www.DRRiders.com

Best thing you can do is pull the carb down and make sure all the jetting is correct, the carb is clean and there are no internal issues. Tough to know what to change/adjust if you are not sure of what you are starting with. Check out the FCR-MX jetting and carb set-up specs on my web page to compare to what you have. Look for vacuum leaks. Is the carb fully seated in the intake manifold and the clamp securely tightened?

yep there are cracks in the manifolds i noticed. Hmm.
the previous owner installed the FCR so im not sure. it also only has 1 throttle cable connected.

i was wrong about the symptoms, its happening even when fully warmed up. Backfiring through the airbox and almost stalling when it happens. very rough idle, but runs fine above there.

i have spent the last few days mucking around with the delorto carby on my mates 2000 sm610.

what a poxy lump of sh*t that is to work on. i still haven't figured out the trick to unhooking the throttle cable. it has a fuel leakage issue. put the bike on the sidestand and fuel pisses out of the carb.

the FCR and even the stock dr carbs are so much easier to work on. wonder if i can fit a mx fcr to the damn thing. local mechanic at the suzuki/husqvarna dealer when i quizzed him about it offered to give me some matches to fix the issue. i'm inclined to agree with him.

pardon the ignorance, but do i need a special manifold for the FCR or does it use the standard dr650 one? the rubber seems old and cracking, perhaps thats the cause of my idle problems

The std rubber manifold works fine. The FCR's manifold spigot does have a larger OD than the BST but it still fits and seals the carb just fine. Based on the above I'd get that thing off of there and replace the manifold and clamp. While the carb is off open it up, clean it and make sure it is set up properly. There is no sense wrestling with issues that are set-up related when all of the info is available to you. My web site has all the info you need to make your machine run like it should.

These are the install instructions that I include with each carb I send out. Go over them before re-installing your FCR.

Just installed my carb today after a 3-4 days bought with USPS on a shipping issue. Anyway, install time was only a couple hours which really could have been shorter had I actually read the directions included rather than skimming the bold print . No real issues to report during the install, but the hardest part was getting the airbox side of the boot to go all the way onto the adapter provided, finally got it on there where I am happy with it. Threw it all back together and fired her up, ran okay but didn't want to stay running. Unfortunately I didn't have a lot of time to mess with it since I had to run out the door, while I was waiting to pick someone up I read the instructions again and found that I hadn't re-connected my vacuum line on the petcock to the carb doh! Hooked that back up when I got home and she ran like a top, idle needs adjustment (30 and snowing wasn't a good time for me to be messing with it), but overall I am very happy with it. I can already tell a difference. Still need to finish off my airbox cutout (previous owner drilled some holes in the top already) and I need to pull the header since I doubt the P.O did that. Bike was kept super clean but he didn't look like he messed with anything.

One last thing, that carb is HUGE. I couldn't believe it when I opened the box. I knew it was bigger than stock but DAMN.

+1

I took the carb off today and found to my shock, that the idle mixture was set to .5 of a turn
put it out to 2 turns and it runs much better. But my manifold still looks dodgy, i just can't seem to remove it due to tight screwheads and tight quarters.

http://i.imgur.com/e1sxg.jpg

Changed to a URL due to image size.... Rob

Jesus christ dude, could you please resize that image and repost?

I think my AP timing is out. At about 1/3 throttle opening, which equates to about 60mph when in 5th gear (stock gearing),
the thing is whirring full-pelt. It starts to kick in at about 1/4 throttle opening. At fuller throttle openings, it starts to drop off.
I would have thought that this is the opposite of what I want; I'd like it to kick in at the fuller openings so that my bike doesn't
lean stumble when I crack the throttle open, but be inactive at cruising throttle openings for better fuel economy.
By the way, it consistently whirrs with the throttle held within its operating range, it doesn't drop off after a while - I thought
its function was just to provide a 'boost' of fuel for the carburettor to keep up with engine demand rather than providing a
constant squirt of fuel.
If it helps to diagnose the problem, I did make my needle jet 1 clip position leaner since
it was running a bit rich, I believe this is due to the differences in Australian delivered fuel
versus US delivered fuel, although it may be due to environmental factors as well.
Jetting seems almost spot on now, enough that I can't be bothered to pull the needle out again to install a shim to see how that feels.