Another max RPM issue

[JJinSC]

Ok, last year, I replaced the bellows, springs, caps and o-rings in the RAVEs. However, I still had oil leaking out of the RAVES. So, I took them apart before the season and found that the guillotines and the housings were worn. So, I replaced them this year and put it all back together. Now I am not getting max RPMs. Today, I tried turning the red caps out to the flush position and still no max RPMs. I have, however found that if I let off the throttle at 3/4-WOT and then hammer it to WOT again, it will then jump up on the RPMS. I have to do this every time I want to go WOT or it will not catch MAX RPMS. The RAVES seem to slide easy by hand. Any ideas on what could cause this with complete rebuilt RAVES?

 

[spx800]

What are you seeing WOT?

 

[JJinSC]

I don't have a tach, but I know the ski and there is a noticeable difference in MAX RPM and what I am getting. You can also hear when I do the trick (Hammer the throttle at about half throttle) it only goes to that same RPM that it does without hammering the throttle and then a second later you here and feel the increase of RPMs. If I had to guess I would say at least a difference of 500-800 RPMs.

 

[Spimothy Leary]

hmm, thats a weird one, but a tad difficult w/o a tach....

is your water regulator on the waterbox in good shape ?

 

[JJinSC]

hmm, thats a weird one, but a tad difficult w/o a tach....

is your water regulator on the waterbox in good shape ?

I removed the cap on the water regular to inspect bellows, retaining clamps, springs, etc. and all looked in good order.

 

[JJinSC]

Any other ideas??

 

[JJinSC]

Ok, so I do not have a tach, but I do have a GPS. When I go full throttle I only get 50.7mph. If I let of the throttle for a couple of seconds and then hammer it all the way, the RPMs definitely goes higher and I get 57MPH on the GPS. It feels like maybe the RAVES are not opening all the way, but I have completely rebuilt them (all new parts including guillotines and housings) and they seem to slide up and down fine by hand. Any ideas on what else to check for?

 

[SabrToothSqrl]

does that ski have an accelerator pump? sounds like when it shoots in the fuel you get that last boost in performance.

 

[JJinSC]

What would cause this behavior? This only started after rebuilding the RAVEs.

 

[JJinSC]

Bump bump..

 

[Strizzo]

it does have an accelerator pump but it only "squirts" as the throttle is first cracked open, so thats not the reason.

when i cleaned my raves, it didn't seem like they moved as smooth as before, and it took a bit of running before they were good and coated with oil and moved smoothly again.

 

[JJinSC]

Well, I go this RPM issue worked out. It does seem like it was a combination of the new guillitines needing to get good and lubed with oil as well as needing to tune the red caps. I have them 1/2 turn above flush. But before tuning the red caps, I did find that the rear RAVE was not wanting to move as freely. Apparently, I had the little plastic piece that screws onto the top of the guillotines a little too tight on that one. I am not sure how this affects the movement of the RAVE, but when I loosened it just a tad, everything was moving fine again. Now I am getting max speed and RPMs.

 

[seneca]

Well, I go this RPM issue worked out. It does seem like it was a combination of the new guillitines needing to get good and lubed with oil as well as needing to tune the red caps. I have them 1/2 turn above flush. But before tuning the red caps, I did find that the rear RAVE was not wanting to move as freely. Apparently, I had the little plastic piece that screws onto the top of the guillotines a little too tight on that one. I am not sure how this affects the movement of the RAVE, but when I loosened it just a tad, everything was moving fine again. Now I am getting max speed and RPMs.

I cleaned mine yesterday and am having the same issue - nott getting max rpm and speed. How far on do you screw the black plastic cap on to the guilitine? All the way or part way? What do the red caps do and how do you adjust?

 

[JJinSC]

I normally just screw them down all the way and just snug them, but for some reason on this one I had to back it off about 1/2 turn and then turn my red caps on both out to flush+1/2 turn. By turning the red caps,you adjust the tension the spring puts on the valve. This is suppose to fine tune when they slide open. The more tension you put on them the higher in the RPM scale you will get before they slide open.

I use a pair of needle nose players to turn them. On the MAG side, I have to remove the black valve cover that houses the red cap to adjust, due to the exhaust.

 

[seneca]

Thanks JJ! All is good now. Makes perfect sense now. Too much spring pressure not allowing the gas presuure to open the valves.
Runs better than ever now.