Jet Kit

Vlad

XS400 Enthusiast
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So, check it out.... Since I installed new exhaust and pod filters I'm going need to rejet. I was looking for a kit that had a good range of sizes so I wouldn't have to order each one individually and I stumbled on this. Apparently you tell this guy your bike specs and the mods you've done and he puts together a kit for you with everything you should need. It doesn't seem like a bad price for everything you get. I'm thinking about getting this a giving it a shot. What do you guys think?

http://cgi.ebay.com/ebaymotors/Yamaha-XS400-XS-400-SH-Special-Carburetor-Carb-Jet-Kit-_W0QQcmdZViewItemQQhashZitem35ae76dde1QQitemZ230560292321QQptZMotorcyclesQ5fPartsQ5fAccessories#ht_2639wt_939
 
Last edited:
So, check it out.... Since I installed new exhaust and pod filters I'm going need to rejet. I was looking for a kit that had a good range of sizes so I wouldn't have to order each one individually and I stumbled on this. Apparently you tell this guy your bike specs and the mods you've done and he puts together a kit for you with everything you should need. It doesn't seem like a bad price for everything you get. I'm thinking about getting this a giving it a shot. What do you guys think?

http://cgi.ebay.com/ebaymotors/Yamaha-XS400-XS-400-SH-Special-Carburetor-Carb-Jet-Kit-_W0QQcmdZViewItemQQhashZitem35ae76dde1QQitemZ230560292321QQptZMotorcyclesQ5fPartsQ5fAccessories#ht_2639wt_939
Doesn't sound too bad. I would ask if it just came with one set of jets, or a few multiple sets. A set of jets by themselves won't run you near $40 total. The only good part about this set, is that they take the guesswork out of the equation. I would still ask myself "Where does this guy get his jetting information?" I would be willing to bet that he just goes by forum information like this, his friend's settings, etc. I think if you put enough time into a little research, you could come out a lot cheaper in the long run. Just my 2 cents though...
 
Regardless of where he obtained his information he did his homework and is offering a good deal especially if you have a 4 cylinder/carbed engine. If I was working an unfamialr bike I'd get it even for a twin.

On the other hand raising the needle jet 1 or 2 mm and going up one main and pilot jet size at a time often produces the desired result.
 
Regardless of where he obtained his information he did his homework and is offering a good deal especially if you have a 4 cylinder/carbed engine. If I was working an unfamialr bike I'd get it even for a twin.

On the other hand raising the needle jet 1 or 2 mm and going up one main and pilot jet size at a time often produces the desired result.
Aren't new jets only like 5 or 6 bucks though? I was just saying that $40 seems a little high. Like i said, he does take the guesswork out for you, so you won't have to buy multiple sizes.
 
Ya individual jets don't really cost much but I was figuring on having to get 2 or 3 different sizes per carb to get it right and then removing the carbs however many times to replace jets. $40 just seems worth the convenience of knowing (hopefully) that they are right the first time.
 
there must be some sort of programme that works out the specs. no way that they have first hand knowledge of individual bikes!
 
Software like Desktop Dyno, that can be used to simulate engines. There you can get the amount of air the engine pumps through at different rpms. After you have that info its just a matter of adding enough fuel.
 
anyone know of a good place to buy new jets? I am also putting on pods and exhaust and need a place to buy single jets, I do not really trust a ebay seller selling kits and then have them not be right and end up buying multiple sizes anyway.
 
anyone know of a good place to buy new jets? I am also putting on pods and exhaust and need a place to buy single jets, I do not really trust a ebay seller selling kits and then have them not be right and end up buying multiple sizes anyway.
MikesXS.com sells jets that fit our bikes. The jets in the BS34 carbs that came stock on some of the XS650s will fit into the BS34 carbs that came on our XS400s. Just make sure you get the jets for the BS34 and not the BS38.
 
mikesxs also has a Heiden dyno tune needle and ket kit that comes with 2 different sized pairs of main jets. Has anyone used bought and used this jet kit? It is also $45 and is made specifically for the bs34 carbs. Just wondering what people thought about this?:shrug:
 
I'm showing my ignorance here, but whats the theory behind the two carbs having different main jets? I'm used to tuning 4 carbs on my Seca. Pilot and main jets are the same for each carb.
 
Well its news to me too. When reading the specs on the carbs it shows 127.5 left and 117.5 right and the european versions had 132.5 left same as the 650's and 130.0 right. I had a 132.5 so I put it in my L carb and moved the 127.5 right. This different jetting between cylinders was recommended on my Guzzi. Has something to do with the heat generated and work being performed between the cylinders. With pods it's working fine for me. I'm sure someone has amore specific and accurate answer. There's a bigger brain trust on the XS650 site that may know the answer post the question there and see.
 
might be something to do with the petrol feed going through the left carb and supplying the right!
 
i don't know about the two size thing i have 137.5 on each. stock was 132.5 (1979 2-f model) and it works fine both plugs are colored the same. had this bike for 12 years now. i also use iridium plugs. main jet are for rpms about 5k and up.:shrug:
 
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