Problem with after market driven pulley on trail master

[Ryanhodge2715]

I bought an new fly wheel so I got a tube of grinding compound. Was curious if I should use it with my new driven pulley as well. Or if that should even be necessary to do. It said 5/8 on Amazon, but could only get about 1/2 on the shaft took a hammer an hit back side of the jack shaft to help work it in but was soo tight after another 1in I stopped an could hardly get the thing back off. Should I try grinding with original pulley to possibly shave shaft down some or do I need a different one.

 

[Ryanhodge2715]

I also put a new air in take and exhaust. Fly wheel come with random assortment of jets. What size do yall recommend me using. And last thing. With fly wheel,exhaust,air intake,and larger jets I should be ok with stock rod an what not right?

 

[Ryanhodge2715]

An you guys always tear me apart on hear. I am noooo professional at all. Got this as a project for me and my son. My spelling and punctuation suck. An I know the engine is a filthy mess just a cheap beater cart I got on a deal on market place. Take it easy and just enlighten a brotha lol.

 

[Denny]

I’ve never run into the problem you are experiencing. Maybe try cleaning the shaft up with some crocus cloth or sandpaper and lube the shaft before inserting it. Just like another activity. (Ha, ha)

 

[panchothedog]

Don't hit anything with a hammer. Remember, every part was made in China. Quality control and machine work both leave a lot to be desired. Take some medium grit sandpaper ( 320 ) and polish the outside of the shaft. Then do the same to the inside of the driver. Pay attention to the gruve for the keys way. They are usually loaded with burrs. Once EVERYTHING is slick and shiny, slather on some axle grease. Can't tell you how many times I have had to do this with almost all new parts. A # 28 or 29 jet will work. With a torque converter and stock valve springs, your engine probably won't spin fast enough to hurt the stock connecting rod.

 

[Master Hack]

Denny is an expert at polishing his shaft. AND his advice is always solid. You should listen up.
Pancho probably hit on the answer, BURRS! Chinese yak tooth tooling does not often leave a ideal surface.

 

[Master Hack]

crocus cloth

WTF is that?
Hey kids! For fun go down to Ace hadware and ask for a crocus cloth!
You'll get that blank dumb stare!
They probably keep it with the musket balls.
I don't think i've heard that in 50 years.
They still make that?
is it different than emory cloth?



C'm awn Denny, just HOW old are ya?

 

[bob58o]

Keep your cloth away from my crocus, said Marcus Dennius Crassas.

Leave me with my femur and conch.

 

[Denny]

Same thing just by a different name. Old enough to know better and not care!

 

[Master Hack]

I coulda done without the optical pollution!

 

[Ryanhodge2715]

I got it on! An the jets it came with was only 3 an emulsion tube labeled 85 90 an 95
. 85 seems to run best so just went with what I got. An the valve springs it came with are 26 lb is that to much for my set up? What's pros an cons to heavier springs?

 

[bob58o]

Cons.
It eats into the energy available to spin the crankshaft. The heavier the springs, the more energy required to compress them.

The heavier springs put more strain on the valve train system.

Pros.
The valves seal against the seats with more pressure.
The valves are able to close more rapidly as the camshaft lobe moves from under the lifter.
The engine can turn higher RPMs before the valves start to “float”

What camshaft are you running? The cam will most likely have recommendations for valve springs.

Stock rod and stock camshaft and 26lb springs are probably too heavy. 18 or 22lb are available (I think… depending on engine type) if you are already floating the valves and need to rev higher than 5200-5400 rpm. But at these rpm’s, connecting rods let go sometimes. It used to be the standard recommendation here that if you upgrade the springs, you should upgrade the con rod as well.

You can adjust gear ratio so you don’t rev so high.

 

[Ryanhodge2715]

Interesting good stuff man. An it's whatever us stock on Lil trail master mid xrx it's like another clone of the predator. This cart has a huge sprocket on the axel Def after market from the folks I bought it from it goes threw where the chain guard plate is I haven't counted but probably like 80 + tooth to a 9 tooth. That will be a new endeavor for me I haven't actually opened the engine yet just little bolt on stuff.

 

[bob58o]

Interesting good stuff man. An it's whatever us stock on Lil trail master mid xrx it's like another clone of the predator. This cart has a huge sprocket on the axel Def after market from the folks I bought it from it goes threw where the chain guard plate is I haven't counted but probably like 80 + tooth to a 9 tooth. That will be a new endeavor for me I haven't actually opened the engine yet just little bolt on stuff.

If you got big tires and a “normal” clutch 80 : 9 might be correct for you.

Standard valve springs with stock camshaft should get you to around 5200 RPM. If you got 18” tires, 5200 RPM is 31 mph.

Using a clutch with 10T might get you an extra 4-5 mph at 5200 RPM.

Gearing for 30-35 mph at 5200 rpm with a standard clutch and 200cc clone is probably where you want to be.

If you went with 12T or 13T with the 80T you might get to a point where you don’t have enough power to reach 5200 RPM. For example if valve float occurs at 5200 RPM and you are geared so 5200 RPM is 45 mph a stockish engine might never get there so you don’t need to worry about upgrading stock valve springs or floating valves. Unless going down hill…

 

[Denny]

Bob’s real good at cypherin maths.

 

[panchothedog]

bob58o, you are exactly correct. I've got 4 tall ( 18" to 20" ) rear tire karts. All of them running torque converters. 3 of them small blocks. Once they get to about 38 to 42 mph that's it. Gear them higher and they lug down ( lower rpm ) gear them lower and they wind up tighter. But top speed is always about the same. I got a built 301 ( all of them are built ) and because of increased torque, it will wind up tighter and reach about 50 mph. I think the torque converter will keep the
O P from over reving the engine. Once they get into high range ratio, the engines just don't have anything left.

 

[Willie1]

I bought an new fly wheel so I got a tube of grinding compound. Was curious if I should use it with my new driven pulley as well. Or if that should even be necessary to do. It said 5/8 on Amazon, but could only get about 1/2 on the shaft took a hammer an hit back side of the jack shaft to help work it in but was soo tight after another 1in I stopped an could hardly get the thing back off. Should I try grinding with original pulley to possibly shave shaft down some or do I need a different one.

I ran into the same issue using generic offshore parts. The input shaft for the Asian F-n-R gearbox was .627, or about .002 oversized and had to be polished down. I used CROCUS CLOTH to do this Both the 6" and 7" - 30 series driven pulleys I had on the shelf were about .003 undersized and I had to run a hone through them to get them to fit.

My (nit-picky) understanding of the term "crocus cloth" was that it was cloth backed strips coated with fine abrasives for polishing, as opposed to sandpaper, which was paper backed with coarser grit to remove material.

 

[bob58o]

Oh man I didn’t read enough (about TC and gearbox)

80T : 9T with a TC and a gear box?
This engine might rev to the moon.

with out the reduction from gear box because I don’t know the ratio, 80 : 9 with TC in low gear is like 24 : 1.

this puppy should rev up fast. You might need to get an ARC Con Rod and some springs.

With the final drive ratio, you may be hitting valve float RPMs before reaching top speed of the kart. For example, if the final gear ratio is 10 :1, 18” means only 28mph before reaching 5200 RPM. The small block engine can probably do more. Say 38mph at 5200 RPM

To travel 38mph at 5200 RPM with 18” tires you need a final drive ratio of about 7.5 : 1.

current…
sprocket ratio = 80/9 = 8.9
Pulley OD ratio = 0.9
Gearbox Ratio = 1.3 ??? (Not sure)

High Gear = 10.4 : 1

You might be better off with a 12 or 13T sprocket instead of the 9T.

80 / 13 = 6.15
Still 0.9 TC overdrive rstio (with 6” pulley)
Still same gearbox ratio (1.3 : 1)
Final drive ratio = 7.2 : 1

5200 RPM = 37.5 mph

 

[Ryanhodge2715]

So what's the ideal ratio for what I got to get the most out of it? I do also have a smaller sprocket from my other carts axel not positive what it us but half the size. I'm really just looking to beat my neighbors stock predator on a tiny frame cart all he has done is locked the governor out an the think smokes my carts *** I know there's a weight difference but I figured with the parts I'd be beating him.

 

[Ryanhodge2715]

Tiers are stock if I had to guess I think 16s there not crazy big