39mm PWK Pilot jet question

[HrcRacing]

I was just wondering what pilot jet you guys at sea level are running on your 38/39mm PWK's.

I bought my PWK from SH so I'm assuming it's a 55, but I didn't take the bowl off before installing it.

So, what are you guys using? Also, will a lean/rich pilot jet effect the starting and, if so, in what way?

Thanks!

[100hp honda]

you didnt see what was in there before you installed it on the bike ?? i used 45 and 48 in phoenix and glamis (1200' roughly in phoenix)

[AlisoBob]

Service Honda does not jet the bike to perform, they jet it so once it leaves the shop, it dosent squeek and come back.

55 is WAY rich on a pwk, even at lower elevations.

I run 40, 42 at lower elevations. I have even ran a 38 at Jawbone Canyon in the summer.

Rich bikes are as hard to start as lean ones sometimes. If you need the crack the throttle to make it start, its probably rich....

When your pilot is correct, the bike should start in 3 kicks max, with the choke on, and idle smoothly. Once a little heat gets i nthe motor, the choke should be shut off, and still idle.

The air screw should be about 1.5 turns out.

If its nothing like this, your set up is way off.

[mega491]

Subject:
91 CR500 in Gen III 250R Frame
Pro Circuit Platinum W 304 Silencer
Mild Porting-Much Polishing
50/50 ERC 110 Octane and Chevron 92
96 250 ECM with stock CR 500 timing, flywheel, stator.
38 Quadvent Air Striker---50' to 600' elevation
35 Pilot
Air Screw - to taste
1466J (DEG) Needle-Middle-ish
168 Main
7 Slide

Although the pilot seems small it is what it took to clean up the "off idle" stumble it had. This thing starts in 1 or 2 kicks and comes on real hard at the crack of the throttle through top end end without detonation and idles down immedaitely at throttle close, runs/idles very "crisp". So much so that a buddy (expert MXer), who is a previous CR 500 rider/racer and now rides/races a CR450F rode it in an open area (field) at a local track last Saturday and thinking it would be safe to wait until he was in 4th gear to open it up, looped it out, it wasn't pretty. Its fixed now though, can't say the same for him, he'll heal up with time.

[100hp honda]

If you need the crack the throttle to make it start, its probably rich

yep. happened on my pwk. had to crack throttle to start, wouldnt idle unless you held the grip part way open....pilot was 5 sizes to big

[HrcRacing]

Yeah, I definitely should have checked it and will the next time I do the filter.

I'm at about 100' and want to be safe with it, would you run a 42 or 45 and say close enough? It doesn't blubber at all off idle, just a bitch to start.

Thanks for all the replies.

PS: I've noticed that it idles way up on the choke, not sure if that points to a problem though.

[redrocket190]

I am still running a 55 pilot, but I have the air screw 2 turns out. I think Bob's is about 1/4 turn out....

[Mad Dog]

I'd order a bunch of assorted, start with a 45 and go from there.

Currently running a 42 in a 38, a 45 in a 39.

[HrcRacing]

Cool. I'll check to see what's in there now and start at a 45 then.

Thanks for all the advice.

Ok, I bought some jets after talking to John at Sudco who said to start with a 52 pilot (must be the humidity in Florida).

Some issues I'm still having:

1. Bitch to start cold. Doesn't really try to start until I turn the choke off. I don't recall any of my 500's starting chokeless when cold (hotter than hell in my garage though so not really "cold").

2. Backfired once before starting.

3. I have to turn the idle screw almost all the way in (2 1/2 turns from bottomed) before the bike will idle but it will idle.

4. On a positive note, the bike smoothed out at 1 1/4 turn on the A/S and it starts first kick when hot.

Anything to worry about or close enough?

[M.F.D.B.]

Ok, I bought some jets after talking to John at Sudco who said to start with a 52 pilot (must be the humidity in Florida).

Humidity will only replace available o2 causing a richening effect.

1. Bitch to start cold. Doesn't really try to start until I turn the choke off. I don't recall any of my 500's starting chokeless when cold (hotter than hell in my garage though so not really "cold").

Chokeless means super rich.

2. Backfired once before starting.

Normal...

3. I have to turn the idle screw almost all the way in (2 1/2 turns from bottomed) before the bike will idle but it will idle.

Also a sign of being too rich, but most, including mine need TONS of idle screw no matter the jetting. You can buy a larger slide if you want. Im too cheap...

4. On a positive note, the bike smoothed out at 1 1/4 turn on the A/S and it starts first kick when hot.

Thats right in the "meat" of the adjustment, sounds like your hard starting could be another issue. Such as:

Low compression
Fouled Plug
Mangina Leg
Reeds
etc.

Anything to worry about or close enough?

My bike, as well as ALL the hundy's ive tuned have always been first kick starters no matter the conditions. Even a not so well tuned bike will start in 1-3 kicks. But that is only on a MECHANICALLY SOUND machine.

[Travis]

"Mangina Leg" That is funny

[HrcRacing]

Ok, I bought some jets after talking to John at Sudco who said to start with a 52 pilot (must be the humidity in Florida).

Humidity will only replace available o2 causing a richening effect.

1. Bitch to start cold. Doesn't really try to start until I turn the choke off. I don't recall any of my 500's starting chokeless when cold (hotter than hell in my garage though so not really "cold").

Chokeless means super rich.

2. Backfired once before starting.

Normal...

3. I have to turn the idle screw almost all the way in (2 1/2 turns from bottomed) before the bike will idle but it will idle.

Also a sign of being too rich, but most, including mine need TONS of idle screw no matter the jetting. You can buy a larger slide if you want. Im too cheap...

4. On a positive note, the bike smoothed out at 1 1/4 turn on the A/S and it starts first kick when hot.

Thats right in the "meat" of the adjustment, sounds like your hard starting could be another issue. Such as:

Low compression
Fouled Plug
Mangina Leg
Reeds
etc.

Anything to worry about or close enough?

My bike, as well as ALL the hundy's ive tuned have always been first kick starters no matter the conditions. Even a not so well tuned bike will start in 1-3 kicks. But that is only on a MECHANICALLY SOUND machine.

I should have mentioned that this is a new (not rebuilt) engine with under 2 hours time on it. The carb is new too and came with a 55 pilot.

So, no low compression, fouled plug or reeds and definitely, not, "Mangina Leg".

I bought a 48 and a 50 too and will give them a try over the weekend.

I'll double check the A/S too as I might have screwed up on that since everything else points towards it still being rich.

[M.F.D.B.]

I should have mentioned that this is a new (not rebuilt) engine with under 2 hours time on it. So, no low compression

Dont say that, I have smoked a new top end in under 5 minutes!! 48 on a PWK is what im running but my bike really likes to run rich. Prolly from the compression...(i run a 200 main at the dunes)

[HrcRacing]

I should have mentioned that this is a new (not rebuilt) engine with under 2 hours time on it. So, no low compression

Dont say that, I have smoked a new top end in under 5 minutes!! 48 on a PWK is what im running but my bike really likes to run rich. Prolly from the compression...(i run a 200 main at the dunes)

What elevation are you at? I'm basically at sea level to maybe 100' or so in flat ass Florida.

[M.F.D.B.]

What elevation are you at? I'm basically at sea level to maybe 100' or so in flat ass Florida.

Vegas, 2300 ft., but when I run the 200 main its at Dumont, about 800 ft.

[HrcRacing]

Cool. I'll start off with the 48 in mine then and see what I get with the A/S, how it idles, etc.

Thanks for your input man.

[M.F.D.B.]

Cool. I'll start off with the 48 in mine then and see what I get with the A/S, how it idles, etc.

Thanks for your input man.

No prob man, thats what we r here for...

[HrcRacing]

I put the 48 in there today and it started, choke on, first kick!

I adjusted the A/S in until it was just about bottomed before it died but it seemed to smooth out around 1 turn, maybe a tad more.

On that subject, are you just going by ear on the A/S or using a tach?

[AlisoBob]

On that subject, are you just going by ear on the A/S or using a tach?

Neither..... buy this and reach dont and adjust it throughout the day to where it runs best.....

http://www.ziptyracing.com/products/pro ... d=MTEwMA==

[dannygraves]

when my pwk39.5 was in my sicky gnar gnars dunes bike jetted for dumont, I was running a 58 pilot, DGN 5th clip and a 188 main. I put that same carb on my gen-4 and didn't change anything becasue I was going to fine tune.
The gen-4 is a stock '90 motor with the pwk and fmf gnarly. She was blubbering all over. ended up with a 45 pilot, dgn 3rd, 170 main and actually both the pilot and main are too rich. I run 44:1 927 and this was all at 2500' and about 90* 0 humidity.
I'm running 2 1/2 turns out on the air screw to get rid of the blubbering and she blubbers a tad when I open her up, so really a 168 main and 42 pilot would probably be spot on.

[dannygraves]

On that subject, are you just going by ear on the A/S or using a tach?

Neither..... buy this and reach dont and adjust it throughout the day to where it runs best.....

http://www.ziptyracing.com/products/pro ... d=MTEwMA==

bobber, I need like 3 of those STAT! how about a web site discount??? since you are a walking advertisement for them anyway

[dannygraves]

do they have one for the mikuni?

[AlisoBob]

do they have one for the mikuni?

http://www.ziptyracing.com/products/pro ... d=MTA5OA==

I've hit them up, they say they have little markup in their stuff, no discounts...

[dannygraves]

aaawwwww

[dannygraves]

well, next check, I think I may need to get one of each and the fork bleeders