Custom Frame For Thumper Motor

[scotto-]

Very cool 4 stroke Scotto....It looks nothing like a weed whacker.
Post a few more pics man!
FR

Huh? That's not my bike, that's Jeff's bike and it's more than just very kool.....it's incredibly INSANE! Oh I wish it was my bike.....do I ever. Culvercityclassic / wolfcreativecustoms just made a huge step for mankind.....something I'm sure he's very proud of. Great job Jeff, can't wait to see you riding that beauty!

weed whacker ?.....that's a D-9 Caterpillar!!!

 

[NEAT TIMES]

Y e s

Motor bike evolution at the highest !!

Ron

 

[culvercityclassic]

This bike should do well at the race, it leaves the line very hard and will come out of the corners fast. I rode it around town today and it kept up with traffic and I was not even on it. Wait till it's jetted.

 

[The 26incher]

Man that thing is bonkers!

 

[dmb]

looks like flattracker on the stand [wheres the steel shoe!]

 

[culvercityclassic]

We posted some more videos...youtube.com/wolfcreativecustoms

I changed a few things on the bike: new front Hayes 8 inch disk, new handle bars with different sweep and black, made some new brackets like for the kill switch and a belt guard. Changed the oil but added too much so it pushed a lot into the head causing it to smoke really bad. I also changed from a 90 jet to a 105 and it does not have a flat spot anymore. I do have a couple more to try. I just need the balls to do it....

 

[city of angels]

thats a beauty cant wait to get my four stroke on my trike

 

[culvercityclassic]

I am posting an update on this bike from past events. The bike is now complete and running. It runs very strong and very quick off the line. I built this bike to race at Willow Springs and did just that. It performed very well but not as well as the built AGK bike that raced in the unlimited class, that bike was sick fast with a top notch rider on it.

I noticed a few issues that I have since corrected; the first was oil blow by out the vent in the valve cover. I added a hose from that area to the air filter, the air filter became saturated with oil and basically sprayed down the side of the bike, back wheel and ground. It was a complete mess and a safety hazard. I searched for an oil catch can for these issues and could not find one to my taste so I designed and made my own; Inlet on side, vent on top, oil sight tube on side and a drain on the bottom. Installed it today, sure works nice…problem solved.

The next issue was the CVT was not geared right, it was quick but wanted to climb the drive pulleys too fast, I was given a 50 tooth sprocket adapter at the race as a prize (Manic Mechanic thank you) that I installed to correct the problem. This helped and the bike will pull the front wheel off the ground from a dead stop and lug along at 45MPH all day. This might be the setup but will need to ride it more to find out. 45 is fast on a bike that has no suspension with only a spring seat.

On a side note: The motor had no problem with over-heating and I ran the crap out of it all day at the race…still impressed with this motor….

Bye Bye China Girl…hello THUMPER…

 

[sketchman]

It just keeps getting better. I wish I had the time/tools/resources to do this, and I'm glad this forum is here so we all get to see how everybody does things.

Great work.

 

[FarRider]

A work of art... very nice.
No rear brake?
FR

 

[culvercityclassic]

It has a coaster brake in the rear, the link is connected to the brake arm. It makes adjustment of the rear wheel simple.

 

[agk]

CCC, it was great to meet you at Willow Springs. Your bike looks and runs fantastic! You have a lot of aluminum braces and brackets on your bike that look great. You're an awesome fabricator.

I love the catch can you added. We had a little oil getting to our breather filter too. We probably need to add a catch can also.

You said you were using a 115 main jet at Willow. I'm curious if you ever had a chance to check your plug and determine how well that jet size was working. We had to use smaller main jets than usual in all three of our bikes due to the elevation at Willow.

It's great to know you can run the motor without the blower housing and cooling tins. Your flywheel doesn't even have fins for cooling. Cobrafreak also reports that he has not had any cooling issues running his 6.5hp motor without the blower housing and cooling tins. You guys are paving the way for the rest of us.

 

[msrfan]

Hey Jeff, your bike pulled our Briggs bikes pretty hard at Willow Springs last weekend. It was great to see what can be done to those motors. Between you and AGK it was quite a show. I don't know if mine will ever make the unlimited class, but thinking of seeing if I can find some left over performance mods from the karting wotld. They're using OHV motors now and may have some flathead stuff available. Anyway, it was fun trying to follow you around the track and watching you disappear. See you at the next event.

 

[scotto-]

I am posting an update on this bike from past events. The bike is now complete and running. It runs very strong and very quick off the line. I built this bike to race at Willow Springs and did just that. It performed very well but not as well as the built AGK bike that raced in the unlimited class, that bike was sick fast with a top notch rider on it.

I noticed a few issues that I have since corrected; the first was oil blow by out the vent in the valve cover. I added a hose from that area to the air filter, the air filter became saturated with oil and basically sprayed down the side of the bike, back wheel and ground. It was a complete mess and a safety hazard. I searched for an oil catch can for these issues and could not find one to my taste so I designed and made my own; Inlet on side, vent on top, oil sight tube on side and a drain on the bottom. Installed it today, sure works nice…problem solved.

The next issue was the CVT was not geared right, it was quick but wanted to climb the drive pulleys too fast, I was given a 50 tooth sprocket adapter at the race as a prize (Manic Mechanic thank you) that I installed to correct the problem. This helped and the bike will pull the front wheel off the ground from a dead stop and lug along at 45MPH all day. This might be the setup but will need to ride it more to find out. 45 is fast on a bike that has no suspension with only a spring seat.

On a side note: The motor had no problem with over-heating and I ran the crap out of it all day at the race…still impressed with this motor….

Bye Bye China Girl…hello THUMPER…

Great to hear you ironed out a few small details Jeff....can't wait to take er for a wheelie.....er... ride again Looks like oil changes are a breeze with that angle the engine sits and I see you swiss cheesed the rear sprocket already......nice. That stainless 52t I got is gonna damage drill bits to lighten up

Looks like I'll be building a race specific bike next for these go-kart tracks we be racin on......seeing as how my 49cc bike is way undersized and under-powered compared to what they're letting race in the 4-stroke class.....the wheels are turnin!

Love your bike man, it rides like a champion! So do you!

 

[zean]

Boy howdy, that bicycle is good looking. More importantly it lifts the front wheel off the ground from a stand-still and runs cool all day at 45mph without engine shroud and without fins on the flywheel. It's not legal, but it's a lot of fun. The big block bicycle engine does that run cool because it doesn't have to work as hard as a 49cc and therefore operates more efficiently? I can feel your enthusiasm with this build, which I believe would sell very well in the world if mass produced starting out in a garage. This bicycle reminds me of a saying back in the sixties regarding a 426 hemi and a 440 six-pac off the line: "there's no replacement for displacement".

 

[silverbear]

Jeff,
I don't know how it is that I just now came across this build. Wow, from the ground up. I'm reminded of how as boys we placed the playing cards in the spokes and imagined a real motor down there speeding us along... the wind in our faces... going, going, gone! I see that you have kept the twelve year old spirit alive and well inside. Combined with the master craftsman you have become, the result is a work of art which goes like the wind... just the way we imagined it could be. Well done, sir.
SB

 

[Ballin on a Budget]

Hey CulverCC

Just wanted to mention that aside from that bike being unreal looking and by the sounds of it, with performance to match, it truly is quite the engineering feat.

Building a frame and all the parts, mounts, etc all from scratch is no easy task, and in this case you have executed it beautifully. It looks raw, purpose built, and mean, and I congratulate you on doing something new and breaking new ground in this hobby. Keep up the good work, and im sure we are all looking forward to the next creation out of your shop!
-Dan

 

[culvercityclassic]

This has been a fun project that has pointed me in a direction I have wanted to go. I am really close to pulling the trigger on building a custom motorcycle, with the time and energy put into this bike why not.

I wanted to thank everyone for the kind words and support on this project. It was exciting racing with the other riders and I am sure the fun will continue.

The future of the four strokes looks real, with the support of AGK and others makes it more appealing and easy for the transition.

AGK: "You said you were using a 115 main jet at Willow. I'm curious if you ever had a chance to check your plug and determine how well that jet size was working. We had to use smaller main jets than usual in all three of our bikes due to the elevation at Willow."


I did check the plug and it looked fine. I did notice that the bike ran faster each race, who knows why. It was a new motor with 10 miles on it to start.

 

[Tre_in_L.A.]

Happy to hear I'm not the only clone builder that's got oil smoke outta the valve cover vent - lots of it. Brand new piston and ring set - probably just needs to bed in. A few heat cycles. Should be nice and easy to drill a hole in the cover for a fitting, hose and catch can. Tucson Death Race - October - be there. I hear some of you guys were wearing shorts and no helmets last Saturday at Willow ??? Huh? Crazy, man. Crazy.

 

[culvercityclassic]

I did not see anyone without a helmet... So that is bad info Tre

On a side note the catch can works good and it is a must on this motor. I would be interested in seeing your project some time or if you want to test ride mine you are welcome... Just let me know