Cobrafreak's board track racer project, has ended

[cobrafreak]

Re: Cobrafreak's board track racer project now COMPLETED!!!

Another way to ger rid of the engine "buzz" is to use a smaller sized rear sprocket.. A lot of the vibrations comes from the engine working at a high rpm.. Mine felt like it was trying to shake it self loose at wot before i switched to a 40 tooth..

I found out what the buzzing was. The front motor mounts loosened up a little. Buzz is gone now. A lot less work to fix this

 

[K-dregg]

Re: Cobrafreak's board track racer project now COMPLETED!!!

Good to hear!

 

[cobrafreak]

Re: Cobrafreak's board track racer project now COMPLETED!!!

I had the intake manifold off today and noticed that the gasket between the cylinder and the intake was too large and blocking airflow. I guess around 4 to 6% of blockage. I just trimmed it with a razor blade and WOW, the bike really takes off now! Smoother, Faster, Quicker. I didn't realize the dramatic effect it had. A completely different beast now. :mrgreen:

 

[cobrafreak]

Re: Cobrafreak's board track racer project now COMPLETED!!!

Guess what this is?

This is my bonehead move of the week. If I had taken care to read the engine owners manuel for my 2 stroke engine I would have discovered that every 5 hours of operation you "MUST" torque head bolts to 8 to 9 foot lbs. or roughly 109 inch lbs. I have about 8 hours on her and never torqued the head bolts and blew a head gasket. Fortunately for me the engine came with a spare head gasket and I put it in, but air was leaking past the gasket on the intake and exhaust side. I suspected the head was warped. I took the head off and measured it and yes, it is warped. I ordered a new head, $9.00, and two new head gaskets, $4.99 each. Cheap mistake to fix. Anyway, since I have new parts coming I attempted to fix the warped head. I took a fine piece of sand paper and placed it on a surface I knew to be very flat and placed the cylinder head on it and rotated it in a circular motion till the warp was out. I put on the engine, torqued to specs and went for a test ride. Everything is fine! No air leak and all the power is here. So I learned that if you do not torque your head every 5 hours of operation you will blow the gasket, the head may warp because of it (only guessing but I presume the warping is caused by the super heated gasses passing the gasket area where is should not, chime in if you know this please. I'm not under oiling the engine or running it too fast, so I know I'm not over heating the engine), and that the head if warped can be fixed. I don't know if this is a permanent repair for a warped head, but since I have a spare coming I will keep running it and keep you informed of it. So far so good.

 

[Beau]

Re: Cobrafreak's board track racer project now COMPLETED!!!

Most of these engines need to have the surfaced milled right out of the box.

You can also use toothpaste rubbed on to a sheet of glass to make the final sanding perfect.

 

[cobrafreak]

Re: Cobrafreak's board track racer project now COMPLETED!!!

So far I have gone through 3 heat/cool down cycles with the engine and have re-torqued the head bolts to specs each time, and each time it gets closer and closer to staying within specs. I really think this is a maintenance issue. Had I started out getting the head within specs and keeping it there I probably would not be where I am now. BTW, the power is great. I now consider proper head bolt torque maintenance "critical" to the life of these little 2-stroke engines.

 

[wheelbender6]

Re: Cobrafreak's board track racer project now COMPLETED!!!

One of the coolest things about your custom boardie is that it is street legal in most states. I love the look and sound of the the bigger flathead motors (like Briggs, etc) but is is tough to street ride them legally in a lot of states.

 

[cobrafreak]

Re: Cobrafreak's board track racer project now COMPLETED!!!

Look at what came in the mail today!!!

The almighty California moped plate! Whoo Hooo! I'm legit now. No longer do I need to take side roads and dodge cops. A sigh of relief. :lol:

 

[masterpoop63]

Re: Cobrafreak's board track racer project now COMPLETED!!!

we now need a picture of you riding it on the street :mrgreen:

 

[stocksucks]

Re: Cobrafreak's board track racer project now COMPLETED!!!

Cool!

 

[cobrafreak]

Re: Cobrafreak's board track racer project now COMPLETED!!!

Here is one of me just getting back from riding on the street.

I have a video but I need to teach myself how to post a vid link.

I am still needing to tighten the head bolts to spec every day. I suspect the hardware (nuts, washers, lock washers) are garbage. I bet if I upgrade the fasteners to grade 5 and use non-nylon lock nuts I would be keeping torque. I will need to find this out.

 

[cobrafreak]

Re: Cobrafreak's board track racer project now COMPLETED!!!

One of the coolest things about your custom boardie is that it is street legal in most states. I love the look and sound of the the bigger flathead motors (like Briggs, etc) but is is tough to street ride them legally in a lot of states.

Absolutely! I would have LOVED to use a bigger engine with better sound and more power, but then I would have to have registered it as a scooter or motorcycle along with the yearly fees and all the other red tape that comes along with it. Mopeds in CA are a one -time fee of $18.00 with no vehicle inspection. I did everything over the internet and through mail.

 

[Gdcast]

Re: Cobrafreak's board track racer project now COMPLETED!!!

Looking good Cobra!!!

 

[cobrafreak]

Re: Cobrafreak's board track racer project now COMPLETED!!!

Here is a video link. Click on picture and it will play for you on Photobucket. This is a little 17 second video of me blasting down the block that my friend took.

 

[masterpoop63]

Re: Cobrafreak's board track racer project now COMPLETED!!!

MOR' POWER! :mrgreen:

 

[deorman]

Re: Cobrafreak's board track racer project now COMPLETED!!!

Sweet motorbike, but sorry mister, you ain't allowed on the boards with all that equipment. :wink:
q.v. brakes, indirect drive (clutch), external ignition source (lights) :mrgreen:

 

[cobrafreak]

Re: Cobrafreak's board track racer project now COMPLETED!!!

Sweet motorbike, but sorry mister, you ain't allowed on the boards with all that equipment. :wink:
q.v. brakes, indirect drive (clutch), external ignition source (lights) :mrgreen:

You mean I cant have an open flame headlamp on my race bike! Why? :lol: At least in the Professional class. In Amateur class board track racing you race what you bring. Front brakes where however unobtainable in 1911. There is a really good board track video on You Tube that shows what board track racing was all about. Very dangerous sport!

 

[cobrafreak]

Re: Cobrafreak's board track racer project now COMPLETED!!!

Remember my blown head gasket and warped head? I ordered a new head just in case and put it on, but I put it on sideways for something a little different.

I works great and does not change the cooling characteristics of the head as the full top of the head is pointed into the wind. I did some testing with my laser thermometer to confirm this. The spark plug is to the right side, which is great for access. Gives something a little different to view on the right side of the bike. You also have a great view of all the cooling fins. They kind of disappear when they are mounted front to rear. I went to a Honda dealership and got a medium reach high performance 2 stroke plug. It reaches to the center of the combustion chamber better without protruding into it. It raises the compression a little more as there is a resistance when I move the wheel with my hand when on the center stand. I went one heat range hotter than stock for better combustion.

 

[masterpoop63]

Re: Cobrafreak's board track racer project now COMPLETED!!!

YAY! mor' power achieved :mrgreen:

 

[cobrafreak]

Re: Cobrafreak's board track racer project now COMPLETED!!!

New news. I have about 500 miles on my 2 stroke engine and I have to be honest, I am having trouble with it. Very very temperamental. I need reliability above all else and the 2 stroke just doesn't deliver it for me. I am thinking of purchasing a 4 stroke 49cc engine kit and will be retrofitting from the old engine to the new engine shortly. My main goals is to make the new engine look good and keep it reliable. I will be posting all pictures as phase II begins.