First mini bike project cat 400X

[follow my ROTAX]

Hello all, new to this site and mini bikes.I just got what I belive is a Cat 400X last weekend.I always wanted a mini bike and it will be my grandsons next year.
It looks mostly complete,I do have the foot pegs but that pipe work nice.It seems to run good but just does not get going with my 230 lb on it.I do not belive it has the original briggs in it.
I am thinking of redooing it in ski-doo colors and getting it running good for my grandson next summer.
I have a couple of ?'s. . . About the clutch,getting a smaller gear on the clutch would give more torque,correct? What should the gear ratio be? Do I need a bigger motor on it to haul me around? How big will go in it if so?
I would appreciate any tips or info on this bike.How many of these things were produced,I am sure this probably isnt one of the collectable bikes.Thanks.

 

[The Restore Kid]

They will handle up to a 5 horse pretty easily.. Gearing depends on what you weigh and how well it runs.. But I've seen 2 horse briggs haul 200 pound loads on a mini bike with not much effort.... Might not be a hill climber but they go... But yeah a smaller drive sprocket will give you more low end power..

 

[james c]

grandkid huh? sounds like an excuse to me!

 

[james c]

the first thing you need to do is :
1. durability test, run it all day (sometimes with a friend,its gruling!)
2. make sure it doesnt sit too long as they tend to not wanna start.
3. tell the wife its gonna be a great investment so you can get more.(retirement fund)
4. next stay online here with other people to support your hobby..(investments) as i do,
my grand kids will be born in a few years and you cant start too soon!

 

[minibikin']

Hello all, new to this site and mini bikes.I just got what I belive is a Cat 400X last weekend.I always wanted a mini bike and it will be my grandsons next year.
It looks mostly complete,I do have the foot pegs but that pipe work nice.It seems to run good but just does not get going with my 230 lb on it.I do not belive it has the original briggs in it.
I am thinking of redooing it in ski-doo colors and getting it running good for my grandson next summer.
I have a couple of ?'s. . . About the clutch,getting a smaller gear on the clutch would give more torque,correct? What should the gear ratio be? Do I need a bigger motor on it to haul me around? How big will go in it if so?
I would appreciate any tips or info on this bike.How many of these things were produced,I am sure this probably isnt one of the collectable bikes.Thanks.

First, welcome to the site. Great bike to work on for sure.
Second, you need a smaller/lower tooth count on the clutch for torque/lower gear ratio. The rear on that bike should be a 72t I think? So, a 12t clutch would give you a 6.00 gear ratio. A 11t would give you 6.54. This is all relevant to your rear tire size as well and size/power band of the motor. You can always install a jackshaft and have almost infinite gearing. Good luck!!

 

[follow my ROTAX]

Hey thanks for the info and advice.Yeah the grandson is a good excuse,I will tell her that.Here is a pic of it.
Are some clutches better than others?I need to check out what it has for gearing and get lower,I am gonna look for a cheap 5hp and maybe do a swap eventualy.

 

[RARECRX]

Maybe clutch is shot? I had the same problem on my cat before.. I picked up a new comet clutch and this thing is geared for top end 13/40 tooth and I am 240Lbs and it moves me quite well even from start.
I only have a 3.5HP also.

 

[minibikin']

My 3.5 Briggs on my Cat has a 10t clutch and a 60t sprocket. I'm 210 and it pulls out well and has 30-35 mph top end without revving the balls off of it.
You may have a clutch issue or the motor is just tired?

 

[supernova]

Any vintage minibike is collectable! Some more than others!

 

[oldsledz]

I did my first mini in ski-doo colors also.

It takes a lot more power to move a 230 pound rider on grass than it will on a paved road.

 

[follow my ROTAX]

I see I have a 11 tooth on the clutch and a 67 on the rear.I hear the clutch squealing when it is getting going.I am also wondering how tight the motor is.What is the compression on this old motor.I took the carb/gas tank unit ( bolted together) off and cleaned it it looked clean.Boy not much to that.What is the purpose of the swirly metal thing on the end?
I am thinking of getting a new 10 tooth clutch and try that.What brand clutch is better.is it worth spending more for the better one? Shoud I get a bigger rear?

 

[follow my ROTAX]

 

[minibikin']

If you change rear sprocets, the Cat's are a one off bolt pattern I believe. You would have to buy a blank with the correct center bore and drill/have it drilled with the correct patter. If the clutch is worn then I'd start buy replacing that. If you are doing more yard/trail riding, I think I'd add a jack shaft or T/C. :grind:

 

[follow my ROTAX]

If you change rear sprocets, the Cat's are a one off bolt pattern I believe. You would have to buy a blank with the correct center bore and drill/have it drilled with the correct patter. If the clutch is worn then I'd start buy replacing that. If you are doing more yard/trail riding, I think I'd add a jack shaft or T/C. :grind:

I am new to this hobby.Explain what a jackshaft would do for me,please.I looked at them for sale and am wondeing how they work.

I looked at some pics in here and now I see what you mean.Putting a jackshaft in would allow me to run much lower gears? Correct?

Does the CAT 400 have room for all of this? It looks like I would have to do some fabricating,which is no biggie.

 

[minibikin']

I am new to this hobby.Explain what a jackshaft would do for me,please.I looked at them for sale and am wondeing how they work.

I looked at some pics in here and now I see what you mean.Putting a jackshaft in would allow me to run much lower gears? Correct?

Does the CAT 400 have room for all of this? It looks like I would have to do some fabricating,which is no biggie.

Yup ,with a jackshaft you can have almost infinite adjustablilty in gear ratios. There should be room on a 400 for one. The only real fab work would be welding the tabs to the lower frame rail. There is another set of tabs that carry the bearings, but the bolt to the weld on ones. Slide the keyed shaft through, a couple of collers and sprockets and....bada bing. Wheelie time.:laugh:
Also, if you are having trouble locating the original Cat brake caliper( I can't see if yours has it in the pic) you could mount a disc or band brake on the jack shaft.

 

[follow my ROTAX]

Thanks for the info,yeah it has the disc brake on it with an aluminum caliper. I think I am gonna try a newer 5hp with the 10 tooth and see what happens. the OLD briggs on mine now looks real OLD,not sure of hp either.Maybe try to sell the OLD briggs,not sure if there is an interest in real old briggs motors or not,then keep my eyes out for my new 5 hp.

 

[minibikin']

I might be interested in the Briggs depending on the shipping. If you decide to get rid of it, let me know your price and we can go from there. I also may have some stuff for trade such as a jack shaft kit and so on.:thumbsup:

 

[oldsledz]

is there a model number marked on the engine?
most of the time with that small tank the engine is only 2 - 3 hp.

 

[follow my ROTAX]

is there a model number marked on the engine?
most of the time with that small tank the engine is only 2 - 3 hp.

I started a post on this engine in the Briggs and Stratton forum with all the numbers and close up pics.

 

[TomH]

the first thing you need to do is :
1. durability test, run it all day (sometimes with a friend,its gruling!)
2. make sure it doesnt sit too long as they tend to not wanna start.
3. tell the wife its gonna be a great investment so you can get more.(retirement fund)
4. next stay online here with other people to support your hobby..(investments) as i do,
my grand kids will be born in a few years and you cant start too soon!

That is priceless. I need to write this down for that magic moment I know is coming.