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Old 05-27-2015, 10:54 AM   #1
Rhody OP
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Honda XL250r keep'm running thread

Alright... I have not seen any official Honda XL 250 threads of any that show these older bikes or attempt to help diagnose problems.

So, I have on that is giving me some issues that I've been unable to resolve.

Here goes...

I have an '84 xl250r that I rebuilt from the ground up. I got it from a guy that didn't want to tackle it due to the fact it was just a pile of parts.... all of it.

Never posted pics up before, if this works then.... This is what my current rendition of what an ol' '84 Honda XL250r should look like...


The good:

Bike starts easily

Bike will pull my 300lbs right on past 60mph.

the issues:

at start up, the engine will idle high at first then settle down and start to miss, then suddenly it will idle down even more like an ol' pop pop hit or miss engine, sounding like a harley idle lope then die. I have to blip the throttle to keep it from suddenly dying.

I also noticed that as I try to maintain a constant rpm that I can feel the bike surge on any gear.

Lastly, when backing down the gears, it's like I'm on a 2 stroke, no compression breaking.

Carb settings:

Primary: 106
Secondary: 125
Air idle: 42
Idle screw: 2 turns out.
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Old 05-27-2015, 06:34 PM   #2
Rhody OP
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ok... did a vacuum leak test.... nada



pulled spark plug.... well, well, well..... I've got a symptom... a black sooty spark plug.... new plug regapped.... started out better then.... same'o same'o....



ahhh ... based on my symptoms....

I just might have a short some where.

I need a

Otherwise I'm all er..
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Old 05-27-2015, 10:02 PM   #3
97707
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Sooty plugs

That sounds like a mixed bag of symptoms.

Sooty plug sounds like a rich mixture. Maybe the needle and seat leaking? The surging might fit with that. So maybe you'd look to a carb problem before spark. Look at the choke, see it in fact opens when you move the lever to open.

Acting like a 2 stroke. Have you done a compression test? Looked at the decompressor, see its not staying open.
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Old 05-27-2015, 10:39 PM   #4
Rhody OP
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I do have that compression cable on this motor...I 'll disconnect it and see if that makes a difference.
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Old 06-14-2015, 12:43 PM   #5
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Cured!

OK, I've been busy reading, learning, experimenting on the XL. I'm going to pass on what I learned about the RFVC engine that should help others get these bikes to run and run like the little banshee it is.

1. Idle issues. I had put an after market carb rebuild kit in it. I disassembled the carb and started measuring the needles for length and and width. The primary needle was longer and narrower than the OEM. Replaced with the OEM a 2BS vs. 270 aftermarket and upped the jet to a 110. Assembled.

I also removed the idle needle (CA no adjustment) and replace it with the aftermarket version.

Results: I now had a bike that idles perfectly I was still having surging and engine not backing down when I closed off the throttle like a 2stroke.

More reading.... and a few....

I then read that most of the carb issues is with the length of the needle and could be cured by how long into the jet vs. slide going up and down. So, I found a company that claimed to have this very tune up set up to handle the carb issues of any bike.... sent off for their carb tune up kit. $40.00

The only thing I used was 2 little nylon washer/spacer 2.5mm id. (equivalent of 3 metal ones) on both needles. I'm lax to say who the business is, but I suspect that one could find metal versions for quite abit less and stack them as spacers.

So, as I was playing with my carb in my hands to make sure it functioned before inserting, I noticed that the secondary carb woldn't back down as fast as the main.... Ya think that this might be the cause of the engine not backing down quickly?

So, there is an adjustment nut on the main throttle linkage that can be adjusted to tighten up that issure, plus there is a split bar that can be tweeked.

Now, one other thing I did was block off the balance tube between the intake manifold barrels.

Test run: got it started and idling properly Took off to run around the ranch... hit 2nd and hit it hard.... no hesitation.... on the dirt it broke loose and I got a little sideways... YEAH.. now that's what I'm talking about. It just kept pulling on up throught the gears... I backed off and the engine settled down quite quickly..

I'm not quite done yet. I'm of the opinion I can adjust the secondary just a little more and get the compression backoff I'm seeking...

Cheers

Hope this little side trip through Honda carburetor issues can help steer one down the path of motorcycle grins.
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Old 06-23-2015, 04:21 PM   #6
Rhody OP
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Eh? Test Ride

Well... it looks like I'm talking to myself....

But, there is more to this tale...

So, I took her out for a test ride up HWY 150 from Santa Paula to Ojai up 33...

Fact is, 250cc's ain't much when burning the twisties uphill.

Made it up to the old diner shack where a few others who had blasted past me on the way up taking a break.

I learned that the seat is a prostate killer...

Headed back down.... just putting, not blasting.... many passing... yeah, I do get out the way.

headed into Ventura pretty much 90% throttle... when suddenly, I lost all power....

thought it was fuel.. no.. no... pulled over ....... no compression....



Then I saw it.... a rocker bolt had backed out.... damn.... I thought I had lock tite all of them...

later, I pulled the head and found that the part had kept an intake valve slightly open and had also managed to distort the head gasket enough that the head no longer held compression.

did a leak test on the valves, no problem. I can see where the valve and piston hit, but no metal distortion and the valve is still straight.... lucky me

Got some parts ordered to seal it back up... can't wait to get it back to running again. That was a fun day trip... except for the Bhole and the breakdown..

cheers
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Old 06-23-2015, 08:33 PM   #7
Argus16
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Good stuff.keeping one of the best dual sports alive and kicking. Once you sort out your current situation you should be good to go.

I had an 85 xl250r and both my riding buddies had an 85 and 86 xl600. Theres' would pull away in the straights but I always caught them in the corners... single track they couldnt catch me.

I now own buddy's 85 600r. But the 250 will still be the best of tbe dozen or so bikes I've owned. Keep it runnin'!
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Old 06-25-2015, 07:09 PM   #8
Rhody OP
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I have an '86 XR350r which I love, but it's not as flickable as the XL250
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