Honda-SOHC

SOHC.co.uk Forums => SOHC Singles & Twins => Topic started by: Craizeehair on March 31, 2026, 06:29:52 PM

Title: XL350 Oil Leak
Post by: Craizeehair on March 31, 2026, 06:29:52 PM
I’m currently looking at an XL350, it has a slight oil leak coming from where the rubber bung is on the left side case. Is this something that anyone has experienced and could advise what it could be? The clutch pushrod seems as though it could be the culprit but I’m hoping to get some first hand experience and advice if possible?
(https://uploads.tapatalk-cdn.com/20260331/cb320cc2dc7a7bf514af569fcb88acc0.png)
Title: Re: XL350 Oil Leak
Post by: Bryanj on March 31, 2026, 11:04:41 PM
Never done one but seal is possible, also gasket to crankcase
Title: XL350 Oil Leak
Post by: Craizeehair on March 31, 2026, 11:19:11 PM
Thanks Bryan,

When you say seal, do you mean any specific one, I’m guessing worst case, split the cases and replace all seals and gaskets to cover all bases?
Title: Re: XL350 Oil Leak
Post by: Bryanj on April 01, 2026, 12:31:23 AM
Looking at the circular cover and gasket i suspect there is oil around the generator so there will be a gasket between that inner casing and the crankcase, i would think those cases are vertically split and seals replaceable without strip down
Title: Re: XL350 Oil Leak
Post by: Bryanj on April 01, 2026, 12:43:10 AM
There are different xl350 and al cms list are usa models and some split horizontaly, couple of screen shots showing pushrod seal at end of transmission shaft and lh case with gasket
Title: Re: XL350 Oil Leak
Post by: Skoti on April 01, 2026, 06:45:19 AM
I've never worked on the XL350 models, but often on the XL250 version.
That 'O' ring between the clutch operating arm and casing looks wrong, I think somebody has messed with this before.

Should be a small 'O' ring that fits on the shaft in a groove out of sight and of course a small oil seal at the other end.

Looks an interesting project.

Good luck.
Title: Re: XL350 Oil Leak
Post by: Craizeehair on April 01, 2026, 08:58:32 AM
Thanks all, seems that it has had some work recently, I’m not familiar with these at all but it has had a small job to rebush the clutch actuating lever, not an uncommon thing on these apparently but I don’t know, I wonder if reassembly could be the problem.
Title: Re: XL350 Oil Leak
Post by: Craizeehair on April 01, 2026, 08:59:35 AM
I've never worked on the XL350 models, but often on the XL250 version.
That 'O' ring between the clutch operating arm and casing looks wrong, I think somebody has messed with this before.

Should be a small 'O' ring that fits on the shaft in a groove out of sight and of course a small oil seal at the other end.

Looks an interesting project.

Good luck.
Looking at the parts diagram you are correct, I can’t see any o ring there
(https://uploads.tapatalk-cdn.com/20260401/8b6dd34a9720aac94eba3f72e37fc2c5.png)
Title: Re: XL350 Oil Leak
Post by: Bryanj on April 01, 2026, 03:44:19 PM
Two possible reasons i can think of for that O ring

1 attemping to cure the oil leak

2 spacing the operating part upwards for some reason
Title: Re: XL350 Oil Leak
Post by: Craizeehair on April 03, 2026, 06:50:17 PM
I think you’re right about trying to cure the leak Bryan, I’m just trying to figure out if sorting the oil leak is gong to be too much to warrant the purchase. There doesn’t seem to be much info out there about these?
Title: Re: XL350 Oil Leak
Post by: Skoti on April 03, 2026, 07:43:38 PM
Could be the clutch push rod oil seal, easy fix and costs about a fiver.

https://www.cmsnl.com/products/oil-seal-8x34x8_91203292005/ (https://www.cmsnl.com/products/oil-seal-8x34x8_91203292005/)
Title: Re: XL350 Oil Leak
Post by: Craizeehair on April 03, 2026, 07:45:37 PM
Thanks for that, I did read that could be a possibility but would be a splitting the engine job, sounds as though that’s not the case hopefully?
Title: Re: XL350 Oil Leak
Post by: Skoti on April 03, 2026, 07:58:51 PM
If I remember correctly (from working on 2 valve XL250's) all you have to do is remove the front sprocket cover and alternator casing to get access to the clutch push rod oil seal.

 
Title: Re: XL350 Oil Leak
Post by: Craizeehair on April 03, 2026, 08:11:43 PM
Thank you
Title: Re: XL350 Oil Leak
Post by: Bryanj on April 03, 2026, 08:17:36 PM
Its a rare enough and fun bike that the oil leak would not stop me, worst i can think of is finding the parts, maybe pushrod, seal, gaskets and maybe some of the operating mechanism
Title: Re: XL350 Oil Leak
Post by: Craizeehair on April 03, 2026, 08:23:26 PM
That’s what I’m hoping and from the little I have found I believe that the 250 and 350 share quite a lot of parts ,so that might help. I know next to nothing and there doesn’t seem to be much resource available but I think I will go for it.
Title: Re: XL350 Oil Leak
Post by: Bryanj on April 03, 2026, 08:41:35 PM
Compare the diagrams on cmsnl and go from there, if you create an account(free) it will tell you what other bikes used the same parts