Thanks to the info on the board here I've got my Weber running pretty good. Now my only problem is trying to get it to start when hot. Anybody else ever experienced a problem getting the bike to start when it's hot? If so, how did you fix it or how do you start it?
On another interesting note: I was talking with a guy who is pretty proficient with tweaking air cooled engines with dual carbs. He was saying that he will sometimes run different jets on the same carb because of the way the engines cool. It made me think, I know our cylinders run at different temps and the manifolds have different angles. Has anybody ever set up different jetting for the horizontal vs vertical cylinders?
Hey Weber guys
-
- Posts: 107
- Joined: Sat Mar 19, 2005 12:00 am
- model: 750 Paso
- year: 1988
- Location: Santa Clarita, Ca.
Hey Weber guys
1988 Red Ducati Paso 750
1999 BMW R1100S
1999 BMW R1100S
-
- Posts: 247
- Joined: Thu Oct 22, 2009 10:38 am
- model: 750 Paso
- year: 1986
- Location: Mildura ,Australia
Re: Hey Weber guys
Sometimes when mine is really hot,it will idle really slowly on initial startup for a second or two,then return to normal running. If it doesn't fire straight up or if it stalls, I use a fraction of throttle on my second attempt of starting.Not a fistfull of throttle though or you'll flood it. J
- higgy
- paso grand pooh-bah
- Posts: 3331
- Joined: Tue Jul 29, 2008 9:50 pm
- model: 907 I.E.
- year: 1992
- Location: Hilltown,Pennsylvania
- Contact:
Re: Hey Weber guys
ahdoman wrote:Thanks to the info on the board here I've got my Weber running pretty good. Now my only problem is trying to get it to start when hot. Anybody else ever experienced a problem getting the bike to start when it's hot? If so, how did you fix it or how do you start it?
On another interesting note: I was talking with a guy who is pretty proficient with tweaking air cooled engines with dual carbs. He was saying that he will sometimes run different jets on the same carb because of the way the engines cool. It made me think, I know our cylinders run at different temps and the manifolds have different angles. Has anybody ever set up different jetting for the horizontal vs vertical cylinders?
Hi Jay
Perhaps you are having an ignition issue ? Mine,at least the last time it was running just required a quick squirt from the pump and maybe slight crack in the throttle to get her going. I have changed out the stock coils on both the 906 and the 907 and have opened up the plug gaps a bit. Dyna 3ohm on both and NGK iridiums dr8eix
Would be interesting to know exactly what the difference in cylinder temp really is. See know reason why slightly different jetting from side to side wouldn't help.
Ducati,making mechanics out of riders since 1946
There's no problem so bad that a little fixing can't make it worse! : )
If it ain't broke keep fixin it till it is
88 750
90 906
92 907ie
There's no problem so bad that a little fixing can't make it worse! : )
If it ain't broke keep fixin it till it is
88 750
90 906
92 907ie
-
- Posts: 247
- Joined: Thu Oct 22, 2009 10:38 am
- model: 750 Paso
- year: 1986
- Location: Mildura ,Australia
Re: Hey Weber guys
G'day Higgy
It's common practice to run different jetting on the rear cylinder with dellortos on the 500 and 600 pantahs,because of reduced airflow and hotter running temperatures.I'm not sure if this is an Australian thing because of our climate or if it is common place world wide ? Fatter on the rear mains I think from memory,but I'd have to check my invoices to see what they sent me last time to be sure. J
It's common practice to run different jetting on the rear cylinder with dellortos on the 500 and 600 pantahs,because of reduced airflow and hotter running temperatures.I'm not sure if this is an Australian thing because of our climate or if it is common place world wide ? Fatter on the rear mains I think from memory,but I'd have to check my invoices to see what they sent me last time to be sure. J
-
- Posts: 107
- Joined: Sat Mar 19, 2005 12:00 am
- model: 750 Paso
- year: 1988
- Location: Santa Clarita, Ca.
Re: Hey Weber guys
The guy I talked to says he's got a special rig he uses to monitor the engine temps on the aircooled's; he puts a temp sensor ring on each plug and has each one attached to a temp guage. That way he can monitor the temp of each. Then he messes with jetting and mixture according to what his data shows him. That's a lot of work with probably minimal differences but he's got a pretty impressive history of building some truely fire breathing engines. Some race classes only allow minimum mods so getting an engine to run at it's top is critical.
Anyway - back to the hot start issue... any ideas? I've got the bottom of my tank insulated and I've even taken the time to sleeve my fuel line with heat reflective tubing. So it's either got to be in the carb or the manifold. Maybe I'll try to put a heat shield between the airbox and the engine?
Anyway - back to the hot start issue... any ideas? I've got the bottom of my tank insulated and I've even taken the time to sleeve my fuel line with heat reflective tubing. So it's either got to be in the carb or the manifold. Maybe I'll try to put a heat shield between the airbox and the engine?
1988 Red Ducati Paso 750
1999 BMW R1100S
1999 BMW R1100S
-
- paso grand pooh-bah
- Posts: 1878
- Joined: Wed Dec 05, 2007 12:35 am
- model: 906 Paso
- year: 1990
- Location: New Zealand
Re: Hey Weber guys
K100 Go cart racers use that temp thingy ( its called a thermocouple ) under the plug and actually fiddle with the main jet whilst on the hop according to what it tells them. There carbs are usually Tillotsen with screw adjustable jets ..... sorta like a chainsaw carb I have not been able to logic out the difference between left and right carb idle screw settings on my Guzzi
Hamish
Hamish
I wish I was young again............Id be heaps smarter than last time
- ducbertus
- paso grand pooh-bah
- Posts: 531
- Joined: Sun Jan 07, 2007 12:00 am
- model: 907 I.E.
- year: 1991
- Location: holland
Re: Hey Weber guys
having different jetting for different cylinders is not uncommon.
Bevelheads like the 900 SuperSport ran 152 main jet in the front and 155 main jet rear, due to the location of the inlet and exhaust port of the rear cylinder.
Measuring the temp. is a good thing to get them "balanced" in heat dissipation.
Bertus
Bevelheads like the 900 SuperSport ran 152 main jet in the front and 155 main jet rear, due to the location of the inlet and exhaust port of the rear cylinder.
Measuring the temp. is a good thing to get them "balanced" in heat dissipation.
Bertus
- ducapaso
- paso grand pooh-bah
- Posts: 1097
- Joined: Sun Aug 01, 2004 12:00 am
- model: 750 Paso
- year: 1988
- Location: siena, italy
- Contact:
Re: Hey Weber guys
It sounds like oil vapour from gearbox. Try removing the pipe from the air breather close to the battery and have a long ride to clean the engine fron oil fog. Afterward you might need to have a leaner CO carb tuning.
have a nice ride, Nicola
Black "DUKE" 751582
ex...Red "smooth" 753349
Black "DUKE" 751582
ex...Red "smooth" 753349
- ducinthebay
- paso grand pooh-bah
- Posts: 1323
- Joined: Sat Sep 03, 2005 12:00 am
- model: 750 Sport
- year: 1990
- Location: SF Bay Area
Re: Hey Weber guys
I have always run the rear cylinder one jet richer on the mains, and kept everything else the same. Of course you make some adjustment in the cables and throttle stops when you balance the carbs. Some older british cars actually ran different/cooler plugs in the center cylinders because they had only one carb and couldn't cool the center cylinders as well as the outside ones.
As far as hot start, the old addage is that a lean engine always starts easier than a rich engine. Try adjusting the idle circuit a bit more lean and see if that helps you.
Cheers, Phil
As far as hot start, the old addage is that a lean engine always starts easier than a rich engine. Try adjusting the idle circuit a bit more lean and see if that helps you.
Cheers, Phil
Duc in the Bay
1990 750 Sport x2-Rosso Blanko (900ss copy) & Nuovo Nudo (Scrambler project)
1991 907 -mostly stock
2002 ST4s - Lots of mods.
1990 750 Sport x2-Rosso Blanko (900ss copy) & Nuovo Nudo (Scrambler project)
1991 907 -mostly stock
2002 ST4s - Lots of mods.