Husaberg
Go Back   Husaberg Forum > Mechanical and Technical > Fuel

Fuel Fuel Delivery


Reply
 
LinkBack Thread Tools Display Modes
September 9th, 2007, 01:53 PM   #1
Senior Member
 
mark550fc's Avatar
 
Joined: Nov 2005
From:

Posts: 159
Thanks: 0

I Ride:
Carb Issue?

What Main jet are you guys using on your 550s?
I have a little hesitation bog when landing and nailing the throttle in third gear. It scarred the you know what out of me last night doing a double and it happened every lap. The track had a table top and when I would land with a short run to a double it bogged on the face each time?

I have the Boysen Quick shot, and fuel squirt adjusted down from two seconds.
The bike did not bog on the start at all so what could this be?

At 4500ft with 82deg temp?

Thanks for your help,
mark550fc is offline  
 
September 9th, 2007, 04:23 PM   #2
Senior Member
 
Joined: Jun 2005
From: San Francisco, CA

Posts: 456
Thanks: 2

I Ride:
RE: Carb Issue?

What PJ and MJ numbers are you currently running?

4500ft has this affect on motors that normally run well close to sea level.
supertireguy is offline  
September 10th, 2007, 12:04 AM   #3
Senior Member
 
Joined: Nov 2001
From: Ely, England

Posts: 16,112
Thanks: 508

I Ride: Husaberg FE501e 2003
RE: Carb Issue?

sounds rich but as supertyreguy says: we need your jetting!

regards

Taffy
Taffy is offline  
September 10th, 2007, 06:29 PM   #4
Senior Member
 
mark550fc's Avatar
 
Joined: Nov 2005
From:

Posts: 159
Thanks: 0

I Ride:
Carb Issue?

I will take it apart this week and get back to you guys as HELP IS NEEDED!
It seemed to be on the money for the start in each race but this issue needs to go or I will loose my confidence/or my life?

Thanks,
mark550fc is offline  
September 11th, 2007, 07:43 AM   #5
Senior Member
 
Joined: Nov 2001
From: Ely, England

Posts: 16,112
Thanks: 508

I Ride: Husaberg FE501e 2003
RE: Carb Issue?

as a race continues an engine needs less and less fuel. if it's at mid revs then it's simple. drop the needle. if you can actually feel something is wrong then it needs to drop between 1-2 times.

regards

Taffy
Taffy is offline  
September 15th, 2007, 02:17 PM   #6
Senior Member
 
mark550fc's Avatar
 
Joined: Nov 2005
From:

Posts: 159
Thanks: 0

I Ride:
Jet Size

I have a 178 main, and needle is 2nd notch from top, with fuel screw at almost two turns out. I think it is a 45?

Taffy or anybody, see a reason for this kind of bog just after landing and nailing the throttle?

I just seen an entire bolt on lower bowl made be R@D to prevent this kind of thing with FCR carbs. It said it has an anti -cavitation area and some other things to prevent bog and provide better throttle responce.

Has anybody purchased one of these units with a report they could give us?

Thanks for any help!
mark550fc is offline  
September 15th, 2007, 03:38 PM   #7
Moderator
 
Joined: Oct 2002
From: Sunland, CA

Posts: 3,117
Thanks: 19

I Ride:
Hi Mark,

You stated at the beginning of this thread that you had the fuel squirt turned down to 2 seconds. Does that mean that you have increased the AP timing gap (see my gallery page 4 for a picture) to achieve this? If this is true this is where you problem is coming from.

The AP timing is critical for those times when you whack the throttle open. The standard adjustment is .100". An alternative method for the bigger motors like ours is to set the slide opening to 1.25mm's, and then set the AP pump rod so that it has no play in it, without depressing the AP diaphragm. The .100" gap is much easier and you don't have to take the carb off the bike! When you bought your quick shot there should have been a little piece of thick construction paper to be used for setting the AP gap, did you use that to set the gap?

The trick is to get the AP to start it's squirt just as the slide is opened but not hit the back of the slide.

There are a couple of ways to limit the squirt to 1 or 2 seconds. One is the BK mod (just do a google search and you'll find it) which requires one to drill the flange of the carb where the dust cover goes and then put a limiting bolt, or stop that goes up to the black AP arm wherein you can adjust the throw of the arm or duration without affecting the initial timing.

The other is to buy a honda diaphragm described in buzzards "$40 FCR spruce up". This will limit squirt time to about 1 second. And is the best method I have found so far in limiting squirt duration, while maintaining correct squirt timing.

If you delay the start of the AP squirt too much you will end up with a lean bog. I have been testing this for some time now to solve a rich stutter problem when just opening the throttle when the motor is good and hot, and found that increasing the gap in 1/4 turn increments did eliminate the rich stutter. However, once the rich stutter was eliminated, there would be a slight hesitation because the fuel squirt was delayed too much. This was anything beyond 1/2 turn, or anything exceeding .115" of gap.

You don't indicate what needle you are using in your post, but, position #2 sounds a bit lean to me if my hunch on which needle you are running is correct, even at 4500'. Please let us know which needle you are using. An easy way to get rid of a an off idle bog when whacking the throttle open is to raise the needle, or lower the clip however you want to phrase it.

You also say that you are using a 45 pilot @ two turns out, correct?

Have you checked your float level lately? Just asking to be sure that all settings are correct so we don't go chasing our tails. Another reason I'm asking this is b/c of your description of the conditions in which it bogs. You say it does it when you land in 3rd and pin it, and you also say that it bogs on the face of the jump. There is an incredible amount of centrifugal force pushing down on everything when you land, and go up the face of a double. This of course has en effect on the fuel in the bowl. That trick little float bowl you are looking at by R&D is $250 bucks, and has an adjustable leak jet. I had thought about buying one myself but have solved my problems without one. But then again I'm not doing the kind of stuff you are either. However, I do ride some pretty gnarly terrain in my desert races and have some pretty severe landings and huge whoop sections and do not experience this kind of bog.

Hope this helps,
DaleEO is offline  
September 15th, 2007, 04:36 PM   #8
Senior Member
 
mark550fc's Avatar
 
Joined: Nov 2005
From:

Posts: 159
Thanks: 0

I Ride:
Fuel Squirt

Thanks Dale
Some of those things have not come to mind recently.
The Mechanic at my dealership set the squirt time as I was walking up to him, so I am not exactly sure what he did? I do know that he said the squirt was to long and it seemed as if he was turning something in the carb to achieve this. The change was visible when he was done.

Is it possible that adjustment could have changed on it"s own ,or the float bowl as well are very good questions?
You have given me some things that no doubt need to be checked, as I completely forget about those at times.

I moved the needle two notches up and went to a 180 main and forgot to check what needle it was and put it back together.
I will pull it apart again in the am if this does not help. Is the #45pilot to small in your thinking since the screw is out two turns?

Thanks for all those notes Dale as it seems there is more to think about!

That R@D part is over priced it seems, but if it keeps you out of the hospital it might really
be cheap?
mark550fc is offline  
September 16th, 2007, 02:16 AM   #9
Senior Member
 
Joined: Nov 2001
From: Ely, England

Posts: 16,112
Thanks: 508

I Ride: Husaberg FE501e 2003
RE: Fuel Squirt

mark

ffs!

you are hopelessly over jetted! you should be withdrawn from the track for criminal intent to waste fuel!

your squirt has nothing to do with your bog first of all. you could turn it off completely and it would still be there!

a 180MJ is way, way over the top. you have a lot of work to do in getting it back down to at tops i would think is a 168MJ and could be even lower. this will lean off the mid rev area which is where you're getting this bog.

the squirt should be reduced to 1-second max and should start from the moment you touch the throttle.

sorry dale but i have this argument with EVERYONE: THERE IS NOTHING WRONG WITH THE SQUIRT HITTING THE SLIDE.

it breaks the fuel up and the air is driving down and under the slide taking the fuel with it. if you waited for the slide to lift high enough before the squirt started you have missed the show!!!! the circus has left town, NASA has been to the moon, come back and had high tea!

what a shame your MX career is being blighted by your own inability to set your jetting.

regards

Taffy
Taffy is offline  
September 16th, 2007, 06:26 AM   #10
Senior Member
 
mark550fc's Avatar
 
Joined: Nov 2005
From:

Posts: 159
Thanks: 0

I Ride:
?

Taffy,
The FC 550 is uncorked and a good deal faster than the FE 550s so will it not want more fuel?
I agree it must be to high and that I am not the best at jetting but it got two holeshots so how bad could it be?
Even though the twostrokes are more finicky I have much better results jetting and you can here the problems better.
Thanks for the schooling guys, as carb work has not been all that easy for me to pick up. I read these post about all the things possible and just think-you guys are very smart-

What about my 45 pilot Taffy at two turns out is it to small?

Thank you

PS: No careers here only trying to file a few more fun memory's
mark550fc is offline  
Reply

  Husaberg Forum > Mechanical and Technical > Fuel

Tags
carb, issue



Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
'02 501 Clutch issue. husaferg Mechanical 5 June 11th, 2012 11:09 AM
clock issue snatch Electrical 0 February 6th, 2011 10:04 AM
Starting Issue DOLLARS Electrical 7 May 16th, 2006 12:33 PM
wheelie issue oyk Mechanical 11 May 7th, 2005 09:45 AM
Carb Issue? mark550fc Mechanical 12 December 31st, 1969 04:00 PM


Facebook Twitter Google+ RSS Feed