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Honda XL Engine Problems

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Compo
Nova Slayer



Joined: 02 Jan 2006
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PostPosted: 21:41 - 02 Jan 2006    Post subject: Honda XL Engine Problems Reply with quote

Hi all
Ive just done a nut and bolt rebuild on a 1980 XL185S ! Why? Well it brings back memories.

Can this old engine seize if it had worn rings/Needed a rebore?
How does the oil get up to the Rockers and cams on this Engine?
Is the oil sucked up from the crank cases by the piston/oil rings?

Im having a real shit day if youd be so kind as to read the dribble below id be most glad if youd share your views.

While im decent with the spanners my diagnostisc skills are shite.

The bike has two serious problems the most serious is engine seizure I bought the bike with a snapped timming chain thinking about it now most likely due to engine seizure. I have completed a bottom end rebuild, big end, mains and all other bearings and seals.I even converted the 5 speed box to six speed.Although the top end was totally stripped i didnt go any further than a visual inspection.

Now for the sad part although running a little rough the engine will start and idles nicely but seems to get overly hot and eventually locks up, i believe the piston but can not be 100%.The bike uses a Trochoid oil pump Ive no real idea how these work and im not sure how oil is reaching the rocker arms and cam.Any views on this would be appreciated? Also when running i do notice oil splater out of the engine breather! Is this a sign the oil control rings are worn? Wished id paid attension to the top end now Could worn oil control/ piston rings cause seizure? What about running it on Super Unleaded? I can not find lead replacment fuel in my area!


Problem number 2 before it locked up was the bike was bogging down when you open the throttle like it still had the choke on that type of feeling.If you hold the throttle it will eventually pick up a bit but sounded rough! Like stuttering I thought this was the timming but i dont have a 6 volt strobe so i did it by ear.I did this by setting the rpm at 1500 then turning the sator till the revs increased and peaked then backed it off i tad. Is this method right or a least ok ish.
What ive tested so far are the coil and pusle generator which both meter as per the spec in the haynes manual.The bike has a brand new carb with correct jetting, float level and mixture setting so im not sure it could be the carb.The only remaining items are the one the auto advance unit which did seem free and springs are in good condition.The generator needs testing for output voltage but the manual crap on this point. Any ideas how to do this? And then last the CDI which im told can not be tested. Is there anyway i can test this?

Well thanks for takeing the time to read this and any info or help would be great.

Its a shame cause ive spent a lot of time and effort restoring this to original condition and it truly looks mint, but it looks like the engine got me .

Ta
Compo
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Knowlsey
Scooby Slapper



Joined: 07 Apr 2005
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PostPosted: 23:12 - 03 Jan 2006    Post subject: Reply with quote

you can buy led additive for the unleaded, but a lot of the older bikes dont have that problem, thing is with the additive you only need to put so much in, thats about one treatment for every 2 to 3 tank fulls, as for the trachiod pump, its usually rare to have problems with them, did you strip and clean the pump during the rebuild, some pumps are sealed and others are not
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Compo
Nova Slayer



Joined: 02 Jan 2006
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PostPosted: 23:49 - 09 Jan 2006    Post subject: Reply with quote

Hi
Yeah i cleaned the pump during the rebuild and it seems to be working, ive just pulled the top end off again and oil is getting to the cams and rocker.It was the piston that locked and i need to rebore it. Thing is i need to sort what caused the lockup, only thing i can think of is the timming is to far advanced so i need a 6 volt timeing light.And the other a weak mixture but looking at the plug its on the black side of brown so id say it was running a tad rich.
Any thoughts?

Compo
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Knowlsey
Scooby Slapper



Joined: 07 Apr 2005
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PostPosted: 04:08 - 10 Jan 2006    Post subject: Reply with quote

could possibly be timing, had an xl many moons ago, but never had the pleasure of a full strip down, not sure if the valves touch the pistons if so then see if there is any tell tale signs on the tops of the pistons as it wouldnt have to be much advanced to lock, are you sure that the crank is running true, or rings are not snagging(although that would be more obvious as they would probably snapped and score the bores)
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BFG
Brolly Dolly



Joined: 14 Feb 2005
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PostPosted: 09:33 - 10 Jan 2006    Post subject: Re: Honda XL Engine Problems Reply with quote

I have an XL600. I'm not sure about the 185, but generally...

Compo wrote:

Can this old engine seize if it had worn rings/Needed a rebore?

A possibility, but not where I'd put my money on a 4-stroke. What it will do is chuck buckets of white / black smoke out of the exhaust if the rings aren't right.

Unlike two-strokes, the bores will typically be lubricated from underneath. Check the Haynes manual.

Compo wrote:

How does the oil get up to the Rockers and cams on this Engine?
Is the oil sucked up from the crank cases by the piston/oil rings?

On all 4 strokes, no sucking involved. There will be an oilway, or a tube where oil from the pump is sent up to the rockers. I would focus all my attention on the oil pump. They often need priming on old bikes. If you don't mind the mess, start it with the rocker cover off - you should see gobs of oil making its way onto the cyl head area. If not - do not run it any further.

The oil rings on the pistons are designed to prevent oil getting into the combustion area. They don't do anything to the oil.

Compo wrote:

The bike has two serious problems the most serious is engine seizure I bought the bike with a snapped timming chain thinking about it now most likely due to engine seizure.

Now for the sad part although running a little rough the engine will start and idles nicely but seems to get overly hot and eventually locks up, i believe the piston but can not be 100%.The bike uses a Trochoid oil pump Ive no real idea how these work and im not sure how oil is reaching the rocker arms and cam.


Snapped timing chain! If this happens, the crank keeps turning, the pistons keep moving - the valves don't - whack (on some bikes). You evidently don't have a holed piston but you might have a damaged valve. Could be bent and sticking or at least not seating properly. Stuck valves sometimes only stick when hot. Also they can mess up the running temp of the engine. Other things to check are cam timing and valve guide clearances, get these wrong and it can run like a dog.

As for oil spatter out the breather - this could be anything. Maybe even crank pressure too high, caused by too much oill in the crank or a blocked oilway, or as you suspect - worn rings, meaning combustion gases are getting past the piston into the crank and pressurising it. Check the colour of the exhaust smoke!

Check your haynes manual for the oil pump. Scan it and post it here if it's a bit vague and we'll try and help. Smile It should run OK on unleaded. Maybe someone who knows this specific bike will post in due course.
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Kickstart
The Oracle



Joined: 04 Feb 2002
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PostPosted: 13:30 - 10 Jan 2006    Post subject: Reply with quote

Hi

I would suspect the most likely cause is the ignition timing causing it to run hot.

Doesn't really matter if you have a 6V or 12V timing light. The voltage from the coil is far more than that. If you have a crude one that just plugs into the plug lead then I doubt it would care. If you have an inductive timing light then just use the battery from another vehicle to power it (even your car).

Think those old Honda singles need a good clean supply of oil to the head. From memory they had a habit of seizing the cam in the head if the oil supply was not good.

All the best

Keith
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Compo
Nova Slayer



Joined: 02 Jan 2006
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PostPosted: 00:06 - 11 Jan 2006    Post subject: Reply with quote

Hi Lads
Thanks for the great suggestions and help.
Ok the top end has now been stripped and nothing sticks out as obvious the piston did seize in the bore and a a result its scored so i will have this rebored. There is oil in the head but not what i expected but i dont see any lobe or bearing damage.
So im still not that wiser as to the cause i still suspect heat, but need to cover all aspects.
Attached is a pic of the oil pump see what you think , thi forces oil into crankcase and up the side of one of the barrel and head studs to the cam and rockers.

Any other thoughts.
Thanks
Compo
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Knowlsey
Scooby Slapper



Joined: 07 Apr 2005
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PostPosted: 15:36 - 11 Jan 2006    Post subject: Reply with quote

mechanical oil pumps rarely go wrong, check that the spring that shown there is not week, whatever it does
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Kickstart
The Oracle



Joined: 04 Feb 2002
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PostPosted: 16:11 - 11 Jan 2006    Post subject: Reply with quote

Hi

Pumps can wear out, but I would expect the top end of the engine to suffer long before the piston.

Not sure that there is any direct lubrication of the piston on that engine, and it might well just rely on a bit of oil being splashed onto the bore.

Think there is a filter somewhere in the system, just like a glorified brillo pad.

All the best

Keith
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Compo
Nova Slayer



Joined: 02 Jan 2006
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PostPosted: 20:48 - 11 Jan 2006    Post subject: Reply with quote

Yeah the filter is the right hand section of the pic, the pump is in the rectangle box.It also has a gauze filter in bottom of box.
Thanks lads
Compo
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Old Thread Alert!

There is a gap of 12 years, 244 days between these two posts...

davidashley
L Plate Warrior



Joined: 10 Sep 2018
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PostPosted: 11:33 - 10 Sep 2018    Post subject: XL185s exactly the same problem!!! Reply with quote

Wow! how weird I have exactly the same problem, appreciate this post is 10 years old but I am desperate. The bike had seized when I got it so has had rebore and new piston. It runs really hot, bogs down when revved and will only idle if the choke is on, i have a new carb but have not rebuilt it to try this on, thought I would check what people think before rebuilding it so I dont have to strip it all down again or do any damage trying to run it.
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Evil Hans
World Chat Champion



Joined: 08 Nov 2015
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PostPosted: 13:12 - 10 Sep 2018    Post subject: Re: XL185s exactly the same problem!!! Reply with quote

davidashley wrote:
thought I would check what people think


I think a lot of people will be annoyed, having started reading a 12 year old thread and then realising that you are a different person asking a different question and a lot of what they have just read is irrelevant.

Well, you did ask. Razz

Oh, by the way, welcome to BCF Wink
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Suntan Sid
World Chat Champion



Joined: 07 May 2009
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PostPosted: 19:19 - 10 Sep 2018    Post subject: Re: XL185s exactly the same problem!!! Reply with quote

davidashley wrote:
Wow! how weird I have exactly the same problem, appreciate this post is 10 years old but I am desperate. The bike had seized when I got it so has had rebore and new piston. It runs really hot, bogs down when revved and will only idle if the choke is on, i have a new carb but have not rebuilt it to try this on, thought I would check what people think before rebuilding it so I dont have to strip it all down again or do any damage trying to run it.


Running hot, won't hold idle without choke, sounds like you have an air leak. What colour is the plug? I fuel flowing properly to the carb?

I was tinkering with my 1983 XL125 a couple of weeks ago, it has always been a sod to start. First thing I looked at was timing, I haven't got a timing light, so it was just static timing. I changed the timing slightly, matching the "fire" mark as best as I could. All that happened was my bike exhibited all the symptoms you describe above. I put the timing back to the original position and It went back to running reasonably.

My initial problem was difficult starting and running rich.
When I rebuilt the engine, (including a rebore), I fitted a carb kit to the original carb. No matter what adjustments I made to that carb I couldn't stop it running rich. During the rebuild I bought a new carb, (presumably a Chinese copy), which I didn't fit.
After messing around with the timing, a couple of weeks ago, I decided to fit the new carb and bingo, solved the problem straight away.
The only conclusion I can come to is, something in the body of that 35 year old carb is worn out!
If you can afford it get an "ebay special" new carb and see what happens!
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