Custom Frame For Thumper Motor

GoldenMotor.com

scotto-

Custom 4-Stroke Bike Builder
Jun 3, 2010
6,505
25
38
Ridin' inSane Diego, CA.
Did you check this place out Jeff? Exhaust Conical Steel Products, Conicals, Tips, Steel Megaphones, Transitions, Reverse Cones

Only thing is you need a 1-1/2" inlet.....shouldn't be to hard to remedy that.....I can visualize a reverse cone megaphone pipe on the market soon, made by you!

dnut

I called RailMakers today, real nice people. I will try to get that way soon. I am also trying to find a reverse cone megaphone small enough for this motor with a 1 in inlet. Any help please.

Pat: I use the rope off the pull starter to start the bike, old school style. The good thing is you won't be able to steal it very easy. But then again I don't plan on leaving it, I plan to ride it... Lol
 

LS614

Active Member
Dec 22, 2009
1,236
3
38
CT and MA
culvercityclassic, that 200cc bike is AMAZING, but my only question to you is what cop on the face of this earth would believe it's 50cc? rotfl. Still...I want one too :D
 

culvercityclassic

Well-Known Member
Sep 27, 2009
3,115
177
63
Culver City, Ca
Hey LS614

I do ride the bike around a lot and fear getting pulled over but do have a few get out of jail cards to try and use. My favorite run is from my house to the beach which is about 3 miles one way, nice long stretch to open her up. The other day was a family ride with my kids and they just looked. Gota love L.A.

Tre

The exhaust is a combination of mig to hold it in place, tig to finish the joints and brazing on the lower silencer area. Before I had the mig/tig available all my exhaust were brazed. I really like that look and try to mix it up when I can.



On a note: when disconnecting the low oil sensor I recommend removing the sensor from the case and tapping that hole to seal it properly. I did not do that and now have to pull the motor to complete this. If you chose otherwise it will become a leak. You are warned….
 

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scotto-

Custom 4-Stroke Bike Builder
Jun 3, 2010
6,505
25
38
Ridin' inSane Diego, CA.
culvercityclassic;303784 On a note: when disconnecting the low oil sensor I recommend removing the sensor from the case and tapping that hole to seal it properly. I did not do that and now have to pull the motor to complete this. If you chose otherwise it will become a leak. You are warned….[/SIZE said:
Good to know......thanks man, I don't like leaks!

dnut
 

culvercityclassic

Well-Known Member
Sep 27, 2009
3,115
177
63
Culver City, Ca
I finally got to work on the oil leak today. Tried to complete this with the motor on the bike but it did not work. When I pulled the side case off the cam came out also, so out came the motor. I ended up tapping the oil sensor area with a 7/16 14 and installed a bolt with copper washer. This is a must that must be completed from the start.

Note: Il am so happy with this motor and the ease to work on...and most of all the TORQUE...this baby rocks
 

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msrfan

Well-Known Member
Sep 17, 2010
1,808
120
63
Southern California
Hi Jeff. Very nice motor. I've got one on a go kart and it runs great in stock form. I like your thoughts on brainstorming and sharing ideas. I was wondering if you were thinking of rigging a recoil starter back onto it. Also, did your motor come with the little compression release on the cam?. And if so, did you leave it on for easier starting? I'm working on a design that allows pedal starting with a Comet Torque-a-verter. If I can perfect it, it would make my life a lot better when I get a Comet on one of my bikes. I don't mind a pull rope so much until I kill the motor and can't bump or pedal start it. Right now my bike just has an autoclutch with a one-way bearing. Works great but I'm stuck with limited torque range. Let me know what you think. Dale.
 

culvercityclassic

Well-Known Member
Sep 27, 2009
3,115
177
63
Culver City, Ca
Hi Jeff. Very nice motor. I've got one on a go kart and it runs great in stock form. I like your thoughts on brainstorming and sharing ideas. I was wondering if you were thinking of rigging a recoil starter back onto it. Also, did your motor come with the little compression release on the cam?. And if so, did you leave it on for easier starting? I'm working on a design that allows pedal starting with a Comet Torque-a-verter. If I can perfect it, it would make my life a lot better when I get a Comet on one of my bikes. I don't mind a pull rope so much until I kill the motor and can't bump or pedal start it. Right now my bike just has an autoclutch with a one-way bearing. Works great but I'm stuck with limited torque range. Let me know what you think. Dale.
I have no plans to install a recoil starter on it, kinda like the rope a dope way of starting it. It has no compression release on this motor, its easy to start since this is a low compression motor to start with.

I am not sure if you can get the coment clutch to work with pedals...it might be a first. The CVT that I have is a GTC brand, works good for now...I think you will really like the operation of the CVT.
 

culvercityclassic

Well-Known Member
Sep 27, 2009
3,115
177
63
Culver City, Ca
Back to post some more updates. I have really enjoyed the ride on this bike but no suspension at high speeds has put some fear in me...so the search was on for some front forks that would look good and perform. Ordered a few online but they turned out to be junk.

The attached photos are what I have now to work with. I have modified it so it is 3 in. shorter. Tomorrow it will be installed and tested.

All I can say is ITS ABOUT TIME....
 

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sportscarpat

Bonneville Bomber the Salt Flat record breaker
Jun 25, 2009
1,844
485
83
california
Those look great, Jeff. Keep us posted. How is the engine surviving running the cylinder upright? I'm guessing you have quite a few miles on it by now. It looks cool with the cylinder in the upright configuration.
 

scotto-

Custom 4-Stroke Bike Builder
Jun 3, 2010
6,505
25
38
Ridin' inSane Diego, CA.
Yes indeed, thems fine lookin forks my friend......they look beefy, yet fairly light, kinda old school Manitou-ish with them drop-outs. Could use a pair jus like em ;)

Gonna make yer bike look sicker than ever!

dnut
 

culvercityclassic

Well-Known Member
Sep 27, 2009
3,115
177
63
Culver City, Ca
This was my 9/80 day so I had the day off and worked on the bike this afternoon. I installed the new fork, what a huge difference in the ride. I had a problem with the tire bottoming out since I lowered the fork, the beauty of this fork is you can unscrew the top cap and remove or add the spacers inside. Problem solved.

The bike looks more and more like a motorcycle…just hope the po po don’t see that…lol

Pat: I do have some miles on this bike and it has had no problems so far, runs like a dream…still amazed at what this motor cost…and the performance.

I am pretty much done with this bike now. It’s time to move on.

Magrider: this fork is 1 1/8 head tube and you may be able to make it into a 1”. PM me if you want to know more.
 

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NunyaBidness

Active Member
Jun 29, 2008
1,062
2
38
memphis tn
Such a beautiful bike, in so many ways. Function, reliability, performance, craftsmanship, everything about this bike is absolutely beautiful.
I can only imagine how much fun it is to ride.
 
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culvercityclassic

Well-Known Member
Sep 27, 2009
3,115
177
63
Culver City, Ca
Update: Is the motor reliable? Yes it is. Is the drive train reliable? That’s a good question. The torque is a big factor and is doing a number on the chain.

Read below:

Decided to ride this past Sunday with a local group called “Venice Vintage Motorcycle Club”, they do a ride once a month. This ride was from Venice area to a place called Neptune’s Net in Ventura, up PCH 33 miles one way. Now what was I thinking? I know what I was thinking...beach, babes, and biker chicks

Upon meeting up with this group the feeling was what is this guy thinking. They were all cool people and enjoyed my ride.

We hit a lot of traffic at the start due to an accident but then the road opened up, at one point one of the radar signs clocked me at 52mph. To tell you the truth it was scary on that 2.5 tire. Made it to the location and really surprised the group. The bike was a hit among all the high dollar machines. Made it 20 miles back then the master link let loose and the chain went flying off the bike. Attempted to pedal it, made it to a restaurant called the Chart House and made the phone call for a ride. Had a few really good margaritas and a shrimp cocktail to end the day. dance1

I really wanted to complete this venture…but things happen.
 

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