more speed!!

[biggoof]

just got my 84 550l up and running(carb rebuild new non vacuum petcock),it runs really good but maxes out at 75mph! I hoped it would go a little faster than that.Once it hits terminal velocity it kind of surges then falls back then surges again..any ideas

 

[salty_monk]

Maybe some jetting issues with the main jet or air leaks or something. Surging means you're off somewhere.
We need a lot more details as to any upgrades, did you replace O rings in carbs, O rings behind intake boots etc.....

Dan

 

[BassCliff]

Greetings and Salutations!!

Greetings and Salutations!!

Hi Mr. biggoof,

The high-end "surging/hesitation" could be several factors, the worst of which would be your cam timing (chain off by a tooth?). Usually it's carb (main jets too small?) or air intake (leaks?) related. In rare cases it could be ignition related (bad ignitor, heat sensitive coils?). Are you running stock intake and exhaust?

Here is your official "mega-welcome". Please take notice of the "Top 10 Common Issues", the Carb Rebuild Series, and the Stator Papers. Now let me roll out the welcome mat for you...

Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

 

[biggoof]

thanks for the prompt replys you guys are fast(unlike my bike)
when I cleaned the carbs I had to replace a torn diaphram..the jets are stock I attempted to purchase the intake o-rings from the guy on this site but he was out of stock however I tried spraying a light lube on them whilst it was idleing and detected no change in engine speed.
Oh it does sometimes take a while to return to idle when the throttle has been cracked open..

 

[Guest]

Surging at WOT usually means lean. Put a bigger main jet in there or you are at risk of going BOOM! Check the color on the spark plugs.

OR

You have an igniter with a built in curve advance. This could be bad.

OR
You have severe intake leaks. Do you have a hanging or surging idle?

 

[twiggy2cents]

just ride with the choke on ;-) just kidding!! get a can of carb cleaner and spray that all around those boots, if it runs like crap and then recovers you need intake orings, you need them any way. If he is out of stock just get stock oem orings.

 

[nelson269]

where do you get these bigger jets?? I've got some of the same problems

 

[tejasmud]

"Terminal Velocity." :lol:

Welcome.

Hate to say, but yep, "terminal velocity" on a 550cc is about 75mph .

Pretty good I would say too, well, for a 550cc bike on the topend.

Teasing of course.

What are you running for filter(s)?

 

[twiggy2cents]

obviously you havent rode one, when mine is doing well it will pull the wheel on the 1-2 shift and easily goes up to 85+(i dont want to take it past that)

 

[Guest]

Do you have those weird dual quad carbs?

 

[twiggy2cents]

yeah, their really not weird just different. They are normal cv's with a twist kinda like sierra mist with a hint of grapefruit

 

[BassCliff]

where do you get these bigger jets?? I've got some of the same problems

Hi,

Here's one place:

http://www.motorcyclecarbs.com/Mikuni_Jetting_Components_C7.cfm


Thank you for your indulgence,

BassCliff

 

[Dan Ruddock]

Does it pull hard in 1st gear. If yes you might have a fuel flow problem, kinked hose, needle valves, rust in tank. Dan

 

[biggoof]

thankyou all.I'm going to replace the intake orings and throw a new air filter on and see how she makes out
PS suzuki want $7 per oring....ouch

 

[tejasmud]

obviously you havent rode one, when mine is doing well it will pull the wheel on the 1-2 shift and easily goes up to 85+(i dont want to take it past that)

Yes. I have ridden one, and they do run faster than 75mph when properly tuned. I just liked the expression "terminal velocity"

BigG,

Reason I ask about the filters/or air box would be an assumed lean condition. Surging is a symptom usually of lean, but rich condition as well in some cases.

Sounds to be getting additional air. Not really enough info, but first would be to change the o-rings, and ensure the air box side is all good assuming everything is stock.

If the exhaust "pops" a little when you let off the throttle in gear would be another indicator of leaks creating lean condition.