1989 750 Sport idle issue

discussion about the 750 Sport and '89/'90 900SS, which share many mechanicals with the Paso series
Mc tool
paso grand pooh-bah
Posts: 1873
Joined: Wed Dec 05, 2007 12:35 am
model: 906 Paso
year: 1990
Location: Newzealand

Re: 1989 750 Sport idle issue

Post by Mc tool »

I have a notion that an injected pump would poke out about 60 psi and if that was hooked to the weber .... return line or not , the carb would look like a fountain :lol:
I wish I was young again............Id be heaps smarter than last time
deswoodau
Posts: 53
Joined: Fri May 02, 2014 10:08 pm
model: 750 Sport
year: 1988
Location: Australia

Re: 1989 750 Sport idle issue

Post by deswoodau »

Perhaps. The current pump pushes fuel at a rather slow rate. I pressure tested it and was only receiving 1 psi from the gauge. That being said it works well enough........the gauge is a cheapy from eBay so it's accuracy could be questioned too. I've since fitted new fuel lines and decent clamps so it could potentially be ok now with the new pump if I were to try again. The main leak point was the return line to the under tank feed point. I replaced all the spring loaded clamps as they're to prone to leaks.

Maybe it's time to buy a Japanese bike again and be done with this home mechanic nonsense!
Mc tool
paso grand pooh-bah
Posts: 1873
Joined: Wed Dec 05, 2007 12:35 am
model: 906 Paso
year: 1990
Location: Newzealand

Re: 1989 750 Sport idle issue

Post by Mc tool »

some of that cheap stuff aint so bad .What I do is measure the same thing a few times and if the reading is the same each time ( and resets to zero if applicable ) Id call is a duck ( walks like a duck , quacks like a duck.........its a duck :P ).
one psi aint a lot .... Id want to see 3psi , perhaps add a bit of length to the return line :)
I wish I was young again............Id be heaps smarter than last time
deswoodau
Posts: 53
Joined: Fri May 02, 2014 10:08 pm
model: 750 Sport
year: 1988
Location: Australia

Re: 1989 750 Sport idle issue

Post by deswoodau »

I'll do some further tests at another stage. I had the gauge connected just before the carburetor banjo so technically it should be at it's full operational pressure point. That being said some pressure would be absorbed by the return line too. Main thing for me right now is that the 750 is operational again and riding beautifully :)

I had to open up the pressure\vac gauge mechanicals and dial it manually (slightly bend it) as it wasn't centered ......hence my comments on it's accuracy.

More fun to come I guess. When time permits I'll open a new thread on the vacuum pump experience if there's interest.
Mc tool
paso grand pooh-bah
Posts: 1873
Joined: Wed Dec 05, 2007 12:35 am
model: 906 Paso
year: 1990
Location: Newzealand

Re: 1989 750 Sport idle issue

Post by Mc tool »

There are post on here re the vacuum pump and fitting thereof .
Pleased to here p750 is going well now ......fingers crossed :)
I wish I was young again............Id be heaps smarter than last time
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