JCL MP 250 A starter clutch replacement By 4950cycle (Read 7,952 times)

[4950cycle]

While I'm waiting for my parts to get here I went ahead and adjusted my valves to make the JCL quit stalling at stops. I hope it works . One thing I can say is the valves had almost 0 clearance when I checked them before I adjusted them. What in the heck were those Chinese thinking ? Anyway, I adjusted them both (intake & exhaust) at .008 instead of the factory recomendations per Jeff at Muddville scooters and small engine repair. I know, I know, Iknow, Sounds like an awful big gap" But I ain't going back in this scooter this deep to adjust valves again" He said those clearances will insure that I won't have to adjust them again and the scooter will run fine.

[JR]

Sorry I disagree. The linhai is finicky on the valves and there are ways of adjusting them with minimal removal of the plastics. Over .006 will rattle like hell and you risk poor vacuum for the fuel pump. Recommended settings are .004 intake and not one bit past .006 on the exhaust.

JR

[alleyoop]

I agree .008 is quite a bit of a gap, which will make the rockers bang against the cam and make a lot of clatter not to mention possible bad vacuum.
Alleyoop

[cruiser]

Have to agree with JR on the valve gaps. He owns two of these scoots and has thousands of miles on them. Trying to avoid a future valve adjustment by over compensating now will only result in poor performance and excess noise. Do a little research and you will find that there are some methods used to shorten this procedure. After the first couple of adjustments you will find the adjustment interval will be longer as the parts have worn in.

[4950cycle]

Got the new correct starter clutch today by US mail from Absolutelyscooters. I Installed it today also. Tried to put it on with starter clutch already bolted to the flywheel like I pulled it off if you remember. But you have to put the key in the keyway first and the starterclutch wouldn't get past the key even though it has a tapered shaft. So I removed the starter clutch from the flywheel. Put the starter clutch on the shaft first then put the key in the keyway. Lined the flywheel slot up with the key and tapped her on then put the three bolts in and tapped the allen wrench with a hammer to tighten them evenly. then put he washer on the shaft and impacted the nut on. Would have had some pics of this but girlfriend had the camera at a Rascal Flatts concert today/night . Still waiting on the gasket kit. So I havn't buttoned the motor up yet. With the cover still off I put the jump starter to the starter to test it. It turned the motor over and eveything worked just the way it should. Will pull the cover off (just sitting on there) tomorrow and take some pics with the new starter clutch installed.

[4950cycle]

Its a scooter not an F-18 or a race bike where 1 horsepower is the difference between winning and losing. If it were going to make a bunch of noise as you say and or not run right Mudville scooters and small engine repair would have no repeat business. His scoots run fine. Hes done ten times the scooters JR has done. Not being a smart arse just fact. Don't mean to come off so harsh. Just the way it is. I'm sure JR is a fine guy, Heck , look at this website ! I'm not so small a man that I won't eat crow if I have to. If it runs bad or makes excessive noise and / or has poor performance I promise I will be honest and take back what I have said. PS almost all OHC engines call for .004 intake, .006 exhaust. Most I have messed with anyway. OHV engines tend to have more forgiving larger clearances.

[alleyoop]

Okie Dokie,
It has nothing to do with JR, Me or Cruiser or how many scoots etc.. you have to know motors and how they really work and what they need to make power or not.

Just common sense and knowing motors, so I have to say good old Jeff at Mudville should know better. The INTAKE you will find will most likely never need to be adjusted after it seats and you reset the gap. That is because the Intake valve does not get as hot as the Exhaust valve. The intake keeps cool due to fresh air and cool fuel it sucks in. Setting the gap on the INTAKE to wide effects the amount of air and fuel it sucks in(less air and fuel less power..pretty straight forward and simple to understand). Same with the Exhaust valve not opening enough to allow it to discharge the burnt fumes sameo sameo your holding the motor back, just like putting on a really restrictive muffler on it. Now if the head was not harden properly the valves will keep on digging into the head and will cause more frequent gap settings. Mind you we are talking MM that will cause problems in either direction. To tight and or to loose can cause hard starting not holding low rpms loss of power, backfiring due to running lean or bogging to much fuel etc..
Even the wrong gap on a Spark Plug will give you fits.
Have to tell you looseing 1 hp on a scoot is a lot and makes a big difference.

You take any sauce on your meat
Alleyoop

[JR]

Sept 29, 2012 22:31:29 GMT -6 4950cycle said:

Its a scooter not an F-18 or a race bike where 1 horsepower is the difference between winning and losing. If it were going to make a bunch of noise as you say and or not run right Mudville scooters and small engine repair would have no repeat business. His scoots run fine. Hes done ten times the scooters JR has done. Not being a smart arse just fact. Don't mean to come off so harsh. Just the way it is. I'm sure JR is a fine guy, Heck , look at this website ! I'm not so small a man that I won't eat crow if I have to. If it runs bad or makes excessive noise and / or has poor performance I promise I will be honest and take back what I have said. PS almost all OHC engines call for .004 intake, .006 exhaust. Most I have messed with anyway. OHV engines tend to have more forgiving larger clearances.

Hes done ten times the scooters JR has done. Not being a smart arse just fact.

Hmmmm? How would you know one way or another what I know or how many of this or that I've done? The facts are you're taking your scooter to someone to fix it, myself I don't have that problem, don't need anyone to do mine and that's a fact.

Eating crow? You just did that.

Most I have messed with anyway. OHV engines tend to have more forgiving larger clearances

You're not messing with it remember? May be the case on some engines but this scooter like a lot of others depends on a good seal of the valves, especially the intake valve to run the vacuum fuel pump.


Alley is also correct about the intake valve, in fact I've never adjusted the intake valve on both of my linhias and they are at .004 and have never moved so if you widen the gap on this one you're wasting your time and doing just what I said making it make noise and risking a poor fuel feed. BTW both of my linhais together have over 25k in miles on them.


Its a scooter not an F-18 or a race bike where 1 horsepower is the difference between winning and losing.

I don't race either but in the Ozark hills where I ride 1 HP means a lot to climb them for sure besides why does one not want the scooter to perform at it's peak power and capability anyway?


Let you in on a little secret, at 66 years old I've seen a lot of engines so think about that when you make statements about someone that you know nothing of.

You came here asking advice and advice is what you got, you can take it or leave it and we also love to get input from others but comments about so and so from any place knowing more or whatever about something is not appreciated or needed and since I know nothing of this place or person I'll not comment on his advice one way or another but my advice like a lot of other people here is based upon my experiences with lots of things including this scooter and working on things a long, long time and when I'm wrong ( and I am sometimes) I'll be the first one to step up to the podium and say it.

I wish you well on your scooter.

JR

[4950cycle]

I'm not going to get kicked off this forum by disrespect for others I hope. So, that being said, I'm sorry if you or anybody felt offended by my comments or opinions. BTW, I don't take "ANY" of my machinery to someone else to get fixed. Where did you get that ? Anyway, Correct me if I'm wrong. You can harm an engine by having your valves clearances to tight for instance burning an exhaust valve. Have them to loose will do nothing "BUT" possibley perform poorly ( believe me I won't put up with that) or stall or stammer because of inadiquate vaccume. Lets not be scared of what might be when it won't hurt a fly if we're wrong (Jeff and/or I). I will do plenty running/testing of the engine on center stand before puting her all back together. So if you fellas are correct in that this .008s idea just won't work and/or cause usatisfactory conditions, You and I will know soon after my gasket set gets here and I put the cover back on and muffler and batt just for motor test. If you have done what I am about to do and it just didn't work out for any reason (besides sounding like a mild sewing machine while cold) then Please, speak up.

[JR]

BTW, I don't take "ANY" of my machinery to someone else to get fixed. Where did you get that ?

Anyway, I adjusted them both (intake & exhaust) at .008 instead of the factory recomendations per Jeff at Muddville scooters and small engine repair.

Anyway, Correct me if I'm wrong. You can harm an engine by having your valves clearances to tight for instance burning an exhaust valve.

Too tight = no clearnce and the engine stalls at every stop, starts poorly and has loss of power. That's why you adjust them and again from experience on this engine 9 out of 10 times the intake valve never needs adjusting. It's the exhaust valve that tightens and an experienced rider of "this" scooter will know it quickly.

Have them to loose will do nothing "BUT" possibley perform poorly

So a poorly running engine is the final goal and as stated since vacuum is pulled form the intake valve to feed the fuel pump which is actually a pulse type pump if the gap is too wide then the scooter will starve for fuel and in most cases not reach top end speed because of it?

Centerstand testing doesn't equal on road open running in various conditions, in my terrain fuel starvation equal not getting up the mountain.

And as far as disrespect like I said before I'll not make comments about the place or person who is fixing/helping you with your scooter, know nothing of them or their place of business so just as you by me I have no first hand knowledge of them to make any such comments about their ability to repair anything.

I respect other's opinions and it's your scooter you can adjust it, fix it, in any way you want, my comments and opinions about this scooter are based upon working with lots of people who own it and lots of miles riding it. Also I base my knowledge from manuals and such that the makers of this engine have written.

If someone else comes up with a better way, idea, etc. then not only am I happy for them but will add it to my base of knowledge to share with others.

Scooter Professor isn't a business but just a place for people to help people it's that simple.

JR

[alleyoop]

HAHAHAHA, No you will not get kicked off this forum for getting pissey about being corrected. We are just trying to help and set you straight or should I say the lawnmower mechanic Jeff telling you some bad info. Lawnmowers and snowblowers motors are set differentially reason being they do not have to take high and low rpms, they run at a constant rpm and are built to produce a lot of torque at low constant rpms.

Intial testing on the stand is good to get it running have way descent but the motor will act differently when a load is put on it. So after it runs good on the stand it may not run good when you jump on it and ride it. On the stand the rpms will climb good and everything because there is no load on the motor. But it may bog all to hell once you take it for a spin or the rpms may only run up to 4k or so due to the load. Like I said before to be a good mechanic you have to have experience and know motors and what causes what.

But you can take the adivce or not that is all up to you.
Alleyoop

[4950cycle]

All I can say at this point is we will see. And I thought about the load test also knowing what you are saying Ally about motors doing different things under load. I do agree with that. And thanks for the open debate guys. And I also agree with JR when he says the intake valve doesn't need any adjustment ever. Its the coldest valve out of the two. Its when the exhaust valve expands/lengthens that its open ever so slieghtly (when there isn't adaquit clearance) and leaks a little causing the motor to stall at idle. The open debate won't kill us, I promise LoL

[alleyoop]

Not a problem we are here to help if we can. And your right Disagreements, Debates are good and someone always learns just a little more. I always say nobody knows everything and more heads are better than one.
Alleyoop

[4950cycle]

Exactly Ally, Hey , if this thing won't run that good with this setup. I'll be the first one piping up about it. I know I hate it if I follow internet advice and its bogus. I don't want to do this to someone else. Let me say this though. I just remebered My 1975 Over head cam (just like linhai) Honda CB 125cc. When I bought it a couple years ago the bike it sounded like a sewing machine at idle. It bugged my friends more than me. The bike ran fine anyway. But I adjusted the vavles per peer pressure. .004 and .006 btw is what the specs were . Turns out the previous owner adjusted the valves per what he read on the internet that were the specs for one of those Honda 125 engines over in India that are "OHV". = close to double the valve clearances needed for Honda OHC engines. I know this because I called him and asked him why the valve clearances were so large before I corrected them . But the bike was running fine before I adjusted them per OHC Honda specs. I don't know if this means anything on this application ? But it might be some indicater. PS When my gaskets get here I will post the pics of the open side before I put the cover back on. Really not much if any different than the pics of it coming apart though.

[alleyoop]

Well hope when you put it all back together it runs to your expectations with minor adjustments. And by all means keep those pictures coming helps folks a lot, A PICTURE IS WORTH A THOUSAND WORDS .
Alleyoop