Old tuneable baffle trick

I've been reading on the internet about making your own motorcycle baffle, and found a trick some old harley riders used on drag pipes. Basically, you weld a washer to the top of a bolt, and drill a hole in the side of your exhaust pipe near the end. Then you insert the bolt with the washer inside the exhaust pipe, and put a nut to tighten it up on the outside. Depending on the angle of the washer, your bike will run/sound different. Has anybody tried this? My kz1000 is still running lean after adjusting the needles to the 4th clip, and I currently have a 4 into 1 header with no baffles, so I'm looking to make the exaust a bit more restrictive in hopes of curing my lean running engine.

Link: hdforums.com/m_79533/tm.htm

toadson wrote:

...My kz1000 is still running lean after adjusting the needles to the 4th clip, and I currently have a 4 into 1 header with no baffles, so I'm looking to make the exaust a bit more restrictive in hopes of curing my lean running engine....

If not already done, would check service fuel level in float bowls, using the clear plastic tube method. Too low fuel levels can cause an overly lean mixture even when everything else is perfect.

Would also use strobe-type timing light to double-check ignition timing and proper operation of the automatic advancer.

Good Luck!

I did adjust the floats using the wet method maybe half a year ago. Before I adjusted the needles from the stock position, the bike would run very lean after a cold start, and would start popping when applying more than 1/4 throttle around 4-5k rpms. After adjusting the needles, the bike no longer needs the choke on to be driveable after a cold start, but still acts lean under a load, just not as bad as it used to be. I'm assuming it wants more gas, so I thought making the exhaust a bit more restrictive could help with this.

That should work, but it's like saying "The front tire is flat, so I'll just let all the air out of the back one to make them even".

Re-jetting the carbs would be a whole lot better than crippling the exhaust to balance the screwed up carbs.

When the Honda 305 Scrambler came out in the mid to late sixties, I saw so many of them with the washers in the exhaust pipes that I thought Honda shipped them that way

Well I would also like to quiet down the ehxuast as well, because I have a megaphone style exhaust tip. The bike is extremely loud and can be heard from over a mile away, which doesn't bother me unless I am wearing a helmet. I bought the bike and noticed someone had used the end of an oil filter and jammed it into the ehxuast pipe. I took it out and it was even louder, so I cut a large hole in the oil filter end and inserted it back into the pipe. It looks a lot better this way and quiets it down a tad, so I thought about sticking another oil filter back in it to see how it would run. I just think having the stock airbox and free flowing exhaust would just hurt the bike performance wise, or am I wrong?

EDIT: Here is how my exhaust looks right now - i143.photobucket.com/albums/r148/toadson...rm/050208_144601.jpg

Why not first try to install a proper baffle . It might be quieter AND make more power . The airflow into and through your unbaffled megaphone is less than optimum . It probably confuses your jetting when exhaust flow hits the the back of the endcap .

Get a long perforated baffle core that extends down into your mid pipe/collector and weld it to the endcap that you have . Wrap the length of the core w/silencer packing wrapped with steel wire to hold it in place . It will still sound good , probably better , and make the power it was designed to .

And then you can sort the jetting...........

toadson wrote:

I did adjust the floats using the wet method maybe half a year ago. Before I adjusted the needles from the stock position, the bike would run very lean after a cold start, and would start popping when applying more than 1/4 throttle around 4-5k rpms. After adjusting the needles, the bike no longer needs the choke on to be driveable after a cold start, but still acts lean under a load, just not as bad as it used to be. I'm assuming it wants more gas, so I thought making the exhaust a bit more restrictive could help with this.

Thinking the '79KZ1000-A3 (standard model) and -D2 (cafe racer) came with 28mm Mikuni's, am wondering if the existing 26mm carbs w/accelerator pumps (shown in your signature) are original equipment on the LTD model.

From posts in other threads, some accelerator pump carbs are notoriously lean and difficult to keep clean.

What is the installation history and performance history of the existing 26mm carbs on this bike? Perhaps carb replacement with 28mm (non-pump version) would be a feasible option.

Question -- Are the pilot ajustment screws located on the sides or underneath the carbs? Thinking it might be appropriate to enrich the pilot circuit mixture.

Also, what does visible inspection of the plug tips indicate relative to fuel mixture?

Good Luck!

I am pretty sure the LTD came with the 26mm, being a B model, while the A models came with the 28's. From what I remember, the LTDs are more for cruising than racing, thus why they have the smaller carbs. The pilot screws are located on the bottom of the bowls, and are a pain to adjust on the bike, but it's possible. I have them adjusted 1 and a half turns out from seated, but the bike seemed too lean when I blipped the throttle. I adjusted them out another turn and it did help, but did not help my midrange/upper end problems.

I bought the bike last year in July, and it had been sitting for 2 years. The first time I took the carbs off and cleaned them, the bike wouldn't run. Cleaned them again and it ran on 3 cylinders. I forget how many times I cleaned the carbs in total, but I finally got it running on all 4 cylinders. I also had to rebuild the accelerator pump, as the diaphram had rotted from sitting, and I replaced all the jets with stock size. The main jets that were installed when I first bought it were made of plastic - was this factory?

I just got done putting a more restrictive oil filter in the exhaust tip, and while it did quiet the noise down, the bike runs the same. On the way home, I tried a little test I learned from the forums. In 4th gear, rolling about 50 mph, I gave it full throttle, then let off just a little bit, and the bike sped up. I believe this means that my main jet is too small, and letting off the throttle a tad is letting it get the gas it needs for the amount of air it is pulling. Now if I only knew what size jets I need.... I think the best thing to do once I figure out new jet #'s, I should go through the carbs once again and clean them throughly, adjust the floats again using the wet method, them synch them up.

This bike is just like everything else I own, either it never runs right or something keeps breaking... haha. Anyway if someone has some jetting advice I would appreciate it! I may just start a new thread in the carb forum, but I hate to keep starting new threads. Thanks all for your suggestions so far!

put the endcap in the header without the baffle,it will mellow it down and help out bottem end torqueB)

I should have been clearer, all I have in it now is the endcap (oil filter). Something else I've realized is that this bike has points. I could have sworn I read that they didn't have them, but low and behold they are there. They have some spots built up on them, so
I took a little sandpaper to them. Not really sure if this is causing my problems though. I once had a 450 Scrambler that had bad points, and man was that a fun job.

Interesting that the '79 LTD kept points when -A3 and -D2 began electronic ignition.

Remember to clean and gap points before using strobe-type timing light to set ignition timing and verify proper operation of automatic advancer.

What air filter is being used (pods? K&N? stock paper?)

If not already done, would also do compression test and check valve clearances.

All toward perfecting ignition and compression aspects before further addressing carbs.

Good Luck!

toadson wrote:

I should have been clearer, all I have in it now is the endcap (oil filter). Something else I've realized is that this bike has points. I could have sworn I read that they didn't have them, but low and behold they are there. They have some spots built up on them, so
I took a little sandpaper to them. Not really sure if this is causing my problems though. I once had a 450 Scrambler that had bad points, and man was that a fun job.

79 ltd's came stock with 26's and points the 80's changed and 28's were stock along with electronic ignition and removable element for headlight instead of having to replace the whole headlight.
Question is does dyna ignition put out more juice than stock kz electronic ignition.
Also I would replace the points with dyna or at least the 80 plate. Points are such a PITA and forget about sanding them that won't work very well. My 69 mustang I had so much trouble with that when I got my bike and changed the points out to dyna I was so relieved. But it's your choice if you like messin around with old worn out points.