a pressure test yet, I did a compression test though and it registered 180 psi, I do realize that I still need to do a pressure test.

[yaegerb]

So what you are saying is it will idle only if the idle screw is maxed out (slide all the way up)? Something is funky with that carb or you have a massive air leak somewhere.

[smoknrv4]

I believe there is an airleak. Has to be.
How much psi should the engine pressure test hold out?
I'm assuming a fairly low pressure, just see if it holds.

[yaegerb]

I believe there is an airleak. Has to be.
How much psi should the engine pressure test hold out?
I'm assuming a fairly low pressure, just see if it holds.

6lbs for 6 minutes with ZERO loss of pressure

[cr480r]

It's not uncommon for a PWK idle screw to be maxed out..or just about. I have even used slides with broken off idle tabs.. Still run flawless at all throttle positions other than not idling on their own. That's a separate issue. Plugged pilot jet?? Can you see through it? The airscrew setting will only end up in the correct range if the pilot jet is the correct size. Under 3/4 start looking at a bigger pilot over 1.5 I would try smaller.. But as mentioned above don't bother trying to jet a bike with an air leak. As far ignition, in my experience a faulty or weak spark will run ok in the lower throttle postions and cut out at as you get into the main circuit.. Opposite of your symptoms

[smoknrv4]

Thanks guys for the pointers. Will report back after leak testing.

[nd4speed]

Have you tried different sizes of pilot jets ?

[nd4speed]

Here is a link for making a pressure tester:
http://www.3wheelerworld.com/showthr...r-for-about-20

[smoknrv4]

I have some pilot jets coming to try a leaner one for starters cause it seems to run not bad with the airscrew turned out 4 turns. So it's getting more air, which leads me to believe there's no air leak.