HI GUYS, ive got a freshly rebuilt, 1mm over, ported, high comp head, advanced timing plate, all new gaskets seals, ext, maybe an hour on the engine, westcoast pipe, dual keihin 40mm carbs with bored throats and ported mid sections to be around 42mm all the way through. Just wondering, both carbs run on a single fuel pump built in on the first carb, no external fuel pump, what would the benefit be of adding a second pulse fitting? more speed? more power? better fuel delivery? or is there no differance unless im running dual carbs with 2 fuel pumps built in? id think it would at least make starting alot better, but thats what the primer is for. let me know guys and please only comment if u know what your saying is correct...
WHATS THE BENEFITS TO DUAL PULSE FITTINGS? BUILT 750 BIG PIN ENGINE
- Thread starter kwakhead
- Start date
Yami-Rider
TigerCraft FV-PRO
- Location
- Texoma
I was told it gives you a better pulse signal. I run dual pulse if i have dual pumps and single pulse if i have a single pump. I have heard you can run a single split into two no problem, but have never tried it myself.
- Location
- the jetski grave yard
you are not supposed to split a single fitting to feed dual pumps. there is no advantage to dual pulse lines or dual pumps, if one pump is enough to feed enough gas to the motor. a few of my setups use a single pulse and a high volume remote pump that feeds both 48 carbs. other 44- 48 setups have dual pumps and dual pulse. mikuni 40I and keihin 38s dont need dual pulse or pumps. dual 44s and bigger always use 2 pumps unless its a single high volume pump
no im not splitting a single fitting into two pumps, im splitting two pulse fittings into one pump, just to ensure the engine gets all the gas it needs and extra pressure in the carbs. i think there would be advantages, it seems like the fuel would deliver more effectively. im not sure if id have to rejet though. but i already added the fitting, if i have any problems with it in the summer, ill just block it off. thanks guys
Big Kahuna
Administrator
- Location
- Tuscaloosa, AL
If both carbs have pumps on them. Then you need to have a second pulse fitting tapped into your cases. It been a long time since I worked on a 550. Cannot remember where the stock fitting is. If it is on the manifold or in the case.
what made u think this is a 550 engine?? its a big pin 750 engine with all the mods listed above....... lol
- Location
- the jetski grave yard
550? go to bed, you're rummy! dual pulse fittings to one pump? waste of time. the pulse runs the pump, it has nothing to do with fuel pressure.
Yami-Rider
TigerCraft FV-PRO
- Location
- Texoma
X2, just cap off the second pulse line.
- Location
- Boynton Beach
Restrict the return line if you want higher pressure. Riva sales the inline restrictor fitting where you can screw in a carb jet. Thats usually done on drilled out carbs.
Big Kahuna
Administrator
- Location
- Tuscaloosa, AL
I was looking at his avatar. Yup. Time for hed
Big Kahuna
Administrator
- Location
- Tuscaloosa, AL
I was wiped out last night when I was reading your post, sorry.
That said, You have OEM 40's. These carb only run one pump, the other carb is slaved to the pump carb. You can only run 1 pulse line to these carbs.
Big Kahuna
Administrator
- Location
- Tuscaloosa, AL
Or, Try Jett's Idea.
Vumad
Super Hero, with a cape!
- Location
- St. Pete, FL
Be careful with that timing advance. I know from personal experience that it will burn up an engine.
Early 750 motors used the timing advance and so did the 2003 sxr. Later model small pin and to my knowledge all big pin motors have the timing advance built in.
I do not know the specifics. I'm just saying to find out before you toast an engine. I didn't know. Sucked for me.
Early 750 motors used the timing advance and so did the 2003 sxr. Later model small pin and to my knowledge all big pin motors have the timing advance built in.
I do not know the specifics. I'm just saying to find out before you toast an engine. I didn't know. Sucked for me.
ltheres no way thats true cause than u couldnt run dual pulse lines period on any dual pump. im not sure ur on the same page as me..
And you're telling your teacher he doesn't know anything?
Exactly, I was checking to see if he understood that or not.