GS450t- stupid newbie question

[mhardig]

Last fall I purchased my first motorcycle, a GS450t. Bought it at a yard sale for $25, with a helmet. Put a battery in it and it started.

there were some minor issues, broken taillights, some frayed wiring, but I managed to get pretty much everything fixed. When I parked it last fall (I still haven't ridden it yet, I have to go take my ABATE class in April) it was starting rough.

Since then I discovered the connector from the inductive sensors had an intermittent open. I squished the metal connectors a teeny bit, and now it starts immediately.

Trouble is, it also immediately begins to race, and I always get nervous and turn it off before it can get too far. Is this normal? I've searched here and found people who say it's most likely a leak around the carbs- the carb boots are crap, but I've glued them together with silicone and so forth, and put fresh O-rings behind the plates, and they seem not to have any leaks (I'll buy a brand new set before I ride it) so I don't think vacuum leaks are a problem. Any ideas, or should I start with the new boots and go from there? My aim is to have this on the road for under $100 (I have $82 invested so far). Once I start riding and enjoy it, then new tires, new other stuff will follow.

Thanks for your patience!

 

[Jethro]

1. Have you tried to vaccum synch the carbs?
2. Are the synch port bolts back in place?
3. Is the bike in stock configuration?

The carb boots can be huge. I have tried to seal a bad set, and even checked for leaks with (gasp!) carb cleaner spray. Even when I had no jump in rpm's with the carb spray, new boots fixed a poor idle condition. I'd suggest new boots before going further.

 

[mhardig]

Ok, that's next then

Ok, that's next then

I don't know if this 'carb synching" of which you speak- but I WILL be getting the new boots just because. As I'll have to anyway, I might as well. I cobbled 'em together to try to make it whole, but I might as well do it right. Thanks, I'll get those and post my next stupid queston in a week or two!

 

[focus frenzy]

I am asuming you have the choke on.

with the choke on the idle will go up pretty high, you just slowly back it off to keep the engine speed at a resonable level till the engine is warmed up good.

 

[mhardig]

Okay, here's what I did:

I started the bike (starts in a turn of the starter, almost instantly) and backed off the choke about halfway. At this point, if I gave it some throttle it would run up unless I backed off on the choke. So I let it idle with the choke about halfway on then let it warm up for about a minute and a half. I slowly backed off the choke until it would idle by itself with the choke all the way off. Whole thing took probably less than two minutes. At this point, I could give it throttle and it wouldrun up, seemed very smooth, and as soon as I let off the throttle it would return to idle. Seems like it's gonna be fine.

I'm gonna get new boots on principle, but at least I know these are sealing well, it was only my inexperience causing the problem. Thank you both for the excellent advice!

 

[tfb]

Yep, get the new boots. Silicone is not fuel-proof. In fact, one of my favourite ways to remove old silicone from gasket surfaces is to rub it with rag soaked in petrol. It goes all crinkly in no time. So guess what will happen if you use it on your intake manifolds...

Mike.

 

[mhardig]

ooh, ick!

ooh, ick!

Thanks for the warning, Mike. I've never heard that about silicone, is that true of Black RTV? I thought that was meant to be used in Gasoline. Anyway, the new boots are a good idea all around, and I'm glad I got the thing running well enough to at least test it. Any idea on ways to keep those spensive boots from turning to inflexible concrete? that's why the old ones broke off.

 

[earlfor]

The color of the silicone makes no difference. None of it has any use on a motorcycle. I wouldnt worry about your new boots. It takes many years for them to harden and crack. UHhh, about 20 or so. LOL

Earl

Thanks for the warning, Mike. I've never heard that about silicone, is that true of Black RTV? I thought that was meant to be used in Gasoline. Anyway, the new boots are a good idea all around, and I'm glad I got the thing running well enough to at least test it. Any idea on ways to keep those spensive boots from turning to inflexible concrete? that's why the old ones broke off.

 

[tfb]

Yeah, I'm with you on that, Earl... the only times I've been caught using silicone is when I've been busy trying to do a 'repair' on the cheap!

If you must use some sealing compound on a fuel-ish area, use some Permatex "non-hardening gasket cement" (or whatever equivalent they have at your local auto store). It's fuel proof, heat proof, flexible, and comes off easy with a rag soaked in methylated spirits.

And there's nothing you can do about those boots hardening and cracking. It's inevitable. Best to buy a set now before Suzuki stop manufacturing the part! 8-[

Mike.

 

[mhardig]

"None of it has any use on a motorcycle"

"None of it has any use on a motorcycle"

I'm surprised to hear someone say this. To my knowledge, there isn't an auto manufacturer, or second tier manufacturer, who doesn't use tons of the stuff- in fact I've installed several systems at Bosch, Allison, Borg Warner, and several other places that dispense room temperature vulcanizing (RTV) gasket materials as seals on everything form transmissions to windshield wiper motors. Is RTV taboo on bikes? And if so is that a traditions thing, or are there specific reasons why RTV isn't used?

 

[earlfor]

RTV when it spreads on a gasket, oozes on both sides. Any that comes into contact with hot oil or gas will turn into jello-glue. The oil passages are small.
Using it in place of gaskets on float bowls will guarantee clogged carb passages.
It isnt a traditional taboo for me. I have opened too many engines and found the slimy gunk. Certainly, anyone is free to use as much of it as they want, anywhere they wish, but If I need a gasket compound, I will buy some Three Bond for the purpose. I say again, if I see any mech using a silicone in engine assembly, he will never do any work for me.

Earl

I'm surprised to hear someone say this. To my knowledge, there isn't an auto manufacturer, or second tier manufacturer, who doesn't use tons of the stuff- in fact I've installed several systems at Bosch, Allison, Borg Warner, and several other places that dispense room temperature vulcanizing (RTV) gasket materials as seals on everything form transmissions to windshield wiper motors. Is RTV taboo on bikes? And if so is that a traditions thing, or are there specific reasons why RTV isn't used?

 

[tfb]

Well, you're right, it is popular stuff, but there aren't too many places on our bikes where I can think that the original manufacturer specifies it. The occasional clutch-cover bolt on some models should get a smudge of it, according to the manuals, but that's all I can think of. Suzuki do have their own proprietary stuff, 'Suzibond' or something it's called, but I'm fairly certain that's not silicone.

If you want to use it, you have to go sparingly with it or it just 'beads' inside and out. The outside stuff we wipe away, but the inside stuff... it sits there in beaded globs, just waiting to harden and then come away, and float off somewhere to block something. OK, that's a worst-case scenario but in a carbie it will mess things up for sure. Never use it on a carbie or near petrol, because it does dissolve in petrol.

Whenever I need a sealant, I use something non-silicone. And whatever I use, I use it sparingly!

Mike.

 

[mhardig]

Ah, gotcha

Ah, gotcha

So it's mostly about retards who have no idea how to use it.

I'd never use RTV on any carb parts, bike OR car,it's just stupid. THe boots I have, I disassembled, bead blasted, blanchard ground the mating surface until it was flat, sanded the old boot surface to roughen it, then used black RTV to attach the disconnected boot to the plate. After it completely cured, I removed all excess both inner and outer. Like I said, it seems to work fine- for testing purposes. I have the new boots on order. I briefly considered casting and machining an adapter that had a ring, and replacing the boots with a short piece of something like radiator hose the right diameter- but if these things last 20 years I won't bother. I just hate to have a maintenance item that dies every year.

RTV is used in cars on transmission surfaces, where an exact-size bead is placed in the spot where, when assembled, it will not protrude after sealing. It's also used to attach things like weatherstripping, to glue airboxes and ducting together, etc. Guess it makes sense that almost none of those things exist on bikes, so not a lot of use for RTV there.

You'll have to excuse my stupid questions, this is all new to me. THis spring when I take my ABATE course, it will be the first time I've ever driven a motorcycle,(well, sober) and I'm 46. So I have everything to learn.

 

[earlfor]

I expect your new boots will last longer than you will own the bike. I've had to replace boots and boot "O" rings on every old bike I have refurbished.
Without exception, all had the original boots and "O" rings. You're good for about 20 years now. LOL Well, not that long on the "O" rings, but hell, they're only a buck each. hehehe

Yep, I agree there are quite a few uses for RTV. Not many on a motorcycle though. There arent any stupid questions. You would be amazed at those that wont spend the $12 for a set of carb "O" rings and fill everything with silicone instead. LOL

Earl

I briefly considered casting and machining an adapter that had a ring, and replacing the boots with a short piece of something like radiator hose the right diameter- but if these things last 20 years I won't bother. I just hate to have a maintenance item that dies every year.

RTV is used in cars on transmission surfaces, where an exact-size bead is placed in the spot where, when assembled, it will not protrude after sealing. It's also used to attach things like weatherstripping, to glue airboxes and ducting together, etc. Guess it makes sense that almost none of those things exist on bikes, so not a lot of use for RTV there.

You'll have to excuse my stupid questions, this is all new to me. THis spring when I take my ABATE course, it will be the first time I've ever driven a motorcycle,(well, sober) and I'm 46. So I have everything to learn.

 

[mhardig]

You would be amazed at those that wont spend the $12 for a set of carb "O" rings and fill everything with silicone instead. LOL

If you were going to do that sh*t, why not just get a piece of goretex and make flat gaskets.

Hell is, after all, other people.

Thanks for your patience and help. I hope I can ride this without killing myself.

When I was 18, speed was the only thing important to me, and frankly, owning a motorcycle would have been a horribly bad idea. Now, I can potentially ride like a sane person and be a little more sedate. ANd I have a lot of twisty country roads nearby, so I look forward to a fun(er) summer.

 

[earlfor]

Riding is a skill that anyone can learn. If you take a class, practice and build on the skills in stages, there is no reason to expect to become a statistic.
I've been riding about 40 years and have owned a bike for 35.
I havent dropped a bike since 1976 and I dont intend to refresh my memory of what its like. I cant say that I am alway sane, but I do always do my best to remain within my skill level. Riding is a great way to to enjoy a day, and I wouldnt do anything else. Just remember, the future comes at a rate in proportion to how far you twist your right hand. You're the one driving. eheh


Earl

Thanks for your patience and help. I hope I can ride this without killing myself.

When I was 18, speed was the only thing important to me, and frankly, owning a motorcycle would have been a horribly bad idea. Now, I can potentially ride like a sane person and be a little more sedate. ANd I have a lot of twisty country roads nearby, so I look forward to a fun(er) summer.

 

[Guest]

RTV means "Room Temperature Vulcanizable". Most curable (vulcanizable) polymers must be heated to around 400F for about ten minutes to cure. Sulfur is a common curing agent, either as raw sulfur or in other compounds that release suflur when heated. "Accelerators" are other chemicals needed to cure the rubber this quickly. Without accelerators, vulcanization can take hours or days. During the curing process, the rubber emits gases which will turn the part into a sponge unless it is held under high pressure until the part is completely cured and cooled.

(Curing or vucanization is the process that changes the polymer so that, when it is deformed, it returns to its original shape. Chewing gum is very soft, uncured 'gum' rubber.)

Different chemistries can cure many polymers much faster, and even at room temperature. Some are cured by adding a hardener, and others react with either oxygen or moisture in the air to start curing.

So far, I've talked about the "cure system", not about the type of rubber or polymer that is being cured. The type of polymer is critical to what temperatures and solvents the cured part can survive in, while the cure system makes only a small difference.

The gold standard for heat and gasoline resistance is fluoroelastomer, or fluorocarbon rubber. The trade names for this are Fluorel (3M) and Viton (DuPont). 3M is the older and bigger company in this business, while DuPont is better at marketing. If I were back in the rubber business, the only way that I'd use DuPont is to bargain with 3M to keep prices down.

Nitrile rubbers are much more common for heat and solvent resistance. They cost a lot less, and are easier to use. But they don't work in extremes. Some silicones can also be good, but their mechanical properties are terrible. There are also several other types of solvent and temperature resistant curable polymers. And fluorocarbons, nitriles and silicones are all large families. It isn't enough to specify "metal", we also need to specify "steel" and then the type and grade.

The same applies to "RTV". Saying "RTV" works or doesn't work is akin to saying that "metal" works or doesn't work. I've never tried to replace a gasket with any type of RTV, but I've known people who routinely replaced paper gaskets with some type of RTV without any problems. Paper gaskets cost less than a solvent resistant RTV, and assembling an engine with a paper gasket should be faster than using an RTV gasket.

Just my two cents worth.

Tom (former rubber chemist)