DF250rtc motorcycle transmission problem! By racerx125 (Read 7,192 times)

[Alleyoop]

Well I was hoping it was just the cable that was not adjusted right and it would save some dough, time and work. But changing plates and springs are easy enough. It could just be the springs which are cheap about $10-20 bucks a set.
Alleyoop

[racerx125]

well the plates are just 23 bucks including shipping might aswell change springs. Better change them too soon than too late If I can find the ones I need

[racerx125]

I found some clutch springs but they say something like for 1500 Rpm, 1000 Rpm and 2000Rpm What does that mean? Is it at what Rpms the engine idles? I really don't know much about clutches.

[Alleyoop]

Yes the RPM rates are for when they will engage. Most 250cc scoots like to idle 1800-2000rpms, 50s and 150s 1500-1800rpms. They idle the smoothest around those rpms.

what does yours currently idles at the smoothest? That will tell you which springs you need, but I would say 2000rpms you want a little lee-way so its not trying to turn the wheel sitting and you having to hold the brake and lugging the motor down and wearing the plates out more.
Alleyoop

[racerx125]

my engine idles smoothly at about 1600 to 1800 rpm so should I buy some 2000 rpm springs?

[stevespidel]

Mar 4, 2014 1:05:33 GMT -6 Alleyoop said:

Yes the RPM rates are for when they will engage. Most 250cc scoots like to idle 1800-2000rpms, 50s and 150s 1500-1800rpms. They idle the smoothest around those rpms.

what does yours currently idles at the smoothest? That will tell you which springs you need, but I would say 2000rpms you want a little lee-way so its not trying to turn the wheel sitting and you having to hold the brake and lugging the motor down and wearing the plates out more.
Alleyoop

Alley, I think I'm about to learn something here. These springs and this part of the thread sound like CVT scooters more than a 5 speed tranny with clutch. That RPM based clutch spring also applies to manual transmissions? Other than using manual transmissions I have no real knowledge of clutch springs in that application. Would it confuse this thread for you to give a quick run down?

[racerx125]

mmm.. maybe steve is right because If I installed these springs wouldn't I need to rev the engine past 2000 rpm in order to get power from a stop otherwise I will stall? Sorry my bad I'm just not familiar with how clutch works. Is replacing clutch springs mandatory when changing plates? they only have about 3000 miles

[Alleyoop]

Yes it is when you want the clutch plates to grab and turn the rear wheel. Now you could go with less rpms and when coming to a stop pull in the clutch lever to coast and hold it or shift it into neutral which most people do when they come to a stop light and they know they have to wait a minute or so.

Stalling is created when the motor is not making enough power to move the weight at certain rpms and you lug the motor down due to not enough RPMS.
2k is really not a lot for anything over 200cc 1 cylinder motor that is about 1/4 of an inch turn on the throttle.

You notice that a lot when a bikes rpms are not high enough and you twist the throttle it has a lag before it really moves out. You can see that even in the VID KZ put up notice when he starts off how there is a hesitation when the guy starts off also notice sometimes just sitting there the RPMS drop and he gooses because the motor is loading up with fuel and has to clear it out that bike is running a little rich. The rpms have to rise to a certain point to move the weight.
Once the weight is moving forward you then can back off and drop the rpms and it will roll at the speed that the gearing and clutch are setup for.

When I got my NCY clutch It came with a stronger CONTRA spring and my trike would not start to move until my rpms were at 3500 rpms. I did not like that so I switched the contra spring from my old OEM clutch I took off and now it will start to move at between 2300-2500 rpms. With the 30 more ccs that were added it now likes to idle between 1600-1700 rpms anything lower it vibrates a lot and the mirrors are shaking a lot. I adjust by using my mirrors and set it where they barely shake at all and at that point the motor is running nice and a lot smoother.
Alleyoop

[jepmedic79]

Well it could be many things, but here are some suggestions:

1. what kind of oil are you using? The DF250RTC has a 'wet plate' clutch and these clutches don't like full synthetic oil. Are you using too low an oil weight? I recommend 20W-50 oil its usually cheaper than 10W-40 due to demand and its just as good as the 10W-40. It say this because the engine is air cooled and gets very hot, so the hotter it gets the thinner the oil gets this could be causing or contributing to your problem.

2. Is your clutch wearing out? Sounds like it may be. Riding the clutch too much and dumping it are the major causes of clutch failure

3. Try using a transmission oil that reduces clutch slipping, if the problem seems to improve--even slightly then its time for a new clutch

hops this helps.
JP

[racerx125]

I fixed this a while ago, my clutch plates went bad and I had to much weight in my backpack which caused me to lose speed I always carry many tools and my school work in my backpack :S I carry tools because this motorcycle left me stranded once and I didn't have any tools so I always carry them around with me and 3 heavy books

[kz1000st]

Glad to hear it got fixed. How fast is it running now?

[racerx125]

about 60 mph max now I need to lose body weight to get a little more speed :S

[kz1000st]

Now that's much better. Try not to carry anvils around too. That will help alot.

[richardv]

As stated the previous owner probably used oil with a friction modifier. Great for better fuel economy but very bad for wet clutches. There is a little badge on the label that will state it has the friction modifier if it does. You are best off using motorcycle specific oils for that reason. It's a lot cheaper than a clutch.

Excessive engine braking is bad on everything in the drive line. Best wishes.