Mk1 Fcr 39 troubles

casnider · Oct 6, 2012

Ok.... I've searched for some different things but was unable to come up with anything conclusive. The bike (98 fe400) ran with the Dell orto previously.

The bike only runs on choke. As soon as I shut the choke off the bike does too. I have assured the slide is in square side down. I have a 38 PJ and the specified PAJ in Taff's table to match it. Turning the fuel screw doesn't seem to have any affect on the situation. When on choke it starts after first or second good kick. I try to kick it after it dies with the choke off and it will start and idle for a half second then die and not fire again off choke.

Carb seems to be really tight so I doubt it's leaking in front of the carb.

Is there another part of the pilot circuit I should check?
Any seals that may cause this?

tinwelp · Oct 7, 2012

casnider,
I've FCRs on another bike and they are forever gumming-up the idle jets. The only way I can leave the bike for more than a few days without riding and expect it to run OK when I next start it (assuming it is actually possible to start) is to drain the float-bowls or turn off the fuel and allow it to idle until dry.

Take a peek at your idle jet; you'll have to unscrew them to get a good luck. I bet you'll find it gummed-up.

I've still got the Dellorto on my Fe400e. It took a lot of time and effort to get the jetting right, but it runs very well now, starts easily and I can leave it for weeks at a time without any gumming problems. Same fuel and stored in the same garage... go figure. Probably not what you want to hear after going to the trouble of fitting the FCR, but there you go.

Incidentally, if gumming is your problem, many people get around it with fuel additives. Don't know about you, but fuel is expensive enough. I simply don't want the added hassle and cost. Maybe another thing to try is buying a different brand of fuel. A long-shot, but you may get lucky.

Let us know what you find when you next pull down your carb. please.

Cheers... Paul

casnider · Oct 7, 2012

Well both the Pilot Jet and Pilot Air Jet were new. Should I try shoving a paper clip or something up throu where screw in? I will take it off and inspect and take pictures

tinwelp · Oct 7, 2012

casnider,
I didn't realise this was your first trial with the FCR...

Yes, wash with carb-cleaner and blow-through every and all the passageways. I wouldn't recommend a paper-clip though; far too easy to damage something. Look here for a wealth of info on looking after your FCR: http://www.pbase.com/jdjetting1/keihin_fcr_manual_views&page=all

I'd look very closely at the float-valve and the float-height too. Assuming your idle circuit isn't totally plugged somewhere, and your jets are somewhere close (and I think they are, but I'm very sure Taff will correct me if I'm wrong), and the bike was running OK on the Dellorto, and you're sure you've no air leaks in the inlet manifold, and all the gaskets and O-rings on the carb are good, there's not too much left providing the float-bowl is filling.

Pictures may help...

Cheers... P

Taffy · Oct 8, 2012

Have a look at where the wheels on the slide run? they groove badly. I put body filler in mine and now it runs well even if it doesn't last forever!

also the slide issue, the plate must be on the back nearer the cylinder head and also the correct way up, you can put the plate on upside down!

regards

Taffy

casnider · Oct 10, 2012

So.... The plate that needs to be 'square side down' needs to be on the cylinder side?

If so, I think we have found the problem!

It was an EBay carb... I blew cleaned the float bowl and most passages with carb cleaner, most stuff looked to be in good shape, but my jetting wasn't stock for a yz400f and some of the screw heads were boogered up so I know the carb has been messed with in the past.

I will try to get into it this weekend and update back with you all!

Btw, I also got the hot start button, can I simply put a T in the hose that leads to the intake by the cylinder head?

Taffy · Oct 10, 2012

no idea

never did it myself.

I think there was a thank you in there somewhere.....

regards

Taffy

casnider · Oct 14, 2012

Haven't had a chance to get to work on her yet, thanks for all the help, was so happy to think to have found the problem,didn't mean to be rude. Tree fell on garage so trying to get that in order before I can work on the bike. :?

Hopefully get to work on it soon :angry:

casnider · Nov 11, 2012

Finally got the garage roof repaired, worked on the husaberg some, unfortunately I was wrong. The slide plate is in correct. I am going to double check the other things listed. The slide plate itself looks to have some wear on it, is this normal?

Going to make sure everything is seating well

casnider · Nov 11, 2012

So I double checked everything was seating well, made sure I trimmed enough from the manifold. I started out at about a half turn out on the pilot jet screw. It won't idle on the choke there but the engine will rev. Conversely with the fuel screw out a turn and a half it will idle forever on the choke, but only die when I touch the throttle. If I turn the choke off after 30 seconds or so, its like hitting the kill switch, won't rev just bogs if I touch the throttle. It seems odd to me bc I didn't think that adjusting the fuel screw would do anything to the bike while choked. It must still play a role. Anyways, I guess next I will take the carb off and spray some more cleaner through it and maybe try compressed air this time and check the floats while it's off. The seal on the back of the plate was in good shape, there wasn't grooving where the wheels run to guide the slide.

What's a good place to start with the idle screw? Is there a good spot to leave it while adjusting the fuel screw?

I'll read on that site you provided also. All help is greatly appreciated. Thank You, Chad

zaga · Nov 12, 2012

Hi

For the slide plate you can check here, there some info there
viewtopic.php?f=7&t=16677&p=137387#p137387

Take the top cap of the carb and put a light in to the intake side (engine side) and check the gap that you have between the carb body and the plate.

I don't know if you have it, but I strongly recomend that you should have the aluminium intake and the new rubber, I only had problems tryinng to adapt the old rubber.

I would sugest that you put your PS 2 turns out and set the idle to a higher rev, if it doesn't work try 2 1/2 turns.

You have a 38PJ, what is your PAJ ?

Good luck
:cheers:
ZAGA

casnider · Nov 13, 2012

Thanks I'll check my plate gap.

My PAJ is a 60

casnider · Jan 12, 2013

yep.... its been this long since i have got to work on it again, terrible...

anyways,

if i shine a light into the intake side to check out the gap there really isn't one. i really can't see any grooving either. If i scratch my nail across the surface there doesn't seem to be any uneveness. The plate probably has about a mm of play if i shove it back and forth from engine to filter side, this includes the springiness of the plate with the gasket on it. I don't see light coming through unless I compress the gasket.

a screw under the floats looks to have been screwed with tho... i am going to research and see if this could be part of my problems...

thanks

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