Changing from single speed to shifter questions...

[fastrnrik]

We have an '06 Cobra that was a single speed. Sold the single speed motors and putting a Cobra shifter motor back in it. I've been trying to sell the Cobra roller and shifter motor seperately with no luck, so I guess now is a good time to throw it together and let him learn to shift. My son has never liked the Cobra, but I'm sick of seeing it sit.

Pipe/Carb.... I have a Cobra motor, 80cc built by Wiley. It came with the stock 70 2 piece pipe, so we'll run that for now. It supposedly ran really good with that pipe. I dunno. It also came with a Mikuni carb, which I really don't want. I'm assuming a 28 PWK would be fine for the 80 motor? Any baseline jet setups for sea level???

Motor mounts.... I have cut the stock swingarm so it fits the shifter motor, but I wasn't sure if the single speed motor mounts would work on the front? If so, does anyone have a set for sale? I gave mine to the guy who bought my last single speed motor.

Gearing... The bike has 14/48 on it now. Is that ok to start out with?

I need a CDI box & coil too....

Thanks for any help.

[fastrnrik]

Anyone?

[jay-r]

Front motor mounts are different for single speed and shifter, they are inexpensive from Cobra. Stock 2 piece pipe works fine with the 80. The Mikuni carb is stock, I don't care much for the Mikuni either. I didn't try different carbs on it, but I am sure there are others that are much better. We have switched to single speed for now. 14/48 gearing is a good place to start. We ran from 46 to 48 rear on the shifter. The shifters run the red coil. Not sure about a CDI. Our 80 had the pvl analog ignition like a single speed. Some of the 70s have a digital ignition, and may require a CDI, but I am not sure.

Hope this helps.

[fastrnrik]

Excellent, thanks.

So I order the stock front motor mounts for the 70 shifter?

[jay-r]

Yes, that is correct. Watch the mounts closely. The shifter engines vibrate a lot. If the engine gets loose, the front mounts crack and/or wallow the holes out. You will need to shim the front mounts and swingarm mounting area to make sure the engine is tight. They tend to work loose.

[fastrnrik]

Ok thank you for all the info. I need to get the front mounts in & mounted so I can make sure the rear is right so the chain runs straight.

Then I'll get a new 28 pwk and figure out what ignition I need. Any ideas on a baseline jet setup for the 28?

[jay-r]

Sorry, I can't help you on jetting. We only ran the mikuni for 8 local races. Mikuni carbs have very strange jetting numbers.

[fastrnrik]

I'm junking the mikuni. I will be running a keihin 28 pwk, D slide carb.

[heathmxracing]

A good place to start on the jetting is 150 / 50. On the motor mounts look at your engine and if it has one hole in the front you need the old style mounts. If it has two holes then you need the new style mounts. On the CDI you will need to figure out what year engine you have as some of the CDI boxes are different.

[fastrnrik]

Ok thank you. I will check it out and call you to get the right parts.

[djdfairchild]

can you run a d slide carb on the shifter motor? i tried to fit one but it was to long, hit the cases. the stock cobra carb isn't as tall.

[fastrnrik]

I assume you can. I haven't played with carbs yet. I will get some out and see how they fit. Seems the mikuni that came with this motor is bigger than a keihin pwk. I will play with it and see.