Paso 750 Dies in 1st gear

[cellardoor]

Im a new owner, just bought this 1988 Paso 750 and it appears to be well maintained. Was riding around fine for about a month then it sat in the garage for 2 weeks during some freezing weather and now it has issues. It starts up fine but then wants to idle below 1000 unless I roll on the throttle. When it finaly seems warm I try to go into first and it dies when the gear fully kicks in. I noticed my battery is 12v/10ah and not 12v/14ah as it says in the Paso owners manual. Could this be the culprit? Also this bike hase less than 6200 miles and appears to be all stock. I have read the "hard to start paso" threads but none seem to answer my issue. Let me know if you can help

[nnnnnnorman]

good luck with your 'new' classic bike. i would start with a new battery. there are many recomendations on these pages.

[paso750]

Hello & welcome,

as the bike has such a low milage it was stored for many years. I guess you fully serviced it before riding it meaning changing timing belts (!), cleaning and balancing carbs, changing all fluids etc.
The battery is not the culprit. As long as it starts the bike it`s ok.
My first question would be if the clutch fully disenganges. If it does not (ie because the brake fluid wasn´t changed or the system not bled properly) it could make the engine stall.
Due to the voltage drop at the coils that most Pasos have the ignition is not very strong. If it was, your bike would probably do a jump forward when putting in 1st gear.
Put your bike on the center stand and in gear, have someone pull the clutch lever and turn the rear wheel. See if it rotates without resistance. (of course when the engine is off)

G.

[cellardoor]

Thanks for the quick info! Got a new battery 12v/14ah but I still have the same problem. I was able to get it into 1st, 2nd, 3rd while riding it around yesterday but still if I roll off the throttle it wants to die. My Paso was fully serviced, belts are new and so are liquids. And the back wheel spins freely without resistance in 1st with the clutch in. I think the carbs were not adjusted correctly because my exhaust smells sweet with gas and any use of the choke kills the engine immediately. Let me know if you guys agree before I take it all apart.

[higgy]

Sounds like the entire fuel system needs a cleaning,carb tank the works.

[Skins]

Sounds like a carburation problem. What kind of carburation does it have - Weber or Del Orto? If Del Orto, what size carbs?

[cellardoor]

cleaned all fuel lines and fuel filter, filter had alot of rust which led me to the tank that has more rust on the inside. I am pretty sure the clogged fuel filter was the problem but I have not tried to run it again yet. Also cleaned air filters.

So I cleaned the fuel filter with carb cleaner till no rust would come out, will that be enough? Also what is a good way to get the rust out of the tank? recomended products?


I have the tank off and once it is clean I will try to run it and we will see how it idles. Dont know what kind or size carbs I have, how do i tell? I was told this bike is fuel injected with desmo valves.

[angelix]

cleaned all fuel lines and fuel filter, filter had alot of rust which led me to the tank that has more rust on the inside. I am pretty sure the clogged fuel filter was the problem but I have not tried to run it again yet. Also cleaned air filters.

So I cleaned the fuel filter with carb cleaner till no rust would come out, will that be enough? Also what is a good way to get the rust out of the tank? recomended products?

I have the tank off and once it is clean I will try to run it and we will see how it idles. Dont know what kind or size carbs I have, how do i tell? I was told this bike is fuel injected with desmo valves.

Fuel filters need to be changed... cleaning them is not enough and it is a silly saving as they cost less than a tenner.

there are fuel filters that are made "to be opened and cleaned" but not on your bike.

as for the tank, cleaning it will solve very little, you need to treat it to stop the rust coming back

There are several treatments, POR15, Tankerite, it can be done at home although could be a little messy.

[jcslocum]

To fix the rust you must coat it!!

Por-15 is great and I have aslo used Caswell's on tanks. Do it now before you put it all back together and you will not regret it.


**Dont know what kind or size carbs I have, how do i tell? I was told this bike is fuel injected with desmo valves**

It has Desmo valve action but not fuel injection. Are there 2 separate carbs, one on each cylinder or one carb high up?? A picture or 2 would help :-)

[cellardoor]

There is one carb on each head. Delorto carbs. How do i tell what size?







^in this pic is my air filters, fuel filter, and 2 little round rubber things??? Does anyone know if these rubber things are essential? i see them jammed in the exterior cyliner spaces.

Going to pick up a new fuel filter and some tank cleaner today and tomorrow we will run it. Im going to go with por15. Should i bother upgradeing air filters? What is the best oil for these filters? and is there a prefered fuel filter? let me know what you think.

[Tamburinifan]

Does anyone know if these rubber things are essential?

No, they just dampen sound from fins vibrating.
They simply migrate over the years, remove them if you like.

[cellardoor]

Thanks I guess I will stick them in somewhere. Interestingly enough here is my bike:

http://forums.ducatipaso.org/viewtopic. ... orto#p8942


Too bad his email is no good, I have tried to find him other ways but still no luck.

[mach5er]

Here I am! I left my contact information on your voicemail. I'll try to help you out as much as possible. I had owned the bike since 96. I was the second owner. Carbs were rebuilt in 2006. Post some pics of what the bike looks like now, I am curious of her condition. It looks as if a lot of the metal is pitting now. Looks like it may have been sitting out in the elements lately. So sad. Check the wiring from the stator. Make sure that the wiring is not corroded to hell. I am thinking the issue is electrical based and not so much on the fuel side. I may be wrong. But worth checking

Michael

[paso750]

on the side of the carb it says Dellorto and above it something like PHB36 or so. That`s the type and size of the carb.

G.

[cellardoor]

PHF36BD is my model of dellorto. I have cleaned the tank, all the lines and most of the carbs. The carbs looked very clean anyway. The problem is still the same, it wants to die in idle. Now i am thinking it has something to do with the choke. When I press the choke it kills the engine if its running, and if I try to start with the choke on it will not crank up and makes an odd squirting noise.. Mach5er I have found no corrosion on any electronics, thanks for all the history of the bike as well. Thinking....