787 Can't hold Top Speed

[dcjar]

Just picked up a 97 SPX. I am now the third owner
Great hull, a ton of fun, however I am having issues at wide open throttle. It bounces of the revs, like it is hitting a rev limiter. It starts alright, with a bit of priming, and it runs mid range beautifully. Has no problems at low revs at all.
My only thoughts would be related to the carbs as they are aftermarket (I have no idea which brand), and that maybe they aren't calibrated correctly.

Any thoughts on this problem?

 

[AdamXP800]

Do you have the grey tempo fuel lines?

 

[dcjar]

Yep, I got the gray lines. 1st thing on my to do list is to replace em.
Will they affect the engine that much?

 

[Spimothy Leary]

they can if your not getting full fuel flow.

I wouldn't run it WOT until after those lines are changed, then revisit the issue and see if it repeats.

Also a great idea to pull , inspect & clean the fuel selector while your in there.

 

[AdamXP800]

I wouldn't even fire that ski up again until those fuel lines are history

 

[AdamXP800]

You will need to go through the carbs thoroughly as well. The internal filters are most likely jam packed with crud

 

[Mekanix]

If those aftermarket carbs have filters to begine with !

Any brand names on them? Got pics ?

 

[dcjar]

I guess the Carbs are R and D(?).
Here are a few shots of the engine bay.

 

[Mekanix]

looks like stock carbs with an R&D flame arrestor. I'd bet there are some dirty filters in those on the forward side of each carb under the covers.

 

[dcjar]

Does that require removal of the carbs?

Any thread with an in depth description of that process?

So I replace fuel line, take off carbs toss in fuel cleaner, polish r up. And pray?

 

[Spimothy Leary]

the carb filters are inside the carbs,,, just a few screws.

 

[CReynoldsMIZ]

He's got a rossier pipe as well.

 

[AdamXP800]

dang the purple rossier pipe threw me off. I completly missed that. Good eye

 

[Ruskeyjdm]

Nice setup

That pipe has plenty of gasket maker sandwiched between the manifold for sure

 

[dcjar]

What is a Rossier pipe?
I am so new to this and ya'll are tossing out some complicated vocabulary.

 

[Mekanix]

Aftermarket performance exhaust pipe.

 

[Spimothy Leary]

Aftermarket performance exhaust pipe.

and IMO a good one