Board index Flathead Power-Technical Questions, Answers, and Suggestions Sporties 1978 XLCH

1978 XLCH

Moderators: Curt!, Pa

Post Fri Dec 18, 2015 1:44 pm

Posts: 1654
Seeing as I've mentioned this bike on another thread, just bought this. I wasn't going to but it was so complete and mostly original, I couldn't turn it down at the price. Turns over freely, plenty of compression, must look more closely over the weekend

http://i1023.photobucket.com/albums/af3 ... feugx.jpeg

http://i1023.photobucket.com/albums/af3 ... t4car.jpeg
Shoot, a man could have a good weekend in Dallas with all that stuff...

Post Fri Dec 18, 2015 10:03 pm
Pa Site Admin

Posts: 5802
Location: Ohio USA

My Son has a 77 but no where near as many original parts as your 78 does. Nice find ! They are strong engines.

Post Fri May 06, 2016 1:20 pm

Posts: 1654
Had a busy afternoon today, fitted the new coil, plug leads and plugs, also fitted a 38mm Mikuni conversion and fiddled around for a while getting a throttle all set up.

After various experiments, the bike suddenly started on the kicker and ran quite sweetly. No obvious knocks and rattles, no smoke to speak of - very good considering it has been stood at least six years. I very much think this bike was rebuilt a while ago, looking at the cases and gaskets..

Then I couldn't start it again! Obviously I'd hit in the starting drill without realising what it was.

So, I'm open to suggestions from anyone with a Mikuni round slide on am ironhead...
Shoot, a man could have a good weekend in Dallas with all that stuff...

Post Sat May 07, 2016 2:56 pm

Posts: 323
45Brit wrote:
Had a busy afternoon today, fitted the new coil, plug leads and plugs, also fitted a 38mm Mikuni conversion and fiddled around for a while getting a throttle all set up.

After various experiments, the bike suddenly started on the kicker and ran quite sweetly. No obvious knocks and rattles, no smoke to speak of - very good considering it has been stood at least six years. I very much think this bike was rebuilt a while ago, looking at the cases and gaskets..

Then I couldn't start it again! Obviously I'd hit in the starting drill without realising what it was.

So, I'm open to suggestions from anyone with a Mikuni round slide on am ironhead...


I had this on my WL, put the thing on choke, but also give some throttle, if it starts then you need to adjust idle speed

Sure there are tons of other possible causes but I dont know em :D

Post Sat May 07, 2016 3:36 pm

Posts: 1654
Had it running again today, seems to be a case of choke plus 1/4 or 1/3 throttle..
Shoot, a man could have a good weekend in Dallas with all that stuff...

Post Thu May 12, 2016 6:42 pm

Posts: 1672
Location: Interlaken, NY USA

Plenty of VM experience on other H-D's, not sportys. Having said that, VM's are designed to start with no throttle and using the enrichener circuit only. I'm guessing that the "idle" circuit is too rich, and the open throttle is compensating for it. Try going down on the Idle jet a bit, most big twin SV's and OHV's like a 25 or30 idle.
Just a shot in the dark from far away,
Good Luck,
DL

Post Fri May 13, 2016 12:32 am

Posts: 1654
I think I just hit lucky, because I certainly can't repeat the trick.

Re the enrichener circuit, Mikuni, Amal Mk2 and the non-pumper Dell'Orto are all a very similar design (especially the Amal) and are commonly fitted to older (pre-1975 two-valve) track racing bikes, especially Jawas. These are methanol engines, so 500cc cylinders with compression ratios typically in the 12.5 to 14.5:1 range, and they start by pulling the back wheel on the stand, or first bump.

I'm convinced it's the ignition system. I've progressively abandoned points ignition on these bikes and never looked back.
Shoot, a man could have a good weekend in Dallas with all that stuff...

Post Fri May 13, 2016 9:01 am

Posts: 1672
Location: Interlaken, NY USA

I feel your pain. I work part time in a small bike shop, and there's no doubt that electronics make for a hotter spark. I think single fire helps that as well. The Iron heads always seemed to need everything to be "just right" to get them to touch off. the earlier "CH"s with a mag were really meant to be a push start bike!
DL

Post Fri May 13, 2016 3:08 pm

Posts: 1654
I haven't tried a bump start, not easy where I live.

I flooded the engine today, also got a brief cough but no luck.

I've seen on another forum that stale fuel can make them almost impossible to start, so I'll change the fuel tomorrow. I think you are probably right about needing everything "just right", the old British big singles were like that at times.

It sounds fine on the odd occasions it feels like starting..
Shoot, a man could have a good weekend in Dallas with all that stuff...

Post Sat May 14, 2016 6:42 am

Posts: 1672
Location: Interlaken, NY USA

With the gas these days over here, if it sits for a week I feel no shame giving the OHV bikes a spritz of ether so that there is something that is actually volatile going into the engine. The Big twin flattie is the only exception. It'll fire on most anything left in the floatbowl for ages. The Knuck is especially sensitive to old gas. (maybe cast iron has something to do with it :-).
Right on with the big singles. I started riding on BB34's, then Goldies. Imagine the irony of having a goldstar being towed by a Goldwing with a stout bungee cord to get started. yeah, glad those days are gone.
What a delight when I got the old M20. It's claim to fame, starting at -20 deg F, first kick, one crazed winter weekend in the Adirondacks of Northern NY.
DL

Post Sun May 15, 2016 10:43 am

Posts: 1654
Zoom f'in' zoom!

I just spent an hour or so going all round the bike.. Fresh fuel, Tappets, points, plugs, clean float bowl ... all the usual stuff. It was becoming obvious that there was something, somewhere that just wasn't QUITE right... anyway I've now started it hot and cold on the kickstart. Final tick over needs doing but it's somewhere near.

Well that seems to be a known quantity, anyway...
Shoot, a man could have a good weekend in Dallas with all that stuff...


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