Pantah won't rev past 5k

If you need technical information or help with your pantah based twin Ducati F1, F3, TT1, TT2, Santamontica, Montjuich, Laguna Seca, Al'azzurra, Pantah XL/TL etc engine - post your FAQs, comments & questions here.
Post Reply
stablemates
Cucciolo - the Lil Pup
Posts: 2
Joined: Thu Aug 31, 2006 12:48 pm
Location: San Diego
Contact:

Pantah won't rev past 5k

Post by stablemates »

Tossed a belt on my 81 500sl. Belt tensioner bearings were seized.
New bearings, valve job, belts, rings, cleaned, washed.

Starts better than it ever did, but when you rev to 5k, it breaks up.
Ocasionally it will rev, but only for a minute, then we're back to stumbling and riding along at 50mph (if lucky). It may be dropping a cylinder.

Carbs cleaned, accelerator pumps checked, still have the problem.

I'm guessing that the ignition system won't advance, or a bad ignition module? I guess I could reach down and pull a spark plug lead while I ride it along. On the bench I can't tell.

[email protected]
User avatar
BevHevSteve
SITE OWNER
SITE OWNER
Posts: 2324
Joined: Wed Mar 10, 2004 8:53 pm
Location: Lafayette, California
Contact:

Post by BevHevSteve »

sounds like you have not sync'd the carbs correctly yet. look in the CARB AND FUEL SYSTEM aread for the procedure explained
Image
Steve Allen (925)798-BEVL[2385] Ride'm, Don't Hide'm
Ducati/Euro Spares -> https://Store.BevelHeaven.com
Cagivaduc
Cucciolo - the Lil Pup
Posts: 3
Joined: Fri Feb 09, 2007 12:04 pm

Pantah Won't Rev Past 5K

Post by Cagivaduc »

This response may be a little late for you, but perhaps it will help others with a similar problem. My F1 had exactly the same symptom and it turned out that the ignition pick-up gap was way too small. The result was poor spark and no ignition advance. My bike backfired badly which led me to understand that there was no ignition advance. Once the gap was set correctly, it felt like the power output was doubled.

Dean
MorDuGuz
Cucciolo - the Lil Pup
Posts: 4
Joined: Tue Jun 17, 2008 1:36 pm
Location: PARIS

Post by MorDuGuz »

Hi.
I bought in March 2007 a Pantah 500SL in good condition. At least I believe. I cleaned and balanced the carbs, changed some cables and the engine starts easily. There is no misfirings and no afterburning in the silencers. When I ride the engine can climb easily to 10000 rev/min on the first, second and third gears, but on the 4th and 5th it doesn't run above 5000 rev/min.
I checked the timing. It is nearly correct, maybe a little bit too early.
By the way, I read somewhere the mainshaft turns as the rear wheel.
Can somebody confirm? And give some clues to correct the problem. It's a pity to be limited at 150 km/h on a bike able to reach 190 ...
wdietz186
Cagiva Alazzura
Posts: 707
Joined: Sun Sep 10, 2006 5:40 pm

Post by wdietz186 »

Check the float levels are correct.If the levels are too low the engine will run out of fuel. This is most common in the higher gears as the throttle is open wider and longer, drawing more fuel than in the lower gears. Also check that the petcocks flow freely as this will cause the same symptoms. Oops! almost forgot, make sure the fuel tank cap vent is clear too.
Vince
750 Sport [BEVEL]
Posts: 203
Joined: Tue Nov 09, 2004 12:28 am

Post by Vince »

My 600 TL has a similar problem,it revs to well above 6000 but there is no point as there is no topend power,lots of noise but short shifting at 4500
makes it accelerate much stronger,I suppose its going to make the engine last and BTW I get fantastic fuel economy ,even going hard it easily tops 60mpg,thats Imperial gallons
MorDuGuz
Cucciolo - the Lil Pup
Posts: 4
Joined: Tue Jun 17, 2008 1:36 pm
Location: PARIS

Post by MorDuGuz »

- I have recently changed the carbs gaskets and checked the gas line (tank, filters, taps and tubings) altogether. Maybe I did an unnoticed mistake.
I will verify the float levels at the first opportunity.
- I have not yet checked the valves. What happens on a desmo when the clearance becomes wrong from wear?
- Vince's problem looks as if only one cylinder was operating properly (at least at high revs).
- I had too an unanswered question on the relative rotation direction of crankshaft vs rear wheel .....
Post Reply

Return to “'Straight Head' Pantah Engines [rear exhaust faces forward] > F1, F3, Pantah, TL, XL, TT1, TT2, Al'Azzurra”