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Discussion Starter · #1 ·
Okay, finally got the bike started, which was a good thing. Wont idle but is running on both cylinders. So, heres the question as the carbs are going to need gone thru.

Bike has straight exhaust pipes and pod filters.

What all do I need to get?
What size jets and where do I get them from?
I can build anything but have never rebuilt carbs before, so this will be a first for me!

So, guru's, throw the man a bone!!!

Henry
 

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450's don't care much for straight out exhaust, they tend to fry the exhaust cam and valves, and they're kind of hard to tune, the bike likes some back pressure to "work against".
You may want to consider putting some kind of muffler on it, just to give the engine a break.
And your ears too - it will be very loud, like a DC-3 on takeoff.
Or if you can afford it, a tuned megaphone or something.
The carbs are very forgiving, but with pods and straight pipes, re-jetting may be indicated, you'll just have to see.
Best to avoid it if possible, as the 450 needles are not adjustable, which is something you often need to adjust when rejetting.

450 carbs are the definition of simplicity, just a few parts..
Take them apart and give a good soak in a gallon can of carb cleaner, then clean them up real good.
Use lots of compressed air.
DO NOT soak the slide needles, as they have a nylon thing on the end.
DO NOT soak the vacuum domes, same reason.
On both the choke and throttle flipper, there are nylon washers and stuff, so that all has to be taken apart.

Or alternately, if they're not too bad, just spray with a can of acetone type carb cleaner and use lots of compressed air, without taking all the shafts apart. See if they pass the "straw test".

Find out what size the jets are right now - let us know that, as well as the engine number.

There's a thread here about 450 carb setup, in the 450 section.....
http://www.hondatwins.net/forum/viewtopic.php?f=29&t=537
 

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Discussion Starter · #3 ·
Thank you Bill for the link and your reply! I knew one of you guys would jump in there and it is appreciated!

I'll yank em off and do the cleaning route first. I know this bike has sat for a number of years (how many is unknown to me) and I would say at least 5 or more based on the overall condition of the bike when I got it. Ill reset everything, like thelink explains, and we'll just have to go from there.

Again, kudo's your way Bill. :D
You're one of the reasons this is a great site!

Henry

P.S. Your right, I cant hear worth a darn right now! It was REALLY loud...
 

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Some el cheapo slip in baffles may be just the ticket on that backpressure..? As far as the rejet is concerned, that's anyone's guess with the current setup you have going. Might prove to be quite the brain tickler.. ;)

GB :mrgreen:
 

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Bird76Mojo said:
Some el cheapo slip in baffles may be just the ticket on that backpressure..? As far as the rejet is concerned, that's anyone's guess with the current setup you have going. Might prove to be quite the brain tickler.. ;)

GB :mrgreen:
It shouldn't be too hard to figure out, the carb is brutally simple, very user-friendly. They just need to be very clean all the time.
Some sort of baffling would help. That's the kind of loud that gets you in trouble in some places.

If they already have the "later" 140-150 jets, you may not have to change anything.
Only two jets, slow and main. Slide needle is not adjustable.......
I'd probably try 135 to start, on clean plugs, see how it goes.
Get a series of plug readings, and see what jet size works best.
You can judge your plug readings at this place -

http://www.4secondsflat.com/plug_chart.html

Make sure you get the float level right - there's another post here about that, maybe.
Here's a PDF I made - http://home.comcast.net/~tbpmusic6/floats.pdf
 

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Henryinva said:
says itas a 130 and a 38 on the smaller of the two.....

I'd still probably try a 135/38 combo, at least to begin.
Better a little too rich than lean......
 

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Well, you already have the 38's.

I'd ask here - these guys arepretty good about swapping jets and things like that.
Someone just posted about having a bunch of 450 jets......
 

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Discussion Starter · #10 ·
Well, I pulled the carbs apart and one of them is pretty corroded on the 38 jet. Looks like I'll need both sets. the threaded cap small hole is completely filled with hard crud. I let it soak all night in carb cleaner, but its a solid plug right now. Ill post a thread and see if anyone can help me out.

Thanks Bill!

Henry
 

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I have the almost the same setup, V stacks and straight exhaust. I love the sound and the design i made, so baffling is going to pose be a problem unless someone knows of a 1.5" slide in short style baffle. I bought a jet kit with 135,140,145,150,155, but ive had a shoulder injury preventing me from testing these jets. Is it worth spending the money to dyno tune for jets with this setup?



i was thinking of maybe using these to help with back pressure, it should run better and not kill the valves right?
 

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Those slip-in baffles should be beneficial to the performance and the valves.... (TIP: I also suggest you use a through bolt that goes all the way across the pipes...I'm unsure as to the technical aspects, but my bike always seem to improve with the addition of this "splitter" bar ).... Steve
 

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I would'nt think that your valves are in great danger but more over, your ear drums. The length of the exhaust should help the valves out all by itself, as burnt exhaust valves (in the automotive world anyway) are usually seen when someone uses only the exhaust manifold, such as in a derby. But by adding length to that manifold (such as open headers) the valves don't get smoked so easily.

Just a thought. :idea:

I bet those baffles will help a little though. ;)

GB :mrgreen:
 

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Bird76Mojo said:
I would'nt think that your valves are in great danger but more over, your ear drums. The length of the exhaust should help the valves out all by itself, as burnt exhaust valves (in the automotive world anyway) are usually seen when someone uses only the exhaust manifold, such as in a derby. But by adding length to that manifold (such as open headers) the valves don't get smoked so easily.

Just a thought. :idea:

I bet those baffles will help a little though. ;)

GB :mrgreen:

I dont wanna thread jack, so stop me if i am.

I rode her today and the straight pipes aren't too loud for me on the bike(outlets behind me) with a helmet on but if i can make more power with back pressure then ill baffle it.

ideas?
 

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Henryinva said:
Well, I pulled the carbs apart and one of them is pretty corroded on the 38 jet. Looks like I'll need both sets. the threaded cap small hole is completely filled with hard crud. I let it soak all night in carb cleaner, but its a solid plug right now. Ill post a thread and see if anyone can help me out.

Thanks Bill!

Henry
You sure that "jet" doesn't have a plug in it from the factory? I don't have a carb right in front of me but I remember one jet having the sealed end, and at first I thought it was clogged.

GB :mrgreen:
 
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