74 Honda XL 350 - The Turd

irk miller said:
I've gotten away with removing a coil- basically cutting off the pigtail and pulling one coil to become the pigtail to replace it.

Nice, I will give that a shot and see if it helps.
 
Alright so I removed a coil and that took out a lot of the slack from the advancer. It's much stiffer now, hopefully not too stiff. Going to re set the static timing and see where the light reads this week.

Made a baffle out of some 3/4 pipe and what was left of a reducer I had lying around.

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Wrapped in some fiberglass packing.

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It's still pretty damn loud. I may end up going down to 1/2" on the inner tube.
 
Lost interest in this thing for a few weeks. Last time I had it out it stalled a few times while riding and now it doesn't want to start.

SO, went back through and adjusted the cam chain, valves and timing again. The valves were pretty tight after a couple heat cycles, so I adjusted all four. I talked with a guy who has had a bunch of these old XLs and he recommended to set the valves to .003" and .005" as opposed to the FSM stated .002" and .003", so I gave that a shot. Still doesn't want to start, even w/a squirt of ether.

Maybe if it cools off later I will try and set them back to factory spec and try again.
 
Don't sound like valve clearance issues seems more ignition to me, I run valves a tad loose on old motors without starting problems


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I agree. I'd check coils and points. Coils could be fried, or the points could be burned up or just cruddy. If you're running a resistor cap, check the coils with and without the cap on the wire. I'd make sure all connections are sound with a meter.
 
Roger that. I was thinking the same as well after no firing with starting fluid. The points are good, I just checked the timing yesterday. Could definitely be coil and/or condenser. I'll check the kill switch(es) to make sure those aren't screwing me up either.


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Don't get discouraged. Once you sort through the bugs it'll be good for a while. These things are so easy to hotrod and the aftermarket is plentiful. You can go big bore, hot cams, FCR- all of it.
 
I think I found the cause for the stalling: The repop fuel cap I put on isn't venting correctly. It looks like it has a small vent hole, but it's not doing it's job. Im thinking drill and tap the cover to install a MX style breather tube?

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I picked up this VM34 at mid-o for a few bucks. The stock carb is 36mm so I'd have to make up a spacer. Wondering if it's worth it or find a vm36? The stock Keihin is just a pain in the ass.

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if you are driving in town the 34 will be better off the line than the 36 but slightly less top end but only a WFO

i have

3.0 slide

37.5 pilot (may be a bit rich for you)

main jet 240

6dh4 needle 2 nd groove down from top

q2 needle jet

no air correct
 
I think I will fit the 34 after I get it dialed in and see how I like it..

Still hard to start. Compression is at 150. Spark is good. Timing has been set. I just cleaned the carb before I tried to start it up. Nothing.

Getting tired of kicking this thing might have to put a decomp in lol


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So I pulled the carb again today and REEEEEALLY cleaned it. Tossed it back on w/the fuel bottle and got nothing after 4-5 kicks. Pulled the plug and it's dry as a bone. Sprayed a shot of starter fluid and it fired right up. Not sure what's going on with the carburetor but something fishy is up.

Once she's running it's like a bat outta hell. This thing is a torque monster. Brought it around the neighborhood for about 15 minutes with no issues whatsoever.

Stalling issue is most definitely fixed. I ran around with the fuel cap just resting on there to see if that did the trick and it surely did. Got some fuel on my legs but at least I got to ride it. I think I'll put a brass barb and breather tube on the cap.

Going to let it cool down and see if it wants to start back up in a bit.


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The plug after today's ride. Looks like a faulty needle and seat may have leaked some fuel into the crankcase. I'm lucky it didn't hydrolock if it did happen. I had to take quite a bit out of the crankcase, like almost 1L, but It didn't really smell of fuel. Shrug. Going to change the oil before I run it again.

Time to start piecing together that Mikuni and put the Keihin in the trash.

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Got the correct amount of oil in there after a change or five... (a long story for another day)

Threw in a new plug and the old girl starts right up first kick every time.

My method is 1 kick with main switch off to prime. Turn switch on and one good kick and she fires right up. Seems to be running really well. I need to do something to quiet this exhaust so I can go down and get this thing inspected. Maybe rebuild the baffle with 1/2" pipe instead of 3/4"?
 
I've noticed while tuning the stock Keihin that the mixture screw does not cause the motor to stall or bog when screwed in all the way. It is on the engine side, so therefore it is a fuel screw if I am not mistaken. In this case, turning the screw IN should lean out the mixture. In this case, it would appear that the idle circuit is too rich, so a smaller pilot jet would be the solution?

The fastest idle speed is achieved at about 1/2 turn out. The manual states typical setting should be between 7/8 to 1-1/4 turns out.

In the factory service manual, Honda refers to the mixture screw as an air screw. Clear as mud. Can anyone help clarify?

A pic of the carb for reference (for anyone unfamiliar, the engine is on the right hand side)

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Any advice on mixture screw?

Meantime, here's a cold start vid.

https://youtu.be/FGFa6xLW5NI


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advCo said:
Any advice on mixture screw?

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Nick, get yourself one of these bad boys. They work killer and will really help you dial in the mixture screw and also help you understand where you fuel is through most of the throttle.

https://www.amazon.com/Colortune-for-14mm-Spark-Plug/dp/B000E9VGNM
 
what is it you dont understand about the air screw adjustment out is richer

stock setting is 1.5 turns
 
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