Protolite MXT 22hp Predator 670 engine

[ProtoDie]

Just finished putting a Predator 670 engine in one of our MXT kids buggies for a customer.
electric start , CV-tech cvt clutch setup.

have not tested it outside the shop yet, but it really has low end power inside the shop

8:1 gear reduction, should have a top speed 55-58mph
20" tires

hope to get some video Saturday,,, snow is melting here

My son is chomping at the bit to test drive it on our snow covered track

here are some pics

[MASCMAN]

Awesome! Why wait for the snow to melt...get on it!

[ProtoDie]

Awesome! Why wait for the snow to melt...get on it!

lol, my test driver is at school then basketball game
I asked wife if I could go get him from school to test drive for me,,,,,,,nope

[Wheels]

lol, my test driver is at school then basketball game
I asked wife if I could go get him from school to test drive for me,,,,,,,nope

man up buttercup... go get your son if you want to.








just kidding. my wife is the boss too. looking forward to hearing about the test drive.

[antioch]

Looking forward to how this one runs.... Love that MXT frame.

[plkracer]

Time to change the stickers to mxt 670!

[herman pahls]

Looking forward to the test results.
I am curious why this build only gets 8-1 reduction and the Vegas buggies got 13-1 in the reversing box.
Are the rear tires that much different in diameter or am I missing an important detail like you are not limiting the top speed to 40 mph?
What size and quality of chain are you using.
I am curious how you adjust those 2 chains.
The rear axle and driven shaft appear to non adjustable.
Does that idler shaft somehow adjust up and down and forward and backward to adjust both chains at the same time?
Thanks
Herman

[ProtoDie]

Thanks guys, yes time to change the stickers to 670

motor adjusts on the motor plate to the first shaft which is fixed / welded to the motor plate. Motor adjustment on the plate is for belt tension

motor plate slides and adjusts on the swing arm to which the rear axle is fixed
this allows for chain tension adjustment on one chain


2nd shaft / bearing assembly is on the bottom of the motor plate and moves with the motor plate and it has adjustment bolts to slide forward or back independent on the motor plate and then lock into place

this allows for independent adjustment of each chain separately

Vegas buggy has 13:1 because it is heavier and 2 person and needed to limit top speed to 45mph

MXT buggy has smaller tires , lighter, single seat and do not need to limit top speed to 45
These are for kids who bracket race sand drags at silver lake
so I set the top speed at 55-58 mph

with the dual jack shaft set up , I can get to 15:1 if needed.
but the drag strip is 300' long and at 8:1 I am trying to maximize low end torque and take off, with a top speed for their application


chain is 428

[Ironleath5]

That's one bad ass little buggy... What does it weigh I can't wait for the video

[herman pahls]

Jody
Thanks for the detailed explanation of how the belt and 2 chains adjust.
Taking a closer look at your photos and noticing the slotted holes it all makes sense.
To help with these builds I just ordered a bigger metal lathe and unfortunately for my Visa card it is becoming clear that a milling machine is also needed, especially to make all those slots.
Is there a poor mans way to make slotted holes other than drilling multiple holes and filing out the slot?
Your website says you do not sell sprockets.
Are you selling the #428 sprockets you used on the 22HP MXT or are those one off for this project?
Herman