Need some help

[Radeon]

Ok so i have a 1981 suzuki Gs450E, it will start up right away, and idle all day long, but i cant get it to rev past 2000 rpms any thoughts?

[Steve]

... any thoughts?

Yeah, I have a few thoughts, some of them might even apply here.

First of all,

Next, we will need some background information:
1. How long have you had this bike?
2. Is this something new or has it been going on for a while?
3. Any engine mods in the way of intake/exhaust?
4. When were the carbs last cleaned?
5. Is there an airbox (or any air filter, for that matter) installed?

If you have just gotten the bike and don't know the history, there are a few things that will be necessary. Among them are valve adjustment and carb cleaning. Dirty passages inside the carb bodies will block the proper flow of gas, and that is not something that can be 'fixed' by simply dropping the float bowls and spraying some cleaner around.

Changes to the intake and exhaust, like individual pod filters and/or a different exhaust system will require different jetting in the carbs. Should let it go past 2000, though.

If the carbs do not have anything on the intake side, they simply will not work well above idle. They need to either have pod filters or a stock airbox.

.

[Radeon]

ok so the history, i bought the bike about a year ago on craigslist for 100 bucks , was all there to run but not all there to be road worthy, the bike has sat in my garage for the past year because i was busy on other bikes, a 1982 Yamaha Xj650RJ seca, and a 1983 Yamaha Xj750m Maxim, i have resently sold both bikes to some friends, which forced me to take a look at the Gs450, i just got it running for the first time, everything is stock, i have around 145 lbs of compression on each cylinder, i cleaned the carbs about a week or so ago, ( they had beed sitting in carb cleaner for a year) i forgot i put them in there, i dont have the gas tank on the bike at the moment, i Kreamed and in the process of repainting it, It has the stock air box but no filter in it yet, i am hoping to have it rideable within a week or so. I also put new plugs, new oil, i took the side covers off and polished them, made some new gaskets for the side covers, i know i need to take a look at the timing but cant find my timing light. I put a new after market master cylinder on, had to rebuild the starter, and wire around the clutch switch ( it was bad). But thats about it.

[Steve]

Depending on what carb cleaner they were sitting in for a whole year , you might just be needing new carbs.
I have left carbs in "the dip" for several days and found them to be rather questionable.
I can't imagine that there would be much left after a year. What kind of cleaner was it?

I did not see where you had adjusted the valves yet.
That shouldn't keep it from revving past 2000, but it needs to be done anyway.

I think the airbox is going to be your problem, if it's not the carbs themselves.
The carbs are designed to have a certain amount of restriction on the intake.
Lack of a filter element can upset that.

.

[GregT]

Find your timing light too - if the centrifugal advancer has stuck it won't want to rev. Putting a light on it will show if it's advancing.

[Radeon]

Ummm it was some old cleaner, nothing 2 strong, but how would i check the valves? and by any chance are the jets in the carbs interchangeable? lie will the pilot jets fit where the mains are supposed to be vis versa, i don't think they were but its worth asking.

[cowboyup3371]

Visit Basscliff's site (I'm sure he'll be along later today for the official welcome) and behold wonderous wonders:

http://members.dslextreme.com/users/bikecliff/

[pete]

Hiya Radeon, another 81 450 owner here, but I haven't started on my carbs or anything yet, still reassembling my engine.

A guy by the screen name of Flaming Chainsaws has just rebuilt his 450 carbs and is doing up a blow by blow photo rich rebuild thread apparently, so keep an eye out for that as it may help.

[Radeon]

ok thanks pete

[chef1366]

I don't think this bike has a mechanical advance.

[BassCliff]

Greetings and Salutations!!

Hi Mr. Radeon,

Have a look at this thread for pictures about where to install new O-rings in your carbs after cleaning them up. Just get an O-ring kit from cycleorings.com and follow the Carb Cleanup series. It's all in your "mega-welcome".

Let me share some GS lovin'.


I just stopped by to welcome you to the forum in my own, special way.

If there's anything you'd like to know about the Suzuki GS model bikes, and most others actually, you've come to the right place. There's a lot of knowledge and experience here in the community. Come on in and let me say "HOoooowwwDY!"....

Here is your very own magical, mystical, mythical, mind-expanding "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