Husaberg
Go Back   Husaberg Forum > Mechanical and Technical > Mechanical

Mechanical Mechanical Forum - spinning bits and gyrating bobs


Thanks Tree3Thanks
Reply
 
LinkBack Thread Tools Display Modes
April 17th, 2019, 05:46 PM   #11
Junior Member
 
Joined: Jan 2019
From: Usa

Posts: 19
Thanks: 2

I Ride: 99 ZRX1100, 06 FE450e; previously 05 EX500, 81 kz550, 07 KLX250S, 93 KDX200, 92 KLR250
What would happen if air was leaking into the carb intake from between the carb and the intake funnel? Wouldn't that bypass the idle circuit, lean out my mixture, and cause my problem? I see there is an o-ring at that joint.

I ask because I squirted a quick burst of starting fluid at the intake side of the exhaust with the bike running on choke, and the revs went up. The starting fluid was getting into the carb somewhere there, and my intake boot was tight. I see there is a gasket between the carb and intake funnel.

Now I need to make a short Allen wrench to remove the intake funnel to investigate...

Also noticed a nice little puddle of fork oil under my left fork leg tonight. Seals next. This thing was NOT well loved.
Kawestonltd is offline  
 
April 17th, 2019, 11:00 PM   #12
Member
 
Joined: Jan 2007
From: Fayence, France

Posts: 95
Thanks: 7

I Ride:
Probably irrelevant, but maybe worth noting my experience on a KTM LC4 some years ago showing similar symptoms. All the tail-chasing finally stopped with the consideration that the carb was worn and a substantial volume of air could simply run around the slide (it had a Dellorto) giving a lean mixture when at idle or small throttle openings.

Replacing the carb was outside of my budget, so I bored out the carb, made and fitted a brass sleeve, then bored it to match the slide. Problem solved.

Cheers... Paul
tinwelp is offline  
April 17th, 2019, 11:48 PM   #13
Senior Member
 
Joined: Nov 2001
From: Ely, England

Posts: 15,548
Thanks: 419

I Ride: Husaberg FE501e 2003
Originally Posted by tinwelp View Post
Probably irrelevant, but maybe worth noting my experience on a KTM LC4 some years ago showing similar symptoms. All the tail-chasing finally stopped with the consideration that the carb was worn and a substantial volume of air could simply run around the slide (it had a Dellorto) giving a lean mixture when at idle or small throttle openings.

Replacing the carb was outside of my budget, so I bored out the carb, made and fitted a brass sleeve, then bored it to match the slide. Problem solved.

Cheers... Paul
wow!

quality!

if you use a Pilot Air Screw, it sits higher than the plastic inlet trumpet (who's real name is the AIR FILTER ADAPTER or AFA) and literally lifts the AFA off the carb. but it isn't a problem with a normal PAJ.

the thing is, you should be able to jet the carb to compensate for a carb problem. every setting is achievable.

note what i would do (once more)

Taffy
Taffy is offline  
April 18th, 2019, 06:20 AM   #14
Senior Member
 
fe600racer's Avatar
 
Joined: Jun 2004
From: australia

Posts: 366
Thanks: 13

I Ride:
Taffy

This is a hard one.....let us know when you work it out?

They all have the same problem....so how can that be.....what is common....kokosan has been good if it was sem then that could easily have been it on all bikes.....bad fuel can happen and that is a common factor?

Valve seals? Crankcase seals?.....oil getting in would do it as the fuel from idle could be overwhelmed by oil.....lean from oil not air? Plug readings using unleaded fuel hard but any signs of oil?

With all the work and checking you've done the only common factor is the fuel! I hate empting the tank and putting in fresh 98 ron only to find it is not the problem but it's the only common factor?
fe600racer is offline  
April 18th, 2019, 03:03 PM   #15
Junior Member
 
Joined: Jan 2019
From: Usa

Posts: 19
Thanks: 2

I Ride: 99 ZRX1100, 06 FE450e; previously 05 EX500, 81 kz550, 07 KLX250S, 93 KDX200, 92 KLR250
Thanks for all of the theories and suggestions. Didn't expect this much from resurrection of an old post.

I agree that the jetting could be tuned to compensate for a lean mixture caused by air getting in where it shouldn't. If it wasn't possible, nobody would install pod filters or velocity stacks on their carbs (for the street, obviously). But in the absence of extra jets kicking around, I'll spend some more time trying to seal up the leak. I've ordered the rubber ring between the intake funnel and carb, and will see how that goes. Didn't have that laying around either, so should have added some jets to the order!

I'm not understanding how a pilot air screw would hold the intake funnel off the carb, or why that would be acceptable or work, but if you've seen it you've seen it.

The ignition theory is interesting, but scary. I believe Taffy's videos on ignition timing are on a model older than mine, and do not apply to my 2006.
Kawestonltd is offline  
April 18th, 2019, 11:41 PM   #16
Senior Member
 
Joined: Nov 2001
From: Ely, England

Posts: 15,548
Thanks: 419

I Ride: Husaberg FE501e 2003
Originally Posted by Kawestonltd View Post
I'm not understanding how a pilot air screw would hold the intake funnel off the carb, or why that would be acceptable or work, but if you've seen it you've seen it.
I'm on about the alloy air filter adapter and not the plastic ones. I reckon sudco get them made in the USA? they aren't from Japan and I don't think the English end has the mental capacity to wipe his own arse let alone make them so I gies they're made in the land of apple pie and fake news.

the PAS sits about 1-2mm proud of the carb and so the alloy AFA's can't sit down and crush the O ring you talk of. it might also be true of the factory plastic AFA but i can't recall now.

but this isn't a problem on the standard bike.

Taffy
Taffy is offline  
April 19th, 2019, 08:45 AM   #17
Junior Member
 
Joined: Jan 2019
From: Usa

Posts: 19
Thanks: 2

I Ride: 99 ZRX1100, 06 FE450e; previously 05 EX500, 81 kz550, 07 KLX250S, 93 KDX200, 92 KLR250
Originally Posted by Taffy View Post
I'm on about the alloy air filter adapter and not the plastic ones. I reckon sudco get them made in the USA? they aren't from Japan and I don't think the English end has the mental capacity to wipe his own arse let alone make them so I gies they're made in the land of apple pie and fake news.

the PAS sits about 1-2mm proud of the carb and so the alloy AFA's can't sit down and crush the O ring you talk of. it might also be true of the factory plastic AFA but i can't recall now.

but this isn't a problem on the standard bike.

Taffy
Good. I've got a standard bike, so shouldn't be a problem. The rubber seal doesn't seem to be treated as a necessity based on the standard FCR MX exploded view not including it, rather it shows up when shopping adapters. Sudco's catalog even states "** Highly recommended for Off-Road and RAM Air applications." Not a must?

I reckon you're not sure where those poor adapters are made, but would be happy to take a swipe at the US. We're not perfect, but one of the best when we don't clamor after repeating Europe's mistakes.
Kawestonltd is offline  
April 19th, 2019, 03:35 PM   #18
Senior Member
 
tourist's Avatar
 
Joined: Nov 2012
From: Iceland

Posts: 2,361
Thanks: 793

I Ride: 1 Berg, 1 Zook
I don’t have much faith in the theory that a worn-out carb can be compensated for with jetting. It seems to me that, say, a mechanically loose slide is conductive to chaotic airflow - it probably passes more air or less air from moment to moment as it shifts around.

There are many stories of regret over time wasted on a worn-out FCR carb on Thumpertalk.

It’s easy to control for this variable: Get a new and known-good carb. Swap the poorly idling bike’s jets into it. Put it in the poorly idling bike. Test.
tourist is offline  
April 19th, 2019, 05:02 PM   #19
Junior Member
 
Joined: Jan 2019
From: Usa

Posts: 19
Thanks: 2

I Ride: 99 ZRX1100, 06 FE450e; previously 05 EX500, 81 kz550, 07 KLX250S, 93 KDX200, 92 KLR250
I agree with Taffy saying "any setting is achievable." Within the range of jets seemingly available for the fcr carb, one could work around a wide range of air/fuel mixture problems. But it's time consuming at best, even with a good understanding and feel of the bike/carb combination. At worst, most people have a poor understanding of carburetion in general, let alone of their specific situation. Then it becomes frustrating and kind of hopeless. It would be fun to have the time to tinker and learn.
Kawestonltd is offline  
April 20th, 2019, 01:57 AM   #20
Senior Member
 
Joined: Nov 2001
From: Ely, England

Posts: 15,548
Thanks: 419

I Ride: Husaberg FE501e 2003
your forgetting that it is a 450 problem and not a 550 or 650 problem. that means what changes? no idea! we swopped carbs once, still the same, then we swopped heads = still the same. we then realised 'we' (the royal 'we') didn't write down what belonged on what and when and where. I was pretty pissed off about it.

That's another reason I don't have a workshop. you're conducting a test by guiding your mechanic, you discuss everything with him in which he's happy to lean back against the wall and say 'yeh' (and like whatever you say, i get paid either way) and at the end of it he hasn't made notes of anything he's done. "Can't be arsed!" cost of tests running into the hundreds.

Taffy
Thanks from Cali
Taffy is offline  
Reply

  Husaberg Forum > Mechanical and Technical > Mechanical

Tags
450, idling, poor



Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
450 2004-2008 liners breaking Taffy Mechanical 0 December 10th, 2016 06:09 AM
2004-2008 Radiator Fan Options - DIY? mattwilkinson Electrical 40 April 6th, 2016 12:33 AM
2004-2008 Sticker Kit mattwilkinson Motorcycle Talk 14 January 25th, 2015 01:37 PM
Is a 2004 engine interchangable with a 2008? franknorway SuperMoto 3 July 21st, 2010 03:14 AM
2004 seat on 2008? GoldenBoy Tech 2 December 28th, 2008 09:31 AM


Facebook Twitter Google+ RSS Feed