New project bike. Need carb help.

onestarcorner · Posted: April 4, 2007, 12:45 pm Post subject: New project bike. Need carb help.

I just purchased a 77xs650. Although it is a 77, it has a tank with only 1 petcock(missing) and the carbs appear to be from a 80 model, judging by mikesxs.com. Also, the side covers dont fit with these carbs installed.
The carbs carbs on the bike look really clean and operate smoothly.

I read that the earlier modle carbs are beeter for performance. I have a set of 74 carbs which are super crusty and will need rebiuld.
-the question is, which carbs should I use? Can I use the 74 carbs and use a 2-1 throttle cable and a "T" fitting from the one petcock to supply fuel for both carbs?
Please let me know what you would do. I would like to start ordering parts today to get this bike going.
thanks
christian

PS. I will be rinning pod filters and slip on pipes

onestarcorner

Holy Huge pic..
sorry guys

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

deleted

onestarcorner

Thanks for the reply. Mike just emailed me the exact same info. I am ordering the t-fitting that goes in between the carbs because I am missing it. I also ordered the petcock that you described I am going to hold off on the rebuild kits and just try a good cleaning for now. The carbs really look good so them may not be that bad inside.

Also, the sidecovers from the 77 dont fit with these model carbs. will any other year side covers fit?
I really like the look fo the xs650's when there are no side covers and all you see is the battery. I sonder how they hide all of the electics and get the battery box out?

oh.. since I already have pod filters. I should order up some jets as well and smaller air jets.
suggestions on a good size just to get me started.
thanks

onestarcorner

ok.... I got everything I needed from mikes xs. fuel lines, petcock, battery.
I oured gas in the tank for the first time and turned on the fuel and gas just cam ouring out of the airfilter from the left side carb.

I am not great at working with carbs so I had my brother clean them,( he rides a 77 xs750)

Can anyone pint me in the right direction?

xsjohn · Last edited by xsjohn on April 23, 2007, 1:12 am; edited 2 times in total

All I can offer on this problem is that Yamaha came out with Viton tipped float needles on the later models. The older ones were steel tipped and did not seat as well. Most people will say to clean them some more but the Viton tipped ones were introduced to eliminate this problem......Don't know if the newer ones will fit in the older carbs seats but I would be interested in knowing....mikesxs...Both of my pre 80 xs's did that...they must have been female as much peeing as they did on the floor.....80 has never done that once in 10 years.....yet.....could be still come junk in there preventing a good seal.......?Maybe I didn't read all the posts well but I hate leaky carbs too.............

John

onestarcorner

ok.... I got everything I needed from mikes xs. fuel lines, petcock, battery.
I poured gas in the tank for the first time and turned on the fuel and gas just cam pouring out of the air filter from the left side carb.

I am not great at working with carbs so I had my brother clean them,( he rides a 77 xs750)

Can anyone point me in the right direction?

onestarcorner

so my problem has something to do with the floats or something being dirty?

76xs

onestarcorner

ok. The leaking stop on its own somehow and I was able to get the bike started for the fist time.

The bike Idled great but ran horrible. Under acceleration. the bike lacked power and was missing. it seemed like it was only running on one cylinder.
aybe its because I had pod filters on it and no jet kit.

At anyrate, we rode it around for a while til the carb started leaking gas out of the filter again so we parked it, pulled the plugs and they were black and indicating rich.

I am going to order up some rebuild kits and try to get the right jets in it and hopefully it will run great......maybe even start on one kick.,

grizld1

You pic didn't show the air filters but it sounds like you may have issues with them; the cheap Emgo type pods have flanges that block the diaphragm port and pilot air intakes in the back of the carbs and have to be relieved in those areas.

onestarcorner

Thats what I was thinking but the carbs started leaking fuel again through the intake side after we removed the filters to try running without them.

I did a search and found something about an airjet that needs to be removed and plugged?

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

onestarcorner

He might not have removed the rubber on the needle. I told hime not to put any parts in his parts cleaner but I think he did it anyway. So is a carb rebuild kit what I need?

onestarcorner

also, what jets do I need to order to make the bike run right with the pod filters. I know there are probably alot of factors to consider. I am at sea level in houston tx...... Fuel injected bikes were so much easier. this stuff makes me miss my TL1000r

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

onestarcorner

#45 Pilot Jet-pair #142.5 Main Jet-pair #127.5 main jet-pair carb rebuild kit 80-84

I just put in an order to mikes xs for these parts. hopefully, this will get me sorted out. I will keep you guys posted.

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

onestarcorner

Thanks for the advice. I am following the tips from the tech section at mikes xs web sight. I was going to install everything all at once. I will start with just the rebuild kit. My brother has the tools to do a valve adjustment and says that it is easy. He also suggested cleaning the points and cleaning all the electrical connections with contact cleaner.

I just want the bike to be dependable to ride. I am not really concerned with high performance. I just think that vintage is cool.

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

onestarcorner

I just cleanded my points with contact cleaner and a toothbrush. My bike fired up on the first kick! wow!

I think I have also discovered the source of my leak. My brother set the float height at 25.7mm
thats way to high isnt it? That would make the bike very lean huh?

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

onestarcorner · Posted: May 6, 2007, 3:45 am Post subject: Re: New project bike. Need carb help.

ok. I got my carb rebuild kits in and jet kits. My carbs are rebuilt and the jets I ordered have been installed and the float height is set properly. We set the float height around 23 mm. My carbs havce the plastic floats. We put the carbs on the bike and tried to ride it and it stil bogs down and deosnt have any power when I tried to ride it around.

When I got back home, I found that gas was pouring out of both airfilters. I dont get it because the floats are at the roight level,s and the carbs are completely clean and rebuilt.

onestarcorner · Posted: May 6, 2007, 3:49 am Post subject: Re: New project bike. Need carb help.

wait... we didnt install the new rubber plugs over the pilot jets. We didnt know where they went because we didnt see any old rubber plugs in the carbs when we disassembled them. Why does the pilot jt need to be capped?

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Yamaha xs650