Hi, a few weeks ago I bought a 1981 Pantah that had been sitting in dry storage for ten years. It has 31,300 km on it and is in nice shape. I ordered new belts, an oil filter, and a battery. I fixed some slightly dodgy wiring with proper connectors and bought a carb rebuild kit. The bike has PHF 36's fitted and the carbs seem to be in good shape. I put all the part through an ultrasonic bath and all parts came up nice and clean. A previous owner replaced the original 500 barrels and pistons with a 650 set from a Cagiva Alazzura. In rebuilding the carbs I found I have a 140 main jet in one carb and a 135 main jet in the other. I would like to check that the PHF 36's have the right jetting for the Cagiva Alazzura barrels; can anyone tell me what the standard Cagiva Alazzura carb jetting/set up should be? I would welcome the chance to chat with any Pantah owner who has a similar conversion Many thanks!
From: http://www.postdiluvian.org/~mason/moto/jetting.html 650 Alazzurra Type: PHF36MD/MS Needle: K8/2nd Main Jet: 132/138 Pilot Jet: 65 Slide: 60/3 Needle Jet: 265AB
Many thanks Rick, this is exactly the information I was looking for. It seems that my carbs are jetted to Alazzura spec's. I greatly appreciate the prompt reply.
Strangely the settings for the 500/600/650 are almost the same . any variation will be down to fuel quality. the tables were most written in the days of 4 star leaded fuel and the modern ethanol fuels run a bit rich so you may need to go down a step on main and possibly pilots but see how you go.
Thanks Paddy. Interesting that the jetting appears identical over a range of displacements. The engine last ran about ten years ago and the plugs looked to be on the slightly rich side when I pulled them. I don't know if the last owner just ran the bike for a few minutes on the choke, or took it for a decent run on the road. I will have to see what the plugs will look like after a proper ride. Looking at previous forum posts last night I see that there are two sizes of main jet, depending on the orientation of the cylinder. I was surprised at this and wasn't aware that this was normal... I last owned a Pantah in 1998 and never had a reason to look at the jetting. This new bike has velocity stacks and a two into one fitted; once my initial service is completed I will ride it for a while and evaluate the jetting. I may well be returning to the forum to bounce some ideas around!
I have never found a need to run difference jets front to back TBH. on Bevels or Pantahs and i dont think Ducati did. this is 500/600 Pantah .
Thanks Paddy. I must admit I was a bit mystified regarding the different main jets that are currently installed. I think I will drop the 140 back to a 135 and see what happens. Thanks for the advice, much appreciated.
BITD my old 500 Pantah ran different sized mains. Can't remember the specific sizes but both were bigger than standard (it was breathing through K&N pods and a 2-1 exhaust) and the one the rear pot was also a size up from the front. I believe the thinking was that it helped the rear pot run a little cooler, matching the front which is more hung out in the breeze. IIRC it was the same on my 900ss (also on K&Ns). Might make more sense on bikes that aren't half faired... Whatever the reasoning, both bikes ran fine and my thinking was "If it ain't broke..."
Thanks Rob. Good to know your experience. I am a probably a couple of weeks away from being able to fire up the Pantah. presently waiting on oil filters and belts; the carbs have been rebuilt and are ready to go. In cleaning all the grime off the chain I found the locking clip on the chain was missing and at some point in the past a previous chain had obviously parted and piled up between the front sprocket and case. The case had been damaged and JB Weld used to patch the affected area. We will see how good the repair is once I have the bike running. At this stage I am very loathed to split the engine to do a proper welded repair. In taking the LHS cover off the bike I also found that the insulation on wiring to the stator and the ignition pickups had become brittle and was falling off in chunks. Not unexpected, many owners had mentioned a similar failing and I had to do exactly the same repair on the ignition pick ups on my Laverda Jota. I will hopefully have all this done by the time the belts and filters show up so I can at least fire the bike up and see what other issues need attention.
I ran different jets sizes in my 600 pantah, this was set doing an old school plug chop at the end of Longniddry dual carriageway so would leave as is. Sam
Thanks Sam, pouring with rain here in BC and probably not due to stop raining until late February... Once the roads dry out I will try and put some miles on the bike and see where I am regarding jetting.
