R5 Autopsy

[Striker1423]

It is very possible air is still trapped inside the pump. But, what does the pump do applying throttle? Have you watched to make sure the pump is functioning correctly? I don't mean to sound redundant, but if for some reason the throttle cable split to the pump isn't opening the pump (i.e. it is broken or falls off), a similar thing can happen.

If the pump is working as intended at higher RPM's visually, then I'd say the pump is either pulling outside air in, or there's air trapped still. Start it and see what's coming out of each line. Give it some gas and see if you can re-create what it's doing in the driveway. Obviously be careful but taking it for a ride and coming back to notice the issue isn't resolved doesn't quite tell you the whole story, savvy?

[Czakky]

Yeah, I've got the cover off and can watch it pump. With throttle applied it opens the stroke as it should.
Revving it in the driveway doesn't put air in the line, I've tried all pump positions. Something happens with sustained revs even on a short ride the injector line fills with air.
It's a quick ride. With premix in the tank I'm being careful, if that's what you mean.

[cygnus]

This winter I decided to throw on some clear injector lines.

Reading through this it seems that right there is where your problems began. I would speculate that a line/lines are not properly sealed on the barb and its sucking air.

[Czakky]

That's pretty much what I'm left with. I've clipped the ends several times but I'm willing to try this as a last ditch effort. It doesn't seem plausible but I can hope.

[SUPERTUNE]

Buy OEM yamaha black lines.
C

[Czakky]

Low and behold that's what I had and for some reason out of paranoia I switched to clear. Then the trouble started... At this point I have to see what it's doing though.
Right?

[Organicjedi]

Yambits makes clear lines to spec. I have those on my 400 no problem. I just put on a clear tygon line that runs from the tank to the pump and have the yambits lines from the pump to the carbs. The OD on the tygon line is a little bigger than stock. I haven't had any issues with the few miles I've put on since it's been installed.

Spring clips on the ends are always a good idea.

[Jspooner]

I run clear Yambits stuff on all of mine and no problems.

[quocle603]

I am running some blue tygon fuel line on mine. Works fine.

[Czakky]

Spring clips for sure are on. I did buy the hose from one of the RD people (HVC or Econ), but who knows. I will try and get the other clear line run tonight and report back soon.

[Czakky]

I thought I had some clear injector hose. I ordered some from Yambits.

[Jspooner]

I thought I had some clear injector hose. I ordered some from Yambits.

m

I have a set I can send you.

[Czakky]

That's nice of you but I've got some on the way.

[murphywv]

I think you are on the right track. I am wondering if the lines to the carbs are pulling air around the fittings on the pump during deceleration (high vac). That is would explain why everything looks good at idle or just setting still. You could test with a vac pump.
I have Tygon lines on mine with spring clamps.

[Czakky]

I'm not ready count my chickens yet, but remember that the injector lines on an R5 go straight to the hot cylinders too. So maybe the clear lines I bought work on an RD (carb fed) but might soften on an R5 causing them to open and pull in air.....

I'm going to be out of town for a few days, but hopefully I'll have an answer next week.