After the motor comes up to operating temperature, it starts idling up to about 2000rpm. Do you think it is an adjustment problem, or could it be something in the electronics?

Preston

Both.
Air leak intake or wrong trottle balancing are the most common mechanical troubles, failed or burst temp gauge in the electronics

Running well now. I pulled the throttle bodies and cleaned the idle adjustmnet screws and ports. The main problem was the choke cable would not move the linkage for the cold speed adjustment. I installed a small push spring around the cable to push the cam to the off position. That was probably the main issue. Not sure if there is supposed to be a spring there or not. running like a champ now.

Preston

There should be a spring on the throttle cable.
Idle lever wire has none.

Nice to follow your progress!

I remembered reading this post a few months ago and just had a similar problem this weekend. Totally different cause though!!

I just finished making the cooling system mods described elsewhere and went for test run only to find the idle speed was way too high and getting higher as the bike really warmed up.

So with much disgust I pulled all the plastics off for yet another time and started to investigate...

Stuck idle cable - nope.

Sticky throttle arms - nope.

Hmm...could it be something to do with the cooling system running hotter with the 16 psi honda radiator cap - I was really starting to wonder what I'd done by messing with the cooling system!! Go get another cap - nope not that!

Finally I spotted some unusual wear on the radiator hose right next to the fast idle mechanism on the left side of the intakes...Ahh Haa!!!

The mechanism was rubbing on the hose and not returning to the normal position when the fast idle was closed. This seemed to only happen when the bike was hot.

When the coolant was cold the system is not under pressure and there is plenty of clearance ...well about 4mm (3/16ish) anyway. When the system warmed up the hoses pressurise and swell a bit...there is really not much clearance for the hose between the throttle linkage and the frame at this point...so I used some cable ties to slightly reroute the hoses and bingo! All fixed!

Hopefully that's the last time the skins will come off this summer!!

Cheers
Andrew

Cheers Andrew!

The plasric does seem to become a chore when it's off more than it's on!!!

I still have the small push spring on the cold warm up cable just in case something goes awry. So far I've clocked about 3000 miles of weekend riding since I've had to do the last repair, which was the sprag replacement. I was seriously going to go with the 944 kit with 11:1 pistons, but why push my luck, it runs good enough for me as it is.

Would it be worth while to get rid of the exhaust banjo and have two separate exhaust pipes? I have access to a TIG welder and can by the radius fittings. Just curious if anyone else has done this and if there is a benefit. I'm still looking for some new cans. I'm thinking if I go this way I can make some for a Monster fit.

Preston

I have over 50,000 miles on my 907. I have had to fix, modify, and work on things to keep it going in top notch condition. Having said this, I agree with the post above about the radiator hose rubbing against the nut on the end of the throttle bodies common shaft.
For a time, my bike throttle would stick or idle down really slow. The more that I rode it, the idle would stay high, somewhere above 2,000 rpm I think. Anyway, the cooling system hose on the left side goes between the frame and the throttle bodies. When the the hose gets hot, it expands and will rub against the nut at the end of the throttle body shaft. I used more and larger zip ties and a stiff piece of rubber and tightened the hose while it was cool against the frame. Also you can shift the air box and throttle bodies to the right as much as possible to make more clearance. This really works. I would guess that after you took the throttle bodies out and cleaned and then re-installed them that you shifted things a little and that might be enough to fix the problem.