EXTREME High Revving

SixtyFiveCA95 · #1 09-08-2009, 05:46 AM

After I (somehow) managed to get the petcock working again, I finally got to see how she would run. On the positive side, the engine is good and a really strong runner. On the other hand, it's idling so high that it's crazy.

Is there an idle screw on these carbs, or is it a clogged jet or something. I'm guessing that I'll have to take it off an get one of those carb kits. I know that I am going to have to anyways since there it leaks a little from the float bowl gasket.

I was just wondering if there was a temporary solution, because I'd like to be able to take the thing for a spin. Without killing myself.

SixtyFiveCA95 · #2 09-08-2009, 05:58 AM

Isn't it amazing how high these little engines rev? I also have a little Kawasaki KZ200. Thing is like a chainsaw.

Smithers · #3 09-18-2009, 07:19 AM

Sorry it's been a few days since I went back through older posts that I missed.

Post a picture of that KZ hot bike!

Yeah these Hondas just rev so high. No wonder they started to dominate the motorcycle scene. They could just do it all day long whereas other brands were scared. I also wonder about the rev limiting measures that were in place and how those were designed by Mr. Honda. It's like there are non besides the carburetor running out of capacity for that much air flow! What else?! The points not being able to keep opening and closing that quickly?

I recommend buying two float bowl gaskets just in case the first one breaks when you are servicing it in the future. The shipping is usually as much as the gasket so you might as well double the order and save the hassle in the future.

Just check out the carb cleaning threads I have and you'll have it made. I got the pictures and everything already up. There is an idle screw but all it does is act as an adjustable stop for the throttle slide. The one controlling factor that no one adjusts is the slide needle. It has a clip on it and there are different positions for it on the needle. Before you touch that make sure the whole carb is super clean and you blow out the passages with compressed air. Then run the bike and we'll work through the symptoms. Another member here ol Rob: he fixed a little idle problem and a lean fuel condition by moving the clip on the needle one notch.

I currently have a lean condition when I go up long grades with my 160 and I'm dead sure that I need to adjust the clip a notch as well. The power just starts falling off after a long pull up a hill and I need to pull over to allow the fuel to catch up with the demands of the engine. Then I can get going again up the hill. This is consistant near full throttle operation that causes the fuel to run out like that. I'm sure a little needle adjust will do the trick. I'm pretty sure the needle adjustments are there to allow for more or less fuel in different climates and elevations. The screw adjustment on the side of the carb allows for minute changes and the slide needle clip is a large adjustment. I'm sure it's all detailed even more in the original service manual and I'll start a thread with pictures of the manual when I adjust my carb on the 160.

Fun times.

SixtyFiveCA95 · #4 09-18-2009, 01:05 PM

Thanks, although my engine is, well, toast. That's why I'm going to rebuild a CA160 motor that I have lying around gathering dust.

I'll have to take a picture of the KZ200. Little thumper that sounds like a chainsaw, but runs perfect. Another bargain bike; paid a whole $130 for it at a car show/swap meet.

SixtyFiveCA95 · #5 09-18-2009, 01:11 PM

The only way I could get the revs down before it broke a rod was to mess with the choke. Seemed like a finicky carb.

I wonder of one of those little Mikuni "pit bike carbs" that you see on ebay could be adapted to these engines. I have one, but it is too wide. What nice carbs for $20, though.

There has to be one that would fit, and probably work alot better. If I ever do this swap, I'll be sure to make a thread with pics.

Smithers · #6 09-18-2009, 02:12 PM

Oh yeah, lol that engine is done for. Yeah the more I think about the little Honda engine performance the more I want to try a different carb. I'll do a look around for the kind that you have.

SixtyFiveCA95 · #7 09-18-2009, 02:41 PM

I bought one thinking that I was going to have to replace the carb on my KZ, but it turned out the carb didn't need anything other than a rebuild kit. Which was a good thing, because I would've had to make some kind of adapter or find something that was originally from another bike to pull it off.

The quality of new carbs is impressive compared to the ones from the 60's. The choke actually stays where you want it to.

Smithers · #8 09-18-2009, 08:32 PM

Haha yeah but those nice and precise carbs take all the magic out of the bike. You really feel like you accomplished something when you get an old Honda running. I took the carbs off a Virago 535 to clean sometime next week. Helping out a friends spare bike that he is attached to. It had to be operated with full choke just to ride it around. That's not good. It's kinds strange how they work. The throttle cable operates butterlys that open and close. There are round slides but they operate off of vacuum or something? I dunno I have some literature in the mail right now that should tell me how to tune them.

SixtyFiveCA95 · #9 09-19-2009, 01:54 PM

Mechanical stuff can be so confusing. Such as my engine blowing up w/o any warning. I guess fixing these things up is kinda rewarding, but sometimes I wish I just had the money to get one like this:

http://appleton.craigslist.org/mcy/1382689027.html

What a beautiful bike, sounds like it's all ready to go. I never see ones that nice in my area for $1500.

SixtyFiveCA95 · #10 09-19-2009, 02:36 PM

But I guess you're never really "done" with one of these. Even if you get a really nice one, they're still 45 years old, so if you want to ride 'em, be prepared to fix 'em, huh?

djbrett · #11 03-27-2011, 07:09 PM

Quote:

Originally Posted by Smithers

Just check out the carb cleaning threads I have and you'll have it made. I got the pictures and everything already up. There is an idle screw but all it does is act as an adjustable stop for the throttle slide. The one controlling factor that no one adjusts is the slide needle. It has a clip on it and there are different positions for it on the needle. Before you touch that make sure the whole carb is super clean and you blow out the passages with compressed air. Then run the bike and we'll work through the symptoms. Another member here ol Rob: he fixed a little idle problem and a lean fuel condition by moving the clip on the needle one notch.

I currently have a lean condition when I go up long grades with my 160 and I'm dead sure that I need to adjust the clip a notch as well. The power just starts falling off after a long pull up a hill and I need to pull over to allow the fuel to catch up with the demands of the engine. Then I can get going again up the hill. This is consistant near full throttle operation that causes the fuel to run out like that. I'm sure a little needle adjust will do the trick. I'm pretty sure the needle adjustments are there to allow for more or less fuel in different climates and elevations. The screw adjustment on the side of the carb allows for minute changes and the slide needle clip is a large adjustment. I'm sure it's all detailed even more in the original service manual and I'll start a thread with pictures of the manual when I adjust my carb on the 160.

Fun times.

I thought my carb was clean, but was having various problems. Replaced the float needle/seat, but it would still occasionally leak out the overflow. Checked the float level and all was good. It seemed that, when run at a constant speed for awhile, the throttle would get hard to turn like there was some kind of vacuum thing going on. Also, it was leaking at the base of the fuel line.

So, today, I took it all apart again and really spent some time on it. First, when I pulled out the fuel line, the fuel pipe came out of the carb. I rtv'd that back in and went to work on the carb for the second time.

I noticed the two holes that appear would allow air in and out of the the top of the bowl. both were plugged. cleaned these out. It seems to me that, with those clogged, I could get some funky issues going on as fuel would be flowing into and out of an sealed system. Put the fuel line back together with a new in line filter and started it up. It idled way to high. My neighbor (who has much more experience with carbs than I) tried to adjust with the screw, but with no luck. Then, read this post. moved the needle up a notch and it went down almost to where it was supposed too. Tried to fine tune with the screw, but it appears that there is now a small hole where the screw goes in, and it will not adjust.

I'm guessing from smithers' carb cleaning post that there is no getting a new slide that will precisely fit my 45 year old carb. Any tricks if not? Maybe I could tighten it with the slide out and then put it back in? That way I could avoid the notch that is in from the screw.
thanks

Spokes · #12 03-27-2011, 07:37 PM

You may have an adjustment mid way on the throttle cable at the front base of the tank. I have seen both adjustments at the carb and mid way on the throttle cable. Maybe you can adjust the idle down from there.

Also (as I actually did this once) The throttle cable stay inside the handlebar can be installed backwards. If the stay is backwards your idle is forever way too high.

djbrett · #13 04-01-2011, 06:19 PM

the idle is now beautiful. the thing purrs. Put it in the garage the other night, and it leaked gas all over. The wife is not very happy. Last night, perfect. Filled it to the top with gas this morning. drove to work. Not a drop leaked. Drove home. Parked it outside (at this point, me or the bike is sleeping outside

). no leaking for about 20 minutes. Now it is coming out like crazy. It's been months of this sporadic leaking. Any ideas? It only happens when it wants to.
thanks