hobb-z help

[tblotske]

i have a hobbz 990 kit on my king. looking for some help on this to get it to runn better egt all over the place. some info 900 bottomend trued welded. top end 990 kit. bored carbs 41.5 mm. vforce reeds. cluching i will have toget back to you on that. zr neadles.50 pilots,and main jets 520n. altitude is 1500 ft. air 1turn fuel 1.5 turn.any one with intake mods seams to run out of air at 6000 plus in the mountains. hobb-z has a great kit im just looking for more help to kick a m1000s a$$ hard!

chassie is vanamburg hillclimb 156 16 by 2.5 camo extream premix slp twins pipes with front dump have pics of it in 1m post thanks for any help. troy blotske

[HOBB-Z]

Troy,

I'll post my set up @ 6 - 9,000 ft running Jaws twins@ 8250 RPM
and bored carbs 41.5
20/46 gears

Clutching
Primary
spring, speedwerx ti 160/310
weights, 62 grams ground down from stock 68s with heavy toes they fling like a stock 64

secondary
55/53 or 53 helix with the stock red/white in the middle hole

Jetting
fuel out 1.5 turns, air out 1
ZR needle in the 2nd clip down from top, stock nozzles
620 mains running strait 114 fuel

I realize this info isn't going to work for you but it gives us a base line to tune from.

I'll call you and we can work out the best set up and I'll reply on this thread
what we found.

[HOBB-Z]

Spoke with Troy about his setup, he has made a lot of changes and needs to run them and let us know how they worked.

He changed the air box, it was running out of air

Needs a little more timing +2 key or better yet a flashed CDI

Probe location is the biggest reason for exceeding temps when jetting is spot on, the farther away from the piston the hotter then read

EGT set ups only aid in tuning and should never be counted on

Let us know how it runs when you get a chance

[tblotske]

mike i will be out of town for the next week i have the pics that we talked about and some more info on the set up. i took it out for some grass runnes and it seems to be alot better with just the airbox work. i also e mailed rory on the sno pro timing box he is checking to see how hard that would be to get it to work. i will keep every one posted. troy

[rdr99]

I am running a Speedwerx 1000 reported by T8RZ. Running a 156x2.5 track with 8 tooth 3.0 pitch drivers in a Gen II chassis with 20/43 gearing. Have 500 mains in bored carbs, primary has 140/320 spring with 64g weights, secondary 53 degree helix with Cat R/W spring. Use Jaws 'D' pipes with 33mm choke, 3 degree timing ket with MC CDI. Sled runs great till 7700 rpm then won't pull any more. Ride 5-9000 feet. Piston wash looks good, but at WOT EGTs drop to about 1000 degrees. Am I running out of fuel or too much gearing. I only had a chance to ride the sled in late spring.

[HOBB-Z]

Originally Posted by rdr99

I am running a Speedwerx 1000 reported by T8RZ. Running a 156x2.5 track with 8 tooth 3.0 pitch drivers in a Gen II chassis with 20/43 gearing. Have 500 mains in bored carbs, primary has 140/320 spring with 64g weights, secondary 53 degree helix with Cat R/W spring. Use Jaws 'D' pipes with 33mm choke, 3 degree timing ket with MC CDI. Sled runs great till 7700 rpm then won't pull any more. Ride 5-9000 feet. Piston wash looks good, but at WOT EGTs drop to about 1000 degrees. Am I running out of fuel or too much gearing. I only had a chance to ride the sled in late spring.

I would jet up, its possible its just to rich but I would find out, if that doesn't help I'd open the pipes up to 34mm.

I don't think your gearing is the problem but I like 20/46 gearing much better
for climbing and hill drags.

The D-pipes are 7800 rpm pipes and its very hard to make them work above the rpm they were designed to work at. On the D- pipes I have used, I cut 1" out of the head pipe to get the peak rpm up around 8-8100.

[Richey]

I'm running Mod shop 990 as well in my 02 800.
Here is my setup.

SLP Twins
Pump Gas
+2 degree of timing

Jetting:

I have 41.5 bored carbs.
instead of the ZR needles I have the bigger Q8 nozzles.
Stock Needle middle position.
450 main jets.


Clutching:

Primary:
Arctic Cat Orange White Spring
64 gram weights ground down to 62 gram


Secondary:
Arctic Cat Red White Spring
53 degree Helix


Hopefully that helps a little my jetting is pretty good, but I know I can get some more out of the clutching. That is what I'm going to focus on this year.

[HOBB-Z]

Originally Posted by Richey

I'm running Mod shop 990 as well in my 02 800.
Here is my setup.

SLP Twins
Pump Gas
+2 degree of timing

Jetting:

I have 41.5 bored carbs.
instead of the ZR needles I have the bigger Q8 nozzles.
Stock Needle middle position.
450 main jets.


Clutching:

Primary:
Arctic Cat Orange White Spring
64 gram weights ground down to 62 gram


Secondary:
Arctic Cat Red White Spring
53 degree Helix


Hopefully that helps a little my jetting is pretty good, but I know I can get some more out of the clutching. That is what I'm going to focus on this year.

Thanks Paul

For some reason I thought you were running more main jet, its got to be spot on. I guess its also possible the bigger nozzle is adding on the top as well.

[rdr99]

Great info here. Something I just noticeid on my primary clutch. I pulled it off to clean it and send it out to be balanced. The spring was stuck in the cover and spider, had to pull on it pretty good to get it out. Wonder if part of my problem was spring bind? I thought that the Polaris and Cat springs were interchangable?

[HOBB-Z]

Originally Posted by rdr99

Great info here. Something I just noticeid on my primary clutch. I pulled it off to clean it and send it out to be balanced. The spring was stuck in the cover and spider, had to pull on it pretty good to get it out. Wonder if part of my problem was spring bind? I thought that the Polaris and Cat springs were interchangable?

They are but the o/d of the cup on the spider and the cover is a little tight, I grind a tiny bit on both and buff all the paint off the springs as well.

Primary spring bind is a big problem that usually results in the spring breaking..

Glad you noticed and brought it up, these are little things I've done over the years and just kinda forget about till its brought up or I'm in the middle of fixing..