Fender Bubbles

[Iriebiker]

Suggestions on preventing the manifold heat from "bubbling" the front fender on the '99 GS500? I'd like to replace the heat-warped fender once the heat problem is fixed.

Candace

[Kerry]

Unless the engine is running abnormally hot due to a too-lean air/fuel mixture, the best thing you can do is make sure the bike is MOVING when the engine is running.

Since the engine is air-cooled, it's not a good idea to leave it idling on the sidestand or in stop-and-NO-go traffic (long traffic jams).  Either keep the bike moving or turn it off to keep it as cool as possible.

Example: The conventional method for synchronizing the carburetors involves running the engine while the bike is sitting still.  The instructions I read before synch'ing my carbs said to aim a good-sized fan at the engine (from the front) during the procedure.

I have synch'ed my carbs 2 or 3 times now, and have been caught in 40-minutes-for-2-miles traffic snarls in the HEAT.  I have logged 30,000 miles on my bike, and so far no melted fender.

PS - My bike is a '99 too!  I broke the front fender when I broadsided a cow at 45mph a few years ago, so I bought  a used fender from someone parting out their '99.  Wouldn't you know; the fender arrived pre-wrinkled from engine heat!  :x  I still haven't put it on, but one of these days....

[hehehemann]

I broke the front fender when I broadsided a cow at 45mph a few years ago

:lol:  how'd you manage that??

[Iriebiker]

Thanks for the speedy reply! There's not much traffic here, so the bike gets plenty of airflow on the road. And I don't leave it idling (on or off the kick stand). How difficult is the carb sync procedure? I'm not experienced at that sort of thing and I'm wondering if a shop mechanic may be the way to go for me.

Candace

[Kerry]

I broke the front fender when I broadsided a cow at 45mph a few years ago

:lol:  how'd you manage that??

Two-lane mountain road, passing a string of cars.  A cow that I thought was stationary on the side of the road decided to cross.  I was actually going about 65; 45 is my estimate after nearly a second of laying rubber with my brakes.  The car beside me (that I thought would hit the car for sure) slowed down in time, and Bessie was all mine.  

INexperienced (4700 miles)   , IN a hurry  :x ... and therefore INevitable.  

Be careful out there!  

[Kerry]

There's not much traffic here, so the bike gets plenty of airflow on the road. And I don't leave it idling (on or off the kick stand).

Hmmm.  You wouldn't happen to have a 2004 faired model, would you?  I wonder if they heat up more readily than the earlier naked models...?  Otherwise, like I said, maybe it's running too lean.  Pull both plugs (use the spark plug socket thingie in the under-seat tool kit, or an 18mm wrench) and check for an overly-white color.

How difficult is the carb sync procedure? I'm not experienced at that sort of thing and I'm wondering if a shop mechanic may be the way to go for me.

It's fairly easy. (Well, easier than removing the carbs, but not as easy as changing the oil).  Once you've had the tank off a few times it's pretty staightforward.  BUT for the "conventional method" you need some tools that most folks don't have: a carb synch tool and an auxiliary fuel tank of some kind.  I bought an "economy" Motion Pro synch tool from Chaparral, but several folks have come up with homemade designs for around $5.  For more info, see the old thread Carb synch and follow all the links to a few other threads.

Someone else came up with a "tool-less" method that didn't require a fancy synch tool.  Let's see, where was that...?  Ah, here it is!  See the post by Lars toward the end of the How to synch the carbs? thread.

(The Search feature at the top of the page can be your friend, but sometimes only when you can remember what to search for.... )

[Iriebiker]

I got "mechanical" and checked the spark plugs. Neither look overly white. It's a naked 1999, no mods. When I purchased the bike it had just over 2,000 miles on it and the fender was already bubbling. :dunno:

[pizzleboy]

OH NO!  Not the COW story AGAIN!!

<pizzle runs and hides>  

[Kerry]

Hey, I tried to keep it brief and to introduce a new little detail or two.  (You keep something back for the folks that join up later, right?)

Just wait until I get my hands on the X-rays (sorry, radiographs) from THAT little incident!   :mrgreen:

[Kerry]

It's a naked 1999, no mods.

My bad ... I had already acknowledged that we both have '99s.  

When I purchased the bike it had just over 2,000 miles on it and the fender was already bubbling. :dunno:

OIC.  So the only question now is whether you're sure that the fender has continued to "bubble" since you bought the bike.  If not, then I would chalk it up to the Previous Owner and forget about it.  

[The Buddha]

OK make sure the front suspension is not drooping or sinking too much. Or you haven't lowered the front more than an inch or so... if you are very light and dont ride very hard.
Cool.
Srinath.

[Iriebiker]

It does appear to have bubbled more since I've had the bike. I am light (chick, around 130) and I don't ride hard. I haven't adjusted the forks.  I have no idea what the previous owner may have done to the bike. The fork does seem squishy soft, but I'm comparing it to my mountain bike.

[The Buddha]

OK your bike might be extra lean, also try wraping the headers in that header wrap they have. People have seen the mufflers glow red from the heat when its running lean. So the real solution may be to rejet.
Cool.
Srinath.

[Iriebiker]

Rejet? Tell me more... What do you recommend and will it cost a few arms and a leg?

[Iriebiker]

I spoke to my brother-in-law about a possible rejet and he had an idea on something to try first. This bike is a '99 with only a few thousand miles on it, which means it sat around a lot. The gasoline could have "varnished" things in the carbs, making it more narrow. He suggested running some injector cleaner in the next few tanks of gas and see if things improve.

[Kerry]

Good thinking!  If you don't get good results using that method you might try some Yamaha carb cleaner.

I've never used it myself, but our resident guru Srinath swears by it.  To read some of his posts on the topic, do a Search at the top of the page for "yamaha carb cleaner", with the "Search for all terms" option selected.

When I do this I get 9 hits.  Ignore the first 4, and start with the bottom one.  Read the next 4 above that if you like to be aware of all the "nuances" before you make a decision.

PS - I have never rejetted my '99, but then I live at 4850 feet of elevation.  I imagine the air is a little thicker down there near sea level....  

[The Buddha]

Rejet on a stock bike is under $15 parts and a saturday if you're a newbie. Oh BTW you'll need a drill and drill bits in addition to wrenches, sockets and screwdrivers. Also varnish... it might affect the low speed more than up high. So if it idles right and runs OK at low speeds varnish is not an issue uaually.
Cool.
Srinath.

[Iriebiker]

It's a cold starter and doesn't idle well until the engine gets a little warm. After that warm-up period, the bike runs fine at slow and highway speeds. Being a Newbie, I'm not sure I'm ready to tackle rejetting the carbs. I may have to shop it out to friends for a 12-pack or two.  

[The Buddha]

They are simple, If you want to start small... shim the needles with a #2 washer first... make sure you dont lose the O ring and make sure the diaphragm sits back in right... It will, just need to use the plastic top part to get it in place and hold it there, and screw in the bolts.
Cool.
Srinath.