Help. Up against a hard deadline to fix the carb on my TE 450

Hi guys,

On a real tight deadline to get my carb working. Hoping you can help out with some advice.

Bike Husky TE 450 2005
Mileage approx. 14 000 miles
Main 180 Pilot 50 Leak 72 Starter 85 Needle stock clip in P5 (stock). Fuel/air screw 1.5 turns out

History: bike has always carbureted well up until maybe 1000 miles ago then developed stumble.

Symptom 1 : Just off idle when pulling away from stopped the bike want's to stumble or stall. More pronounced on an uphill start. This can sometimes be worked around by slipping the clutch. This condition has been present for about 1000 miles.

Symptom 2: Within last couple of days the bike has started to leak fuel out of the pipe at the bottom( carb drain) occasionally with the engine off. Turning off the petcock or tapping the side of the float bowl with a screwdriver handle/hammer will also stop the flow of fuel.

Within the last couple of days I cleaned the carb body (dirt was present) and removed all jets to soak in sea foam, inspected the float needle (looked good) and seat with little round screen cleaned(again looked good).

Reassembled bits and problem persists.

The fuel overflowing suggests an overfilled float bowl.....?
If the float needle appears in good condition are there any other components that would lead to too much fuel in the float bowl....?


This bike is going to Baja soon and is becoming unrideable.

Any help, suggestions, tips.

Many thanks,

Bugsinteeth

Fuel coming out the overflow means that the float level is set too high, or the float system is not sealing. Pretty easy check. If the float level checks out (I assume you already checked this), replace the entire needle and seat assembly. There is an o-ring behind the needle seat (that seals the needle seat to the carb body) that often dies and cracks out over time, resulting in leaks even with a good needle valve. You want to replace all of this.

I've seen this on several bikes, so I make a habit of replacing this whole assembly on any older bike I buy, and I expect to replace them occasionally on my bikes. The o-rings just sit in fuel all the time, it's amazing they even last as long as they do.

Sometimes needle and seats "look" ok but aren't, so I just replace the needle, seat, screen, and o-ring all at once. Usually the problem disappears after that.

PS: My old DRZ developed this problem in the middle of a trip to baja last year, so I feel your pain. I didn't have the parts with me to fix it, so I just had to be careful about turning the fuel off, and mindful of additional consumption. It was a real pain to start too, because it would be too rich due to the extra high fuel level in the bowl.

The pic below shows how to see if the level is set correctly, and a trick I used in the past, to see of the float needle was leaking, pull the carb, take the bowl off, fill a bowl with gasoline, blow air thru the supply hose while lowering the carb into the bowl. If the floats come up and stop the flow of air, keeps lowering it until the supply orifice is submerged to check for a leak/bubbles.

These are excellent recommendations. I will follow up as you suggest.

Is it likely that the bike would run poorly at idle/ low throttle (symptom 1 above) if the float bowl is overfilled?

Thank you very much for your helpful suggestions.

Bugs

Is it running poorly at idle due to being rich or being lean? Let it idle a few minutes and then pull the plug. If it is dry and chalky, you might have a plugged up idle jet.

The leaking bowl could be a entirely different problem from the poor idling.

Plug looks good, Grey in colour. Normal looking in my experience......

Jets all appear to be clear, soaked in Seafoam and blown out with compressed air. Daylight can be seen clearly through all jets. Actually no change between pre and post soaking of jets. No jets appeared plugged prior to soaking.

Bugs

Seafoam and air will not remove caked on varnish in pilot jets, your idle jet may be smaller than it should be and you won't even really know to look at it.

have not read any responses but will throw this up. before chasing a bunch of avenues you need to completely dissassemble the carb clean and inspect all the components. jets and passages all cleaned and blown out, A/P assy diaphragm check, best to replace with carb rebuild kit the bike is more than a few years old. before reassembly, AP setting inspection, float height check/set.

Thanks for your continued tips.

Robertaccio,

The carb basically has been disassembled, body cleaned (manually with rags, q tips), and blown out ect.
I will check the float height.
AP is set to 2.75mm I believe this is stock setting??
AP diaphragm I was hoping to leave alone but I will disassemble if deemed necessary.... The bike runs great at higher throttle settings, just at idle minimal throttle settings do I have a problem. I was under the impression the AP only kicks in later so would not effect carb at idle low throttle????? This is a time sensitive problem so my approach has been to start with the most likely problems first and not disturb stuff that doesn't need changing. Do I need to disassemble the AP stuff based on my conditions or leave well alone??? Parts are not easily acquired at this point in the game.

I have spoken to Chad at Sudco and he is expediting some likely culprits. Some stuff is unavailable (needle seat, starter jet)so need to make due with what I have.

Husky may have a rebuild kit but I'm not gonna get that in time. Sudco has no kit, just individual parts.

Again. Thanks to all for your helpful contributions.

Bugs

Jets are cheap. I would replace the pilot jet with a new one as they are hard to get 100% clean with todays "envro" cleaners. I have heard good things about Yamaha Ring Free fuel treatment. I have never used it but there is a lot of positive talk about it on the web. I used Seafoam for a while but then switched to Startron as preventive measures.

Could be a sticky accellerator pump that's activating too slow when opening the throttle. What do you guys think?
Could check it by taking the black cover off and whacking the throttle (engine off) and watching the ap linkage. Is it slow to catch up to the adjusting screw? If so, add an ORing around the linkage... Should be pics of the ORing mod on here somewhere...
Also, ap function is explained here better than I can. http://www.thumperfaq.com/ap.htm

Ok. Just going to catch up a bit here.

Did several float height tests, results were quite inconsistent.

All registered above the junction between the floatbowl and the carb body.

lowest was +9mm above junction, highest +18-20mm these tests were done with carb on the bike. I did a couple attempts with the carb perfectly straight up and down holding it in my hand and got a couple +15 mm results.

I believe + 9mm is correct?????

AP or squirt: Open throttle a bit and it squirts a bit, open wide it shoots a couple of feet. I'm not sure how to test proper operation of the squirt but it appears Boogie has posted an explanation of this process above. I will check out his link.

Sudco has some new jets coming my way but not all. Pilot and leak they have.

I really do appreciate your guys thoughts on this. If nothing else I'm learning quite a bit about this carb!

Regards,

Bugs

Shoots a couple of feet? Wow...
Maybe the leak jet is blocked.

Be sure and put the new pilot and old pilot jet side by side and look up at a light.

Guys,

Just waiting for parts to show up now.

Does anyone know the correct fuel level height setting as described in post #3 by oldhuskyrider?

Thanks,

Bugs

My DRZ was nearly impossible to kick start and idled like crap when the needle seat o-ring was leaking.

Gents,

I put a bunch of new parts in this carb, checked adjustments ect.... No change, same symptoms as described in first post.

I changed the CDI to one from a known good bike. Again no change.

Finally, I borrowed buddy's known good carb. Again no change. symptoms persist

I have a clue to the problem condition that I will try to confirm tomorrow.......

When I changed to my buddy's carb, for the first five to ten minutes (from cold) the bike ran well and I thought I had the problem sorted. Then the problem surfaced. Now that I think back to when I changed the CDI, I think the same scenario happened. I thought I had it fixed but after 5-10 minutes the problem showed up.

I intend to test this theory out again in the morning with a stone cold motor and will report back.

With this new information do you guys have any solid leads as to what my problem is? Are there any ignition parts that are known to fail with heat or 10 min riding?


Keep in mind that if you throttle up through the revs the bike works great. The problem is only noticeable at idle or light revs/throttle openings.

Thanks again for your ideas and experience. My Baja departure deadline is within days.

Regards,

Bugs

Sort of interesting issues you have ... That slow drip \ leak from the CARB is most likely the o-ring in the needle valve seat as mentioned above... I have to change them on my bikes from time to time ... I usually end up playing with the float height but my problems were always that seat o-ring ... If the needle valve itself is the problem, gas will pour out the over flow most times... This o-ring leak never has any effect my my engine running though ...

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Good luck and I hope you fix this and do that Baja ride ... My 08 WR250 was acting a little weird a few weeks back ...Can't remember what the symptoms were exactly but it was the plug wire (the cap) giving my issue ... I need a new one but we used electrical tape to fix it. The coil comes into play here also ... If your other theory does not pan out, both these items can be swapped over to your bike without alot of pain ...

Ignition will not cause fuel to leak out of the overflow. Has that problem been resolved or not?

If you think that the ignition might be causing the stumbling problem, and you have a friend's bike to swap parts with, try swapping his coil and see if the problem persists.

Check that you don't have a vacuum leak after the carb, such as a cracked air boot or a vacuum tube fitting without a plug on it.

Did you change the plug? How about swapping the coil and plug wire?

yeap!-check those. and...

How about fuel venting?
Maybe... your gas cap vent hose/ cap/ or valve is blocked creating vacuum or pressure. I'd guess pressure since its forcing fuel past your float valve as well as creating a rich condition.
That would explain why it doesn't matter what carb you use...

don't use the check valve bling doohickies for tank ventilation- they are prone to failure some by design out of the box. Use a straight hose (normal).