XS850 - Monoshock & USD Fork (pics pg 13)

[treitz]

Truth! There's been a few cool carbs out front motorbikes on here they fixed it! haha.

Always good to be cleared up before we start adjusting things ))))))

So true! Honestly, it never even crossed my mind that they could be backwards being in the back half of the carb. Learn something new everyday! Main reasons I love forums so much. Now I can give the same advice to my next buddy who doesn't know and sound all smart and stuff haha

 

[treitz]

I got my new clutch cable installed last night, so I'll be able to do some more testing on the bike here soon. Just haven't had a chance to run it again yet as it's really loud, and I typically can only work on it at night.

Alright, now changing gears...

I installed these LED signals that I've never been able to get working. Attached is an image of the flasher relay that I bought. I think this is the same relay that I bought for a LED signal set before, but maybe I bought the wrong one? Anyway, if you see something on this relay that's a red flag, let me know. I can hit the auto parts store and grab the right one if I know what's wrong.

If this is the right relay... then I guess I have another issue.

 

[MotorbikeBruno]

2-4 lamps at "up to 162W" seems insane for LED bulbs.

For example. If an LED draws .4Amps, it draws 4.8W

http://www.rapidtables.com/calc/electric/Amp_to_Watt_Calculator.htm

Just a thought? Might be made for some large LED lights with 50+ LED bulbs in them? I could be wrong as I no very little about them, just thought that 162W was a bit high for 4 little bulbs.

 

[treitz]

Hmm... So the LED's probably aren't building enough resistance you think?

The LED strips I'm using probably have 10 bulbs on each. So with the left or right signals on, I'd be powering 20 bulbs?

 

[datadavid]

Parallell connect resistors to the led's, or get a load-independent relay! Thats the way to go!

 

[treitz]

Parallell connect resistors to the led's, or get a load-independent relay! Thats the way to go!

Load independent relay was my goal... I must've bought the wrong thing? I'll swing by the auto parts store tonight and see what they have. I was under the impression that the LED specific relays were by default load-independent. My bad I guess.

 

[treitz]

Alright gents... took the ol' girl for another ride last night and it still ran like shit. Got home and checked the plugs again, same thing. #1 - black black black, #3 - white.

So I had no choice. Pulled the carbs and started to go through. I THINK I found the issue. These carbs have a threaded cap that covers the pilot jet housing. As you can see in the attached close up image, the housing has a stress crack from some jackass tightening it too much I imagine (I won't take credit). Anyway, I guess my only option is to find a replacement #1 carb Is it safe enough to assume this is the issue? I can't see anything else that could cause it. Float height looks good.

For reference, here is my jetting currently: Main = 130 / Pilot - 42.5 / needle in the stock middle slot

On a side note, while riding it I noticed that there is a spot in the low - mid throttle range where it responds well, but at full throttle it pretty much completely cuts out. Complete loss of power. Makes sense that I would be lean there, so I imagine a main jet jump is in my future.

 

[datadavid]

Damn your carbs are dirty! I would weld up that crack and ride happily on, but thats me
I have a set of incomplete bodies of what i believe is mk2's lying about which i have absolutely no use for, theyre yours for postage if you want them, theyre clean and crack-free.
By the way, mine have copper washers under those screws, so i guess theyre supposed to be sealed off..

 

[treitz]

Damn your carbs are dirty! I would weld up that crack and ride happily on, but thats me
I have a set of incomplete bodies of what i believe is mk2's lying about which i have absolutely no use for, theyre yours for postage if you want them, theyre clean and crack-free.
By the way, mine have copper washers under those screws, so i guess theyre supposed to be sealed off..

These carbs went through a carb cleaning even... but I don't have a soda blaster or anything, so not as good of a cleaning as they could have I guess.

I'll have to see if I can find some copper washers... I don't recall pulling them off when I disassembled, but that does make sense. Probably helps with the seal for sure.

JB weld crossed my mind... but I assumed I get a ton of flack for it on here. haha. But if it works... it works... ?

You're across the big pond, so I imagine shipping would be a bitch. I'll keep my eyes out in the states and see what I can find first.

 

[MotorbikeBruno]

I'm all in for (if it works, it works) I might use the gas tank/radiator repair putty stuff before I used JB weld in a submerged gasoline environment.

My father's entire kit plane was built with this ProSeal....including the gas tanks etc. They say you could pull the rivets out if you wanted once this stuff is dry Here's a gas tank putty version of it.

http://www.zoro.com/pro-seal-putty-gas-tankradiator-070-oz-strips-62020/i/G0940161/?utm_source=google_shopping&utm_medium=cpc&utm_campaign=Google_Shopping_Feed&gclid=Cj0KEQjw_rytBRDVhZeQrbzn_q0BEiQAjnbSHFwqdJwk4dSHFJ_MAwDW2R0CRtIA4FkDucvzmURdW8UaAv5H8P8HAQ&gclsrc=aw.ds

 

[treitz]

Rad thanks. I might run by the local NAPA and see if they have any gas tank specific stuff before resorting to JB weld. However I did read a bunch of posts online by people who have used JB weld without issue... but something built to resist gas might be a better bet.

Anyway, do you guy think that this little crack is likely the culprit of the insanely rich #1 cylinder? I mean I guess it makes sense, but it's just such a small crack, I can't imagine how THAT much gas is getting through to cause such an issue.

 

[Tune-A-Fish]

I hate be the spoiler, but that carb looks like its beyond its useful life and a lot of grief could be avoided by smashing it and getting something usable. what size is it?

 

[MotorbikeBruno]

I hate be the spoiler, but that carb looks like its beyond its useful life and a lot of grief could be avoided by smashing it and getting something usable. what size is it?

Although I tend to agree...I also think that with the vacuum of the pilot jet at idle, this would definitely pull in excess fuel and cause some issues. For the $5 it takes to give it a shot, I say go for it. If THAT doesn't do it...get you some new carbys.

 

[Tune-A-Fish]

Here's a "rebuilt" set for $200
http://www.ebay.com/itm/1981-Yamaha-xs850-xs-850-carburetor-/231629491887?hash=item35ee318eaf&vxp=mtr

 

[Tune-A-Fish]

Although I tend to agree...I also think that with the vacuum of the pilot jet at idle, this would definitely pull in excess fuel and cause some issues. For the $5 it takes to give it a shot, I say go for it. If THAT doesn't do it...get you some new carbys.

Yep... I agree, but if nothing else the carbs are too far gone from the looks and other things are likely adding to the list, that much pitting tells me air is leaking past through holes for mechanicals.

 

[treitz]

I believe those are the hitachi's. I've heard nothing but bad things about them... the Mikuni MK2's are a decent carb. I'm with Bruno... there's not harm in trying. If it's still jacked, I can think about a replacement set.

I can get a left carb body for $50: http://www.ebay.com/itm/78-79-YAMAHA-XS750-XS-750-SPECIAL-MIKUNI-CARB-CARBURETOR-LEFT-EMPTY-BODY-/291521243908?hash=item43e0052b04&vxp=mtr

Or all three for $150.

But if I'm going to spend over $200 on a new rack of carbs, I might as well make the jump and spend $300 on a set of VM34's http://www.spec2.com/xscarbs.html

Assuming that guy is still in business and selling the kit. His website is 16 years old...

 

[Tune-A-Fish]

I believe those are the hitachi's. I've heard nothing but bad things about them... the Mikuni MK2's are a decent carb. I'm with Bruno... there's not harm in trying. If it's still jacked, I can think about a replacement set.

I can get a left carb body for $50: http://www.ebay.com/itm/78-79-YAMAHA-XS750-XS-750-SPECIAL-MIKUNI-CARB-CARBURETOR-LEFT-EMPTY-BODY-/291521243908?hash=item43e0052b04&vxp=mtr

Or all three for $150.

But if I'm going to spend over $200 on a new rack of carbs, I might as well make the jump and spend $300 on a set of VM34's http://www.spec2.com/xscarbs.html

Assuming that guy is still in business and selling the kit. His website is 16 years old...

Was a $100 set on also, but rusty tops... You could build a set of triple pull Keihins and use an old RD cable setup and have something you can count on

 

[datadavid]

I put triumph legend carbs on my bronze bike build, its a straight swap, cheap and easy to find i think. And they perform really really well..

 

[jpmobius]

After seeing that close up, I think I would just cut my losses and move on to some new(er) carbs since you are having so much trouble. That looks like some pretty long term corrosion not so much still "dirty"at least in the pic. No telling what else may be lurking. I'm all for using the old and seemingly unsalvageable, and have used carbs myself that looked every bit as bad as those that worked fine, but also had carbs that looked great but had crap so solidly packed in that I just abandoned them rather than keep putting work into them. I hate throwing anything away, but sometimes there is no other sensible choice. You may solve the problem now, but consider the possibility of more trouble down the road. Tough call either way.

 

[treitz]

I put triumph legend carbs on my bronze bike build, its a straight swap, cheap and easy to find i think. And they perform really really well..

Like these bad boys?

Was a $100 set on also, but rusty tops... You could build a set of triple pull Keihins and use an old RD cable setup and have something you can count on

What kinda triple pull keihins?