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JSlezak83 03-08-2021 02:50 PM

1200 Project
 
I’ve had a ‘79 1200 for a little over a year now, that I bought with the intent to take to the county fairs and attempt to have a little fun. I’ve spent much of that time fixing the years of neglect . The K301 in it was knocking badly and had prob about .020” slop in the bore. I replaced it with a used K321 as the class I’d be pulling in allows for up 14hp. I have replaced the iso bushings with solid mounts and have a 3 puck clutch with red spring. I need to remove the shifter to verify gearing, but I am supposed to have a 17T second gear. I still need to get wheelie bars and a weight box. I’m guessing with my 240lbs in the seat, I’ll need about 150-200lbs to hit 1050lbs. I still have what looks to be the original Goodyear 23x8.5-12 tires, so I know that’s going to be an issue. The good news is they are plenty hardened lol.

The K321 came from a green tractor. It has the large valves, spark plug over the exhaust, and a #30 carb. I’m only running 3800rpm +/- with a stock flywheel. My very basic changes will be a milled head and timing advanced. I’ve read guys taking .040” or more off there head. It looks like I only have about .015-.020” until I’m into the chamber. Are these guys taking .020” out of the chamber and leaving almost nothing for a gasket ridge at the cooling fins? I have a dial indicator and degree wheel for the timing. Here comes my stupid question....when are the points open? Should I use say a .002” feeler gauge? Would I be better off marking 24* BTDC on the flywheel to align with the bearing plate? I’ve only ever timed with an inductive timing light, so I’m not sure how subjective the old “as the points begin to open” is.

Back to the carb for a second. I’ve gone through it, fixed the slop in the shaft with bushings, new rebuild kit, adjusted the float so it’s just slightly pitched up when the needle is seated, but that is all. I don’t think I need much else for a stock motor. Would the #30 be too big at only 3800rpm? I have a #26 that I could use too.

Obviously this is going to be my first attempt at this. It’s basically a stock tractor. I’ll be pulling against much more experienced folk, so my expectations are quite low. I’ll be happy just to make the events this year and learn to get the tractor to do it’s best with what I have. The next year will hopefully see new tires and some engine work. Refresh the bore, valve job/undercut valves, a bigger cam, ect. I brought my flame suit, so feel free to fire away. I’ll post the rules below.

JSlezak83 03-08-2021 03:00 PM

These are the rules for the class I plan to run in.

1050 LB ECONOMY STOCK TRACTORS
1. Stock wheel base.
2. No seat box.
3. No high torque starters.
4. No electric fuel pumps.
5. Stock air cleaner assembly. (No alterations)
6. No velocity stacks.
7. Stock flywheels only. No cutting, welding, or adding weight.
8. No electronic ignition. Chevy points are allowed.
9. No added spinning weight to the crank.
10. Max tire size 23x10.50x12. No cutting allowed.
11. Stock appearing carb up to 1 inch (no aftermarket carbs)
12. 4000 RPM max. (Zero tolerance)
13. Stock front end in the stock location and must pivot.
14. OEM valve size in stock location.
15. OEM head gasket only.
16. Engines may be replaced up to 14 HP max, 1 cylinder only.
17. Choke must be installed and working.
18. No aluminum wheels must have steel wheels and they can be widened up to 10 inch.
19. Stock head-no LP, no billet heads, and no aftermarket recast heads, and no welding of the stock head.
20. Stock OEM governor set up.
21. Weight is 1050LBS.
22. Must have kill switch.
23. Gas pedal or hand throttle allowed.
24. 13 inch hitch height.
25. Front tires no smaller than 3.50x6, tri ribs permitted.
26. Max cam lift .330
27. Muffler or open exhaust must be vertical +/- 10 degrees.
28. FUEL- VP C12 green in color only!
29. 72 inches overall length from the center on the rear axle to the furthest most point forward including weights.
30. Stock stroke Max 3.25.
31. No piston pop up.
32. Port and polishing allowed.
33. No locked or possi rear ends unless OEM (Pullers responsibility to prove it)
34. Max bore 3.530
35. Flathead engines only, no ohv engines allowed.
36. MANDATORY TEAR DOWN-Every 4 wins, your tractor will be torn down, if you refuse to tear down or are illegal, you will lose your points up until that point, and will not be allowed to compete until you fit the rules. Zero tolerance!!

DRohacek 03-08-2021 05:21 PM

Ok, on the head there is no need to cut it past the gasket ridge. Once you cut much more you will begin to loose flow. Flow is more important to a flat head than compression. Also if you mill too much your valves could hit the head. So then you have to cut over the valves. Then you begin to loose what you did by milling. So You can angle mill the head also. In other words have it milled more over the bore area than over the valves to keep more room for flow over and around the valves. You rules say your cam must be .330 lift. no limit on duration. That means any serious puller is going to have a reground cam that is still .330 lift but with more duration and different lobe separation etc. You need something like this. https://vogelmanufacturing.com/singl...ange.html.html
Notice that the cam specs are V338-245/338-238-3 That means once you have set your lash at .008 you will still be only .330 lift. Trust me when I say you need a cam like this. Most everything else is experience, and preparation for the stock class. Also you can advance your ignition timing by opening your points .022-.024 Good luck

JSlezak83 05-24-2021 12:49 PM

Well the first event came and went this past weekend. I didn’t have the tractor ready, but I went and observed. Spoke to a few people and have a slightly better idea of what I’m getting into. I was advised to start in the beginners class, which best I can tell is all about 6-8 year old children. Should be pretty embarrassing getting my tail handed to me.

I had the local machine shop take the the head down to the chamber. I never bothered to actually measure how much that was. Like a dummy I had an incorrect spark plug with a longer reach and the exhaust valve closed up the gap. I wasted about 20min chasing that. Frustrated and feeling defeated I went in for dinner, only to find today that I left the key on overnight. At the minimum I drained the battery. I suspect I’ll be doing new points and a coil in the near future.

This week I hope to get a hitch put together, wheelie bars, and a shifter lock. I also need to strengthen the clutch hanger as most of my pedal travel goes to flexing that. The next pull is on June 26, so I need to scrounge up some weight for this thing and get things in order.

JSlezak83 10-24-2021 11:04 AM

1 Attachment(s)
Summer flew by and any progress on the tractor was pretty slow. The original tires were just too dry rotted, so I replaced them with 23x10.5-12 Kenda Turf Boss in the rear and Deestone 3.50-8 tri ribs in the front. I have Zack Kerber wheelie bars and weight box.

I finally made it to the last pull of the year yesterday. I pulled in the 1000lb Bone Stock class with a 3600rpm and 2.5mph limit. I weighed in at only 890lbs, so I wasn’t expecting to be very competitive. My draw bar is about 4.5” behind the axle center line and was 13” high. No load RPM was around 3550. The track was hard packed. First pull was only 65’. At about 25’ The front lifted a bit, so I think the tires finally bit. I leaned forward and it settled back down. Looking back, maybe I should have just let it ride, the wheelie bars never touched the ground. I never really tuned the carb, so after the pull I checked spark plug. It was sooty, so I leaned it out about 1/8th turn.

After all the other classes ran, the track was back bladed and even more hard packed. I dropped the tire pressure to 4.5psi and went 69’ this time. The front never lifted on this pull, and I only hit 1.5mph. Clearly I’m lacking traction. My carb adjustment got the plug looking just a little richer than tan. Another puller suggested that I should have increased the tire pressure for the harder surface, but that seemed counterintuitive to me.

I’m happy to have finally made it to a pull. I’ve got myself a starting point, but now I’ll have to wait 6 months until the next pull. Over the winter I’ve got to source more weight. I’ll get a mid weight rack, and something for the front. I also need to rebuild the steering box. I’ve got about 1/2 turn of play in either direction. Even with the front wheels on the ground, it was easier to just steer with body weight. The spindles are also sloppy, so I may see about sleeving the front axle.

I think for next season I will continue pulling in the 1000lb Bone Stock class. Once I get the weight dialed in I may see about a 13T pinion if my ground speed doesn’t pick up. When revving the motor, I’d notice a bit of smoke. During both pulls I didn’t notice any. In all the excitement, I definitely had some tunnel vision. Hopefully someone posts some pics to the clubs ******** page so I can see. I’ve thought about freshening the motor with new rings, a valve job and maybe a bowl blend in the ports, but I have plenty of power at this point with the stock K321. I need to focus on using the power I’ve got.

This has turned into a pretty long winded post. I can’t wait to get out again next year.


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