Kyle D
New member
Just opened a new to me 2002 srx700 to do maintenance. All 3 power valve cables were broken at the cables, not the end pulled through but frayed cables at ends. After monkeying with the housings and studying the diagrams only the PTO PV would come out willingly. The center and mag side cylinders were removed and variety of chemicals (brake Cleen deep creep etc. and heat) applied but the 2 remaining PVs won't give up their current positions. They are going for the hot tank soak this week to try to free them up that way.
I did a fair amount of surfing the forums and parts for sale and noticed the PVs don't match the PVs for sale. The difference is there is a point on the end yielding a bevel on the top that is 40% on top or combustion side and 60% exhaust side. It appears to be ground out as does the wall of the cylinder leading to it from the combustion side.
I'm assuming this is part of a porting job? There are also mega-power performance heads on it. There were also included a set of V Force reeds but seller included but owner installed the oem prior to sale.
Exhaust appears to be stock but I'm thinking this May have been a raced sled of some sort
So my questions are
Is this a port job and if so does it need bigger jetting to match increased airflow
It idles rough then goes up to 4000 Rpm then hang idles down & quits.
Carbs are coming apart so the jets get cleaned, what else besides a plugged pilot jet contributes to this?
Where can a full set of PV cables be purchased from? As well as gaskets for the PVs?
I have PMed a couple of times to folks on the forums but not heard anything back.
Anyone have thoughts or directions?
Ideas and direction greatly appreciated
Kyle D
I did a fair amount of surfing the forums and parts for sale and noticed the PVs don't match the PVs for sale. The difference is there is a point on the end yielding a bevel on the top that is 40% on top or combustion side and 60% exhaust side. It appears to be ground out as does the wall of the cylinder leading to it from the combustion side.
I'm assuming this is part of a porting job? There are also mega-power performance heads on it. There were also included a set of V Force reeds but seller included but owner installed the oem prior to sale.
Exhaust appears to be stock but I'm thinking this May have been a raced sled of some sort
So my questions are
Is this a port job and if so does it need bigger jetting to match increased airflow
It idles rough then goes up to 4000 Rpm then hang idles down & quits.
Carbs are coming apart so the jets get cleaned, what else besides a plugged pilot jet contributes to this?
Where can a full set of PV cables be purchased from? As well as gaskets for the PVs?
I have PMed a couple of times to folks on the forums but not heard anything back.
Anyone have thoughts or directions?
Ideas and direction greatly appreciated
Kyle D
joejammer
New member
- Joined
- Mar 19, 2014
- Messages
- 71
Power valve cables are available from Yamaha. They are expensive at around $50 a piece . Seal kits you can get from the aftermarket e.g. winderosa around $30.
Kyle D
New member
It certainly looks to have been altered or modded for some reason.The cut of the bevel looks like it was made into a V shape and a stock valve doesn't have that kind of cut on it.
I have never seen a power valve cut like that...only advantage I can see would be so you could install them any way you wanted as there would be no upside or downside.
Kyle D
New member
So far 2 of the 3 are out of the cylinders and all appear to be the same design. As they move in and out it looks to open up the airflow to the exhaust substantially.
Overnite soaking with PB Blaster and then see about cleaning all 3 up nice.
Has anyone been successful at the coating of power valves? These are looking tired and I am thinking a recoat may make them easier to clean
By the looks of them they haven't been serviced in quite awhile but I figure they are custom cut for a reason so I am hesitant to replace them
Anyone have ideas?
Thanks
Kyle D
Overnite soaking with PB Blaster and then see about cleaning all 3 up nice.
Has anyone been successful at the coating of power valves? These are looking tired and I am thinking a recoat may make them easier to clean
By the looks of them they haven't been serviced in quite awhile but I figure they are custom cut for a reason so I am hesitant to replace them
Anyone have ideas?
Thanks
Kyle D
There would be zero gain to doing that, actually youd reduce the compression down some and not gain anything, its just a void above the exhaust port, its not until the exhuast port roof raises or the valve opens it will gain power.