Fe450 08 new valve and now slow returning to idle...

Good Evening,
I have an issue where my bike is running good (not perfect) but the biggest issue is that it is slow to return to idle...(the bike is 100% std)

The bike had been laid up for nearly 8 months while I had a knee reconstruction but I'm now ready to go so I got it out, some fresh fuel, fired it up and it dropped an inlet valve... **** happens but it's all back together now with a new valve. Work was done by a very good mechanic (he only had the engine).

First issue was (once rebuilt) the bike would only start on the kicker whereas before the rebuild it would start on electric... I'm not that fussed because it is really easy to kick over, I'd say almost 2 stroke like! Any ideas..?

Second issue (now cured), once started on the choke the engine would fast idle. I rode for some 30 mins - obviously with choke off and at no point would the bike idle, it would just stall. It did also backfire like crazy when ever I let the revs drop off or shut off the gas. Seems to be cured by a complete clean up of the carb where I found the main jet blocked with some dirt.

Third issue, the dreaded 'bog' seems to be present if I try the 'snap wheelie type test' (low idle, quick snap and bog...). I know this needs fixing and am almost convinced that the jet kit from Taffy will fix it but I have a fourth problem and this is the biggest.

Fourth issue, the bike seems to be slow (say 2 seconds) to return to tickover or low idle. The drop from full to half and even quarter throttle is normal but the last quarter is slow almost like there is too much fuel and it wants to over run... I guess running rich or an air leak (I have checked the rubber boot between carb and engine flange and it is like new).Any ideas on this one?

I'm reluctant to start messing with jets etc because the bike was close to perfect before the rebuild and I'm hoping something obvious will be suggested!

Cheers for any help

Andrew

Thanks for the feedback chaps! You'll be pleased to hear I played with the pilot screw until it dropped out... whoops! So I stripped the carb again cleaned everything and then reassembled. Turned pilot screw out 2 turns and all of a sudden 'hanging idle' was gone. Went out into the paddock and tuned the pilot screw a bit more. Found the sweet spot (3 full turns out) and it is now 100% back to its old good self.

One very noticble point was that before tuning the pilot screw to perfection the bike was a dog to start on the button, but once the pilot screw was in the right place, it is easy peasy to start on the button or with the kicker!

All set now for a pay and play day down at Erzberg this weekend (I live in Austria)

Cheers Again

Andrew

Taffy, how did you 'know' it is a 40PJ? (because it is)

Just some info from yesterday at Erzberg.
All was good when starting up the engine for the first 10 times, straight off the button, but then the fun began... It wouldn't start unless I used the kicker... noticed a fair bit of fuel running out of the carb over flow pipes... then I could not even start it with the kicker and resulted to bump starts (which made me nervous riding that nasty technical stuff Erzberg is famous for). I was in a bit of bother with a stalled bike in an area where I could not bump start the engine into life when a kind Austrian turned up on a 08 650 enduro and suggested I use the 'hot start' tab on the choke, bingo it fired up lovely and continued to do so for the rest of the day! (well 90% of the time)

What I would like to know is the function of the hot start device? and what does it do?
By that I mean is it supposed to be used when the daily temperature is hot or when the bike is hot? (yesterday it was 32 degrees C)
It would also be good to know how it differs form the choke?

An internet link would be good if one exists or alternatively feel free to explain.

Thanks
Andrew