Yamaha EX 440 Mod

C

Chris

New member
Joined
Jun 5, 2006
Messages
111
Age
34
Location
Ontario Canada
Hey i made a mod 440 ex its a 1978 pics will be coming soon i dunno if it will be all alright with the stuff i have in it so could someone tell me if it will work ok all together and how many HP it should have
Its a stock 440 EX moter
440 GPX pipes
Phazer carb intakes
Stock reads for 440 EX
40mm 570 Exciter carbs Mik Butterflys
Any ideas ? ?
Thanx
 

Chris,
It looks as though you are going to be over carbed, 40mm? I know that the GPX pipes wake the engine up. I would work on clutching, A proper working clutch and set up nice will make those sled fly. I you take the cylinders off and clean up the ports (intake, exhaust and transfer) you will notice a good gain. Brad
 
Ya i think they might be 38s with K&N filters . . . i am looking to put a comet C 108 on it . . . prolly not gunna clean the ports this winter not quite sure yet tho winters still a long way away Does any one know about how many hp i should be able to see with it and how many mph with a stock clutch and gears . . . im not going to race it all the time jus looking to on my spare time and be a driver . . .
 
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Help

Hey Guys in need of help i got the 440 EX all back together and running idles great but snuffs out when you give it throttle i do not have the chokes in would that be why i jus have a bare whole where the chokes should be . . i thought the port was to small for the carbs with the reeds in it but i took them out and it would no offer . . . ANY IDEAS PLEASE > >
Thanx
 
You don't have the choke plungers and cables attached. You are choking the thing out. You need to intall them What is the jetting on it. Hp is going to be hard to determine. What about your GPX pipes? Install those and wake that engine up. I have a set of GPX pipes and a tuned pipe for the 440 Exciters on my 78 Exciter. You are going to need an air box (you are going to ruin the engine). Brad
 
Hey Brad i have 2 K&Ns on it now i didnt have them on for the pic the GPX are jus stock pipes ill get the chokes in it Those are the pipes on it, And where on them carbs is the jetting and does it say what size it is . . .im guesing its stock jetting for a 570
 
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What carbs did those carbs come off from. I would go with the jetting for a Phazer. That engine is a 433cc and the Phazer is a 485cc. The jetting would be a closer set-up than a 570cc Exciter carb. It doesn't matter that your pipes are stock or not. The stock GPX pipe will make a bigger difference than the carbs in power. Brad
 
Hey Brad any idea how fast it would go stock and how fast when im done every thing with a Comet C 108 Clutch

Thanks You have been a good help
 
unless you rev the engine higher or change the gearing it will go no "faster" than stock. quicker possibly. i would say ditch those butterfly carbs and get some 38 mm mikuni VM's. also you would probably be better of with an aaen single exciter pipe as the stock GPX pipes im not too fond off them there not a true expansion type chamber they have a giant mass of metal tubes and sound diffusers inside those cans.
 
AHood is right. The 108c is a nicer clutch than a 102c, but you won't gain more speed from changing the clutch. It will function smooter. You really need the extra power to make the sled faster. If I were you I would gear it down a tooth or two on top, and add some weight to the fly weights ( to keep the RPMs down around stock). The stock clutches work very good if they are kept clean and all bushing aren't worn. First I would consentrate on just getting the engine running good. Then work on the running gear. Brad
 
OK Brad now what could i order for the top gear that would work i went in and tried to order one and they said they couldent look it up what kinda machine would have a gear 2 teeth bigger on the top. . .. Oh and i should get better lower end if i do keep it stock would the duel carb and exhaust make better lower end im racen on a small oval so lower end is better than top . . .Im fairly new at all this im 16 so i realy appreaciate all the advice thanx
 
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Chris work on the engine first. You should make sure the engine is running good before you sink more money in it. Let me know when the engine is runnging properly and I will help you out with the rest. Brad
 
OK brad thanx . .. the jets are coming in on tuesday . . . i orderd 1 size smaller and 2 size smaller than the phazer . . . . to test them out . im use to doen this type of stuff jus not this much of it i got about 1200 invested into it so far but thats not a whole lot its in good shape and all . i have had lots of toys so i knoe some what what im doing i have had 11 sled , 3 3 wheelers , 3 dirt bikes , 3 boats . . So Ya ill get back to you umm prolly some time next week when i get the parts in
 
Hey brad i got it running good i put mukuni 117.5 jets in it . . . i put new needle and seat , 100 ice pics , 9 inch race carbides and a wideing kit its about 4 inches wider on each side . . . any other sugestions ?
 
I would start working on the exhaust next. You said you were going to run GPX pipes. Those should be set up next. Keep an eye on the plug color. As this will change your jetting some. Also go through your clutches. Clean them and replace any bushings needed. Your clutching is one of the most improtant things to make sure they are set up right. Then all you need now is some snow to try it out. I think you are going to do alot of trial and error, to see what set up will work best. Brad
 
Ya brad i got it running great with the GPX pipes . . i am getting some elan skis to lighten it up a little too it should be almost ready for snow
 
Chris,
when you get this machine together, could you take some pictures of it for me. I would like to see the bad boy. Anything I can help you with, just let me know. I will do my best to help you out. Brad
 
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