Jetting

[project9]

Could anyone please advise how best to jet a Husky Cr500 1983?

 

[project9]

Thanks for the info Steve.
No I do not want to sell it yet as I have only just bought it, but I have been having trouble starting it,I shall fit new jets and see if that helps.
Ian

 

[Leftcoast leftkicker]

Project9- I restored & raced an '82.5 (see the pic at top of this site) and would suggest that since yours comes with a 40mm round slide Mikuni, virtually everybody dropped them for 38mm. You'll get easier starting (very important with the kick shaft gear train) and more low end. You can make it even easier to start by lowering the compression (mill the dome in the head).
- the jetting specs I have for the 40mm are:

82.5 500 Stock 82.5 MXA 83 stock 83 MXA
44mm 40mm 40mm
Slide 2.0 3.0 2.0 2.5

Needle 7DH3 7DH3 6F7

Clip 3rd 4th

Needle jet BB-5 BB-0 AA-5 BB-0

Main jet 400 480 340 400

Pilot 35 30 45 45

Air Screw 1.5

Air jet 0.7

Hope this helps

 

[HuskyT]

LeftCoast do you have any recomendations for jetting for a 1980 CR390?

Have thought about doing the 420 conversion ( husky bulletin 8-077)

Do you have any opinions or recomendations?

Go to a flat slide?

This is my first 390 / My rebuild motor appears to be at 1st oversize.

I'm in Corona, Ca

T

 

[Leftcoast leftkicker]

'80 390

That was the motor of doom! Only thing it needs (other than cleaning up the ports) is a pipe, don't run the crappy stock or after market- find or beg George Erl for one of his.

Are you running it in a '78 frame or the '80?

I wouldn't spend extra $ on f/s, run the stock 38mm Mikuni. See jetting info below, only change I'd make would be to a 3.0 slide:

78 390 CR
38mm Stock 80 MXA
Slide 2.0

Needle 6DH3 6F15

Clip 4th tbd

Needle jet Q-8 R-0

Main jet 430 480

Pilot 45 50

Air Screw 1.5 tbd

Air jet 2.0 -

 

[HuskyT]

That was the motor of doom! Only thing it needs (other than cleaning up the ports) is a pipe, don't run the crappy stock or after market- find or beg George Erl for one of his.

Are you running it in a '78 frame or the '80?

I wouldn't spend extra $ on f/s, run the stock 38mm Mikuni. See jetting info below, only change I'd make would be to a 3.0 slide:

78 390 CR
38mm Stock 80 MXA
Slide 2.0

Needle 6DH3 6F15

Clip 4th tbd

Needle jet Q-8 R-0

Main jet 430 480

Pilot 45 50

Air Screw 1.5 tbd

Air jet 2.0 -

My MM frame is a late in the model year CR 1979 that has the 1980 style MN rear CR subframe if you will. Kind of a Hybrid of sorts. I am assuming that this was late in 79's model year and they were starting to experiment with the new rear frame style. I am also running the longer 1980 swingarm off of a OR ( solid brake stay) . I have 40 mm forks off of a 83 CR500 (front DLS 83 wheel and brakes) that are going on it as well. Also using a 82/83 18" rear wheel and hub. I intend to race this bike. It will not be a garage queen so I am looking for the best on track changes/advice/tech tips out there.

I do not have a pipe..... yet.....IS THE VINTAGE IRON PIPE NOT WORTHWHILE? I'm hear to listen to your experience and judgement.

A lot of people claim that the 1980 was the best 390 motor.....?has the thickest amount for overbore sizes etc... Why "motor of doom" is there something to watch for?

I had a 83 YZ 490 that I increased the slide on. 3.0 to 3.5. Made it start a hell of a lot easier and run cleaner.... better bottom end as well.... do I expect the same thing with the 390 Husky?

IS the 80 MXA the recommendation from the 1980 Motocross action mag?

It is very similar to what I found with Procircuit

"Jetting for 250/390 CR 1980 ProCircuit
Here is the reccomended jetting for the 1980 250/390 CR from ProCircuit for Southern California elevation 0 to 3000 ft

Pro Circuit knew Huskys back in the day information is a direct quote from ProCircuit

250 CR Husky 1980
38 mm Mikuni Round slide
Stock Needle 6DH3 change to 6F15
Stock Main jet 430 change to 480
Stock R2 Needle Jet change to R0 or Q8
Go to a 60 Pilot
These changes from the stock factory bike will result in cleaning up the bottom end and make the top end a lot fatter.

390 CR Husky 1980
38mm Mikuni Round Slide
all the same changes but go with a 50 Pilot"

Thanks for the help and advice. I appreciate further input.

Thanks, T

 

[Leftcoast leftkicker]

390

Your frame & suspension mods sounds great, should be no problems there.

By "motor of doom" I meant that it rocks big time! Light, fast, broad power band, everything except primary kick start. Be sure to add 1-2T on the rear sprocket with 12T c/s.

No knock on the VI pipe but it's a copy of the stock thru-frame pipe although it is lighter than stock. An Up-Tite pipe is in another universe!

Yes, the 3.0 slide makes it easier to start and run crisper in the bottom 1/3rd.

 

[Coffee]

When I was at Uptite a while back there were many things on the wall such as exhaust systems that appeared to be intended for older bikes. Can't find the phone number right now but think you already have it.

 

[HuskyT]

Your frame & suspension mods sounds great, should be no problems there.

By "motor of doom" I meant that it rocks big time! Light, fast, broad power band, everything except primary kick start. Be sure to add 1-2T on the rear sprocket with 12T c/s.

No knock on the VI pipe but it's a copy of the stock thru-frame pipe although it is lighter than stock. An Up-Tite pipe is in another universe!

Yes, the 3.0 slide makes it easier to start and run crisper in the bottom 1/3rd.

What do you reccomend for a rear sprocket.... I have been told to run a 55 T rear .... do you concur? I am going ot have Sprocket Specialists make me a brand new aluminum one. Also for the 82 /83 hub I have found that you can either use a straight sprocket flange head sprocket bolt our a tapered "V" under the head /chamfer in the sprocket. WHich do you reccomend and why? I currently have good Bufo bolts straight flange head but am thinking the taper/countersink ( more modern style) may be the better way to go. Did 390's tend to torque off the sprocket bolts... in either case I would loctite.....

T

 

[Leftcoast leftkicker]

390 ?'s

Husky T- 12/53 or 13/56 work best for moto depending on track type. I use counter-sunk bolts on my '82 hub/sprocket and once they're seated in (with Locktite) they never loosen.

Coffee- George Erl's number is 714-540-2920, located 111 W. Dyer Rd., Santa Ana 92707.

Huskydoggg- what carb, jetting, pre-mix, plug and gear combo are you running? The stock 38mm Mikuni should have come jetted with 440 main, Q-8 needle jet, 6DH3 needle w/clip in #4 slot, 45 pilot, 1.5 turns on air screw, 2.0 air jet and 2.0 slide. Timing was 2.2mm BTDC. Compression should be 11.1:1. Hope this helps!

 

[HuskyT]

Husky T- 12/53 or 13/56 work best for moto depending on track type. I use counter-sunk bolts on my '82 hub/sprocket and once they're seated in (with Locktite) they never loosen.

Cahuilla Creek MX Main and Glen Helen are the primary tracks that I will be riding.... so what combo should I go with? 12/53? If I have a preference I would take power over speed......

Again , thanks for the input!

T

 

[Leftcoast leftkicker]

390 gearing

I'd try them both. The 6 speed is set up so that 1-5 are closer than 2-6 so if you run taller gearing (13/55) you'll end up using the higher gears overall, like in a GP.

 

[project9]

Project9- I restored & raced an '82.5 (see the pic at top of this site) and would suggest that since yours comes with a 40mm round slide Mikuni, virtually everybody dropped them for 38mm. You'll get easier starting (very important with the kick shaft gear train) and more low end. You can make it even easier to start by lowering the compression (mill the dome in the head).
- the jetting specs I have for the 40mm are:

82.5 500 Stock 82.5 MXA 83 stock 83 MXA
44mm 40mm 40mm
Slide 2.0 3.0 2.0 2.5

Needle 7DH3 7DH3 6F7

Clip 3rd 4th

Needle jet BB-5 BB-0 AA-5 BB-0

Main jet 400 480 340 400

Pilot 35 30 45 45

Air Screw 1.5

Air jet 0.7

Hope this helps

Thanks

Thanks for the info.

Ian

 

[Picklito]

Huskydoggg,
I'm concerned that you have a problem other than main jet size... or, you're way too lean. I found the stock jetting rich everywhere, but lean on the main (for extended WOT). I had to lean out everything but go richer on the main. Ended up with 45 pilot, 3.0 slide, 6DH3 needle in middle clip, and a 480 main. This was sea level, so yours might need to be a touch leaner, but should give you some comparison.

I found the bike sensitive to spark plug gap. If too big it would not rev out. Run it at .024" and no more. Are you SURE there is no restriction in the silencer/spark arrestor? No two-year-olds running around, stuffing toys into the exhaust when you aren't looking? (actually happened). Hope this helps.

 

[plesh490]

1980 390 to 420 conversion

That was the motor of doom! Only thing it needs (other than cleaning up the ports) is a pipe, don't run the crappy stock or after market- find or beg George Erl for one of his.

Are you running it in a '78 frame or the '80?

I wouldn't spend extra $ on f/s, run the stock 38mm Mikuni. See jetting info below, only change I'd make would be to a 3.0 slide:

78 390 CR
38mm Stock 80 MXA
Slide 2.0

Needle 6DH3 6F15

Clip 4th tbd

Needle jet Q-8 R-0

Main jet 430 480

Pilot 45 50

Air Screw 1.5 tbd

Air jet 2.0 -

Hey guys. This is my first post so i hope that it works out. I have 2 1980 420's. They are wicked bad. They make my 81 Maico 490 seem tame. With out a doubt the best motor husky ever built. 430's are short shifters and vibrate a lot. 500's rev out even less and vibrate more. The 420 motor will put the boots to either one of them in my experience. A stock pipe will work just fine. I run one on 1 of my 420's, and an Asche/Uptite pipe on the other. Both bikes are scary fast at any rpm, and they absolutley scream when you turn em loose. I have riden them all, and the 420 motor is the best IMO. A 390 is a very powerful bike by anyones standards, and they are very underated, but the 420 will make you feel like a little school girl. When i have time I will post some pics. One bike is a factory ProCircuit bike from back in the day. The other is a 420 conversion that i did myself. Both rock.

My jetting recommendations are as follows for 2500 ft, but will definitely be in the ballpark whever you are at.

480 main
2.5 slide (3.0 is too crisp) Husky's like to run a bit rich
40 pilot
2.0 air jet (inside of bell at the back of the carb)
R2 needle jet
6DH3 needle jet

14 counter
56 rear

Watch out bud! Your arms are gonna be longer when you get off this beast.

Take care guys - awesome forum.

 

[schimmelaw]

Phlesh490,

Please, please and pretty please post photos of your ProCircut 420. Have the same bike and would love to see what you are working w/. Thanks in advance.

Asche/Uptite pipes still available? Want/need something other than the stocker.

Rick

 

[hawaii-rider]

Engineer Head and research

I have my Miss Ten Fins down to the frame and have been checking/researching and digging for any info I can find.
Well so happens I have the Dirt Rider Magazine where they test the 500XC.
So, in there that was a sidebar from these two really pitifully slow guys, some "Husky unknowns" named Dan Smith and Dan Ashcraft....


that had their set up tips for racing etc.
here is the scan of that wonderful old 25+ year Old Dirt Rider magazine.
In there is precise Jetting, front legs set up and other items...

I have it in PDF as well

HR

:usa:

 

[schimmelaw]

Hawaii,

Any litature for a 81-82 430? Anyways - cool stuff. I like reading material on the old Huskys - black and white print no less. Brings back floods of memories. Post more!

Rick

 

[hawaii-rider]

Hawaii,

Any litature for a 81-82 430? ............
Rick

I will dig, if I find anything I will scan and post.

I do love the riding gear of the period...
OMG

 

[hawaii-rider]

Heres one....

here is a test/review on a 430

PDF

HR

:usa: