XJ650RJ Seca Build

I just glanced the thread over but I’m leaning towards two areas.

One, did you replace the intake boots? I got some aftermarket ones and they delaminated in just a few days after install. Make it hard to start, unable to idle well, and colortune was ineffective. How are the caps on the intake boots? Are they clamped tight?

Two, I don’t see any mention of you doing a through carb rebuild. I see you mention that the PO replaces needles and you replaced them again. You might have internal issues causing it to run lean or have air leaks in throttle seals etc.

 

Thanks for the feedback.
Yes I’ve replaced the intake boots with the oem ones from chacal. (Not cheap) And I’ve replaced the trottle shaft seals during the rebuild. I’ve also used multiple sprays to test for vacuum leaks with no results.

Regarding the caps and clamps, they are also new replacements from chacal. However I’ve noticed that even with the clamps on, with a set of players, I can grab onto the top of the rubber clamp and pull the rubber and clamp off the intake hose. However when spraying carb cleaner to test for leaks, I’m not getting an rpm increase.

 

Mixture screws & synch.

 

Cool, yeah I had to go the OEM intake route as well. Not cheap but should last another 30 years. I had the same experience with the vacuum caps as well, can pull off with little effort with pliers but they seem to seal just fine and have not moved in 1.5 years.

Kinda running out of ideas. Did your slides pass the clunk test? Maybe they are hanging up. In your vid your throttle response sounds slow too when opening the throttle.

 

I also just watched your video showing the carbtune hooked up, those readings are way low at idle. You definitely have some air getting in somewhere or something else going on.

I'm no carb guru but I will put this out there, mainly because I'm wondering. I'm wondering if you have an issue with the idle circuits in the carbs and you're not actually running on them. Does turning the choke (enrichener) on make any difference on the idle speed? It only comes into play at idle and just off idle. If there is an idle circuit problem you might have the idle stop screw in too far just to keep it running, effectively "achieving" an idle.. This would keep the throttle plates open further and lower your vacuum readings when attempting to sync.

 

Yes they’ve passed the clunk test. While having them on my carb stand when wet setting carbs I compared the clunk speed of all 4 carbs and they all were the same.

I’m going to try to carbtune again today (it was too hot to work outside without any shade since I’m working on an open parking lot). I currently have the resistors in the carbtune hooked up based on an old recommendation but will try without them to see if the reading is better.

For th idle circuit, I actually haven’t been using it lately. But I’ll confirm what effect it has.

I’m thinking of starting back from square 1 and filming everything for reference and keeping a detailed log of all adjustments.

Start placing your bets people on what the issue is haha.

 

They are there to "smooth" out the readings, not increase/decrease the amount of vacuum measured. The rods will be bouncy without the restrictors.

If you're not using it, then it's not going to idle nor can you tune it I think you meant choke.

 

Oh haha that’s what happens when I try to multitask at work... Ill work on it tonight and report my results.

 

First off, thanks everyone for the feedback. Right before I left work, I re-read the recent posts to get back into the mind-set of motowork instead of database work. Once I got home I only had about 30 minutes left of light, so I fired it up and took it around for a quick few laps around the neighborhood to get it warmed up and proceeding to re-sync the carbs with the resistors removed in the carbtune. Such a difference, I was actually able to read the carbtune and see the difference a turn of the sync screws would make. So I was able to dial in all 4 carbs together and the bike idled better. I wasn't too badly off beforehand, but every little bit counts. Taking it for another lap around the neighborhood, I could feel the engine braking actually kicking in. Its still a little slow to return to idle but it does a lot better. And after a future round of colortuning, I should be in a better place.

During the whole process, I also tried spraying carb cleaner and electronically cleaner around all throttle shaft seals, all intake boots, intake boot rubber clamps, and airbox clamps with no change in rpm.

Ultimately, I think my idle was set a little too high to start, and in combination with the 4 carbs being out of sync, this caused the idle to be very hard to return to normal as each carb was competing against each other.

Next days plan:
1. Colortune
2. re-carbtune
3. Possibly color tune again,
4. Install new plugs (So I can get a good reading of work)
5. Cross fingers
6. Suit up and enjoy a ride along the coast this weekend.

 

YES!!

I would recommend executing your plan in the following order:

1. Install new plugs (So I can get a good reading of work)
2. Colortune cylinder #1
3. re-carbtune (synch) entire engine
3. Colortune cylinder #2
4. re-carbtune (synch) entire engine
5. Colortune cylinder #3
6. re-carbtune (synch) entire engine
7. Colortune cylinder #4
8. re-carbtune (synch) entire engine
9. Suit up and enjoy a ride along the coast this weekend.


No longer necessary:
10. Cross fingers

 

So I am curious about this. In your first video without the restrictors the gauge indicators fluctuated wildly and it was pretty much useless. Note that it is important to add the restrictors at the proper point (near the engine) so that the open hose downstream from that actually helps dampen the reading by acting as a storage capacity for the vacuum reading. You can read about it here:

http://www.carbtune.com/inst.html

An excerpt from above:

"Set-Up

Damping. The restricters must always be used.

Without restricters the rods will fluctuate wildly. There are two components to the damping.

1. The small amount of friction between the rods and guides which is overcome as soon as the pulsating vacuum of the engine is connected. This friction can vary from tube to tube in the Carbtune and is not a fault.

2. The air-flow restricters that fit inside the rubber tubes and damp the fluctuations. There will always be a small amount of fluctuation and this is necessary for the gauges to work properly. Do not oil the rods."

 

So hooking up the colortune again provided unclear results. For cyclinder 1&2 I could adjusts the mixture screw all the way in vs out and not see a change in the color of the flame. So I reset to where I was at. I looked at the old plus and leaned out carb 1 a hair, and richened carb 3 a hair and re synced the carbs.

I’ll put some miles this weekend and adjust based on the plug reading.

 

And you opened up the enrichment circuit momentarily to verify a change in the colortune color to yellow?

 

No I did not, I only adjusted the mixture screws on the 2 carbs. But I guess that would make sense to open up th me “choke” / enrichment circuit as it would have a dramatic impact on the mixture going into the engine.
I will try that 1 more time and see what happens.

 

Ugggh. Sounds like the mixture circuit passages are stilled a problem on those carbs. Hitting the choke as Rooster53 suggests will confirm this theory (assuming the choke circuits aren't plugged, too).

 

The test will confirm. I feel like I will have to take the carbs off the bike again and re-clean those.

 

Hey mate loving the build!
Just bought a 650 seca here in Australia! Just wondering what bars you are running? Planning on doing something similar with the seat and bars. Cheers mate!

 

Awesome! Be sure to show us photos of your build. I picked up a set of biltwell tracker bars. I’m not 100% sure on how they would fit/look with the stock triple tree clamp as I have a custom one for the gsxr swap.

 

Yea will do for sure! I've taken on your advice and I'll definantly have videoing vas much as possible too!

I'd hate to be that guy asking what everything you have is but those mufflers look insane! What are they

 

They are the stock mufflers actually. I guess the us seca had a different version vs other countries.