Update- Honda XL350 Milestone

More in the continuing saga of Gunner and 2 wheeled iron......
The 1974 Honda Xl 350 that Ive owned, but never started, and left to
languish in the weeds for 10 yrs, has been one of the 3 bikes Ive been putting with. The Royal Enfield/Indian Chief I started several weeks ago, after 37 yrs of ownership....chuckle.
I orignally found the wiring had been torn up badly, and the coil not putting out a spark. I fixed the ignition wiring, and installed a used 6vt AC coil, and condenser from a pickup truck, along with a new plug and cap (the old cap wouldnt conduct through it), I managed to get a nice blue spark. But it wouldnt start consitantly or run for any period of time.
Taking the carby apart, I found it missing a Slo Jet with some fucktards impromtu jet stuffed into the hole. Tuesday, I found a used jet at a motorcycle shop in Bakersfield and Wed I reassembed the carby, after checking float height, replacing all the seals and o rings and so forth.
I installed the carby, put fresh gas in the tank, kicked it 3 times and she started and sat there idling rather nicely. Gray smoke slowly cleared out and became a bit of black smoke but it idled pretty fair.
Since the clutch appeared to be frozen, I put it in gear with the engine off, and rocked it back and forth for a few minutes, checking for clutch action and suddenly the clutch came free. I went into the house, dug out a helmet, and puttered up and down the alley way for 15 minutes, getting used to the bike, changing gears, seeing what it needed . A quick punch of the rear break pedal did little, so adjusted that. A quick grab of the front brake caused the front wheel to freeze, so adjusted that. Sprayed the chain with Kroil, checked this and that.
It idles with black smoke, indicating a rich condition, and the air jet really doesnt do much of anything when turned in or out. So evidently there is an issue there. I didnt check the needle clip position, so that will be done tommorow. There is a hose that comes out fo the carby and goes back into the airbox (airbox not installed) and that opens and closes a diaphram on the carby that makes the engine speed up or slow down...no idea what it does. The Clymer that a neighbor gave me today gives the carby much of a pass, no details to speak of, not even clip position, the bastards!!
It leaks badly at the exhaust port, Im not sure if there is a gasket in there, but it did quiet down after the engine got warm. Valves need to be adjusted, oil changed, new points installed and so forth.
Anything over an idle, the engine bogs and sputters in a certain range, then speeds up rapidly while riding when you crank on it. So there has to be an air leak somewhere, and it pushes out black smoke at any speed range. And the timing may not be advancing....sigh
But it runs, doesnt push out oil smoke and no Bad Noises come from the engine... Now its just detail work. Getting the lights and other wiring fixed up, Replacement or repair the seat etc etc
I didnt want to sink any money in it because I didnt know if the engine was hosed or not. Now I can feel comfortable putting some time and effort into it.
Many of the internal seals were flat black rubber disks, which I replaced with O rings that I had on hand, not having the same rubber disks or stock to make em from.
Anyone familar with the Keihen carby with the lever that lifts the slide, rather than having the slide lifed directly by the throttle cable? Anything I should check to see what the over rich condition is caused by? Ill drop the needle valve a slot to the recommended one from the www.oldrice.com website, but the air jet adjustment not doing much of anything at idle, and the bogging, and sputtering when applying throttle are the main issues.
After this is resolved, comes the BMW, which should either be the easiest, or hardest to get running again...sigh
Gunner
"Upon Roosevelt's death in 1945, H. L. Mencken predicted in his diary that Roosevelt would be remembered as a great president, "maybe even alongside Washington and Lincoln," opining that Roosevelt "had every quality that morons esteem in their heroes.""
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http://www.xlintperformance.com/airvalve.htm
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Ah HA!
Most interesting!
Ive got to ponder on this a bit......
Thanks!
Gunner
"Upon Roosevelt's death in 1945, H. L. Mencken predicted in his diary that Roosevelt would be remembered as a great president, "maybe even alongside Washington and Lincoln," opining that Roosevelt "had every quality that morons esteem in their heroes.""
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Gunner Asch has brought this to us :

The bogging you experience could also be a fuel delivery problem. Make sure the tank is clean, not full of rust floating around. Add an inline fuel filter (or replace it) if you haven't already. One of the passages in the carb my still be partially plugged.
When you say bog, does it sound like the engine cutting out or does it make a burbling type noise. The former is lean, the latter rich.
As far as jetting goes the pilot jet affects idle & just off idle. The air screw also, but it is only good for about a half turn either direction from where the manual says it should be set. The cutaway on the slide affects off idle. Then the needle and the needle jet take over. Finally the main jet takes control.
If you see black smoke and hear burbling on all throttle settings, the maybe there is some other issue. I wouldn't think that all the jetting circuits would all be wrong.
I had a '78 XL350, 1st dirt bike, which gave off black smoke. I didn't know nothing about bikes then, and got the dealer to fix it. They wanted to do a tune-up, standard reply. I told them no, just fix the problem. They did and it wasn't too expensive. Unfortunately I don't know what they did to solve the issue.
Wayne D.
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Sounds like you got it running awfully rich. Too rich and it will run cooler, but the extra fuel will wash down the oil on the cylinder walls too much.

Back then a lot of folks use a regular automotive motor oil not knowing that they could either cause clutches to stick or worse some with certain types of friction modifiers could cause them to slip. Draining it and refilling with motorcycle engine oil might help, but the odds are the clutch discs will always be a little sticky at first start up now.

Usually a crush gasket. A temporary trick we used to use was rolling steel wool up in a strip and wrapping it around the endand putting it in place just like a crush gasket. It will last for a week or two of regular riding, but you really should replace the exhaust gaskets.

That sounds like a lean condition. LOL. Interesting.
Maybe to much idle mix, and a still partially plugged main jet?

Could be. Its always a good idea to replace ALL rubber lines on an old fixer upper like that. Also might pay to pull the fuel tank petcock valve and assembly and give her a once over. I recently fixed all my run problems with a Honda Shadow because the filter screen inside the tank was plugged solid. Also, I think those have a filter screen in the bottom of the petcock itself. You could be running rich at idle and not getting enough fuel due to restrictions when you close the throttle. Does it have a rubber mounting flange for the carb or its it hard mounted? Also those little Hondas are pretty sensitive to the airbox condition. I have a little 400 twin out in the shop that really likes a nice tight airbox, with a good clean filter. If its open it doesn't run right and, if the filter is dirty it doesn't run right.
Good luck.
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Sounds like you got it running awfully rich. Too rich and it will run cooler, but the extra fuel will wash down the oil on the cylinder walls too much.

Back then a lot of folks use a regular automotive motor oil not knowing that they could either cause clutches to stick or worse some with certain types of friction modifiers could cause them to slip. Draining it and refilling with motorcycle engine oil might help, but the odds are the clutch discs will always be a little sticky at first start up now.

Usually a crush gasket. A temporary trick we used to use was rolling steel wool up in a strip and wrapping it around the endand putting it in place just like a crush gasket. It will last for a week or two of regular riding, but you really should replace the exhaust gaskets.

That sounds like a lean condition. LOL. Interesting.
Maybe to much idle mix, and a still partially plugged main jet?

Could be. Its always a good idea to replace ALL rubber lines on an old fixer upper like that. Also might pay to pull the fuel tank petcock valve and assembly and give her a once over. I recently fixed all my run problems with a Honda Shadow because the filter screen inside the tank was plugged solid. Also, I think those have a filter screen in the bottom of the petcock itself. You could be running rich at idle and not getting enough fuel due to restrictions when you close the throttle. Does it have a rubber mounting flange for the carb or its it hard mounted? Also those little Hondas are pretty sensitive to the airbox condition. I have a little 400 twin out in the shop that really likes a nice tight airbox, with a good clean filter. If its open it doesn't run right and, if the filter is dirty it doesn't run right.
Good luck.
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wrote:

The airbox is not mounted on the bike. Im working on it with a simple sock filter on the intake.
Gunner
"Upon Roosevelt's death in 1945, H. L. Mencken predicted in his diary that Roosevelt would be remembered as a great president, "maybe even alongside Washington and Lincoln," opining that Roosevelt "had every quality that morons esteem in their heroes.""
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On Thu, 01 Jan 2009 03:53:51 -0800, Gunner Asch wrote:

Well, congratulations!
It sure sounds like you still need to work on the carb -- the techie part of me wants to ask if there's a bolt-on electronic fuel injection for small motors, the rest of me knows that's absurd...
You've verified compression &c, to make sure that you don't have a valve or ring seal problem masquerading as a carb problem? Reading all the other responses it sure sounds sensible to clean or replace _anything_ that touches the fuel or air going into the carburetor.
(I have to admit, that given a choice I think you should work on the Enfield. That's _my_ choice of what _you_ should work on, of course, so take it for the BS that it is.)
--
Tim Wescott
Control systems and communications consulting
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Tim Wescott wrote:

Actually not.... I did a bit of looking into this, and there is a hobby level control kit for fuel injection. I have a back burner project to recreate a bike I built in the mid 70's, a 350 Ducati engine in a Maico chassis. Mikuni was the carb of choice back then, but just out of curiosity I thought I'd look into FI. Thought maybe I could drive a small pump off the right end of the cam with a setup similar to the tach drive used on some of the road bikes. Anyway, it's out there and doable.
For Gunner's 350, personally I'd look for a Mikuni off a 4 stroke. A 2 stroke carb will be way too rich and may require replacing enough parts to render conversion too costly. Used of course, new Mikunis are not cheap. or, find a motorcycle bone yard and try to find a better condition OEM carb.
I do have a brand new 26mm POSA carb I'd sell for 1974 retail sale price ($39.95). It's nearly infinitely adjustable for jetting but has no float. Turn on the gas tap, and you'd better have the sucker running real fast or it'll flood. 26mm would hurt top end but give great low end response. Just for kicks, I once fitted a Tillotson forklift carb to my 350. Don't know the bore size, but it was real small. Engine predictably had no top end, but low end was almost like an electric motor. And even hot, it would fire first kick, hands off the throttle, and idle so slow you could hear each slurp of air on the intake stroke!
Jon
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wrote:

That was my first choice, but turning it into a bike thats street legal is going to cost some money, lighting, speedo etc etc, so once I got it actually running, I mothballed it until I can afford to actually proceed with the project to completion.
Ill probably use the Enflield Bullet (India) running gear..speedo, amps, headlamp etc that are available on Ebay. Much of it is the same stuff as the original, but its still gonna be several hundred bucks and a bunch of mount fabrication and so forth. While the basic bike is there, all the street important bits and pieces are gone, or are in poor shape for actually riding on the street without refurbishment of them. The tires are 45 yrs old, and thats close to a couple hundred bucks to replace em unless I use Yen Chengs and then its still a $100.
Shrug. Ive not had a service call for nearly two weeks, most of my big money shops have shut down for the holidays and Christmas expenses were , while not high, expenses.
The BMW is the most practical street bike, and I rode it for many years to work, 42 miles each way, until I took the machine tool service tech job and found I had absolutely no time to ride anymore.
The asshole roommate didnt do it any favors, trying to play mix and match with the parts. Reinstalling the ignition switch alone took me most of a day, trying to puzzle out the wiring diagrams.
Ive been saving it for last, as I wasnt sure the other two were worth doing anything at all to them. I needed to get them running to determine if they were hosed, or easily (read cheap) repaired/setup.
It appears that they are, so now I can get them up. The Honda makes a lot of sense, because I live in the middle of the desert, and having a place to ride means about 2500 square miles surrounding me. I plan on putting on a luggage rack of some sort, and a bolt on side mounted rifle scabbard so I can go fool around in the hills.
Ill probably be back down south after Monday, and swamped with work for a week or two, after they try to start up those machines that have been sitting idle and turned off for the past two weeks.
Ive used this "vacation" to do a lot of work on the property, tossing tons of crap, emptying boxes of Stuff, building storage etc etc. When you are only home a couple days a week, Honey Do's pile up. The ex is physically unable to do much, and she refuses to do anything outside of the home. So its left up to me. The bikes are being tinkered with between other more important chores. Kinda a reward for doing the other needed stuff.
Hell, if I retired today, it would be two years just to finish the stuff Im already behind on....sigh
Gunner
"Upon Roosevelt's death in 1945, H. L. Mencken predicted in his diary that Roosevelt would be remembered as a great president, "maybe even alongside Washington and Lincoln," opining that Roosevelt "had every quality that morons esteem in their heroes.""
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Gunner Asch wrote:

I might know a little bit about this carb, as I have a Kei Shin carb from a similar 350 on my lawn tractor, and it works pretty well, far better than the ghastly updraft toy that it was originally fitted with.
Jon
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Hi Gunner, Tell me more about the BMW. I am restortin my 1964 R69S which I have owned since new. Had the frame powder coated, and the next step is to disassemble the engine so I can get to the oi slinger. Only 27k miles on the bike.
Ivan Vegvary
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might want to look here
http://www.geocities.com/loudgpz/GPZheiModForPoints.html
say goodbye to burned points, those GM modules are cheap, easy to hide and work really well.
Some googling will show sites that you can rid yourself of points all together, did that with a Briggs Twin using a crank trigger sensor from a late model Hyundai
** mike **
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wrote:

Now that~~ is way cool! Ive saved it for further consideration
Many thanks
Gunner
"Upon Roosevelt's death in 1945, H. L. Mencken predicted in his diary that Roosevelt would be remembered as a great president, "maybe even alongside Washington and Lincoln," opining that Roosevelt "had every quality that morons esteem in their heroes.""
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I saved it for possible use in my IC engine that is in progress. Simple points are always not simple on a small engine. Thanks.
Martin
Gunner Asch wrote:

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