Smackley's G1 restomod, plus big block 440cc

[raydhd]

With gas pouring out of the bowl it sounds like the float is hung up. Maybe try removing carb and just use starting fluid after taking the plug and spinning the engine to clear the cylinder and then make sure to use clean dry spark plug and then try to start.

[smackley]

Originally Posted by raydhd

With gas pouring out of the bowl it sounds like the float is hung up. Maybe try removing carb and just use starting fluid after taking the plug and spinning the engine to clear the cylinder and then make sure to use clean dry spark plug and then try to start.

Thanks Ray, yes the float was stuck. I "unstuck" it, and the fuel spilling stopped, but no success on turnover.

I stopped, walked away for a minute to clear my frustration, and came back wanting to take another look at my valve lash/gap. I remembered that during my build and recent "rebuild" efforts, the HD rockers were on a pivot arm that bolted down to the threaded rod that had to be threaded into the head when I installed it all. I started to wonder if I hadn't accidentally torqued down that center nut, which through off all of my gapping, meaning the valves were either not opening far enough, or staying open some during compression/intake strokes...


Well, I'm a dummy and that's what I had done. Flipped it over, re-gapped exhaust and intake, and the it fired up first try...

I'm mad at myself, but also stoked to have it running finally. It's running rich...very rich. I'm going to have to start the whole carb tuning phase again, but at least now I have a running engine to work from! I'll post some final updates, with some running video, later this week. Thanks for the help and ideas from all the usual experts here.

[raydhd]

It is kind of funny my next question was going to be how are you doing your valve lash. I use the very simple method shown in Aaron's sticky in the clone section. The big time racers use a much more complex method but with the overlap on the twister cam it is really not needed. P.S. I think that is actually Geoff doing the video but Aaron posted it here.

[smackley]

Still running pig rich. Fouled my autolite spark plug so quickly that I dropped my main jet all the way down to a #140. Still not perfect. I haven't messed with the needle position yet, so rather than dropping again, I may try lowering the needle in the slide.

Otherwise, it's a fun cart. Lots of torque, but not big on acceleration. My very long cvt drive belt doesn't seem to like me stabbing at the throttle too much. Long term I may have to try and move the engine closer to the diff so I can use a shorter belt.

I'm also working on a harness bar and some seatbelts so my son and I don't fall out at speed!

[smackley]

The carb is now jetted in a way that seems like it's tuned enough to start up without the choke on cold start, but main jet is big enough to make top end power.

The harness bar was finished up and painted. Harnesses are installed, and I made a slim windshield to complete the look.

Unfortunately, I think I now need to completely change my engine mount position and belt length. I have shredded my belt and it is just way too long for the amount of RPM and torque. I could add a tensioner but honestly a shorter belt will be cheaper and easier to buy in the future.

[slonomo]

On my G1 with a built Vegas Carts 460 I used a 59" long belt from a John Deere utility vehicle, cost about $100, held up well. I still have the belt, it looks almost new. I used to rev that thing past 6000 rpm. I'd question the quality of your belt or the alignment of the clutches.

[smackley]

Many months have passed by, and I have been constantly 'tuning' this cart to modest improvement. I have swapped out different carb jets several times, and can't quite get the perfect settings. The cart will either start like a champ in the cold, with little choke and then run lean at WOT, or..it will take forever to start but run like a top until it fouls a plug (rich). I'll keep tinkering here.

The biggest problem continues to be the clutch/belt combo. As in previous posts, I had a problem with the belt getting flipped and damaged. I ended up raising the engine up a bit to make sure the belt was not getting into contact with my header at full RPM on the drive clutch.

The belt/alignment is spot on at idle. I can run it a slow speeds just fine, and can creep to full speed just fine, but if I am rolling slow and I stomp on the pedal, the cart shudders and the belt eventually will flip inside out (as if the clutches are not aligned).

I have lifted the rear axle off the ground, and put it up on jack stands, to see what happens to the clutches during the full RPM range. With the wheels off the ground, the clutches work perfectly, and the driven clutch fully opens and the drive clutch fully closes, and the belt stays right on track just fine. I can stab the throttle and everything stays in sync perfectly.

So, my current theory is that the old G2 driven clutch is opening under the torque of the new big engine and comet 780. When wheels are on the ground, the resistance at low speed forces the old tired driven spring to compress too soon, and then the clutches are out of sync (both are mostly open at same time) which would mean the sheaves are getting misaligned and forces the belt to flip (not to mention the belt now has a bunch of slack).

If this theory sounds good, then my thought is to try and high torque spring on that driven clutch?

[smackley]

It has been a while, but wanted to post an update. It seems I have solutions for most of my previous issues.

-belt flipping & burnout was due to my brake cables being completely rusted out and locked when brake was applied. This meant the engine was essentially fighting full brake all the time. Further, the sheaves on both pulleys had been glazed with melted pulley coating and would cause belt slippage at nearly any RPM. New brake cables and cleaned up sheaves, and I haven't burned a belt since.

- running rich was due to a knockoff mikuni carb getting delivered on my original order, and the air fuel screw was sheared inside making adjustments impossible. Installed a VM 34 from gopowersports and with very little tuning I am running so much better in all RPMs.

- I also had lots of exhaust issues due to using flex pipe to absorb vibrations and simplify using an old muffler. I made a complete header that runs to a 2" slip on muffler. It's noisy but sounds awesome

All in, I'm loving a built 440cc Duromax that can wind up to 6k RPM. It is not nearly as smooth as my 670cc v-twin cart, but is very torquey and makes a good noise.

[slonomo]

Ah Chinese carb quality at it's best. Nothing like a genuine Mikuni.

The belt issue....wow, glad you figured that out. Never heard that one, I'll have to remember that for future.

I always liked my VC440 when it ran good. I too had the same issue with the carbs. Wish I had ponied up the money for a Mikuni. I never had any clutching or belt issues, even with a 59" belt. Did you ever change the secondary spring? I've found heavy springs make it shift worse, keeps it from upshifting and stays in low gear for longer. Good for climbing steep hills and towing though.

I never had any luck with flex pipe either. I have since gone to fully welding pipe sections. I have used kits from Vegas Carts and from Robertsons, both good products. I'm a fan of the thick walled stuff in 1" size. What size pipe did you end up with?

[Jbrowne479]

awesome build! thank you for sharing.

quick question, did you end up running the balance shaft in the motor? also, did you use the factory piston on the billet rod?