Katana owner in search of peace of mind...(overheating)

[tirone]

Hi everyone,
i'm Michele from Italy, and i have intrduced myself yesterday.

Now it's time to intruduce my Katana. This is my bike, salvaged from the oblivion one year and half ago.



Love the colors and the design of this version. Unfortunately the bike has still some problems. Always need to start with the starter lever. You must keep it activated for at least one minute, idle is low and the bike shut off if the idle is not "kept" from time to time with the gas throttle. When the engine starts to reach the operative temperature, the idle starts to be too high (almost 2000 rpm).

Carbs have new needles and they are now synchronized, the stock exhaust has been reinstalled, but if i restart the bike when the engine is hot, it needs 10 seconds of desperate pressure on the "Start" button. Figuring it was a vapor lock problem, i also tried to prime for 10 seconds with the fuel petcock - no result.

But the main problem is the heat. It becomes terribly hot after 20-30 minutes of slow-speed ride, so hot that you can't touch the frame near the head and the fairings turns to be extremely hot. Once i was forced to stop because my lower parts of my body had enough of that and i was covered in sweat. It seems that the problem worsened with the new needles and new exhaust. I was wondering if the coils are responsable for these problems.

Thank you in advance. I don't want to sell the bike, i like it a lot (except for the forementioned problems, it runs fine), and i did a lot of work - still there is lot of work to do. I would be already glad if i could live without the sensation of a moving oven.

[Keefypee]

Hi. Nice looking bike!
It sounds like it might be running too lean. Were the pilot jets set correctly when the synchronising was done? They should be about 2 to 2 1/2 turns out.

[steves]

For your first issue, it sounds like you should take a closer look at the carbs.

For the heat issue... I would inspect the oil cooler, and oil cooler lines to be sure they aren't kinked or blocked. It does sort of sound like a lean condition though. It may be worthwhile to inspect the spark plugs, your issues could be related.

[tirone]

Hi, sorry for bumping a so old thread.
I have partially solved the problem - the engine was running low on oil, however the level was still between the two markers on the oil window.

I have added oil (the engine actually needs to be refilled every 1500 km, valves and gaskets are quite worn unfortunately), carb jettings are set richer, now it's running fine enough and at least it does not overheat like before - you can actually ride it without burning your legs and bottocks.

However, when i touch the frame near the engine head (the part visible through the fairing), it is still damnly hot and you cannot resist one single second with the thumb pressed on it. Is it normal for this old air/oil engine, or there is still something wrong?

[Kreylyn]

Hi, sorry for bumping a so old thread.
I have partially solved the problem - the engine was running low on oil, however the level was still between the two markers on the oil window.

I have added oil (the engine actually needs to be refilled every 1500 km, valves and gaskets are quite worn unfortunately), carb jettings are set richer, now it's running fine enough and at least it does not overheat like before - you can actually ride it without burning your legs and bottocks.

However, when i touch the frame near the engine head (the part visible through the fairing), it is still damnly hot and you cannot resist one single second with the thumb pressed on it. Is it normal for this old air/oil engine, or there is still something wrong?

That still sounds abnormally hot to me.


Krey

[tirone]

That still sounds abnormally hot to me.


Krey

So i guess the frame should be cold near the head cover. I'm using the bike every now and then - checked everything, radiator lines, carbs, etc, and i really don't know what to do. Did 150 km today, no major problems, except for the hot frame in that point.

I have spent too much time and money to fix the bike - new exhaust, new needles in the carbs, etc. Probably the engine has some serious internal problem. I think it's not worthy of a major rebuilt, as there are too many small issues on the bike. I will continue to use the bike "as it is", as long it is still rideable. Then i will buy another engine or i will sell the whole bike. A pity, because i like it a lot.

Thank to everyone who helped.

[Kreylyn]

So i guess the frame should be cold near the head cover. I'm using the bike every now and then - checked everything, radiator lines, carbs, etc, and i really don't know what to do. Did 150 km today, no major problems, except for the hot frame in that point.

I have spent too much time and money to fix the bike - new exhaust, new needles in the carbs, etc. Probably the engine has some serious internal problem. I think it's not worthy of a major rebuilt, as there are too many small issues on the bike. I will continue to use the bike "as it is", as long it is still rideable. Then i will buy another engine or i will sell the whole bike. A pity, because i like it a lot.

Thank to everyone who helped.

Are there any other running issues at all. Bouncy idle, climbing or hanging idle, bad throttle response?


What kind of MPG (KPG?) are you getting?


Krey

[tirone]

Are there any other running issues at all. Bouncy idle, climbing or hanging idle, bad throttle response?


What kind of MPG (KPG?) are you getting?


Krey

The bike does not keep the idle when cold (you need to keep it with the gas throttle). Idle starts to stabilize after 10-15 minutes, or sooner if you "force" the engine at 4000/5000 rpm in first gear for some meters (quite strange thing).

Same thing (missing idle) if you try to restart the bike with warm engine after some minutes of pause. Very hesitant to restart too.

No bouncy idle - it just increase by 500 rpm after long traffic drive. Never tried the engine at dyno, anyway the throttle response is normal, but the bike was more reactive with leaner setting.

[arsenic]

The bike does not keep the idle when cold (you need to keep it with the gas throttle). Idle starts to stabilize after 10-15 minutes, or sooner if you "force" the engine at 4000/5000 rpm in first gear for some meters (quite strange thing).

Same thing (missing idle) if you try to restart the bike with warm engine after some minutes of pause. Very hesitant to restart too.

No bouncy idle - it just increase by 500 rpm after long traffic drive. Never tried the engine at dyno, anyway the throttle response is normal, but the bike was more reactive with leaner setting.

There is absolutely nothing wrong with your "engine". You are running really lean is my guess. That will certainly cause your engine to run hot. That is a jetting ie carburetor issue.

[Kreylyn]

There is absolutely nothing wrong with your "engine". You are running really lean is my guess. That will certainly cause your engine to run hot. That is a jetting ie carburetor issue.

+1 agreed.

Could also be vacuum/air leaks with issues with bad engine /carb boots for example.

It's definitely running lean, as all the symptoms you have pointed at so far match to that. If it has the normal jetting and a/f settings and is still lean, then you have other problems that need to found and fix that is causing that. Just changing the jetting won't fix the problems.

Krey

[tirone]

+1 agreed.

Could also be vacuum/air leaks with issues with bad engine /carb boots for example.

Yes, that's another possible reason, although it was already inspected in the past. Probably i must change mechanic, not jetting.
Thank you everyone for the help!