Engine Vibration (Possible Dampening? Does it happen to you?)

[Syndacate]

Hey,

I have a '97 750 - it's my first bike, I've been riding it about 4 or 5mo.

I have 2 questions, actually.

A) Holding it at about 6k-6.2k there is a good amount of engine vibration..you typically don't notice this when you're winding out the gears, perhaps because you're not spending a lot of time at that RPM. I typically feel this on highways doing about 70-75. It's enough that my hands are a bit "iffy" after 20min or so. Is this normal in prekats? It is definitely an engine vib, goes away if I clutch, or is still there if I put it to the same RPM and hold it there in 2nd or so.

B) Is there any (quick/cheap) way to dampen the vibration? I have gloves (Cortech GX-2 Air), they dampen it a good amount, but I'm about to make my first long trip this weekend (hopefully, if all goes well) and would like to know if there's anything I can do quickly to dampen it for the trip. Any tricks or anything? My friend mentioned bar dampeners, but I don't have time to wait for parts if I was to order them, and the only cycle shop in the area only caters to Harley owners.

Any help/advice would be greatly appreciated, thanks . As of now I'm just going to keep the speed at 60-65 and hope the vibrations don't get to me.

[paul.miner]

Pick up a crampbuster from a local shop, they help on long trips. It'll reduce the time you spend gripping the bar. Doesn't solve the problem, but it's a quick workaround for the time being.

[Kreylyn]

FP stage 1 jetkit, OEM everything else...

the vibrations are due to an overly lean condition at those RPMs. The jetkit allows you to smooth out the vibrations by increasing fuel delivery at the needed rpms.

About $102 + shipping from star cycles.


Krey

[scottynoface]

FP stage 1 jetkit, OEM everything else...

the vibrations are due to an overly lean condition at those RPMs. The jetkit allows you to smooth out the vibrations by increasing fuel delivery at the needed rpms.


Krey

Yep. I had to raise my needles one clip to help alleviate that exact problem.

93 600, Yoshi 4-1, Uni air filter

[yngveny]

+1 on the crampbuster or throttlerocker

Doesent remove the vibration but helps a lot comfort wise.
Also keeping a loose grip and use your legs and back to take weight off your arms

[Sasquatch]

what everyone said.


Also, get your carbs sync'd, and relax, do not get the 'gorilla grip of death' on the bars!

[1990gsx 600]

what everyone said.


Also, get your carbs sync'd, and relax, do not get the 'gorilla grip of death' on the bars!

many people have come to regret that grip. imho it reduces your reaction speed

[Syndacate]

FP stage 1 jetkit, OEM everything else...

the vibrations are due to an overly lean condition at those RPMs. The jetkit allows you to smooth out the vibrations by increasing fuel delivery at the needed rpms.

About $102 + shipping from star cycles.


Krey

From what I know about the bike it already had a jet kit on it. Apparently it was bought as a kit, the exhaust, the air intake (probably just a regular filter), and the jet kit, all bought to match. I haven't looked yet and aside from the vance and hines there's no way to really see it...although I do have the stock air box in the closet, it's possible the old jets are in there.

Why would it run lean? Just the jets need to be opened a little more or tighten the air screw a bit?

EDIT:
That cramp buster looks sweet for long trips, beats the **** out of $100 + in CC and you don't have to dick with the wires. Most of my driving is on campus now (*Cries*), so I suck up a nice 24mpg with all the ****ing stop signs every 50 ft. Though if I ever have a long trip, this would def. help. For $10, can't beat that. I'll have to pick one up, I've seen nothing but good reviews on amazon about it. In their promotion video, they make it look like it's the best thing since sliced bread.

[DClark]

I hate vibes. I use a carbtune to make sure the synch is perfect Synch, imho, is the most important way to reduce vibes.
I just got back from a 1000 mile ride on my bike. Here's how I deal with vibes:
Handgrips- gel type, with foam wraps around them. I wear finger less gloves which have a gel insert in the palm. Over those, I wear a regular JR glove which also has gel. With all of that, my hands are buzz free.

[katanarider]

I'm not a expert but if its a lean condition I would try all I could to alleviate that problem. I dont know for sure if what I'm thinking will work but its probably not too bad of a idea????
I would keep a full tank of high octane gas with the petcock on reserve the whole trip. That will push more fuel into the carbs due to gravity. Also, racing gas may help you out.
I might even try to eliminate some of the oxygen from entering the carbs /airfilters by restricting air flow in some fashion.

Maybe its not the best ideas but I know you would hate to burn up a piston or a valve.

[JayBell]

I'm not a expert but if its a lean condition I would try all I could to alleviate that problem. I dont know for sure if what I'm thinking will work but its probably not too bad of a idea????
I would keep a full tank of high octane gas with the petcock on reserve the whole trip. That will push more fuel into the carbs due to gravity. Also, racing gas may help you out.
I might even try to eliminate some of the oxygen from entering the carbs /airfilters by restricting air flow in some fashion.

Maybe its not the best ideas but I know you would hate to burn up a piston or a valve.

kats are lean from the factory for emissions reasons, your best bet to eliminate a lean condition is to pull he AF screw plugs, and reset them 2.5-turns out for stock, and 3 turns plus out for a jetkit... a colortune set can help get the right mix.

Also, high octane or race gas wont do anything to help, the Kat engine is designed to run on 87 octane fuel. Increased octane fuel actually reduces performance in an engine with stock cams and compression.

Instead, try high DETERGENT gas, or a cleaning fuel additive, i run Berrymans Chemtool b12 every few tanks to reduce buildups and issues from ethanol fuel, and water.

Running on reserve wont push more fuel..the carbs only carry so much fuel, thats what the floats and float needles are for, to ensure they only hold so much gas

every couple tanks i run on reserve for 1/4 tank to ensure I have removed ..."old" fuel, or whatever may be lurking at the bottom, tho its probably not necessary...and REMEMBER to turn it back to run!!

also, i have a post, which has a fule filter, if you have a filterless PRE, make sure your tank is RUST FREE before running i reserve.

[KAT TOY]

try putting lead shot in side your bars. you could seal the ends with rtv silicone. that would make a removable seal. +1 on the cramp buster.

[katanarider]

I thought the higher the octane, the higher the flash point. Therefore, race gas would take alot longer to ignite and cause a richer fuel mixture.

Edited: Higher flash point

and another possible solution: If your problems are at a certain RPM only, then why not switch one of your sprockets ? Its a quick fix.

[JayBell]

I thought the higher the octane, the higher the flash point. Therefore, race gas would take alot longer to ignite and cause a richer fuel mixture.

Edited: Higher flash point

and another possible solution: If your problems are at a certain RPM only, then why not switch one of your sprockets ? Its a quick fix.

Err...



you want useable fuel mixtures designed for the compression ratio the kat has, so, at that point, you need to increase your air/fuel mix, you do this by installing a jet kit, and tuning it correctly.

also, changing your sprocket ratios will just change the speed the RPM matches at, not the RPM itself.. you;ll still hit that RPM at some point.

[katanarider]

I wish I could actually watch that video but its taking too long.
Well be safe on your trip either way.
Peace