disintegrating float bowl gasket?

well - i've enjoyed about 350 miles of trouble free engine performance. until yesterday, that is. exhaust started popping while engine braking.

i rode to work this morning and got more popping at low rpm's.

the last time i had my carbs off (to put larger pilot jets in). i noticed a bunch of black "flecks" in the bowls. i had been running a pretty high concentration of sea-foam at the time and chalked it up to the sea-foam eating my float bowl gaskets.

well, no sea-foam in the last 3 or 4 tanks of gas, and i'm running lean again. . . i'm guessing my float bowl gaskets are crumbling apart and clogging things up.

i was just wondering, before i go ripping the carbs off (again), if anyone has experienced this before?

 

BUMP

so i looked and bike bandit has replacement gaskets for around $35. i called the local auto parts store and they carry sheets of gasket material that claims to be appropriate for making float bowl gaskets for $5.95. (1 sheet should do).

so - anyone ever have any luck making their own float bowl gaskets?

 

I've been cutting mine out of Fel-Pro rubberized gasket paper (grayish-black)... You can get a roll of this stuff for a few bucks at a parts store. It helps to have a sharp exacto blade... I got a leather punch tool at Harbor Freight to make the screw and enrichment tube holes.

 

cool. thanks for responding.

 

$35 !!! my mikinuni's were like $4 Cdn
From my local dealer

Then again the larger word there is Bike BANDIT
Chose the name well I think... some of the prices are crazy high

Did you check with Chacal?

 

D-I-Y Carb Bowl Gaskets.

Color the Mating Surface of the Bowl with Lipstick.
Press the Bowl down onto Gasket Paper that is Taped-down flat.
Don't "Smear" the kiss.

X-acto Knife the Inside portion of the Gasket Paper to be removed.
X-acto -or- scissors the Gasket Paper Material on the outside.

Use a Leather-workers "Watch-band Hole Punch" to make the various precision hole cuts for Tubes and Fasteners.

http://www.bestofferbuy.com/index.php?m ... h3g0122881

 

for accuracy's sake - it was $35 to replace all four.

thanks for the tip, rick - although i don't think my wife has any lipstick - i'll come up with something, though.

 

$3 a piece plus $7.95 or so for shipping. Less that $20 shipped.

http://www.carbkitscapital.com/carb_kit_list_model.php?make=Yamaha&model=XJ750

 

I don't think it's the SeaFoam eating the gaskets; it may be eating the floats?

First bit of advice: I noticed an appreciable negative effect on how my 550s ran under the influence of SeaFoam. It was my impetus for switching back to Sta-Bil for winter storage. I wouldn't run SeaFoam all the time.

Second bit: I would simply buy proper replacement gaskets; check with chacal or any of the sources posted. DO NOT buy them from the Yamaha dealer, then you will get hosed.

You never answered about an inline fuel filter?

 

sorry about the no answer - yes, running an inline filter.

the last 4 tanks of gas haven't had any sea-foam - just gas.

i wouldn't be surprised if the gaskets that are in there are not the correct material. all i can say for sure is that the last time i had my carbs off, there was a bunch of little black flecks in the bowls - looked a lot like the gasket material.

i've been picking up a LOT of overtime at work lately, so i haven't had time to pull my carbs off and look at them, but i'm pretty sure i will see more little black flecks.

i also have brand new fuel line - so i don't think that's it, either.

thanks for the link, rpgoerlich - sometimes i forget how much it pays to shop around. i'm starting to lean towards buying replacements instead of worrying about whether the material i use will come apart and cause me more problems.

however - out of curiosity - why do you guys (stereomind and rickomatic) punch holes in the material instead of drill holes?

 

it makes a cleaner cut

 

I get my gasket material from the bearing store, it cost $8 for a piece 0.8mt x 1mt, enough to last forever.

 

well, i'm on day 9 of 12 12hr midnight shifts in a row - i've been pecking away at this every morning after work for a couple hours and it's looking good.

i thought long and hard about going up one more pilot jet size and decided against it, as the bike performs great - except it kinda struggles to get from 5k to 6k RPMS. this seemed to me to be more related to the needle position, so i stuck another washer under each one. we'll see how that goes.

this morning, i buttoned everything up and put the carbs on and she fired right up. didn't even need an initial helper shot of starter fluid. all the pipes got hot and the bike sounded nice and smooth*. i put some cardboard under the carbs to help see any dripping gas - and there was none. so my home made gaskets seem to be holding.

stereomind - thanks for recommending the fel-pro rubberized gasket paper, i was able to find some at a local auto parts store for $6.

as per Rick's suggestion, i tried the lipstick** and it worked good. I also used a tiny bit of RTV on the corners of the bowls to hold the gaskets on and marvel mystery oil on the carb body and other side of the gasket (also a rick suggestion from another thread).

i didn't buy a punch to make the holes, but i did try drilling one in some scrap and can definitely see why you wouldn't want to drill the holes. i was able to "borrow" some [i'm not sure what they're called, but they kinda look like spent .22 casings] from work and punch holes using those and a clamp. worked good.

all said and done, i'm not sure if i would cut my own again - it's pretty painstaking - if i paid myself minimum wage to cut the gaskets, it would've been cheaper to just buy them. but hey, i saved like $15 - that should at least justify a case of beer.

tomorrow morning i'll put the airbox boots on and take her for a shake down run. wish me luck.

*not to get into the harley bashing thing, but i do think it's kinda funny how the crappier my bike is running, the more it sounds like a harley.


** i can't believe the price variation on lipstick - you can spend anywhere from 97 cents to $6 on a stinking tube of lipstick. WTF?

edit: i wanted to add - i can't begin to stress how nice it is to have another, reliable, bike to ride while working on my Seca. It's fun enough to ride that i'll keep fixing it (as long as it's not crazy expensive) - but before i had a spare bike, i would rush through jobs as fast as i can so i can get back to riding. now - no pressure, just ride the KLR, you'll get it when you get it and take your time and do it right.

 

AAAAAAAAAAAAAARGHHHHHHH!!!!!!!!!!!!!!!!!!!!!!!!!!

ok. now that i got that out of the way. here's how the shakedown run went:

started the bike up and it idled good. took it for a spin down my road (about 2 miles of gravel, 1 miles paved. heard a few pops, but convinced myself it was rocks getting kicked up.

once i got to the pavement, i deliberately revved up and cut the throttle to see how my engine braking was. all seemed well.

once i got to the end of my road, i took a left on the highway and headed for the nearest gas station - about 10 miles away.

the seca seemed to perform great until i got to 5th gear and tried to go above 5k RPMS. she just wouldn't do it. i slowed down and tried it a few times. i got a kind of surging thing going on - like, ok there's power, oh wait, nope no power, the, ok, here ya go, have some power kind of thing.

i figured i was maybe too rich from putting the 3rd washer under the needle, so i got to a steady cruise at 4k rpms and threw the choke on to see what would happen. the bike responded very similar to what it was doing at 5k+.

so i pulled into the gas station convinced all i had to do was remove the 3rd washer and see if that improved anything.

rode home on the hiway with the same results.

HOWEVER - when i got back to my road, going slow - i tried some more engine braking and when trying to engine brake from 5k to 3k rpms it sounded like i was making popcorn. i then noticed that the bike had no engine braking about 3k rpms - so i'm running lean???

it occurred to me that something might be opening up an air leak as the engine warms up so i pulled into the garage and left the bike running and grabbed the propane to look for air leaks - found none.

as i was preparing to pull the tophats off to remove the washers from the needles, i noticed my fuel filter was nearly empty, so i started thinking gas tank vent or petcock. i hooked up a tube to the vacuum line and verified that the petcock is working ok.

i could use a little info on the gas tank vent - there's no mention of it in my hayne's manual . . . from what i can tell it's venting ok, but i'm not sure how to check it.

and that's where i'm at - any insight would be appreciated.

 

I am a little late, but I used RTV gasket maker making sure there is none in the bowl at all.

 

no takers? i'm really at a loss here. also - for clarification - what i was asking about the gas tank vent is - where is it? i'm assuming it's in the tank cap somewhere, but without disassembly, all i can see is a latching mechanism with a rubber gasket.

i "checked" the venting by putting it on prime with the cap closed and gas comes gushing out.

 

well - i made some progress today i think.

i took 2 of the washers out (left just one in) and the bike performed much much better. pulls through 5k alright and i still have engine braking.

i'm still getting popping in the exhaust, though. it only pops when i engine brake while the bike is under load in the neighborhood of 4k rpms.

i checked the plugs and they are just barely off white. they don't look fouled at all.

the only other thing i noticed is that my fuel filter keeps filling up with air. whenever i put the fuel line back on, i have to kind of "massage" the fuel line to get the filter to fill up with gas. after i ride for a little while, the filter just has a little bit of gas in it.

because of this, i tried looking into my gas tank vent. i took the cap apart and found what looks like might be a missing piece.



i can see what looks like a ball bearing in one hole, and the other hole is empty. don't know if this could cause anything or not.

i also know i have an exhaust leak right where the 4 headers come together - do you think the leak is causing the problem? or do you think the leak is the actual problem? i.e. if it weren't for the leak, i wouldn't hear the popping and all is well . . .


thanks again, for any input.

 

I just pulled the bowls after using RTV. It works, but make damn sure there is nothing in the bowls. The gas just melts right through the RTV. So I would not advise.

Going to make my own gaskets next time.