Smackley's G1 restomod, plus big block 440cc

[smackley]

Engine is in the cart, but not afixed yet. I needed to measure some different positions to see what belt options I could get. I settled on a 49" and 51" belt as two options to try. They were more expensive than I hoped and not on many websites, but I found a Gates distributor that was able to help.

It's a longer variable speed belt than typical, but allows me to keep the engine seated low in the cradle. Comet 780s are now hard to find as well so I had to go with a knockoff. I hope it holds up well enough.

My last concern before attempting to run the motor is my carb. I had a pz30 lying around, but it had a flanged manifold side. I found a manifold adaptor designed for a different carb but the bolt pattern lined up. I don't think it makes a good seal, and worry about bad flow between the adapter and venturi neck of the carb.

[smackley]

Some progress today, mostly on a custom muffler/header setup. I reused a factory muffler from my predator 670, but in reverse so I could get a dual exit exhaust.

[smackley]

Ok, I'm back from a long vacation, and trying to wrap this one up. I thought I'd simply be wiring in the old keyswitch, and off to the races by now, but I've hit a snag...

- I cut the original key switch wiring loom and added some jumper wire between each lead, back to their original location.
- I had to swap the original starter from the duromax to a HONDA GC390 starter, due to my billet flywheel. Apparently the original starter from duromax does not have enough throw to reach the teeth on the new flywheel, but the Honda original does.
- After all the wiring, I dropped in a brand new battery, fully charged.

I turn the key, and the engine turns very very very slowly. Not enough to get it running. I worried I had too much compression, or something not pre-oiled or something. I used the pull start, and it seemed to spin freely, but even after what seemed like 40 pulls, nothing.

It did take a while to get fuel into the filter through the new pulse pump setup, so I figured I just needed to prime the carb. I will pull the carb bowl to make sure there is fuel. I pulled the spark plug and grounded it while pulling the pull start, and it has spark, so no ground out in my wiring that I can tell.

The brown wire from the charging coil is wired up to the diode in the ignition as it was originally. The black wire from the key switch grounding wire is connected to the coil grounding wire (*black). Since I removed the oil sensor, I left that black connector on the engine floating (it appears to just be a Y line connection to the ignition coil anyway). I don't see any loose connections, but I will pull back the whole wiring loom and recheck everything again.

Anyone have a clue on why the starter would be struggling to turn the engine over? It will turn slowly for a few turns and then just stop as if the brand new battery has dropped below 11V. I've even paralleled a second larger battery with jumper cables just to make sure I didn't have a bad battery...and same result.

In any case, I'll keep hunting/checking everything this afternoon and hope I have a forehead slapper moment to laugh about.

[smackley]

Welp, I think the vacation break gave me some time to digest my problem. After a few minutes tinkering, I figured I'd add a ground strap to the engine, from the frame. I worried the rubber vibration pads added to the engine mounts were preventing a good solid ground to the engine...or that even the swing arm itself was isolated from the rest of the frame by the bushings. sure enough...the starter fires up at full speed now.

Now I have to hunt for my fuel issue...the carb bowl was empty. I swapped in a Mikuni 34mm carb before my vacation as I was unhappy with the PZ30 manifold setup. I am going to pull the outlet line from the pulse pump to make sure fuel is flowing, and then move through the carb.

[slonomo]

Make sure you are using small enough fuel hose on the pump. If it's too large it can have vacuum leaks. Ask me how I know. Make sure they are all a tight fit on the barbed fittings.

Also, make sure where you are pulling your pulse vacuum from is a reliable source. Briggs engines use the closest valve cover. Clone engines usually don't like the valve cover, although some seem to work. On the clones I like the pulse fitting on the intake spacer. You can buy them for next to nothing for the plastic ones, or spend more for the billet ones.

Check your fuel pump by usine a vacuum pump on the pulse line. You can also use your mouth lol. Basically just check it to make sure it squirts fuel every pulse. Volume isn't as important as "full squirts". But I'd say that for every 60 seconds of pumping you should get a few ounces of fuel.

[smackley]

Thanks Slonomo. I checked the fuel lines (used 3/16 line so I'd have good fuel line pressure). I pulled the line on the outlet of the pump and it squirts just fine. I have my vacuum pulse on the intake manifold just like you mention. Fuel seems to be making it's way to the bowl.

I pulled off the cone filter and choked the intake side by covering most of the opening by hand, and got fuel misted on my hand so I think it is spraying. I opened up the idle screw to make sure enough air was getting in on startup. I pulled the spark plug to check again for spark...and it's sparking. Im thinking I need to pull the main and pilot jet and just generally check it over. Air. Fuel. Spark...how hard can it be, right?

I did some searching and it looks like people are recommending a 170main and 65 pilot jet on a 34mm for a 440cc. Anyone thinking that sounds like a good starting point?

Originally Posted by slonomo

Make sure you are using small enough fuel hose on the pump. If it's too large it can have vacuum leaks. Ask me how I know. Make sure they are all a tight fit on the barbed fittings.

Also, make sure where you are pulling your pulse vacuum from is a reliable source. Briggs engines use the closest valve cover. Clone engines usually don't like the valve cover, although some seem to work. On the clones I like the pulse fitting on the intake spacer. You can buy them for next to nothing for the plastic ones, or spend more for the billet ones.

Check your fuel pump by usine a vacuum pump on the pulse line. You can also use your mouth lol. Basically just check it to make sure it squirts fuel every pulse. Volume isn't as important as "full squirts". But I'd say that for every 60 seconds of pumping you should get a few ounces of fuel.

[smackley]

Ok carb masters, I'm doing something wrong here. I have a feeling I must have bad timing. Fuel and spark is good but no magic. I get a small backfire every 20 rotations or so, but it just won't truly fire up. I think the backfire is either vapors finally sparking after building up either because I'm very lean or my timing is off

I ordered a jet kit since the main jet is only a 140 right now. The pilot is a 38. I think I'm way undersized. That said, I feel like it should still be able to idle.

I worry my cam and crank gears were not perfect (could have sworn they lined up). The other worry is my flywheel magnet not timed correctly with the spark magneto. I guess I'd have to pull the engine back apart if the jetting doesn't work out. What a mess...

[raydhd]

I would try a shot of starting fluid next. You will find out quick if timing is an issue. One other question. You do have an UT1 type coil with your billet flywheel?

[smackley]

Originally Posted by raydhd

I would try a shot of starting fluid next. You will find out quick if timing is an issue. One other question. You do have an UT1 type coil with your billet flywheel?

Starting fluid didn't spark. Ill double check the coil gap to make sure there is enough spark, but when I pull the plug and ground it against the frame it does spark just fine.

My flywheel is the ARC 6623-E, so it should use the UT1 coil.

Good thought though!

[smackley]

So, over the weekend...
- removed oil & side cover, removed cam, reinstalled and triple checked the timing mark alignment with the crank gears.
- Re-gapped the valves with the rockers
- Replaced the carb main and pilot jets with #160 main and #55pilot (can play with this once I can get this thing to turn over
- Bolted it all back up and refilled with oil/zinc modifier
- Removed the billet flywheel to try and confirm that the magnet aligns with the old flywheel's location (I may try installing the factory flywheel just in case)

This morning I tried turning it over, and...nothing. I get a big backfire after attempting to turn it over for a while. I get a fireball out of the exhaust and/or one back out of the carb. I also now get a steady stream of gas pouring from the lower bowl vent tube after a long attempt to turn over, so that's new.

I wonder if I should try the factory carb at this point? I'll have to fab up a pulse vacuum port of some sort.