I received a 99-01 (not sure yet) Cat 300 yesterday. I plan to make it a mud/trail bike.
I have a wireless winch I will be putting on it. also going to start looking for spring spacers and maybe larger wheels/tires and maybe look at doing a small snorkel on it. All it needs at the moment is a good intake cleaning and a few CV boots. Are there any quirks or anything I need to know about these old cats before getting to work on it? Anything that commonly goes wrong that I can replace or be prepared to replace?

 

That unit uses the same engine/drive train as the Suzuki King Quad 300. I have had several of both. The suspension,
front and rear, uses wishbones, and the rubber bushings wear out. AC requires you buy the whole wishbone (x4) to
repair them ($$$). I had one unit where I replaced them all with acetal bushings, custom-made.

 

Thanks for the reply. I will take a look at those bushings, I also have the means to have a set custom made. I have heard to pay very close attention to the batteries on these units because the ignition system runs on battery power until 2k rpm then the magneto after that. Would it be productive to look into running a dual battery system?
Are the CVs hard to replace the boots on? I have to replace 3 of them (1 front and 2 rear)

 

I do not recall anything different about the AC half-shafts vs. any other make. There is a snap ring you have
to remove, then the CV joints come right apart. You do not have to buy OEM boots. If the ***** or channels
are warn from dirt, toss it.

Same with the voltage reg. Non-OEMs are cheap, and I have had a number of dead OEMs. The AC and Suzuki
quad CDI boxes need a signal from the stator and the battery to work. I have not had the battery problems you
describe.

 

I was able to take a look at some stuff tonight.

The Carb seems to be brand new, The idle was not set at all, it was bottomed out. The fuel screw was about 1/32 turned out (its also super hard to get to with the carb installed... is there a good setting to put it to?) and the needle was set on the second from the top. There was also not an air filter like at all... luckily there is an intake screen. I ordered a no-toil oiled clamp on filter for it. In the meantime the carbs gonna get a good cleaning...

I pulled the plug out of curiosity and it was jet black. new plug is ordered and on the way.

On the carb there are two barbed nipples on the intake side (picture). when I removed the carb there was a hose connecting those two, is that correct? there is also a 90 degree nipple on the engine side with a cap on it (picture) what is this and should it be capped?

I checked the engine oil and diff oil and there was no water present so I got that going for me. The battery looks relatively new and has good charge. There are two plugs in the front one 3 wire and one 2 wire. the 3 wire one is only powered when the lights are off. the 2 wire one only gets 8 volts...

Once I get a chance I am going to wash all the mud off the wheeler to get a better look at the wiring and add my winch and swap the lights for LEDs. Also wanting to set up a gauge pod on the handlebars. It seems like running a snorkel is going to be pretty easy since the front is very open.


capped nipple

these two were connected together

some filter....

airbox luckily wasnt filled with mud, just a little dusty.

 

Looks like a Chinese carb, maybe a Koso, or unbranded. Too bad, the OEM is much much better. At least it
has adjustable main jet needle. I also find that KeiHin PD jets work in many Chinese carbs, Open the
float bowl to see what it looks like. They often take a lot of adjusting to get them running right. You may have
to customize the cold-start enrichening valve cable connection as well.

The PO probable gave up.

 

I was able to take a look online and find the carb I have. It seems it is a universal style replacement for AC and Polaris 250-500 engines. I found a closer-to-stock carb for $44 >>
(https://www.ebay.com/itm/Carburetor-...e/173625760509)

I think I may get that one and see if it works better, the stock carb is $200
I've tuned quite a few carbs so I know how hard it is to get a carb that is not meant for a specific engine to work.

I am going to go ahead and adjust the valve lash as well, it seems very similar to my XR600R in adjustment style. Is there a good place to get a pdf manual for this unit? I have always been able to find honda manuals but AC seem harder to find.

Also the unit has 03/98 stamped on it as the manufacture date, does this mean it is a '99 year unit?

 

One more thing. I am looking for tires. Is it true that I have to stay with the same ratio front-rear or can I do 26" all around? it has 24" fronts and 25" rears at the moment. The rears are decent but the fronts are super worn down. I may just get new fronts and do 25" all around.

 

If the carb looks uncorroded inside, you might as well get that one going. Another Chinese unit will
require the same efforts. I find them usually too lean, and require at least a new low speed jet of a bigger
size. Sometimes a PO drills out he old jet and makes it too big. PD jet kits are cheap. OEM KeiHin carbs
are usually $500 or so, new. Same for Mikuni.

As for the tires, don't change the OD. They are designed to run at the same road speed in 4WD. You
don't want a lead/lag ratio, like they do with 4x4 tractors.

 

The carb looks brand new. I will try to use it instead of a new one. What are the two tube fittings for that the PO had connected to eachother?