MC 54 250B with 244c engine 2008 build concerns By bobf (Read 1,456 times)

[bobf]

Now that it appears my efforts to end leaking and finish the crankcase repair has happened OK, I will bring up other concerns as I attempt to put it all back together and get it ride able again.

First is the problem of the temp gauge that does not seem to do anything. I may have to take off the front cover once again to check it out. Where does the signal come from and how best to trace the signal to find the problem.

I looked in the Honda engine manual but not much said about this situation. I never got a decent manual with my new scooter. The book I got was for a 150cc scoot. So any help will be appreciated.

As I reassemble I may find more things just not working either.

[Alleyoop]

Try replacing the water temp sensor, they are the ones that usually go out.

www.ebay.com/itm/like/331737544898?lpid=82&chn=ps&ul_noapp=true

[bobf]

Thanks. Ordered.

[bobf]

I have good sensors in the radiator and also the thermostat is good. I did a continuity from the temp gauge back to the sensor near the thermostat. Line checks out to be OK. So I guess that means the sensor by the thermostat must be bad or the temp gauge is not working, I think. I have one of those sensors so will try that next. ADD ON - just installed small sensor near the thermostat and used water pump gasket stuff to seal it. Tomorrow morning I will add coolant.

Can't run the engine till I get the coolant back into the engine. Just finished another repair by putting Helicoil into the right crankcase housing for the top left bolt on the water pump cover. Same strip out of threads on the new casting as I had on the original casting.

I still had dripping on the repair so I have now added gasket material to the lower right screw which is also the drain screw. It has always leaked since I first took it off last summer. Now I hope it will hold the water in.

Sometime next week I will be able to comment about the leak, fixed or not.

[bobf]

Leaking follow up. Finally have found the location of the leak. It was not the drain plug as I suspected. I have spent plenty of time chasing this leak and was using mirrors and flash lights to finally find the cause. It was leaking from around the hose connection above the water pump. The water would travel along the casting and actually gather and drip from the drain plug area. The hose clamp on the hose end had broken and loosened allowing some water to escape while still looking like a clamp in place doing its job. It would start leaking as the internal pressure built and forced coolant to leak.

Put a new clamp on that hose and now all is dry again.

So some time was lost waiting for different repairs to the water pump cover and drain plug screw to take place and cure between efforts.

More adjustments needed to control idle. Will start with the reset of idle by readjusting the screw on the carb and then trying to reset the idle speed.

[bobf]

Question about the screw to adjust on the carb. I am using the Honda instruction manual for the 250cc engine published in 1993.

In it it speaks of the 'pilot screw adjustment' and says -

"*The pilot screw is factory set and no adjustment is necessary unless the pilot screw is replaced (page 4-7).

*Use a tachometer with graduations of 100rpm or smaller that will accurately indicate a 100 rpm change."

I sure don't think our dash tach would do very well. And I don't have a tach otherwise.

Right now when I do a cold start the engine will run up into the 3,000 range for a minute or so and then start dropping down slowly till it ends up in the 1,000 to 1,500 range.

Just not sure what next to do. That extra fast start up doesn't last too long but it sure does seem to be a possible problem for those on the ground starts. A runaway bike seems to be the threat.

Has the limiter cap been moved somehow? Or am I looking at the wrong screw?

[Alleyoop]

Wear and tear and parts not working at peak and mostly TEMP changes require changes to the Fuel Ratio Mixture of ANY CARB. Folks that do not have to adjust so much are the ones that live in a climate where it is always HOT or always COLD with no Temp Swings. Also due to the EPA pollution requirements the carbs are set really lean to pass emissions tests.

So put that Honda manual aside and follow this procedure.
Alleyoop
Most of your 250cc+ Carbs the fuel ratio mixture is UNDER the INTAKE SIDE of the Carb which by the way is a PITA to get at. Very few carbs for the 250s+ you will find have the screw on the side of the intake side where it is easy to get at.


scooterdoc.proboards.com/thread/1499/4ts-carb-tuning

[bobf]

Thanks for the detail. I will have to write some of that off on to a tablet for reference. At my age, 83, memory is not very good. So I will copy some of the details for my use.

Too bad I can't just print it off.

[Alleyoop]

Why can't you just print it? If you have a printer you can print it out.
Alleyoop

[bobf]

Best tell me how. Each time I try to find a print command I get told 'Function disabled etc.' So if there is a way to print from this file I would appreciate some education for sure.

[Alleyoop]

Click on the thread you want and then look all the way on top of your browser on the left. You should see something like -- File Edit View etc.. Click on File and the print options should come up.

Alleyoop

[Alleyoop]

CLICK TO EXPAND SO YOU CAN READ WHAT I WROTE:

[bobf]

Thanks Alleyoop. Your last idea worked OK. I was looking for something more local so I would not get the entire thread and just the parts I might have highlighted and ordered printed. For this situation it worked fine as the thread was actually limited to the topic.

Now I will need to take some time and get the job done. Not sure when, but hoping soon. Not sure how I will be able to adjust that screw with the air intake tube still on and in place. I will have to go back and review some of the other notes you sent me. Something about loosening the carb clamps and rotating the carb a bit so turning that screw could happen.

Thanks for your help.

[Alleyoop]

To just print a certain page or pages CLICK ON FILE then CLICK ON PAGE PREVIEW then you can say pages 1-1, 1-3 , 2-4 and then click on print and just those pages you want will print or you can print 1 page at a time and skip pages.


To get at the screw you need something small to get at it while the motor is running.
Alleyoop

[bobf]

Thanks again Alleyoop. I think I have one of those types of wrenches in my possession, if I have not given it to my son or daughter in recent years. Will have to look for it soon.

Once the engine is warmed up it runs so much slower. What causes the engine to run so fast when cold. That is the thing that concerns me and would like to control those cold moments or so when it runs at 3,000rpm for a while than starts to slow down. Could that be because of the starting enrichment valve in the carb? Should that be replaced to get slower starting speeds?

Will likely need to remove the carb if I need to remove a cap over the screw so I can use a screw driver to adjust. Just projecting some of the ills of trying to fix this engine.