New to the Forum

Raymond

likes to play with old motorbikes
Top Contributor
XS650.com Supporter
Messages
2,944
Reaction score
14,744
Points
513
Location
Scottish Borders
Can't help wondering what good de-ionised / distilled water will do, given that the very instant you plonk a manky part into it, it's fecked up again. :)
Yeah, the guy who dropped his tuna sandwich into a vat of very expensive pure liquid mercury . . .
 

Frank Henry

XS650 Member
Messages
21
Reaction score
63
Points
13
Location
New Jersey
I thought it would be good to ask where to buy a carb rebuild kit. Also, while looking on u-tube, I noticed someone using a tool that had different sizes of wire that are used to clean out or ream out the air holes in the jets. Does anyone know something about this tool?. Thanks....Frankie
 

Jim

Beyond the edge is the unknown. Here be Dragons
Top Contributor
XS650.com Supporter
Messages
15,185
Reaction score
59,677
Points
813
Location
Kansas City Mo.
I thought it would be good to ask where to buy a carb rebuild kit. Also, while looking on u-tube, I noticed someone using a tool that had different sizes of wire that are used to clean out or ream out the air holes in the jets. Does anyone know something about this tool?. Thanks....Frankie
"Different sizes of wire" is most likely a torch tip cleaner. Don't believe everything you see/read on the internet. :cautious:.... and don't use a tip cleaner to clean jets!!!
Those wires are stainless steel... and the jets are brass. All you're most likely gonna do is ream out the hole and make the jet worthless.
If you must try and clean out a jet hole, take some electrical wire (copper) and untwist the strands. You can even double up the strands if need be. Copper is softer than brass and won't destroy your jet.


1691855732847.png
 
Last edited:

5twins

XS650 Guru
Top Contributor
Messages
24,587
Reaction score
21,806
Points
813
Location
WNY
Yes, carb rebuild kits are not recommended. Besides having the wrong jet sizes many times, they are aftermarket so there's no way to know if the jets are calibrated correctly. It's best to use only genuine Mikuni jets. The float needle and seat assemblies included in the kits are also of questionable quality, many bad right out of the box. They are best sourced directly from Yamaha. Expensive yes, but you will be insured of the quality and they should be a one time replacement, lasting for longer than you'll have the bike. If the floats have gone bad, it turns out they are nothing special, just the common Mikuni VM24-171, readily available from many places for less than $15 .....

Mikuni-VM24-171-Genuine-Brass-Float-Dimensions.jpg
 

Jim

Beyond the edge is the unknown. Here be Dragons
Top Contributor
XS650.com Supporter
Messages
15,185
Reaction score
59,677
Points
813
Location
Kansas City Mo.
Last edited:

Frank Henry

XS650 Member
Messages
21
Reaction score
63
Points
13
Location
New Jersey
Yes, carb rebuild kits are not recommended. Besides having the wrong jet sizes many times, they are aftermarket so there's no way to know if the jets are calibrated correctly. It's best to use only genuine Mikuni jets. The float needle and seat assemblies included in the kits are also of questionable quality, many bad right out of the box. They are best sourced directly from Yamaha. Expensive yes, but you will be insured of the quality and they should be a one time replacement, lasting for longer than you'll have the bike. If the floats have gone bad, it turns out they are nothing special, just the common Mikuni VM24-171, readily available from many places for less than $15 .....

View attachment 249018
I think the best bet is to take everything apart to see how bad it is. I bought the bike about 20 years ago and it was reportedly running but roughly, now smooth. So I know there's trouble from the get go. We'll see. I'll take some pictures or a video as I go along...............Frankie
 

5twins

XS650 Guru
Top Contributor
Messages
24,587
Reaction score
21,806
Points
813
Location
WNY
About the only thing you could use for sure from the rebuild kit would be the float bowl gasket. But if you're careful with the disassembly, you can usually save the original and re-use it. They are quite robust. The only other gasket on these carbs is for the choke housing and I normally don't disturb that. There's really no need to remove the choke housing. The passageways in it are quite large so never plug up. All I do is remove the choke plungers from the housings and clean them.

There are only 2 o-rings in each carb as well, and neither comes in the rebuild kits anyway. But, we've figured out their sizes - for the needle jet, a 1mm x 4mm o-ring will work and for the mix screw .....

BS38MixScrewO-Ring.gif


78-79MixScrew2.JPG


78-79MixScrew3.JPG
 

Frank Henry

XS650 Member
Messages
21
Reaction score
63
Points
13
Location
New Jersey
You can usually get everything you need from either...
https://www.jetsrus.com/index.html
https://www.nichecycle.com/ncs/

both have genuine Mikuni parts as well as aftermarkets. To me it's worth the little extra to get the Mikuni brass.
Please don't laugh at my ignorance but is Mikuni that original manufacturer of the carbs or a company that supplies parts for the original carbs? And...as long as I'm asking questions that might cause you to laugh, here's another. I have both a pressure washer and a steam pressure cleaner. Which would you recommend for the outside of the bike. I realize I'd have to be super careful with the steam on the paint.............Frankie
 

Jim

Beyond the edge is the unknown. Here be Dragons
Top Contributor
XS650.com Supporter
Messages
15,185
Reaction score
59,677
Points
813
Location
Kansas City Mo.
Please don't laugh at my ignorance but is Mikuni that original manufacturer of the carbs or a company that supplies parts for the original carbs? And...as long as I'm asking questions that might cause you to laugh, here's another. I have both a pressure washer and a steam pressure cleaner. Which would you recommend for the outside of the bike. I realize I'd have to be super careful with the steam on the paint.............Frankie
Your carbs are made by Mikuni
No opinion on the second question.
 

Raymond

likes to play with old motorbikes
Top Contributor
XS650.com Supporter
Messages
2,944
Reaction score
14,744
Points
513
Location
Scottish Borders
. . . I have both a pressure washer and a steam pressure cleaner. Which would you recommend for the outside of the bike. I realize I'd have to be super careful with the steam on the paint . . .
Frankie, you're going to get to know this bike well. Need to spend a bit of time with her. Sit on a stool, go at the engine with a kerosene rag and see if that removes the alloy corrosion. Perhaps move on to alloy polish. Remove bits from the bike to get at them for cleaning, like the chain guard. Decide whether you're happy with the state of it, or get it re-chromed, or replace. Strip the carbs, see what parts you need to replace. Fuel tank could lead to a whole lot of issues. Sometimes rusty fasteners come up clean after a night soaking in vinegar. Iterative process of clean, inspect, refurbish, clean again using graduated methods. Sorry, but you can't really expect a once-over with a pressure washer or a steam cleaner is going to give you a restored bike.

Months of fun. Ask questions, plenty of help around here.
 
Last edited:

gggGary

Just call me squirrel brain
Top Contributor
XS650.com Supporter
Messages
29,919
Reaction score
54,413
Points
813
Location
Baraboo, WI, USA
I've had at least 4 pressure washers over the years. Have a good 220 electric one now.
I DO NOT use it on assembled motorcycles or engines.
Been there done that regretted it. You always end up with water where it shouldn't be and you won't find it til it's already done damage.
Bought late model bikes from guys that pressure washed them and wished I hadn't bought them. Rust and corrosion in hidden joints, bearings, bolt threads etc. blech.
Mineral spirits in a spritz bottle; various brushes, especially old tooth brushes.
 
Top