92 400vv info wanted

[jimathan]

Hi Guys. first post. just got a 92 bandit 400 vv. its being stood up for 4 years and its being a sod to get running. carb O rings rubber jet plugs ect. unfortunately someones been playing with float heights and it took a while to find the info and dial them in. now set as per book at 14.8mm and it now runs. its great over 3000 rpm but keeps messing the plugs up and spiting back and back firing occasionally under 3000rpm. this is also accompanied by a rattle from the rocker cover and inability to rev over 1000 rpm.turn it off and back on a few mins later and it may be ok. i puled the engine out, took cover off expecting to find timing chain rattling but it wasnt. all valve gear seems ok, and i now think the problem is a bad contact from the relay to the vvt actuator.  I think it looses power and goes to full advance on the vv. anyone else experienced this? Also there is a rattle in the clutch/gearbox that goes when you pull the clutch in. any ideas before i strip the box?
thanks Jim

[Chris H]

Hi Jim.

Sorry for late reply but have you sorted this?

Sounds like the main clutch basket is loose or if the sound is on the left then a worn clutch adjuster.

Regards the VC if it is under 10,000rpm the cdi should send a signal to the large relay and then this turns the VC oil valve to low, this is allowing for the cam sensores etc working ok.
The relay is prone to water due to its location.
If you bypass this OR there is a fault then the bike will run in high setting (as when above 10,000rpm) and it does sound like its rattling when acually ok, this is due to the different cam angles and is ok.

[jimathan]

The rattle from the bottom was the clutch basket.
Well. Full top end rebuild, polish and port, set tappits, hone bores, rings ok. After making the missing bungs for the low running jets I spent three days playing and failed to get it to run reliably at idle. (spark plugs fouling) Mid range and top end were fine. Eventually took carbs off and took the bungs out. Low and behold, twenty minutes balancing and tweeking carbs and it runs quite well. The spark is very weak and after checking everything else and repairing wires to crank sensor I still think CDI is on its way out. A repair looks out of the question, as the box is fully potted, not just at the end.  I haven’t leathered it to within an inch of its life as I want to let it settle down and bed back in, but it does run smooth and pull clean from 2,000 rpm in top, if your gentle with it. Above 6,000 it goes like hell. Anyone got any thoughts or know of a cdi for sale.
32900-33D00
BB724?
Thanks
Jim

[jimathan]

Great, thanks for that
Jim

[interfuse]

Above 6,000 it goes like hell. Anyone got any thoughts or know of a cdi for sale.

With the cdi they either work or they don't. Since you're getting spark its okay. I'd test the charging system. A bad r/r or battery can wreck havoc on your low rpm and r/r failure is a common issue.

[Chris H]

Jim,

If you PM me your email i can send you a pdf with all the test resistances to check the cdi.
Common fault that gives weak spark is pick up fault, check its giving around 100 ohms.

[jimathan]

Well more news. The rec/reg was below par, idle was 13.2v and 5000rpm was 12.6v! new reg sorted that and it is running better. Got out on it today and found a short dry road. It appears that it wont pull any gear above about 10/11000rpm. It just dies like turning the key off. If you roll of a little it comes back on but only just. I suspect its running lean at the top. Apart from that It pulls well. I need to luck into it a bit deeper.
jim