Ninja EX500 carbs on an XS650?

[Signal]

Update on the pilot screw. The pattern part looks identical to the stock part where it matters. It is very slightly different in the screwdriver slot height but this is below the thread and will have no effect on the pilots screw's operation. The screw came with the spring, washer and O ring.
It is a Keyster part made in Japan Part number on packet KHSS-110 screw set.

 

[bosco659]

I just learned about this today. Another rabbit hole for me? Lol

 

[CanadianSteve]

I just learned about this today. Another rabbit hole for me? Lol

FYI the 38/138 and JJJ needles were ordered today. I’ll let you know when they are hooked up Will be interesting to see what they are like compared to the VM34s.

 

[bosco659]

FYI the 38/138 and JJJ needles were ordered today. I’ll let you know when they are hooked up Will be interesting to see what they are like compared to the VM34s.

Can wait to hear the beast run! Thx for the update

 

[Signal]

Still quietly working on these carbs. No JJJ needles available here in NZ, I tried to order from Allens in the UK (during November 2023) they have them on backorder and when I asked of a ETA no reply. That was disappointing and I wont waste my time with them again.
Jets R us have them and I was putting off ordering as I was in no rush and the cost with the currency conversion was getting up there.

Stumbled across some on Ali Express $11 for 4 with clips. Knowing they are not genuine but worth a punt I ordered some. Today they arrived and I compared them to some genuine needles I have in another set of CVKs. The tapers are as near as I can measure identical, the only difference is in the length of the needle past the highest clip ring. The distances from the rings to the needle point are the same. So I will run them and report back . This will take some time.
Link to seller: https://www.aliexpress.com/item/100....order_list.order_list_main.25.14e71802u6gXuq

 

[Its been a long time]

Reading with great interest. I have decided after a lot of work to retire my ancient BS38 carbs. I have bought what looks like a clean set of ER5 carbs. Even these are now 20 years old, but that's nothing like 50 of course.

If I understand correctly, I need BS34 inlet rubbers, 38 pilot jet, 138 main jet, JJJ (PWK) needles. I'll be using foam pod filters.

The only thing I'm not sure about is using the Yamaha throttle cable. If anyone has advice on throttle cables, I'd appreciate it. Thanks.

 

[bikefreakjon]

Reading with great interest. I have decided after a lot of work to retire my ancient BS38 carbs. I have bought what looks like a clean set of ER5 carbs. Even these are now 20 years old, but that's nothing like 50 of course.

If I understand correctly, I need BS34 inlet rubbers, 38 pilot jet, 138 main jet, JJJ (PWK) needles. I'll be using foam pod filters.

The only thing I'm not sure about is using the Yamaha throttle cable. If anyone has advice on throttle cables, I'd appreciate it. Thanks.

I rigged up a custom throttle cable with a generic single pull CR250 throttle, I had to cut the cable housing a little shorter with a grinder.

Also there's a lot of talk about needles in this thread, on my bike the stock CVK needles with one .5 mm shim runs really nicely.

I haven't messed with it for a while but the one thing I think I'm going to change right now is to install a slightly larger choke jet because on cold days even with full choke it can't quite get going.

I mean, it will start in the winter. I have to slowly kick it over a couple times with the ignition off and full choke and then when I kick it for real I have to catch just the right amount of throttle.


Jon

 

[Adamc]

Reading with great interest. I have decided after a lot of work to retire my ancient BS38 carbs. I have bought what looks like a clean set of ER5 carbs. Even these are now 20 years old, but that's nothing like 50 of course.

If I understand correctly, I need BS34 inlet rubbers, 38 pilot jet, 138 main jet, JJJ (PWK) needles. I'll be using foam pod filters.

The only thing I'm not sure about is using the Yamaha throttle cable. If anyone has advice on throttle cables, I'd appreciate it. Thanks.

I usually build my own cables using kits / products from VENHILL
Quality is excellent and you can build custom cables yourself quite easily and cost effectively.

 

[Its been a long time]

I usually build my own cables using kits / products from VENHILL
Quality is excellent and you can build custom cables yourself quite easily and cost effectively.

Thanks for that. I have been looking at the Venhill website already. I'm afraid I don't have a solder bath or any of the tools to do that. I'm hoping I can buy an XS650 cable (so at least it's correct at one end) and modify the other end to suit the ER5 carbs. I obviously don't know until I get them quite what's involved. I will have to think about it.

 

[Adamc]

Thanks for that. I have been looking at the Venhill website already. I'm afraid I don't have a solder bath or any of the tools to do that. I'm hoping I can buy an XS650 cable (so at least it's correct at one end) and modify the other end to suit the ER5 carbs. I obviously don't know until I get them quite what's involved. I will have to think about it.

You dont need a solder bath. Just a large brass blank off end stop will suffice; (what I use, remove rubber seal); mount in bench vice, and melt solder into it with a blow torch. Just dip your cable ends into the solder and done.

Heres a video I used for guidance. Brass nut version is from about 24min in:

 

[Its been a long time]

You dont need a solder bath. Just a large brass blank off end stop will suffice; (what I use, remove rubber seal); mount in bench vice, and melt solder into it with a blow torch. Just dip your cable ends into the solder and done.

View attachment 335998

Heres a video I used for guidance. Brass nut version is from about 24min in:

Thanks for that, I'll take a look. What flux do you use?

I don't have a blow torch either

Once the carbs get here, I'll see what's what and what the way forward is.

 

[Adamc]

Thanks for that, I'll take a look. What flux do you use?

I don't have a blow torch either

Once the carbs get here, I'll see what's what and what the way forward is.

I use the pot of ancient flux my dad left after he passed, with a roll of ancient solid core solder he also left; it will last me years. Some modern hollow core solder have a flux core that eliminates the need for separate flux; that will burn off during the ‘melt’. Any pot of cheap flux will do the job with solid core or self flux hollow solder.

 

[Its been a long time]

I use the pot of ancient flux my dad left after he passed, with a roll of ancient solid core solder he also left; it will last me years. Some modern hollow core solder have a flux core that eliminates the need is separate flux; that will burn off during the ‘melt’. Any pot of cheap flux will do the job with solid core or self flux hollow solder.

You know what? The number of people I know who still have solder, flux and soldering irons from their dad or grandad is amazing. I'm surprised anybody still manages to sell any new these days

I'll see what I need later in the week when the carbs get here. I have ordered the carb jets etc.... that I need as per this thread. Then I'll work out what to do.

(When I was an apprentice many, many years ago I recall we made our own soldering flux by putting zinc pellets in hydrochloric acid. Doubt you can do that these days).

 

[Its been a long time]

I have the ER5 carbs now. One of the pilot mixture screws is seized so I'll have to find someone with a milling machine to remove the threaded portion of the brass that's screwed into the body. I am not doing this one myself since my Chinesium pillar drill isn't accurate enough for this. Otherwise the carbs look promising.

Can I ask please what Uni Pod filter people are using on the CVK34 carbs? I was all ready to order the 4229 ones with an ID of 2 1/4" or 58mm. But the carbs I have seem more like 2 1/8" or 55mm. So, 2" will be too small and 2 1/4" will be too big. What are users finding please?

I have just measured the carbs properly. The engine side measures 42mm OD and the air inlet measures 55mm OD.Thanks.

 

[Its been a long time]

I have the ER5 carbs now. One of the pilot mixture screws is seized so I'll have to find someone with a milling machine to remove the threaded portion of the brass that's screwed into the body. I am not doing this one myself since my Chinesium pillar drill isn't accurate enough for this. Otherwise the carbs look promising.

Can I ask please what Uni Pod filter people are using on the CVK34 carbs? I was all ready to order the 4229 ones with an ID of 2 1/4" or 58mm. But the carbs I have seem more like 2 1/8" or 55mm. So, 2" will be too small and 2 1/4" will be too big. What are users finding please?

I have just measured the carbs properly. The engine side measures 42mm OD and the air inlet measures 55mm OD.Thanks.

Answering my own question, I think these Ramair filters with 55mm inlet look to be a good bet for the ER5 carbs -

https://ramair-filters.co.uk/mr-015-55mm-id-neck-motorcycle-pod-air-filter/

 

[arcticXS]

Answering my own question, I think these Ramair filters with 55mm inlet look to be a good bet for the ER5 carbs -

https://ramair-filters.co.uk/mr-015-55mm-id-neck-motorcycle-pod-air-filter/

It is really annoying how all manufacturers of universal clamp-on filters do not show how they look inside. This goes for K&N, UNI and now Ram-Air. I suspect that the filter shown in the picture may have a step or reduced diameter upstream from the neck. At least some UNI filters with a large neck ID do just that. That is really not the best setup for good airflow. I would try to get hold of the stock Kawasaki setup, and study it closely, to see if maybe parts of it could be used.

 

[Its been a long time]

It is really annoying how all manufacturers of universal clamp-on filters do not show how they look inside. This goes for K&N, UNI and now Ram-Air. I suspect that the filter shown in the picture may have a step or reduced diameter upstream from the neck. At least some UNI filters with a large neck ID do just that. That is really not the best setup for good airflow. I would try to get hold of the stock Kawasaki setup, and study it closely, to see if maybe parts of it could be used.

Unfortunately, that's not going to be possible. The standard filter is in an enormous looking air box. It just isn't going to fit an XS650 -

 

[arcticXS]

But what about the carb to airbox rubbers, maybe #14073 in the parts diagram? They look like velocity stacks to me. Those+ some kind of aftermarket air filter setup would be better than clamping a filter straight to the carb

 

[Its been a long time]

Progress. The carburettor that had a sized mixture screw is fixed*. The mixture screw is M6 x 0.75 pitch thread. 5.2mm tapping size. So the carburettor body was set up on a milling machine and a 5mm end mill used to remove the threaded portion of the broken screw. However, the last mm or so of the screw actually screwed itself deeper into the mixture screw hole rather than being cut by the end mill. I thought at that point the job was a failure. But a careful 5 minutes with a Dremel this morning removed the remains of the threaded mixture screw. Happily the spring, washer, O ring and remains of the mixture screw fell out. So the carburettor body is undamaged. Need to buy a suitable tap then run the thread down ready to fit new brass to the carburettors.

*Lesson learned, never buy carbs off anyone unless they demonstrate all the brassware removed first before buying.

Picture, still a trace of brass dust on there, but essentially it's done -

 

[Signal]

Good work on saving that. See post #1041 for after market supplier of mixture screws. Note although they look identical where it counts l I have not run the bike to test fully.

With regard to the air filters I think the clamping area on the CVK is to small. I turned rings that slide on and are secured with a grub screw to the carb that extends the clamping surface.
The ring is removable as with the rings fitted it is too hard to slide the carbs into position past the upright frame member.

Small clamping area note small dimple to centre grub screw.

Ring fitted note proximity to frame upright
I missed a trick doing this as it would be easy to make these longer and give more intake length. I have made two sets of these on one set I tapered the inlet side so there is no step at the ring. I didn't bother with the second set as I believe it is too far from the port to have a big effect.