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XS850 Triple Cafe Project

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cafe triple xs850 yamaha
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62K views 135 replies 20 participants last post by  n8isarockstar  
#1 ·
Hello everyone. I am totally a noob when it comes to bikes...so forgive me.

I have been trying to pick up the right bike to start this project and had been leaning towards a virago. After too long of a wait from one seller and a bit more research, I have decided to go with a Yamaha 850 triple and am VERY excited about it.

Has anyone seen how sweet BlackBII's sounds and runs? thats exactly how well I want mine to work. Currently, it backfires constantly, sounds like something is clanging around inside (when it is idling with the choke all the way down). On top of that, it doesnt get a lot of power when driving.
BlackBII suggested to have the Carbs synched but im not sure what that means or if its something i can do myself.

Before anyone asks "have you done_______"
The answer is no...i have done nothing yet. Please..and advice is MORE than welcomed. THANKS

Ps. ill get some pics up of it tomorrow most likely
 
#2 ·
So, here is a quick vid of how it looks right now. I have done nothing to it..this is how I bought it.
You won't hear a lot of backfiring, but it just trust me...it does...almost constantly.
What you will see/hear is it idling weirdly..then when i turn the choke down, the clanking and stalling...and just straight running bad. When i blip the throttle...it sounds like a lawn mower.
Ideas? Suggestions?
it sounds nothing like BlackBII's that he just finished up.


as far as looks go, I want something like this:
Image
 
B
#5 ·
Looks like you have the hitachi carbs, which I don't know much about. And it sounds like you need to turn up your idle. There is an idle adjustment screw in between the 1-2 carbs, turning it in will open the butterfly valves a little to let more air in, increasing the idle

Synching the carbs. It's like this. You have three carbs, each one with it's own butterfly valve. When you sync the carbs, all you do is make sure all the butterfly valves are opening the same amount when you twist the throttle. (You can also include the pilot screws, but we can just use the stock setting on those and you should be fine)

Here is a pic of two carbs showing their butterfly valves. When you pull yours off, you will notice there is a small gap at the bottom because the valves are slightly open in order to keep enough airflow to keep the engine idling. Most people and shops will tell you that you need some vacuum sync gauges in order to sync the carbs, but these older bikes aren't picky enough to make that matter. So what I do is use some small steel wire and place it in the gap at the bottom of the butterfly valve, using it as a guide to make sure all the gaps are even.

Image




It looks like you have pod filters and straight pipes, which means your bike is running lean, because it's getting more air than it used to. The fact that your bike dies and sputters when you turn the choke off proves this because the choke on these bikes actually just add more fuel via a tube running down into the carb bowl.

I'm willing to bet the pevious owner didn't put bigger jets in the carbs to compensate for the increased airflow. Also, it sounds like it may be missing on a cylinder, although with the 3-2 exhaust it's hard to tell. I would pull out the spark plugs and see how they look. White? Black? Corroded? etc.

Also, is each header pipe getting hot? And, I would check the timing as well.

One other thing, if you have the budget for it, is to look for some Mikuni carbs. Either off a triumph sprint, being 36mm flat slide mikunis, or, off an xs750, being 34mm MKII's (which is what I used on my 850)

The stock hitachi carbs are hard to tune and hard to get parts for.
 
#48 ·
BlackBII said:
One other thing, if you have the budget for it, is to look for some Mikuni carbs. Either off a triumph sprint, being 36mm flat slide mikunis, or, off an xs750, being 34mm MKII's (which is what I used on my 850)
Click to expand...
What size Jets did you put in there? just change the main jets? or the pilot jets too.

I'm hoping i should get the Carbs in this week. might as well be ready.

ps. I remember reading your 850 build and you waiting for your seat to come in....
IT REALLY DOES TAKE FOREVER (or at least feels like it)
 
B
#6 ·
Also, how many miles are on this bike? Checking the compression might be needed as well.

Since you are going Cafe style, I would look into getting a 'standard' tank, like the one on my bike. The 'special' tank that you have has too much of a teardrop shape to it in my opinion.

Also, make sure you put in new oil, new middle drive gear oil, new final drive gear oil and new brake fluid, cleaning out the calipers and the master cylinders.
 
#7 ·
this is great info and sounds like i have a busy weekend ahead of me :)

miles: something like 50,000...a lot

I did just order my seat from airtech btw

I went with
Image


Im at work now, but I will hop on ebay and see if I can find a set of those carbs and see how much they are. I live in flint (Vehicle) city..which basically means its all american cars and harleys....so im like on my own as far as my city is concerned.
This help is great though.
 
B
#8 ·
That's a good seat. Same one I used on my 1100, only I shortened it like 6 inches.

Make sure you mount it using rubber bushings, otherwise any uneven stress will cause cracks.

Good luck finding some carbs.

You can make the hitachi's work, but I don't know much about them or how much you'd spend on rebuild kits or bigger jets or even what jet sizes to use.

These guys may help you out with the hitachis
http://yamaha-triples.org/category-view.asp
 
#9 ·
Ok, so I pulled my carbs off last night. Was not nearly as scary as I expected. Gonna spend some time cleaning them properly and maybe try to see if I can up the jet size. I kinda wanted to just keep taking stuff apart :) I also have to change the fork seals (if you have a suggestion for that as well) I have already ordered and received the new fork seals to do that so I will start that soon.
I have read mountains of different opinions of what the best "solvent" is to clean carbs...from dish detergent to spray carb cleaner to boiling water. What do you all think?

Also....what is this? is it supposed to be connected to something?
Image
 
B
#10 ·
That tube used to go to the airbox that you no longer have. The idea is to have the motor burn any crankcase fumes coming from that breather hose, to protect the environment from pollution. Your bike will run fine with that hose as it is.

I would just use regular carb cleaner in a spray can. Pull the bowls off, and pull the jets out. Spray them out with the carb cleaner and also spray out all the passages within the carbs. Also take a look at your butterfly valves and make sure they are all opening the same amount. Also check the float level.

With your pod filters and open pipes, I would go up about 3 jets sizes or so, but, that's going off how I tune Mikunis.... The stock hitachi jet sizes for the 850 are a 142 main jet and a 40 pilot jet, and I honestly can't tell you how much to go up on the Hitachis

I don't even know where you can get bigger jets for the hitachis, but google is your friend.

Also, while you are working on the bike, make sure you remove and clean/wire brush every ground connection on the bike. You want to make sure every component is getting it's juice.
 
#11 ·
So check this out...
I called a local shop that a customer at work recommended to ask about custom making me a 3-1 system. The shop guy says he would love to help (bonus..considering no one around has been able to help at all). He further asked me what i wanted to do eventually. I mentioned all the things i want to do, including putting a modern sport bike fork on it...he said "well, I have a perfect front end from an R1 or a KZE or something here..I can't quite remember...but its got brakes, wheel..tires..everything."
I asked if it was wrecked and he said no, that basically another customer wanted the engine from the bike used for a custom chopper...and said he could trash the rest of the bike.
So, i said..ok..well...how much are we looking at. He said...eh...probably about $300.


....
....
....
....

I said i'll be there as soon as I get out of work.
Needless to say, I will be parting out my current front end. Anyone interested in anything?:Evil_smile:
 
#12 ·
So I bought the fork and wheel today...not sure what all I have to do to put it on...pretty sure fitting the headset is going to be a mess...its pretty much the exact same height with the wheel to the top if the fork as the original. So my rake shouldn't change at all. Only problem is its from a honda...and what model or year...I have no freaking clue.

Think im gonna have to change the back wheel somehow now too cause its now larger than the front wheel. Is that weird? Looking for any suggestions on this stuff.

Took the carbs off and thoroughly cleaned last night. Reassembled when I got home today and bout to adjust them With your method. Will put them back on after I get back from my quick trip to PA tomorrow.
 
B
#13 ·
300 for a new front end is a great deal! Are they upside down forks?

All you need to worry about is the stem length and bearing sizes. I would pull the lower triple out and pull your forks off. Then place the new lower triple into your frame and see what bearings you will need, if the steering stem is too long/too short etc.

Good luck on the carbs. If you get them clean and adjusted, and it still has problems running, we'll need to look into getting some larger jets.
 
#14 ·
Figured out the model, looked up what the difference was in bearings and ordered from www.allballsracing.com
now just waiting for the seat and the bearings. I wonder if i need to research hooking up different brakes, or if they are all standard sizes for the lines.
Hmmm

Also, put the carbs back on today...bike wouldn't start. ughhh..will try again tomorrow.
I think I would put a set of those Mikuni MKII's you mentioned on if I could find some...
 
#15 ·
Bike is running! Little bit of starter fluid did the trick...sounds wayyyyy better after the "sync". Got the idle adjusted too. Think these stock carbs will work just fine ...only thing is....it is still backfiring a ton. Im thinking the timing? I dunno. IGot the new fork all pulled apart for cleaning and painting. I might pull all the electrical and get all that squared away for the new lights. I also got an integrated light from motodynamic that is made or an R6...promise it wasn't to copy. I had that shipped over a month ago. Im going to install it flush on the back if the tail. I would love love love love to do a monoshock...but I think that's a little past my abilities. Should I look to upgrade my rear shocks?

Anyone have a decent standard tank? I want to get rid of this special one like...now. id do a fiberglass one, but I worry about fitting it to the bike properly
 
#17 ·
Ill try to get some pics taken tomorrow..not really a lot to look at right now. tanks off...not really adding a lot right now.

Wish i was as good at this stuff as you though cruuz....fricken changing it to a chaindrive and monoshock and everything? Im just trying to stop it from backfiring. haha

Black- No, they are not upsidedowns...but they are still 100% better than what i had. im really digging them and cant wait for my bearings
 
#18 ·
Is it backfiring on deceleration mostly or if not when? Cos straight pipes on no throttle decel will def make some noise. Get yourself a Haynes manual too if u don't already have it, if u don't use it now u will later
 
#19 ·
got the service manual already. Its backfiring like constantly while idling. It does a little as its coming down in RPM's but mostly while idling. its embarassing :)

I do plan to do a 3 to 1 exhaust system and at that time i want to put a slip on sport muffler on. should provide some back pressure and also make it sound sickkkkk
 
#35 ·
Enormous good or enormous bad :) seriously though...I can't find a decent tank for a decent price to save my life.

Im gonna pick up a timing light tomorrow...I did read about it in the book...but it makes me nervous.
:CK187:
 
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