Track Warrior 850 WOT jetting

[jmarkaudio]

Try a crossover vent tube between the vents, 90 degree spark plug boots with a tube between them. Drill holes from several angles thru the tube, see if that affect the AFR.

[Duh]

I can try that this coming season. Currently I think I have the 950 good enough to start the season. I'm still a bit iffy on the 850 due to fact that it just seems to need alot of fuel. Large jets and a big squirter compared to the 950. Is there any deficiencies in the 850 main body compared to the old 1000HP main body? If I have time I might try an old style 850 that I need to repair.

[Duh]

So I finally got around to working on the Track Warrior 850 again. Make a long story short after changing it around a bunch aways from metering blocks to boosters I believe I figured it out. The new aluminum main body is just plain junk. I found some pictures of an old 1.56 HP main body and it is different. The big difference is the distance that the venturi starts to tapper in. The new housing starts much lower making the entrance into the venturi less tapered and more bull nosed. That is the only thing I can figure out. If I get my hands on an old zink 1.56 HP main body I will try it.

[rgalajda]

[Duh]

Brawler is a BR-67302.

The smallish jests in the 80496 950 might be from the unknown metering blocks. They were not the HP blocks, just a zink block with a three stack emulsion. If I recall correctly they were .028. It ran very rich at first especially at transition so I plugged the centers and than helped a lot. I then swapped those blocks out for some blocks from an 850, it ran exactly the same. I'm happy with the smaller jet.

I think the 750 ran well down low was due to the fuel coming from the booster quicker due to good signal. Fuel from the accelerator circuit doesn't atomize as well. Just my opinion.

The thing is the 850 track warrior just takes so much jet and squirter to make it run properly at WOT. Otherwise it drives well. It actually has good idle and part throttle. I just don't understand why it needs so much compared to my old 80513 and 4781. The last test I did with the 850 TW I had 50cc front and back with 45 squirter and 79 with PV / 87 no PV with a annular booster, going WOT AFR went to 14.0 and held steady, way lean. I upped the jests to 83/91 and it went to 13.7 lean. At that point it was useless to go any further as I was running out of time. I quickly threw on my old (27yrs) 4781 that I just put back together. It had 83/91 jetting with stock press in air bleeds and 42 squirter. At WOT it ran great, a bit rich at 11.0. The 80513 that I no longer have on a motor making about 50hp more than this motor only needed 84/92. This is why I am thinking the 850 TW is not right, it just shouldn't need so much jet.

[Duh]

So I bought a Pro-form 1050 main body (1.56).
I put 83/91 jets just like the Holley with annular. I left the air bleeds just like I received it, 28/73. WOT was good at 12.9. Cruise was a bit leaner than I like. I think I just need to make the high speed air bleed 25 and some minor jet changes to make it right.