Fox Campus Trail Bike Build

[nightgrider]

Recently purchased a Fox Campus, planning on building it into a nice little trail bike to putt around the yard and fields on. Here's a short run down of what I'm thinking:

- 10 inch dirt bike wheels
- CVT to the jackshaft
- New seat
- Honda CFR50F front fork
- 8 inch mini ape hanger handlebars
- Rear drum brake
- Repaint frame

The maybe pile:
- Front drum brake
- New exhaust and muffler
- Generator coil and flywheel for engine
- Headlight
- Taillight
- Tachometer
- Speedometer

With moving to the larger diameter wheel I need to make sure I maintain a good gear ratio for off road use. I'm thinking the CVT should aid with low end torque multiplication for acceleration. With a 12 tooth drive sprocket on the jackshaft and a 72 tooth driven sprocket on the wheel. This should roughly give me a 6:1 ratio. I'm not sure if I can find a sprocket of that size that will work with the dirt bike wheel. Also I've never owned a mini bike with a jackshaft before. It seems simple enough to add the CVT with the correct length jackshaft. But I'm not sure how to help prevent side to side movement of the jackshaft (maybe it will become more evident as I disassemble the bike). If anyone has any input it would be much appreciated. Thanks

 

[nightgrider]

Working on some sketches of how I think the campus might look with the modifications. Currently just a work in progress.

 

[nightgrider]

Little more progress made on the sketch tonight.

 

[nightgrider]

Finished up the sketch this morning. I might make some copies so that I can try out different color combinations.

 

[nightgrider]

Here is what I'm thinking for the Campus with a red frame.

 

[nightgrider]

I've finally got my rear in gear and have ordered my new throttle assembly and cable. When I purchased the bike the one on it was broken. I've also been doing some thinking and to maybe help simplify the project and hopefully save a little scratch I might for go the CFR50F front fork and drum brakes. Does any one on the form know how hard it is to rebuild the Fox front fork? I've looked at it and I'm not quite sure how to disassemble them. In the mean time I need to get the rear wheel off so that I can get the wheel bearings replaced.

 

[nightgrider]

 

[manchester1]

Not sure how those fork springs come off. I would say to start twisting. :laugh: Use the google custom search at the top of the page to do some research. I do know those rear shocks are wrong and way too long.

 

[nightgrider]

Yes the rear shocks are definitely incorrect. Haven't been able to find shorter shocks. These are 11 inches eye to eye. I'm ok with the extra suspension since I'll be using it as a trail bike.

 

[manchester1]

https://youtu.be/BO1z8Mtv9Aw

 

[manchester1]

Perfect video:thumbsup: I was curious myself how they came apart.

 

[nightgrider]

Thanks for the video link. I'll have to check it out. My throttle assembly came today. Got it and the kill switch installed. There is a dead spot when you Rev the engine. I'll need to take the carburetor off and clean it. Hopefully that will clear up the dead spot. Dropped the rear wheel off to have new bearing installed. They didn't have the bearing in stock. So that should be back on next week and should be rolling around under its own power.

 

[nightgrider]

Thanks for the video link. I'll have to check it out. My throttle assembly came today. Got it and the kill switch installed. There is a dead spot when you Rev the engine. I'll need to take the carburetor off and clean it. Hopefully that will clear up the dead spot. Dropped the rear wheel off to have new bearing installed. They didn't have the bearing in stock. So that should be back on next week and should be rolling around under its own power.
View attachment 107708
View attachment 107709

 

[manchester1]

OldMiniBikes has those bearings. They are like 2.50. Its only a 5 minute job to replace a bearing.ut:

 

[nightgrider]

Thanks I'll look into it for next time. I'd already left the rear wheel at the shop. They said that they'd order the bearing today. I hope to have the rear wheel back on the bike by the end of the week. I've also ordered a new centrifugal clutch brake that I hope get here by Saturday. Should be rolling and stopping by next week. Got a camping trip coming up and want to have the bike ready to take to that. I'm thinking I'll consider this stage 1 of the build. Enjoy it as is for a little while then really tear into it once I get bored of it in its current state.

 

[nightgrider]

Picked up the rear wheel with new bearings last night from the shop. Brake assembly should be coming in the mail either tonight or tomorrow. Just need to see if I can find a correct length 5/8 bolt to replace the chewed up rear axel.

 

[nightgrider]

The brake parts came last night. Wasn't able to get it all installed do to a tiny snag. It appears that the nut-sert was installed crooked. In the image below when the bolt is threaded into the nut-sert it doesn't line up with the hole. The bolt is in backwards to how it should be installed in the image but if I try to thread the bolt in the correct way it gets prematurely tight and I worry about cross threading the nut-sert. I could relieve the hole and make it work just that's a little disappointing with the amount that I paid for the kit. Otherwise the kit looks to be good quality.

 

[nightgrider]

Contacted OldMiniBikes Warehouse this morning about the bracket. They are sending me a new bracket. I hope it comes in time to have the mini bike going (or really stopping :wink by my upcoming camping trip. Customer services was very quick and excellent.

 

[nightgrider]

The new band brake bracket came yesterday and was able to get the 5/8th bolt from fastenal at lunch today. Should have all the parts required to get the bike back together and buzz around the yard a bit.

 

[nightgrider]

Got the bike back together last night. Buzzed around the yard a little. Need to get tires with more aggressive tread to help with traction. Also a rear sprocket with more teeth to increase the gear ratio wouldn't hurt.