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Honda XL 350 1978 Project.

Posted: Thu Apr 20, 2017 5:21 pm
by Newtsalad
Well I've had it a while, but here it is.

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Re: Honda XL 350 1978 Project.

Posted: Thu Apr 20, 2017 7:26 pm
by Andrewwoey
I like very much. Great machine.

Re: Honda XL 350 1978 Project.

Posted: Thu Apr 20, 2017 8:22 pm
by barker
have you managed to register it yet

Re: Honda XL 350 1978 Project.

Posted: Fri Apr 21, 2017 11:36 am
by Newtsalad
No. Just got the dating cert and got it insured. Had an MOT booked for 11am this morning, but I've had to cancel, electrical problems. :(

Re: Honda XL 350 1978 Project.

Posted: Fri Nov 24, 2017 11:30 am
by Newtsalad
Two full days on the XL350. Still not sorted. Rear tube replaced, spokes tightened, wheel bearings replaced, carb off, run it through the ultrasonic jewelry cleaner umpteen times. Found an airway blocked, and managed to clear it with a hypodermic full of very, very nasty acid, the fumes of which would take your face off!

New throttle and R/H switchgear in place, all electrics now working bar indicators still to be installed.

All the handle bars, headlight mount and choke mount have been blasted and 2k painted, and the black paint removed from the chrome, so its looking a lot tidier now.

Mirrors fitted, side panels fitted.

Got it all back together and decided on a run to Dedham to surprise Su. Bastard is still baulking and backfiring when the throttle is opened fast at around 4k revs. :( :( :(

The mirrors were in the wrong place for travelling the A14 / A12, so I bottled it, I can't be sure if its rich or more likely lean, and I don't want to risk seizing it.

So I bottled it just before the A140 and headed for home. On the three miles or so back, the zip blew out on my jacket.
Good call I reckon.

Its now sat looking at me for more attention.

Plan today, after I dispose of the rat I shot while in my dressing gown at 6am this morning, is to check the plug. Change the plug, even though its new. Put in a 130 jet in place of the 115. Install the electronic ignition kit.

If none of that works, it'll be trying to find a carb of similar dimensions to the PD 01A fitted to it which was only fitted to the 1977 and 1978 models, and is as rare as rare can be, and then rarer still. :( :( :(

Re: Honda XL 350 1978 Project.

Posted: Fri Nov 24, 2017 11:35 am
by Newtsalad
For the unfortunate owners of such machines, here's some info. Carb is PD 01A. Needle fitted to mine, which may not be correct is F2350E. Main jet is and should be 115, Slow running jet is and should be #45, float height for this model is 14.5mm and not the 18mm frequently quoted for the model.

I'll try and get some pics up today.

Re: Honda XL 350 1978 Project.

Posted: Fri Nov 24, 2017 11:48 am
by Capitano
IIRC a popular mod for old Yamaha XT500s is to fit a modern 36mm mikuni.

I don't know if one will work on the XL but it might be a good place to start from regarding advice.

Re: Honda XL 350 1978 Project.

Posted: Fri Nov 24, 2017 12:11 pm
by barker
have you looked at the American site for off road bikes they may be able to offer some help
may be

Re: Honda XL 350 1978 Project.

Posted: Fri Nov 24, 2017 12:40 pm
by Newtsalad
Capitano wrote:
Fri Nov 24, 2017 11:48 am
IIRC a popular mod for old Yamaha XT500s is to fit a modern 36mm mikuni.

I don't know if one will work on the XL but it might be a good place to start from regarding advice.
Yes, following advice found on the web I splashed out £77.09 on a brand new Mikuni 36mm In May 2016. It's 20mm longer, the inlet is 62mm as opposed to 45mm, and the outlet is 43mm as opposed to 39mm.

By pouring a kettle of boiling water over the inlet rubber, I was able to persuade it to accept the Mikuni. And I did get the bike started, which confirmed it's poor starting as carb problems. However it ran crap and needed setting up, which is to be expected.

However... the extra 20mm in length meant there was no way to hook it up to the original air box, the rubber manifold from the airbox to the carb is only 63mm long with the original carb sitting only 43mm or so from the original air box. Also, the carb and airbox are offset from each other, and the rubber manifold moulded accordingly.

So to use the Mikuni, I would have to remove the airbox, and fit a K&N. It would so alter the appearance and limit it's fording ability that the Mikuni has been set aside.

After this, I decided to buy a carb from a '73 to '76 model, as parts kits are readily available. I stripped it, sand blasted it to pristine and fitted an overhaul kit.

However, when I went to fit it, I was in for a shock! Although it looked very similar, it wasn't until I went to fit it I found it was about 30% bigger all round! :shock: :?

The earlier models had a different head, and the carb and airbox went on the right side of the bike rather than straight back.

So... That's also sat on a shelf, and hence I've persevered with the original carb.

The air cutoff valve diaphragm had four holes in it too, and replacements aren't available. However I plumped for two, and yesterday I was able to modify the brass pin on one for a 750cc bike to exactly match the original, so that was a result. :D

Re: Honda XL 350 1978 Project.

Posted: Fri Nov 24, 2017 12:54 pm
by Newtsalad
And yesterday I fitted a new inlet manifold O ring, 42mm part no. 91304-704-000

Treat the rear hub to some new brake shoes too. The cam was turning so far the back brake was jamming on. Fun on the byways! :roll:

I met up with aliengravy on his KTM for a bit of byway action about 3 weeks ago now. After a particularly nice set of moguls I handed the XL over to him and said here, have a go, see what you reckon.

Five minutes later he returned with oil pissing out of the engine! :shock: :o :shock: He assured me he hadn't hit anything, and it transpired the plastic battery breather tube had come loose, wrapped around the front sprocket, and compromised the oil seal, which also acts as an oil gallery, so the oil was being forced out under pressure, hence it looked so dramatic.

If I hadn't let him have a go, likely I would have followed him and been none the wiser until the motor seized, so lucky escape I reckon!

I got to ride his KTM 690cc back home while the poor lad sat with the XL, to collect the car and trailer, which was, errr... interesting! :twisted: :twisted: :twisted: