98-02 XP Carb 951 performance

[SabrToothSqrl]

To those of you who own/ride a 98-02 XP, Carb, Stock, 951:

When you floor it from idle (wide open throttle)

does your engine (tach) hit 7,000 RPM instantly, or does it hit say 5 or 6 then build up to 7?

I can recall mine being able to hit 7k off the line, but now it hits 6k, then builds to 7k.

I wanted feedback from people who use/own this ski... ONLY.

That way I can compare apples to... apples...

thanks!

 

[Dr Honda]

If your pump is in good condition... you shouldn't be able to hit full RPM off the line. If it's accelerating good... the "Out of the hole" RPM will be close to full... maybe around 6500. Then... as the pump unloads a little... the RPM's will come up that last 500.

Anyway... if it's staying down around 6000... that at least tells us the pump is OK... but it does sound a little low. Check the compression, the RAVES, and I would also check to make sure the carbs are opening all the way, and are in sync. One other thing... on the 951... as the reeds wear... they may be leaking back a little. Fresh reeds will help bring back a little of that "Crisp" throttle response. As an FYI... when I was racing MX, and Open Desert... I would change the reeds in my bike twice a year, and put a new piston and rings in every year. (Just to keep it running good)

 

[SabrToothSqrl]

Thanks for the help:

I've done the whole verification of RAVES, water reg, RAVE solenoid, clipped plug wires, new plugs, etc. I actually have NEW OEM carbs coming this weekend. SES engines also suggested new carbon tech reeds, which they are hooking me up with. I run a Solas Concord 15/20, and that's the ONLY mod. It does do between 6k and 6,500 from idle to WOT, then will rise to 7k, but I know when I bought it that it would slam to 7k and just hold it like a MoFo 24/7 any load, turn, etc...

It accelerates well, actually quite fast, but I know there's just a hint more of GO that it should or used to have... approx 120 hrs on the reeds, if they are the originals. I recall being able to jump/spin/slam it in turns and just hold 7k... (this is w/the Solas)

It will hold 7k all day WOT, I just want it to get there just a bit faster.


Pump has a solas with approx 10 hrs of use, same with wear ring.. approx 10 hrs... looks newer than new.

Engine has approx 4 tanks since new. (rebuilt from SES)
New engine, new reeds, new carbs, this thing should be at the peak of it's performance. (once I get all the parts in the mail lol)... mean time my '99 GTX project and garage reorganization need me... ugh.

 

[Dr Honda]

Personally.......... I don't like carbon reeds. They are stiff, and brittle. Because of that... their life is extremely short. Glass reeds have the best life, with good performance. Stainless reeds live even longer... but when they crack, it will cause damage.

 

[SabrToothSqrl]

How short is short? I'm really tired of messing with this thing... should I just stick w/OEM?

I have another set of reeds in my basement on my spare 951... i could remove those to put in this engine.

Or are the stiffer reeds what I need to get the performance I like? (I've only ever had OEM reeds).

 

[mikidymac]

Like I mentioned in your other post, same as DR. Honda. Just stick with new OEM reeds, they will geive you the best performance and longest life. I have seen full mod 951's running just fine on stock reeds. The carbon loose thir memory much faster and are not worth spending money on. Back in the day they had carbon rotary valves too.

 

[Dr Honda]

I've seen carbon reeds give up in 20 hrs or less. (as in, break) There were a few companies who were making 2 stage reeds with a glass upper, and carbon lower. (I didn't like them either) But they lived longer since the glass reed was doing most of the work below 3/4ths throttle.

OEM reeds are good. They will live for a couple hundred hours. Boyson glass reeds are some of the best. They will hold their performance for a long time... and regardless of that... they should live the life of the engine.

In all my years of 2-strokes... I've never had a boyson glass reed fail.

 

[SabrToothSqrl]

hmmm.... ok, I guess I'll toss in the OEM ones I have. It did snap to 7k, with OEM ones, but that leaves me back with not knowing what to replace / fix next... when the reeds wear out, do they show any wear? the ones I removed appeared to be in fine condition...

 

[mikidymac]

Look at the tips, they should be smooth and sharp. When they get old they will chip at the tips. The other thing is that they should be nice and flat to seal on the reed block. They should have good tension and there should be no gap between the reed petals and the block. If there is a gap they are done. I have had some new ones not seal so you sometimes haf to flip them over and try again, the Boyesen are notorious for this so you just have to try, flip, try, flip until you get it right.

 

[SabrToothSqrl]

by those standards the existing ones are fine... i thought about flipping them as well. too many choices!

if new carbs/reeds/engine doesn't fix it, i guess I have to give up and accept that it's fast enough...