OK guys, I need your expertise! MC-54-250

[mikeyscootin]

the latest is that the switch that causes the fan to go on and off depending upon the temperature of the engine is no longer working and needs to be replaced. the solution from the dealer was.. "what they are doing now is wiring it directly so that the fan is always on" .

I told my mechanic to go ahead and do it but the dealer is still sending the switch i need and i plan on replacing it later..

what do you think? is it ok to let the fan run all the time? if all is well should i replace the switch?

also i bought the vacuum fuel pump, the rectangular one from the internet. the mechanic says this pump is about half the size as the one that was on it and he said the one that was on it is round. he will install what i bought anyway and we hope all is well.. i got the fuel pump because of fuel starvation at WOT.. for those who aren't familiar with the previous post.

thanks for any imput..
mike

[scooterollie]

Mike;
Wiring the cooling fan directly is an option that some have exercised. Stan Jessup has wired an LED into his fan and mounted it on the dash so he knows when the fan runs and that it is cycling properly. While running the fan constantly assures that it is on, that really isn't necessary and places additional stress on a part that might not be of the highest durability. For short term, until the thermoststic switch arrives, it will be OK. Personally, as an owner of two scoots with cooling system fans, I prefer the automatic system, as it was designed.

If this is the one that Stan Jessup recommended and it's capacity is suitable for the 250s, the physical size should not matter. I have not had problems with the vacuum fuel pumps on my scoots, nor do I have any experience with the after market pumps, so that is all I know about the pump issue.

[tortoise]

mikeyscootin said:

for those who aren't familiar with the previous post.

Why segment same model issues with numerous threads . . just makes it more confusing to read!

[Showme]

Nujwt( <Did you know that those letters spell Mikey when your fingers are on the wrong keys)
Sorry, that seemed funny at the time. You probably checked your fan switch and I am off base here but my fan did not run and it was the fuse in the fuse block under the seat. Vibration caused the fuse and wire to seperate. No fuse, no fan. To look at it you couldn't tell it was disconnected. Also running your fan all the time puts an extra load on the battery and charging sys.

[monty57]

Once again I have to agree with scotterollie here. If the fans were meant to run all they time they would have been wired that way from the factory. I believe they are really used to move air when the scoot is not as speed and there is little natural air flow to the radiator. Running it all the time will greatly shorten its life and lead to premature failure and possibly at time when it is really needed. Replace the switch and put the scoot back as it was originally designed to operate.

[scooterollie]

How often the fan runs is also related to the position of the radiator. My Roketa Bali 250 has the radiator behind the gas tank where air flow at speed is somewhat reduced. It works OK but the fan cycles more than on the Linhai SS300 with the radiator just behind the front wheel. The Linhai has insulation around the radiator area as well as panels to direct air flow out and underneath the scoot.

[mikeyscootin]

thank you all for your response. my radiator is in front under the handlebars. i too question the constant fan thing. so while i wait for my part to come i have fans blowing all the time.. hope it won't drain the battery too much.. sorry about multiple threads, thought this was kind of a specific question and didn't want to cloud any issues.. if i have offended anyone i apologize.

[scooterollie]

Mickey;
Don't worry, we may grumble a little at times but we are here to help! As long as the scoot is running at speed, the engine should put out enough charge so the fan will not drain the battery. If you let it idle for a VERY long time, you could drain the battery. Radiator positioned up front, behind the wheel is good!

[mikeyscootin]

for the fuel pump i bought the rectangular one from heeters.com #DF 44211 D ( a 14 LPH) for my fuel starvation problem as recommended on this site. My mechanic did all my normal maintenance and wired my fans to run constantly until the new switch comes in. (see above)

I picked up the scooter today and got on the expressway, got up to 70 mph for about a quarter mile and the bike just lost power like before and actually stalled. I pulled over and tried to start it but i only had 3 attempts worth of battery and ended up stranded on the expressway. Not sure if the battery was so low because of the fan running constantly or not.

My mechanic brought me home and we looked on the computer on the heeters site and he thought maybe i bought i fuel pump that was too small. he is a certified mechanic for suzuki, kawasaki and bombardier....not chinese scooters, but he is trying to help me just the same.

there is a 35 LPH fuel pump on heeters.com that is round part number DF 52 21 D... is that the one i should get? will it make a difference.. does anyone know what LPH a 250 cc should be? Could there be another problem?

Today earlier the mechanic changed the oil, gear oil, cleaned the carburator( he said there was no problem in the carb) and air filter, checked the spark plug. He also wired the fans to work constantly until my switch comes. he drove it for 15 minutes but not at WOT... he called me and told me to pick it up...all was fine.. when i drove it , it was about 2 miles to the expressway and it rode just fine.

so now im home wondering if i should buy the larger fuel pump or what to do..

thanks guys.. if you can help please do.

[mikeyscootin]

hi again, to whoever it was, i didnt' start a new thread for fear of being chastised again, but I obviously do have a new development and was hoping someone would come to my rescue.

Its funny, i am a chiropractor and am used to fixing things and i feel like I am useless in my new pleasure. i guess we all have to depend on one another for some things.

[brycegtx]

My wife's MC54 gets almost 80 MPG. At 60 mph, that would be less than 1 gallon per hour. 1 gallon is almost 4 liters. So my wife's MC54 would require probably no more than a 4 LPH pump. Anything more is ok, anything less is not good enough. 40 LPH would be good enough for a truck that gets 6 miles per gallon.
Bryce

[auckie]

Just bought (2) mc254b's last week. One bike refused to start at prep. Traced to a pinched Vacaum supply line to fuel pump. (Line from intake manifold & 'y' connection to pump). Line was being pinched between frame & plastic body panels. Re-routed line & corrected issue. (What a BUGGER to reach thru that litttle access door!) Possibly you have same issue but not completely 'pinched', just restricted some? Maybe ok at low loads & die under high demand?
Note:From what I've learned here Roketta has had this pinched line issue for a while. My bikes built at same factory, presumably on same day ( @20 vin's apart. one bike last digits 937, other bike last digits 953).Earlier built bike had line routed in a completely differant path and no restriction, other bike built LATER and had the same old problem. Shows me serious process variation (QC) not only over a period of time but daily between a couple workers who can probably see & speak to eachother while they are working. (One could only hope it's not a single worker installing 2 different ways)Gotta love it!!

[scooterollie]

Auckie;
Yeah, we can't even attribute it to the old Monday morning, Friday afternoon syndrome. QC just seems to be catch-as-catch-can! Heads up like yours really helps!

[roadster250]

I installed the Mikuni vacuum pump from Heeters (the 35 LPH round one) and it made absolutely no difference; as soon as the float bowl is out of gas, the stalling begins.

Aukie's comment above about a pinched vacuum line might help, but mine is the same configuration and it did not appear to be pinched; i'll take a second look.

In the meantime, I've found a used Yamaha pump made for mounting outside the fuel tank (unlike the Aprilia one I purchased earlier). And having the same bike as you, I'd steer clear of the universal automotive pumps recommended in other threads on this site, as it drew more current than my stator could replace and overwhelmed the float chamber at idle, resulting in very poor idling.

[mikeyscootin]

I spoke to a lady at heeters.com and she said that to her it sounded like my fuel cap wasn't vented or the vent was blocked.. hmm.. guess the 14 lph pump is enough and another solution is needed. i relayed info to mechanic, hopefully he'll be able to figure it out..

I'll let you guys know if i find the answer to the very common problem of fuel starvation. apparently its not the fuel pump itself.. atleast not in my case.

[roadster250]

I did the "stupid" test on the vented cap causing the problem; I was testing the new Mikuni vacuum pump on my MC250 and after the bike died at a few seconds after reaching 65 mph, I uncrewed the fuel cap, closed the access panel, and after enough starting attempts to get fuel back in the carb, got it up to 60+ again and no suprise; the thing chokes and dies again.

These bikes have devices using the vacuum both ahead of the pump and somewhere rearward of the engine. I wonder if anyone knows if cutting or reducing the vacuum serving these functions can be done without screwing something else up?

[mikeyscootin]

thanks roadster 250 for keeping this thread alive. this is a serious problem. so many have fuel starvation problems and so far the solution is eluding us all.... hopefully someone will have an answer soon.. such a nice machine to have so many problems..

[T W I S T E R]

get a kymco - no problems.