Starting a long dormant engine.

[Nessism]

I haven't heard that term in ages. All the Brits will get it but for everyone else just call them Vice-grips.

Well I agree that its got to be something simple.....and likely stupid on my part.

I have quadriple checked the valve timing and it appears spot on. I'm going to double check the valve clearances today and I'm going to pick up a new compression tester too.

I reread my manual on the carbs last night and I can't see any reason why they wouldn't shoot a little juice at least with or without the airbox.

Well I'm getting tired of these sleepless nights so I have to get it to fire or.....find a new hobby.

I'll see what today turns up.

cheers,
Spyug

Spyug,

When you verified the cam timing did you make sure the cam notches are pointing inward with 1-4 at TDC?

Photo below shows notches facing inward like they must with #1 at TDC. Pull the plug and make sure the piston is there too.

 

[Ponderosa]

Alrighty then!

Alrighty then!

Still no start? Try pulling plugs, cleaning/drying plugs, blow out each cylinder with compressed air, install plugs, crack each carb plunger open with a pencil, small non marring round item/ or some other item, crack throttle open, put a little gas in the throats, then say a prayer, keep thumb on kill switch, and crank.

 

[spyug]

Ed,
That diagram is etched in my brain and I have a copy taped to my tool box. I've checked, checked and rechecked so I'm certain that is all good. I haven't yet looked for a piston top at #1 so I'll do that too but if everything else lines up how could a piston be off? There's no weird sounds so I don't suspect any broken rods or such.

The more I ponder this, the more I'm feeling the silly airbox has something to do with it. I can't say why and it does fly in the face of logic but that's what I keep thinking. Last night I restricted the carb mouths with a piece of towel and plugged the vacuum tube but that did nothing so I guess I'll need to somehow get that airbox in place.

I'm not easily frustrated but this is starting to really kick my butt.

I appreciate everyone hanging in with me especially you Ed.

Cheers,
Spyug

 

[Guest]

You still haven't verified the timing at the ignition.

 

[lurch12_2000]

Spyug,

When you verified the cam timing did you make sure the cam notches are pointing inward with 1-4 at TDC?

Photo below shows notches facing inward like they must with #1 at TDC. Pull the plug and make sure the piston is there too.

Nice pic!....I make sure and count the 20 links too, to be sure, as the notches don't exactly line up at a perfect 90 degree angle facing each other and aligning even with the surface of the head...along with trying to determine if the #3 and #2 marks are perfectly perpendicular...and checking the timing mark for 1/4 at TDC at the same time.

 

[doctorgonzo]

First time I tried to start mine post rebuild I had set it at TDC on 2-3 instead of TDC on 1-4. The second time the cam had rotated ever so slightly when I bolted it down. Verify the cam timing is spot on first thing. You MUST lock them down with mole grips (for the Brits) or the cam WILL move and screw up your timing.

 

[Guest]

Pull the plug and make sure the piston is there too.

Good suggestion Ed, at least then you'll know if you're 180 degrees off.

Hopefully that's the problem, easy fix...

 

[spyug]

At the risk of showing my total dweebishness, I haven't looked at ignition timiing as I was of the belief that it is a factory set situation and once set wouldn't move unless physically knocked about or changed out. It is stock and does not appear to have been moved at all. I don't recall any info on that in my manual but I will definitely look again.

As all my little elves are happily working away this afternoon and there are no work related pressures, I believe I will slip out to the man room and start wacking on that lump again. Maybe this time with my 10Lb persuader if I don't manage to get a peep out of it.

Recross your fingers for me.

Cheers,
Spyug

PS Just had a quick look at cam timing and with alignments as per the diagram, I have now confirmed piston#1 at TDC so one less thing to think about. Thanks for mentioning it, It had actually slipped my mind as we always checked that when building the sports car engines back in the day.

 

[old_chopper]

If you don't have the airbox on it you might try using your hand to choke the carbs as you crank it over. That should help pull some extra fuel in to start.
Another way out in left field idea, make sure the battery is hooked up correctly. I'm sure it would not function and spin the engine over in reverse, but...

 

[doctorgonzo]

"I haven't looked at ignition timiing as I was of the belief that it is a factory set situation and once set wouldn't move unless physically knocked about or changed out."

It won't unless you remove the cams. I was operating under the idea that you had (removed the cams). Though I think the bolt holes on the ignition plate are slotted and thus can move a little bit.

 

[Guest]

If you don't have the airbox on it you might try using your hand to choke the carbs as you crank it over. That should help pull some extra fuel in to start.
Another way out in left field idea, make sure the battery is hooked up correctly. I'm sure it would not function and spin the engine over in reverse, but...

Happend to me on a riding mower once. Very weird thing.

 

[Guest]

At the risk of showing my total dweebishness, I haven't looked at ignition timiing as I was of the belief that it is a factory set situation and once set wouldn't move unless physically knocked about or changed out. It is stock and does not appear to have been moved at all. I don't recall any info on that in my manual but I will definitely look again.

As all my little elves are happily working away this afternoon and there are no work related pressures, I believe I will slip out to the man room and start wacking on that lump again. Maybe this time with my 10Lb persuader if I don't manage to get a peep out of it.

Recross your fingers for me.

Cheers,
Spyug

PS Just had a quick look at cam timing and with alignments as per the diagram, I have now confirmed piston#1 at TDC so one less thing to think about. Thanks for mentioning it, It had actually slipped my mind as we always checked that when building the sports car engines back in the day.

I may have missed it but did you try new plugs? I bet I went through at least 3 sets before I got the 850 started.
I still suggest putting fuel into the cylinders.
Also make sure the coils are wired correctly?

 

[spyug]

I may have missed it but did you try new plugs? I bet I went through at least 3 sets before I got the 850 started.
I still suggest putting fuel into the cylinders.
Also make sure the coils are wired correctly? Today 04:53 PM

Well yes I'm on my first set of new plugs, installed last night. I tried the fuel in the cylinders too and yup the coils are wired right and things are sparking the way they should. The battery is in good shape and it is wired the right way too.

I picked up fresh gas today and an atomizer for shooting spray into the cylinders.

Right now I have the heaters on in the garage and halogen lights on the block to warm up the oil. I have the charger topping up the battery so in an hour or so I'll have at it again.....I'm trying to stay positive.

One of these days its got to go.

Cheers all,
Spyug

 

[spyug]

Sad to report I continue to strike out.

No gas getting to the cylinders. Bone dry plugs. Got spark but still weird that it won't fire off with a shot of gas or ether in the plug hole.

I am going to pull off the carbs ( again 4th or 5th time) and first try firing with a tiny spray of gas to each port.

I just have to prove (to myself)that it fires.

Man this is kicking my butt. I've never had an engine give me this amount of grief in all my 40+ years of wrenching.

Here I go again.

Spyug

 

[duaneage]

I went through this with cloudbreakMD last year. Turned out the carbs had stopped up low speed jets, wouldn't pull fuel. We exchanged carbs and it started with airbox and no filter.

Take your other 750 carbs and try them, they are jetted differently but will still work. Same model.

 

[Guest]

I went through this with cloudbreakMD last year. Turned out the carbs had stopped up low speed jets, wouldn't pull fuel. We exchanged carbs and it started with airbox and no filter.

Take your other 750 carbs and try them, they are jetted differently but will still work. Same model.

Good idea but wouldnt it at least fire with fuel in the cylinders?

 

[Guest]

Make sure to open the throttle when spraying the fuel in the cylinders or put directly in the spark plug holes.

 

[spyug]

Many thanks guys for the continued support and the many good ideas.

As I mentioned I had tried a spare set of carbs that came of the GS and which had run and were then cleaned, rebuilt and stored. The carbs that came with the bike were the first thing that I cleaned and rebuilt and I took great pains to do the job right including a week or so in the carb dip, wire probes through all the holes and jets and blowing everything with the compressor. I'd have to say they were squeaky clean

Now as I'm buggering about tonight, I was thinking that it was not turning over quickly enough despite a fully charged battery and the block being heated to "liquify" the oil. It seemed to be labouring. As I'm cranking away I see smoke rising from the area of the solenoid On closer investigation, I find the power lead from the solenoid to starter is loose????? I thought I had torqued that bastige down. Cleaned off the contact and bolted it tight. Pulled off the contact on the starter and cleaned it to bright and shiney. I did a voltage drop test with battery at 12.8v and it showed 12.7v at solenoid and 12.6 at the starter. I reckoned that wasn't too bad.

Question I now have is could this have any bearing on things? I suspect not but everything makes me wonder now.

I'm letting the battery charge up again and I'll bolt the carbs back on and see how it goes in an hour or so.

Stay tuned.

Cheers,
Spyug

 

[duaneage]

Good idea but wouldnt it at least fire with fuel in the cylinders?

We poured gas through the carbs even. It took swapping carbs to get it started. I opened the others up and the smaller jet tube (I think it's the low mid speed jet) was plugged in all four. Another set of carbs allegedly rebuilt that weren't.

He has another set of wallet drainers, I would give it a go.

 

[Nessism]

I wish I could come out and see this bike. It boggles the mind to think that it won't even spit an odd pift or two with gas dumped directly into the cylinders.

If you put a finger over a plug hole and spin the engine does the compression force your finger off?

When rebuilding your carbs did you spray carb cleaner into the choke tubes to make sure there is clear flow up to the choke plungers? If there is compression, and spark, it has to be fuel. I trust you removed the pilot jets when you cleaned the carbs and poked a wire though the center to make sure they are open right? How many turns open are the mixture screws?

Don't give up...