Bout done with these og carbs.

[rickthefix]

I've had these carbs off IDK how many times trying to get them to work properly on the 75 277.
They have been overflowing, leaking and just not running properly. Never had this many issues I could not solve and I've rebuilt/repaired bunches of carbs over the many decades.
I have a set of Mikuni RS I bought from a guy going out of business a few years ago, was keeping them for my 79-SF resto-mod build. Also a set of replacement manifolds.
And I also have a set of EX500 carbs I might rebuild to see how they run, but gotta dig them out from wherever they are boxed up.

R T F

 

[rickthefix]

Well, no EX500 carbs on the shelf . . . I have a couple EX500 front calipers though
Did find my og set of carbs from my 79-SF. May match the jets that are in the 75 carbs n see how they do.
They were running great before I decommissioned the SF.
May order some of those EX500 carbs in the mean time.

 

[650Skull]

Match the jets to the carbs. Not the bike to the carbs.

 

[rickthefix]

idk what that means. I'll be matching the jets that are in the 75 carbs for the 79 carbs I'll be putting on the 75. Basically the same carbs, except the 75 uses a dual cable n the 79 is a single cable.

 

[Jim]

idk what that means. I'll be matching the jets that are in the 75 carbs for the 79 carbs I'll be putting on the 75. Basically the same carbs, except the 75 uses a dual cable n the 79 is a single cable.

It means you match the jets to the year of the carbs.

If you put '75 jets in a '79 carb, it ain't gonna work right.

 

[650Skull]

Carb guide.

 

[rickthefix]

It means you match the jets to the year of the carbs.

If you put '75 jets in a '79 carb, it ain't gonna work right.

View attachment 357929

Yeah I’ve never looked into this. Thanks. It’s a 277 but I don’t guess that will have any affect on the jets, but the 2/1 to a SuperTrapp will doubt the 75 carbs jets are stock.
Also I took my emotions out of it. When I blip the right carb, it responds, nothing on the left. So another look at the left carb I guess.

 

[650Skull]

A bit of info on the different years.

There is a link, (at the bottom of the 76 carbs), to a comprehensive discussion on setting up a set of, BS38, carbs where 5Twins, (resident expert on all things carbs) gives sage advice.
May not b exactly for either of your sets of carbs, but related to tuning and how exhaust and air delivery effects jetting

https://www.xs650.com/threads/carb-id-mikuni-cvs-bs38-bs34-70-84.43392/

 

[rickthefix]

So my 79 had 2/1 exhaust. I think I’ll install as is to see how the 75 runs. Last night I bought a set of EX500 carbs on eBay for 150 delivered.

 

[Its been a long time]

So my 79 had 2/1 exhaust. I think I’ll install as is to see how the 75 runs. Last night I bought a set of EX500 carbs on eBay for 150 delivered.

I have been running my 77 650D this summer with Delkevic 2 into 1 exhaust and the Kawasaki CVK34 carburettors. Runs great. My posts are to be found near the back end of the very long thread that discusses the topic.

 

[rickthefix]

I have been running my 77 650D this summer with Delkevic 2 into 1 exhaust and the Kawasaki CVK34 carburettors. Runs great. My posts are to be found near the back end of the very long thread that discusses the topic.

Can you send me a link n what page it starts?

 

[Its been a long time]

Can you send me a link n what page it starts?

There's 59 pages and most of it is worth reading. The thread has been running for years.

Thread 'Ninja EX500 carbs on an XS650?'

https://www.xs650.com/threads/ninja-ex500-carbs-on-an-xs650.13070/

From my own experience, first thing to check is that both the mixture screws can be removed. One of mine was siezed in place and presented a problem.

Otherwise if you follow that thread, it's a fairly straightforward conversion and it's certainly a good alternative to ancient worn out BS38s.

 

[650Skull]

Start from page 2. The first 20 pages have a lot of information setting them up from different people.

Seems a lot but can narrow it down by using the search by individual peoples posts in that thread.

1), click search icon top right...
In drop box put members name in the box ....By

2), click on ...this thread



In the drop box click....this thread

Now hit search....
The members posts come up, last to first. Need to scroll back to their beginning

 

[Its been a long time]

There's been various jetting set ups proposed in that thread over the years. The end point seems to have settled down around what I ended up with and it's running well on my stock engine 650D.

 

[rickthefix]

I read up to about page 35. LOTS of info. But I'm stuck on throttle cable and controls. I'd like to keep the og control and replace just one cable instead of the dual cable the 75 has, one to each carb on the BS38's. I might be able to order just one of the cables, both og cables are not smooth to operate.
Unless there is a an alternative. This 75 has lower bars, pretty sure they are drag bars.

 

[rickthefix]

Oh! forgot to say I ordered and received a set of EX500 carbs, 120 main & 30 pilots, they may not actually be EX500's with those jets.
Ordered the BS34 holders from JBM earlier today. Getting ready to order the various jets n needles.
Put on the BS38's from my 79-SF after I got back from a 100 mile ride on the 2006 SV650 that was given to me a couple months ago.
That things a lot of fun!
Will try to fire up the 75 with the 79 carbs tomorrow after getting some hose adapters to match the 75 spigots to the 79 carb hose barbs, different sizes.

 

[rickthefix]

So looking at needles on JetsRus, them boys SPENSIVE!. I think I'll only order 2 sets, JJJ & JJH to start with. Don't see any on Mikes.
Other cheaper sources anywhere? Mikes has the pilot n main jets that are less costly.

 

[5twins]

I quite like the original carbs and wouldn't bother with any other type. But granted, I've only used later linked sets. I wouldn't use the older single carbs unless the bike was a total restoration and required them.

And the '78-'79 BS38s are about my favorites. I'm currently running them on both of my 650s, and I'm experimenting with XS400 5Z1 needles in them. I just went up another main jet size on the '83 and wow, what a difference. I can't believe the additional power that generated. When your jetting is close it's amazing what one size change will do sometimes, lol.

 

[Its been a long time]

So looking at needles on JetsRus, them boys SPENSIVE!. I think I'll only order 2 sets, JJJ & JJH to start with. Don't see any on Mikes.
Other cheaper sources anywhere? Mikes has the pilot n main jets that are less costly.

IMHO, on a stock motor you want to start with 38 pilot, 138 main and JJJ needle. On my 650D it's running just fine like that. I bought the JJJ needles off Ali Express as they were recommended by another member. They're very low cost. It's all detailed in the one long thread.

Post in thread 'Ninja EX500 carbs on an XS650?' https://www.xs650.com/threads/ninja-ex500-carbs-on-an-xs650.13070/post-865805

Throttle cable free length has to be a bit longer than a stock 650 cable using CVK34 carbs. I shortened the outer sheath on a XS650 throttle cable, put on a 6mm threaded adjuster and soldered a new nipple on the XS650 cable. Works fine.

Post in thread 'Ninja EX500 carbs on an XS650?' https://www.xs650.com/threads/ninja-ex500-carbs-on-an-xs650.13070/post-872357

 

[rickthefix]

IMHO, on a stock motor you want to start with 38 pilot, 138 main and JJJ needle. On my 650D it's running just fine like that. I bought the JJJ needles off Ali Express as they were recommended by another member. They're very low cost. It's all detailed in the one long thread.

Post in thread 'Ninja EX500 carbs on an XS650?' https://www.xs650.com/threads/ninja-ex500-carbs-on-an-xs650.13070/post-865805

Throttle cable free length has to be a bit longer than a stock 650 cable using CVK34 carbs. I shortened the outer sheath on a XS650 throttle cable, put on a 6mm threaded adjuster and soldered a new nipple on the XS650 cable. Works fine.

Post in thread 'Ninja EX500 carbs on an XS650?' https://www.xs650.com/threads/ninja-ex500-carbs-on-an-xs650.13070/post-872357

277 rephase, 2-1 custom headers with a SuperTrapp w about 35mm of baffles.
I tried using the 79-SF carbs and it leaks from the crossover hose. I put the bottom brace on but not the top. Couldn’t get them fully flush in the holders. My hoses and filters I think were causing fuel delivery issues due to routing and height of one of the filters. I sprayed some starting fluid into the left carb and it fired.
Ended up with just a short piece of hose no filters. Recently recleaned and POR-15 liner so no chance of rust or debris. The leak will now need to be remedied.
But carbs coming back off.
Just going to continue acquiring parts for the CVK swap.