ZZR600 D1 Dynjet advice

Tribal-Wolf · Two Stroke Sniffer Joined: 02 May 2008 Karma :

Just bought a 1991 tidy ZZR600 on which the last owner fitted a Motad nexus 4 into 1 and a stage 1 dynojet kit. He has given me what is left of the kit plus the old jets etc. On looking it seems he has fitted the 144 jets which the kit states to use for a free flow exhaust. Can anyone tell me if this is right for this particular exhaust? It seems to be running rich and bogs down on heavy throttle. I think it should have been the 140 jets thats were fitted as I think this is just a run of the mill exhaust system. It also only has a stock filter.

Pete. · Super Spammer Joined: 22 Aug 2006 Karma :

Yeah the Nexxus is in no way free-flowing - I'd take it for a ride without the air filter and see if that improves it, if it does then go for a new filter and smaller jets.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good Very Happy

Tribal-Wolf · Two Stroke Sniffer Joined: 02 May 2008 Karma :

Hmmm I have found a slight problem, the guy who fitted the dynojet kit was an idiot, two needle spacers were not on one of the carbs and one spacer was missing of another. Put that right and bike idles nice and smooth and runs well unless you throw open the throttle, then it just bogs down like hell. I did change the jets to the smaller ones so I am at a loss. The balance is fine and they are really clean. I have some standard carbs but they are a little grubby so I didnt really want to fit them. I am beginning to wonder if it's fuel starvation due to a block fuel tap.

Pete. · Super Spammer Joined: 22 Aug 2006 Karma :

Won't harm to check the tap but it's almost certainly not that.

Dynojet kits have a habit of wearing out the emulsion tubes - look down the tubes and see if they look out-of-round or have wear marks down the sides. You could even fit the needles and tubes from your spare carbs.

Did you set the float levels in the carbs when you stripped them?

Try also lowering the needles as low as you can make them and see if it's any different.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good Very Happy

Tribal-Wolf · Two Stroke Sniffer Joined: 02 May 2008 Karma :

The dynojet kit was only just fitted by previous owner (badly). I have now fitted a set of standard carb which I stripped, cleaned and set up.
The problem I have is still there, bogs down on big throttle openings in any gear. It seems to run fine around the doors but if I try and accelerate hard down a slip road etc it is crap. Maybe this is why it was for sale lol.