Atmospheric valve on early motor

[sirhrmechanic]

Got a question about an atmospheric valve. Friend of mine has one of the Timeless bikes like mine and we've been working on getting it running. It starts right up, runs great, but after about 30 seconds appears to starve for fuel then quit.

We have great gravity fuel pressure and the bowl is staying full. The spark is hot right up to the end. No issues there. Engine is free and turns nicely even after it quits. No seizing at the piston or bearings.

My current theory is that the atmospheric intake valve may be a bit tight in its guide. When it gets hot, it is hanging up enough to kill compression and stop the motor... in a way that appears to be fuel starvation.

When cold, the valve seems fine. I have not yet measured the clearances. Does anyone have a specific clearance for an atmospheric valve in its guide? This should be the same spec and the 1909 - 1913 Harley motors as that is what the folks at Timeless copied. Should there be any lubricant up in the valve guide?

Any thoughts from you guys who have more experience with atmospheric valves?

Cheers

Sirhr

[Ross]

If you are running a timeless with their carb it maybe the problem. I would change the carb and I think you'll find it will run fine. It will leak however. Dick Orloff (yellow spear fame) is the guru on upgrading a timeless to be a dependable runner.

[sirhrmechanic]

Hi Ross: The original carb was the first thing to go. It's on a shelf looking pretty. I built a new manifold and we adapted a Linkert from a WL/Servi to the engine. You can see how we did it here on the forum as I posted a pile of pictures of mine while I was adding a magneto...

One of the things we may try is swapping on the Linkert from my bike because it works well. But before we do that... I was curious about the possibility of the valve being the problem. Every indication we have is that the Linkert (which is rebuilt and seems to be in perfect shape) is doing its job. The bike cracks right to life an runs like it wants to. But after about 30 seconds, dies. We checked fuel flow. Made sure that the fuel line was not mounted so it trapped an air lock in it... it was fine. The gravity feed dumps plenty of fuel in -- more than enough to keep up with the motor so we're not draining the bowl.

I'll see if I can get Dick's input. Thanks for the lead and I appreciate your time!

Cheers,

Pierce

[23JDCA 808]

Would be easy to try a little oil on the valve/valve guide?

[Ross]

I know this is elementary but is the gas cap drilled.?

[sirhrmechanic]

Ross. First thing I did when we started working on the bike. Because it's not drilled as it comes from Timeless. Hole is plenty large. We have great flow into the carb.

We are going to pull off the valve both to see if it's tight in the guide or if it has some rust or a burr. And we'll lubricate at the same time.

Bike is really 'trying' to run. Wants to go and sounds like it 'really' wants to go. I think it will be a great motor...

Cheers,

Sirhr

[Ross]

I would be interested in the outcome of your tinkering.

[sirhrmechanic]

Thanks for the good thoughts, Ross. I'll definitely keep you in the loop.

If you didn't see it, here's the 'tinkering' thread from before. This is my bike, which I converted to Magneto and M16 Linkert.

http://www.antiquemotorcycle.org/bbo...-Magneto-Drive

Cheers,

Sirhr

[rwm]

try lard with graphite powder on the valve and guide. the lard will burn off but the powder will stay. i guy told me about doing this to an anzani 8 valve. and how this treatment made it sound run like a whole different motor.

[c.o.]

I wonder if it's a spring tension issue???

[sirhrmechanic]

Hi Cory.... THAT is worth checking as well!

Love this place!

Cheers,

Sirhr

[pete @ occhiolungo]

Hi Sirhr. Were you able to get that Timeless intake to work? (I only check this forum every so often, and just saw your thread). It sounds like you have checked the fuel flow at the carb. One thing that I like to try is to flood the carb with the tickler button on the float. If the motor runs better, then it needed more fuel. If it runs worse, maybe it needed more air. Also, are your loops in the copper fuel line horizontal or vertical? The old bikes always used horizontal loops to prevent any air bubbles from forming and stopping the fuel flow.

Did you drop any powder graphite onto the valve stem? It might not last long though. Try a squirt of 3in1 oil while it is running to see if that helps. Also, the intake valve springs can be tricky to dial in. A stiff spring is better for higher rpms, but a weaker spring is better for low rpms. When you let the bike run for 30 seconds and then it dies, is it running at the same rpm the whole time? Or is the problem related to the motor speed?

Keep at it, you'll have it on the road soon. I really love the idea of buying a Timeless and riding it, modifying as needed. They are very affordable compared to the 100 year old bikes, but give the same feel when you are going down the road.

regards,
Pete

[flyin.mauer]

Hi Ross, my name is Jay im new on here and also with the timeless motorcycle. Id really like some solid advice and first hand experience knowledge on the carb, timing and any other tips as id really like using what it comes with, il tinker til the cows come home. If you could call me im in edmonton at 780297 1544 its Jay.

[flyin.mauer]

Hi my name is Jay, im getting into a timeless bike and aware of some things needing attention. I was really hoping we could talk over the phone as ive read a lot on the forum ( what ive been able to find so far anyways) could we talk? My number is 780 297 1544, im in edmonton Alberta, and im new to the AMCA, so any help would save me a ton!!

[flyin.mauer]

Hi Cory my name is Jay im trying to get as much help on a timeless bike as im able, ive read a lot so far on the forum as ive tryed searching different areas, but id really like to keep the parts mostly that it comes with, the carb, battery ignition, and just tinker to make the thing work, so i was hoping we coyld talk on the phone as its way faster and easy. My number is 780 297 1544, its Jay. Or if i can call you back id do that too. Any other people you know with this bike id really appreciate to know!!