Ernst from Turllock Ca

Lets see. I need to find the way to the journal function but I can say the expansion in on and it is welded.

So far with me being a heavy guy and having the new rear de-railer I went to the highest ( smallest rear sprocket ) and put all I had into it as I accelerated with the gas after the pipe was on and the engine warmed up. It wasn't too dramatic but the front forks fully extended and I believe I had an inch or two off the ground for a moment or two.

The sound is more throaty, the putt-putt of between 8 and 16 mph is easy so there is more low range there. The comfort zone of 20-22 is now 23-24 or so.

Now There is still airflow issues and I plan to try something to fix that so long runs in open country on a hot summer's day like this week is will not heat the motor to diesel-ing.

Tonight in about an hour or so I will hit that back roads and see how she likes a long cool run.

I have some pictures and I attached one. My friend Dale did well to put up with me and get most of the work done with me chattering on all day.

Lets see if the attachment works.

Okay, I think I can update.

So first off I have wondered where that motorcycle motor sound is coming from at speeds of about 18 mph. I have to get used to the idea that the exhaust is now down and aft of the seat post.

Now I read what you friends wrote on the SBP's expansion and installing and my friend and I did our best to keep it as long as possible but on the Giant Boulder there are some limits.
I did not want to have the expansion up near my legs so that ruled out running up and back.
That left down and under. So, I'll bet it's close to the best it can be if not right there for me.

lets see obvious difference is low end and slow speed 8-16 mph. It's all good.
Now I am going to observe over the next few days how it runs but generally everything is to the plus two mph and I can take it up to 31 without shaking it to death and 28 is something I believe is going to replace my 26 mph as a long run highway speed.
My friend Dale did a great job.

I'd say the expansion unit is worth the effort but to weld is the better way and we welded. I even burned some wire after a couple years. I do it for a living when there is a job so I remember but it's odd to do it after so long.

Alright then.

More glowing reports.

I added a second mini handle bar today. Used a BMX handlebar mount to lower the basket so I can fit more extras.
The motor continues to adapt to the new exhaust if that is possible and I run 28 where I ran 26 before.

The Bicygnal front a rear turn signal units are here. YouTube - ‪Bicygnals Blinker Video‬‏

I now have the front end lighting I dreamed of. Distance + local and spot light for watching the road edge where traffic is bad and the bike lane is the edge of the road.

I look forward to a long run at night soon.

The only negative with the unit was that the AA batteries were low power / drained,, out of the box and I thought maybe there was a problem with the electronics assuming those new batteries were good.

So now to mount the rear unit at the end of the book rack. Or I may weld a seat post size pipe on the end of the rack but I don't know for sure yet.


I find the night ride the better when I can clearly see the road.

I may have to ditch the front basket. I have to see about that.

So the light mods are under way.

yeah, got to do some shots for sure.

It's official this Bicygnals front light shuts itself off. Lets see if Amazon is as quick with the replacement.

Now call me light freaky but once this gets set up I will feel very relaxed at night along stretches of highway as well as I will in less travelled back roads.
Great lights offer us bicycle riders respect since the on coming traffic thinks it's a motorcycle or other than a simple bicycle which this MaB is not.

Well I have a set back on this but I see I ordered the Maxxon brake light and it's coming from overseas. Hopefully not on the slow boat.

The question is now what to do? I have a book rack I like that swings away when pushed hard because it rotates on silicone tape. I like that because I try to clear the gas can with the leg as I mount the bike but sometimes I connect with the top of the jug and it's easier to reach back and straighten rather than get back off and reattach the jug.
Still there is the world of rear rack bags called panniers. Obviously I can make use of a rack and pannier.

At this point I hope the basic mechanicals of this build are stable. What has happened although is the local bike shop I bought the bike at requests that I not bring the bike into his shop any more. I can still buy things and he will repair what I bring in such as truing a wheel if I disassemble the MaB for him. Something to do with insurance costs. I guess money is good, Motor Assisted bikes bad. Mmmkay?

Any one know of bike shops that work on mabs?


So a couple weeks to decide on the tail end of this bike. The front light concept works for me so panniers seem the logical way to go.

Adding panniers means the cool swing tail I have may need to be replaced.
The basket is off in this new configuration and I have to do a ride to really know if I am happy with this light configuration because that basket was really useful so I will weigh the two and see.

Well as it is with mail order I have to wait. I have as of writing this, I had the idea that I can connect the swing tail to the seat bottom. I may save myself from another purchase unless panniers need to tie to the down rods? Eh, I need to learn but one thing is for sure that swing tail and an 18 pack balance nicely.

There ya go more read.. More MaB soft porn stories.. You love it!

I do too.. I want the most highway long distance functionality I can get.

725 Miles RIP lil'china girl.

Well I was puttering along at about 19mph and the motor went chunk.

That was it. Something in there stopped the engine and lucky I was quick to the clutch which still worked.

No danger to me but now that I have spent for all the Bling Bling I think I can go better than a hundred dollar motor.

I'm open to suggestion for a replacement.

Even if it can be fixed I am not so happy at this moment.

I trust the story of a new owner and a lot of Sunny miles on a painted engine in a short time will help some.

I have not opened up the engine to see what went wrong or if it can be fixed but I plan to do so. I should shoot that.

I garnered the help of several folks on the site and I understand the EZM 4-Stroke is the best for me in respect to long rides but my Giant Boulder Boulder (2011) - Bikes | Giant Bicycles | United States isn't the frame I want such an engine on to be honest.
Morini is more a custom fit option that I am not ready to do either but both deserve respect and I would like to do one of each in time.

I went with a RAW replacement and two are now on the way. If nothing more I hope to get 750 miles out of each and I am considering going through with the wind wings to channel air on-to the engine. I have the clamp and the rod holder. I saw the rods I want to use so it's just a mater of fabrication.
So I will ride again soon.

Perhaps the cause of failure is obvious on the painted black motor but heat was a problem for it and from that several potential failures present themselves.

So I will install this new motor myself and we shall see how far I can take the hobby/transportation "bicycle" down the road.

If the next 725 were as fun as the first then I can't complain. I would like to go fishing and camping with the trailer.


So now to review breaking in a motor. Might as well brush up again.

Well, it's a saga.. A blog.. something...

I took the jug off and I don't know enough about piston and rings to tell if they seized up but I cannot move the piston by hand.

I see what looks like a nick in the piston and what seems to be a similar sized nick in a port hole.

Now these port holes are rough. Sharp and not at all what I would think is appropriate for a hard working machine.

So starts the task of engine discovery and maybe rebuild. Interesting enough is that this thrusts me directly into the heart of darkness. The joke being the "unknown" area of motor disassembly and reassembly.

Also i wonder what the RAW engines will look like? Rough and sharp edged ports? Nicks in the piston?

Well please have a gander at these two pictures . Pardon the blur as my eye sight has changed in the last 4 months and I am not shooting pictures as well as I once did.

I welcome input on disassembly and rebuild. I would do this to learn. Sounds like a reasonable education and what better than this 2-stroke?

The piston is not moving up and down at least not by my hand.

Is this a chromed cylinder? I see some scaring or I think I do.

I called my friend and we agreed to tap that piston out of the jug and it was in there tight..

I did and it sure enough is the ring.

Look at the piston and look at the sleeve.

I think the sleeve is in good shape but is it replaceable?

The piston took the damage from what I can see at this time.

Ah.. I think that is true there Mike.. I was puttering along @19 mph when it went.

I don't know if I need a new cylinder,, I'll check but it could be steel/ The piston is aluminium for sure.


Thanks for the input!

Indeed. It's not steel but I'll have a friend check the cylinder.
I'd say it may be okay but this is my first look at a small engine cylinder.

I think rebuilding it for the experience is in order.

Yes the Raws are on the way. if this motor can be rebuilt then that will make two spares.
I'm seriously into this MaBs for transport so lets see what it takes to ride two years.

Thanks MikeB

Thanks for the input. I look forward to finding out what I can.
I'm unsure how to disassemble the rest of the motor so I have stopped at the jug. That was easy enough.
In my limited experience I would say there is only one flaw and that is seen in the first set of photos I posted in this thread. Pardon the focus but other than knowing what an actual scaring looks like that is the only flaw I see. Nothing like the piston gouges. See the nick on the top of the piston and see the nick on one of the ports. The port nick is all the damage similar to the piston I see. Bad picture I know and sharing technical details through a forum is even harder. Trust me I am all for starting with a replacement cylinder, rings and piston with the ideal bearings. All of this to learn how and do a good job.
Perhaps recommended site links for the act of disassembly? I have a blue tub with a lid holding the whole project. I can take the time since I did the crime

I like to ride!

I have 5mp shots if anyone wants them. 5MP is better detail than the 1024 by... I appreciate the privilege to upload here but I have better shots of what I have shared and I can surly shoot the cylinder with my camera in as many angles as needs to be.
My take is no gouges exist that are like the piston on the cylinder. There is some question of ware, in my mind, but this all seems strange. Please follow. There is a nick in the piston in a different place than the nick on the cylinder wall port edge. See the early pictures.
That drew my attention. I thought what if a small BB got into the rings?

I am open to cracking the case.. Pun intended. What indeed metal is in the bottom and what state are the mechanicals in.

Thanks.. here is the thread started to ask about rebuilding fyi http://motorbicycling.com/f3/disassembly-motor-engine-31331.html

I have much to learn and do.