Would everyone recommend one or the other? Any differences. The Riva is almost 25 dollars more expensive. Any reason?

dsiggi, I don't have any first hand experience with this but I've heard the R&D has a smaller hole and gives the more desired back pressure.

keep your cat-con for a relatively stock set up..you'll get more speed and rpms

Yes, from the posts I have read it would appear the cat conv is the fastest, though the D-plate is a close second. R&D being slightly smaller is probably the better choice. I have also read numerous posts describing cat failures that occur around the 40 to 50 hour mark. So if you leave the cat in be prepared to replace it eventually .......

I've been told by the Yamaha region rep that the cat will break if you do not allow it to reach proper operating temps before thowing a full flow of exhaust at it by going WOT to soon.

Also the cat has had some revisions in production since inception.

You can pick up a spare cat from someone that removed if you want a spare,,

my 01 is approaching 60 hours with no problem.

my 00 failed at 40 hours when I tapped it WOT right off the trailer...

Not according to Stefan in Malta and a Yamaha Watercraft Division engineeer that I spoke to after Riding a Canadian XLT

From MaltaGPR


When I race with a US model, stock to stock i am always 5 to 6 boats in front

From dead start i am 3 boats front, after quarter mile i will be around 6 boats difference

What I can say is that when I ever raced with a US boat(as in Malta we have both us and europe boats) I was all the time in front and all the time making a bigger distance, and its no joke, maybe my boat was from the ones of 65-66 from factory

I didnt test mine today, hopefully I will tomorrow, what i can say is on my friends 00 GPR, he has exactly same setup as i do.

With jetting 1.5 N/S (90 gsm pop off) and 110 lows at 7/8 turn. (accelarator pump removed)

The Boat Kicks a** out of the hole !!!! I felt it more powerfull than with acc pump in place

--------------------------------------------------
I went out today with my GPR for testing, I ride in salty ocean water, so the boat porposes because sea is never calm in my country. I found a coast about 250m long with swell coming in so it wasent calm either.
My modifications are the following:

Riva Ride Plate
Riva Intake Grate
Riva Free Flow
Riva Pump Plug Kit
Solas 13/19
Skat Trak Impeller Boot
ADA 40 cc head
Tau Ceti F/A
1.5 N/S
110 lows (removed acc pump)
120 highs
95 gsm pop off
7/8 out on lows
1 1/8 out on highs, carb #3 is 1 3/8

In that chop i managed to spin the 13/19 7250revs and speed of 67.8 mph. in just 250 metre distance

The boat pulls hard , out of the hole is FANTASTIC !! I recommend people to remove that Accelarator Pump, less problems without it.

I will continue tuning my boat, I have in mind advent Cdi and porting of exhaust and cylinders.Ant recomandation about impeller ??

I use my boat for closed course racing so I need a good hole shot and accelaration, Im not such the guy to achieve top speed.

Thanks to all people posting on this forum, special thanks goes to : Brett @TSI, Fercho, Go Faster, Suzan GPR, Greg & also Riva

Thanks GUYS !!!!

.

This is from a guy who got to see the best of both worlds actually all three worlds, So you see Its all about jetting. The cat con runs so hot that it actually robs power because of engine air temp being so high. Feeding more fuel with the D-plate wakes up the ski.


Fercho

[ 05-06-2002: Message edited by: Fercho ]

[ 05-06-2002: Message edited by: Fercho ]

By the way I have two brand New cats for $175.00 each if interested.


Fercho

I paid $25 for a spare cat...

That little d plate will also put you in a class (IJSBA rules) of GPR'S with tripples! Now who is going to be faster? a gpr with dplate or your tripple project??

It all depends on your goals..lake drag racing or sanctioned racing

Wow in the class with GPR's with Tripples. Ouch!! I will probably just be grudge racing so it should not be and issue but always something good to know. Thanks again.

Anyone know why the riva is 1.5 times the price of the R&D?

Fercho

take a stock gpr with a cat installed.
remove the seat and run at wot on glass.
Feel the exhaust chamber near the cat for
temps with your left hand while running at WOT.. then do it with the d plate.


Let me know what you think

[ 05-07-2002: Message edited by: MDKOCHE ]

The US cat con ski has a lenaer jetting because air in the engine is very hot and second because any unburned fuel will actually burn in the cat and damage it.

Have you ever taken a look at a cat from a car that has a carb running rich??? Well, is Red-Hot.

The jetting on the US GPR has to be on the lean side throught the entire power band to prevent this from happening.

Fercho

[ 05-06-2002: Message edited by: Fercho ]

so are you saying that a gpr that has a cat problem is running too rich?

I thought cats on cars got red how when they were clogged and/or calasped on the inside? not from running rich..

No i did not say that but Yamaha also claims that the use of unproper oil will deteriorate the cat because of this same reason, The oil will burn in the cat raising the temperatures. The cat for 2002 was redesigned according to Yamaha

MD I had a car whose carb was not properly repaired by GoodYear. I was fouling plugs and my brand new cat was glowing. Eventually the honeycomb inside collapsed and it was completely clogged, because the fuel was burning in the cat, Top speed was 25 MPH. We settle in court. I got a new cat carb and entire emmisions system.

Read this
web page

[ 05-06-2002: Message edited by: Fercho ]

Fercho

I have always wondered why my jetting (Canadian boat) was so different from the US boats. Because there is no fear of excess fuel burning in the Cat the ski can be jetted far richer than the US boats? The richer jetting provides better performance and less risk of seizure.

With a stock US ski, if you changed just the cat for a D plate would it go faster, slower or stay the same? I will be honest I don't have any firsthand experience comparing the two. I know Carl at Island Racing contends the Cat is the fastest.

But from your post if you change out the cat then you really also want to change the jetting - the real gain to be had is not from the D plate but from the jetting the D plate allows you to use.

I think I may have learned something tonight.

Phillip after talking to the Yamaha Engineer, not a rep and revising everyone's opinion everything falls in place.

The only way to actually confirm Carls theory is by having an American and a European spec GPR side by side. Malta had then and tested tham back to back as you can see. So i have to disagree with Carl on this one. It is ony logical that installing a d-plate on a cat-con jetted GPR will not perform its best.

Pro tunners have always looked for a way to introduced cooler air for a better combustion and a cat-con in the engine compartment does completely the opposite.

Some Canadian GPR have been introduced with the Cat Con in place and the jetting is the same as the American GPR's while the 2000 Canadian Cat-less gprs have a richer jetting only because they require more fuel.

If properly jetted a ski with a D-plate installed should accelerate faster and out run an GPR with a Cat con in place.

Here are two more opinions from other members

OhioGPrider
New Member
Member # 1979
posted 04-18-2002 02:05 PM
--------------------------------------------------------------------------------
My friend just bought a 2000 GP1200r and the first time out was yesterday.The speedo said 105 at top speed.I noticed that it is reading in KM/ph.
Does this mean this ski came from Canada.Would this mean it does not have a cat.converter.This ski seems to run better that the 2001 I rode last year.

GP1200R-acer
Member
Member # 713
posted 04-18-2002 07:38 PM
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All I know is its true, the European GPR (mine)out performs the standard cat con verson!

[ 05-07-2002: Message edited by: Fercho ]

Fercho
did that Yamaha engineer tell you the difference between the cat con and D plate GPR's cdi's and carb's? Are you 100 % sure that the carbs and cdis are identical between the two models?

Also did you call Japan to speak to this yamaha watercraft engineer? Didn't think they were imployed in the USA?

The European boats have much richer jetting and three accel. pumps. We suspect the CDI timing is the same

If this makes sense I suspect we are all right.

1) By proper warming up the Cat it will last longer

2) US boat with stock jetting with Cat will have a higher top speed than the same boat with the Cat replaced by a D plate

3) US boat with custom jetting with Cat replaced by a D plate will have better perf than a stock jetted cat equipped boat.

dsiggi
So, if I have this right if you replace the Cat with a D plate to get the best perf. you should also change the jetting. If you don't want to get into doing jetting changes it may be better to keep the Cat - but make sure you warm the Cat up properly.

[ 05-06-2002: Message edited by: Philip_GPR ]

[ 05-07-2002: Message edited by: Philip_GPR ]

MD this Engineer was here in the US he rode an XLT and was wondering why the hhell it accelerated so fast, he removed the seat and found no cat temp probe on the oem pipe, he later found out that he had ridden a Canadian ski.

I spoke to mikuni in reference to the carbs. The machining of the carbs is identical, the throttle plate has a different angle cut but this is only affect idle speed.


Also did you call Japan to speak to this yamaha watercraft engineer? Didn't think they were imployed in the USA?

What are you a wise guy????

[ 05-07-2002: Message edited by: Fercho ]

no I call Japan every other day for work..thought you might do the same..most speak very good english too..was he Japaneese? or working as a US citizen with a temporary work visa in Japan?

now are you sure this engineer was really a yamaha watercraft engineer? what component was his group responsible for designing? powerplant group? electrical group? hardware group? pump group? BS group? just kidding

[ 05-07-2002: Message edited by: MDKOCHE ]