Alright so I got a 60 tooth sprocket and put it with the 9t driven sprocket. I’m now running around 53mph and 5300 rpm. I think my belt is stretched/worn. There’s a lot more slack when taking it on and off compared to the stock ones that come with them. It’s one of 3 that I bought off of Amazon for $20-30. I did swap out for a fresh one the other day but it completely shredded it about a mile down the road. Pulleys are aligned so I’m guessing it’s most likely a <$10 belt doing what they do.
What’s a good brand of belt to get?
I looked into valve lapping and there’s nothing to it. I have a lapping tool on the way.
That's great!!!! You jus keep gaining!!!!
You are creeping up on that cam now. I'm sure you are seeing how much harder it pulls at 4k then it does at 3k.
I have the best luck with bando belts, but are limited in sizes, comets belts are a very close 2nd.
When playing with timing, always check where it's at with the stock key, then make adjustments. These mass produced cranks, the keyways are cut different. Anywhere from 18-27 degrees with stock key and flywheel. The last pred hemi I checked was 27 (stock flywheel), matched with a ARC flywheel came out to 35 and that was too much for the CR, rider weight, gearing, and 87 octane. Made it too hard too start, too much pressure on the rod bearing, and lost a ton of "outta the hole pull".
I have an old 168cc mocked up with crank (24 degrees), rod, piston, and side cover for checking clone taper flywheels, with a dail indicator. I don't bother checking pvl's or arc's any more. They are always 28 and 32. But always check the cranks.
You won't feel a difference on the butt dyno when running 28-32. You need a tach, speedo, and a buddy with a stop watch. I see faster times at 60 ft, 100, and 200 ft at 28-29 degrees, but I keep my builds under 10.5:1 CR, run SA bored carbs, 87 octane gas and live 1200 above sea level.
With the pvl flywheels, I set airgap at .060" and arc's at .075". I also use dover power performance coils, wires and caps. They retard timing less at higher rpm (5k +). 1-2 degrees retard compared to the 6-8 with the stock coils. Also use non resistor plugs, they help with retarding timing.
I really like that tach/temp gauge. I see kart racing sites selling it $80-$150. You have to manualy turn it off tho. I've left mine on for days more then once, and it's still the same battery.
Since you don't have hills, and now a 6.66:1 gear, you might could possibly move that driven spring to less resistance holes, jus for experimenting, after you get the best carb, timing tune. I keep different drivens set up for people to test.
Another thing, if you could handle it, and keep it under control, is adding more stall to the driver, a little at a time (100-200) for experimenting. That cam was designed for 13" or smaller tires, 4000+ stall and never see below 5500 rpm during a race. Lol. I can show you how without spending any more money on springs. Jus takes a drill, 3/16" bit and a cheap doper's scale, in grams.
We can do that after you get the tach/temp gauge.
You broke your 50+ mph mark. Are you done now,???? lmao
Good luck, keep updated your progress
