Re: The Official Yamaha Chappy (LB50) Thread!!!

Dirty30 Dillon /

> Jack Rutherford Wrote:

> -------------------------------------------------------

> Right. Spring on 2nd gear.

>

> How much did you shorten 1st gear clutch spring? 1/4"?

If I had to wager, it was closer to 3/4". I will also admit that you should be prepared for a struggle. The way the clutch is designed you can't loop the spring and roll it into place like a tomos. You have to snake the spring through the clutch arm guides and than loop the ends.

Re: The Official Yamaha Chappy (LB50) Thread!!!

Jack Rutherford /

more info: seems simple but Hey, there's a dipstick on the trans oil cover. How frickin' nice! Yamaha didn't do that for the qt or the mj and probably not the lc.

I need to look at the flywheel for any similarities with past models or, for that matter, no similarities

Re: The Official Yamaha Chappy (LB50) Thread!!!

Jack Rutherford /

> Dirty30 Dillon Wrote:

> -------------------------------------------------------

>

> If I had to wager, it was closer to 3/4". I will also admit that you

> should be prepared for a struggle. The way the clutch is designed you

> can't loop the spring and roll it into place like a tomos. You have to

> snake the spring through the clutch arm guides and than loop the ends.

"To moped is to suffer."

"I hope you like wrenching more than riding."

"Expect failure more often than success."

“It’s a moped dude. It’s 40 years old. It’s not like you can just pick up OEM parts anywhere.”

some rules of mopeds on my wall

Re: The Official Yamaha Chappy (LB50) Thread!!!

Jack Rutherford /

Re: The Official Yamaha Chappy (LB50) Thread!!!

Jack Rutherford /

Mine came with B7HS plug installed. What are you guys running on the lb80?

Re: The Official Yamaha Chappy (LB50) Thread!!!

> Jack Rutherford Wrote:

> -------------------------------------------------------

> Mine came with B7HS plug installed. What are you guys running on the

> lb80?

B8HS

Re: The Official Yamaha Chappy (LB50) Thread!!!

Jack Rutherford /

thanks. I've just about finished up my current qt50 project and then to get some more Chappy seat time!

Re: The Official Yamaha Chappy (LB50) Thread!!!

Looking forward to seeing it on YouTube

Re: The Official Yamaha Chappy (LB50) Thread!!!

Jack Rutherford /

> Hunter Skiff Wrote:

> -------------------------------------------------------

> Looking forward to seeing it on YouTube

overdue, right?

Re: The Official Yamaha Chappy (LB50) Thread!!!

Both of my LB80 sprockets were heavily worn and needed replacement. Replaced the rear 30 tooth sprocket with a 28 tooth to try and squeeze out more top speed. Take off is noticeably softer, even with only a 2 tooth drop on the rear. Top speed is exactly the same, no more, no less. Interesting

Re: The Official Yamaha Chappy (LB50) Thread!!!

Jack Rutherford /

It would be interesting to know (if you had a tach set up), what the rpms were at top speed with each rear sprocket.

Re: The Official Yamaha Chappy (LB50) Thread!!!

I have a trail tech vapor that I can hook up to see the RPM with the new sprocket. RPMs seem much lower at cruising speed, obviously.

Re: The Official Yamaha Chappy (LB50) Thread!!!

Jack Rutherford /

so my thought was - if rpms are lower then how will the pipe react. I was initially thinking of getting a smaller rear sprocket but maybe a larger one is the way to go because my mlm pipe doesn't hit hard.

Re: The Official Yamaha Chappy (LB50) Thread!!!

Bike used to creep on the pipe at 27mph or so, now it’s closer to 33 sometimes 35 mph before it stays pulling. I think given the fact that top speed didn’t change with the rear gear you could go higher numerically, maybe 36 rear, and get better performance overall, even if you sacrifice a few mph on the top end. I agree that this pipe is very soft hitting compared to an MLM on like an express or something.

Re: The Official Yamaha Chappy (LB50) Thread!!!

Jack Rutherford /

I was thinking the same thing but I'll up the ante - I bet you can go with bigger rear sprocket and gain top speed and acceleration.

Re: The Official Yamaha Chappy (LB50) Thread!!!

I’ll second that. I think this is one of those cases where stouter gearing will also gain top speed. Sprocket availability seems to be the limiting factor. Seems to be plenty of LB50 profiled rear sprockets, LB80 not so much. Treats only has LB50 profiled sprockets, I found that out the hard way lol. I bought my 28 tooth sprocket from “i_love_japan_motors” on eBay

Re: The Official Yamaha Chappy (LB50) Thread!!!

Hunter & Jack,

I personally like to thank you both for kicking the dust off this thread. I've been a chappy owner for 15 years now (LB80 1976) and have spent countless hours searching the web for information on parts or solutions to problems. With the help of others on here I was able to obtain some information but really appreciate you both contributing to the pot.

With that being said, I come ask the community for some assistance as I'm a computer major, not so mechanically inclined when it comes to two stroke engines.

The shop that serviced my chappy closed 3 years ago, I haven't been able to find anyone around me who can service the bike properly, it is no longer running correctly.

At the start of last year it would start to choke on itself when I was opening it up after 2nd gear kicked it. Now I can't get it going long enough to get into 2nd gear with it reaaaving so high. I'm also experiecing power loss when driving, doesn't seem to be able to handle me and I haven't gained weight.

I had the carb cleaned recently by a shop.

----Do I need to have the exhaust cleaned?

---Does the top end need to be replaced or bored?

Many thanks!

-Michael

Re: The Official Yamaha Chappy (LB50) Thread!!!

Moped Army,

I have three additional Chappys, all LB50s other than the LB80.

1 - Red 1980 *I believe*

Added polini 70cc 45mm cylinder kit

Replaced carb with non OEM so now the white housing plate doesn't sit on top of frame.

Runs but looking to get it to run higher than 22mph.

-I have an exhaust from treatland but haven't installed it yet, would have to remove the pedals which are stuck(locked) into place.

1. Have you guys had to cut off the pedals

2. will the exhaust installation get me higher mph to over 30mph

3. Are there any additional upgrades that need to happen?

2. Blue 1981 *I believe*

The bike is almost 100% completed with parts but doesn't run.

I have an LB80 motor that did run and I wanted to know if I could swap the engines and get this LB50 to perform better?

-To make that happen what would I need to do?

1. Change rear sprockets

2. modify bicycle pedals

3. add new non oem exhaust

3. Blue 1980s..

--Parts bike- Frame with stuff and no motor.

Was thinking of adding the LB50 motor from bike #2 if the LB80 engine fits and slowly add parts to get it running.

I'm trying to keep as many of these chappys on the road, where I live there is actually a good amount still running on the island.

Thank you all for your help,

-Michael

Re: The Official Yamaha Chappy (LB50) Thread!!!

Dirty30 Dillon /

> Michael Blank Wrote:

> -------------------------------------------------------

> Moped Army,

>

> I have three additional Chappys, all LB50s other than the LB80.

>

> 1 - Red 1980 *I believe*

>

> Added polini 70cc 45mm cylinder kit

>

> Replaced carb with non OEM so now the white housing plate doesn't sit on

> top of frame.

>

> Runs but looking to get it to run higher than 22mph.

>

> -I have an exhaust from treatland but haven't installed it yet, would

> have to remove the pedals which are stuck(locked) into place.

>

> 1. Have you guys had to cut off the pedals

>

> 2. will the exhaust installation get me higher mph to over 30mph

>

> 3. Are there any additional upgrades that need to happen?

If you have a polini kit and aftermarket carb, you should be running more than 22mph.

1) As far as I know, you can just disassemble the pedals, you don't need to cut anything off.

2 If you install the exhaust and tune the carb properly, you should be in the mid 30's, even with stock gearing. Please note, it must be tuned or you will roast your kit.

3 Nothing really, besides making sure your brakes function, etc.

> 2. Blue 1981 *I believe*

>

> The bike is almost 100% completed with parts but doesn't run.

>

> I have an LB80 motor that did run and I wanted to know if I could swap

> the engines and get this LB50 to perform better?

>

> -To make that happen what would I need to do?

>

> 1. Change rear sprockets

>

> 2. modify bicycle pedals

>

> 3. add new non oem exhaust

The LB80 Motor bolts onto the LB50 frames, but does require a sprocket change to maintain correct end gearing.

2 I am not sure why you need to modify pedals, but sure, maybe.

3 I think the LB50's have the same flange position and size as the 80, so you maybe could get away with it, you'd have to look.

> 3. Blue 1980s..

>

> --Parts bike- Frame with stuff and no motor.

>

> Was thinking of adding the LB50 motor from bike #2 if the LB80 engine

> fits and slowly add parts to get it running.

>

> I'm trying to keep as many of these chappys on the road, where I live

> there is actually a good amount still running on the island.

>

> Thank you all for your help,

>

> -Michael

I have an LB50 with Polini 45mm, Polini Pipe, VM20 and some clutch tuning and it pulls a VERY stout 35. Perfect trail or camp bike. I am hoping to up my spring tension in first gear to get off the line response increase.

Re: The Official Yamaha Chappy (LB50) Thread!!!

> At the start of last year it would start to choke on itself when I was

> opening it up after 2nd gear kicked it. Now I can't get it going long

> enough to get into 2nd gear with it reaaaving so high. I'm also

> experiecing power loss when driving, doesn't seem to be able to handle

> me and I haven't gained weight.

>

> I had the carb cleaned recently by a shop.

>

> ----Do I need to have the exhaust cleaned?

>

> ---Does the top end need to be replaced or bored?

Thank you for the kind words Michael! The lack of information on these bikes is what has motivated me to be active on this thread.

I had a similar issue with my Chappy when I had removed the intake boot connecting the carb to the airbox and filter. The bike would start and run decent through 1st gear. As soon as it hit second gear, if it got there, it would totally fall on its face. I would check the intake boot to make sure it is installed correctly and doesn't have any splits or gaps. Its common for the rubber boots to come off the airbox side. That being said it doesnt sound like your exhaust is plugged nor does your top end need to be replaced. If you exhaust was plugged the bike would struggle to do anything above an idea, let alone make it to the top of first gear. If it were my bike I would check the intake boot, then next air check for air leaks where the carb clamps to the intake. It is possible that in the process of servicing the carb the rubber insert where the carb clamps to the intake has been damaged/ is missing.

Hope this helps, please feel free to post back here with your findings!

~Hunter

Re: The Official Yamaha Chappy (LB50) Thread!!!

1.

I agree, 22mph seems really low for a kitted bike. Assuming your carb is jetted correctly (jetting might be off because of aftermarket carb), I would expect top speed in mid to high 30s as suggest above ^. What gear ratio is currently on that bike? Like Dillon said you should be able to achieve over 30 even with stock gearing. Pedals can be a bitch on these bikes and similar. Ive had to use 2 prong gear pullers in the past to remove stuck pedals/ kick start levers etc. They may be stubborn but they will come off without the need for cutting. Which pipe did you order from treats? and which aftermarket carb (size) are you running? I remember reading an article that the MLM pipes fit even on LB50s with pedals.

2.

An LB80 engine will swap into an LB50 bike with no issues. Stock gearing on an LB80 bike is 15/32 to the best of my knowledge. I believe the LB50s have both a smaller front sprocket and bigger rear sprocket, but don't quote me on that.

I think I touched on everything, but if not feel free to respond below.

~Hunter

Re: The Official Yamaha Chappy (LB50) Thread!!!

Jack Rutherford /

Re: The Official Yamaha Chappy (LB50) Thread!!!

Just gave it a watch. Her official debut!

Re: The Official Yamaha Chappy (LB50) Thread!!!

To answer your question about the key. All the way left (CCW) is off. Middle position is Run but no lights. All the way right (CW) is run and lights

Re: The Official Yamaha Chappy (LB50) Thread!!!

Jack Rutherford /

thanks, I watched the video too and saw the lights come on when I turned it all the way to the right.

Re: The Official Yamaha Chappy (LB50) Thread!!!

Dylan,

I appreciate not only the fast response but the well provided information. I will apply said knowledge & report back to you. Hope to get this back on to the road before June!

Regards,

-Michael

Re: The Official Yamaha Chappy (LB50) Thread!!!

Hunter,

I appreciate not only the fast response but the well provided information. I will apply said knowledge & report back to you. Hope to get this back on to the road before June! I live on an island were there are few roads that have a speed limit over 25, we have a large community of Chappy's here.

Looking forward to sharing pics and some successful troubleshooting.

I've had some luck ordering from this company when it comes to parts, as I tried the ebay route, it's hit or miss if the part actually fits/works as advertised.

Parts are out of the netherlands, but arrived pretty quickly.

https://www.cmsnl.com/yamaha_model8287/

Many thanks!

-Michael

Re: The Official Yamaha Chappy (LB50) Thread!!!

Jack,

Thanks for sharing the video, it was informative and clear! Hunter beat me to it but yes that key turn is for off/on/running lights.

Looking forward to sharing pictures of the 4 Chappys that I have with you all soon.

Greatly appreciate the other video review that you posted.

With shared knowledge, we can help get more Chappy's back running & on the roads!

Regards,

-Michael

Re: The Official Yamaha Chappy (LB50) Thread!!!

Jack Rutherford /

part 2 - taking the Chappy out for a ride

Re: The Official Yamaha Chappy (LB50) Thread!!!

I have a 76 lb802ac that I’ve been restoring/recently just got running. She runs pretty strong will need sone fine tuning, major issue I’m having is the trans is not shifting well/slipping going into second gear. I have tried flushing and refilling oil a few with no imporovemt. Any thoughts would be helpful! Thanks!

87E72EDC-EA11-4868-A036-363C24ABBD95.jpeg

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