Baja Warrior(?) 196cc Stock Throttle Assembly Setup

#1
Hi, new member here. I picked up a mini bike off CL a couple weeks ago that was just listed as a "baja mini bike". No plastic can, repainted with a rattle can, and needing some reassembly. I've concluded it's a baja warrior (MB165?), with a 196cc stock motor. I have most everything put back in the right place, but for the life of me I can't figure out where two of the four springs go. I got the throttle limiter screw and spring back in place, and what I believe is the governor spring on the linkage, but the slightly heavier gauge spring shaped like the governor one, and a much bigger spring shaped like a trampoline spring are lost on me. Currently the bike fires up in one to two pulls, but the throttle doesn't give it gas, so I know I'm close.

Basically signed up here in hopes someone could share a clean picture of a stock assembly for me. Can't find anything online, and the part list baja has is very low res and possibly wrong, if me buying a M12x1.25x25 bolt for the clutch is any indication of either of these issues. Also, sorry if there's a post for this very issue. I tried using the search function but nothing popped up for "throttle assembly", and I'd like to get this running this weekend.
 
#3
Did my best to get some good pictures of the setup. The springs that are obviously wrong are the ones in question. was just seeing what sort of tension I needed to actuate the throttle. My more sincere attempts didn't result in much better, I'm afraid.
 

Attachments

#4
These are of a Ducar 212, but it should be set up roughly the same. The spring in the governor arm will be in a different location due to these engines being governed to over 5,000rpm out of the box. The pics are all of the same engine. It just has a different pull start housing in the 2 pics.
 

Attachments

#5
@Strigoi These are great pics! This clears up the second spring for sure, and the final spring appears to just be a return spring so it can hook onto anything from the looks of it. Thank you so much for the assist!

Update: Wind is howling so I didn't mess around too long, but after hooking the springs up, I'm still not seeing any motion. I can tap the linkage going to the governor and it wants to run, but throttle still gives me nothing. it honestly seems like there's a missing linkage from the throttle assembly that should to go the governor, or something.
 
Last edited:

SAS289

Well-Known Member
#6
The spring that connects to the blower housing.... That reminds me of what some may do when they pull the governor and run it with the stock linkage. The spring is added there to move the throttle back to idle because the governor is no longer there to do it.

If you try matching a stock linkage and run without that spring with the governor removed the engine may overrun. Make sure you test with the back wheel off the ground or chain off.
 

desert rat

Well-Known Member
#7
This may not solve everything you got going on but will give you insight on movement of the arm. You may be able to link off of it to find other videos that will get you fixed up.
 
#8
I appreciate the replies, fellas. I took another look and fussed with some stuff for a bit. My conclusion is there is no reset on the governor. I'm awful at explaining things, and not a mechanic so I always fail to use the right terminology, but essentially with all the springs off, the governor arm does not move forwards to the "neutral" position. It also looks like no matter what I do, none of the springs assist in putting it back that way, only further pull it towards the throttle assembly. Further, on this setup it looks like the governor arm needs to be pushed away from the throttle assembly (into the neutral position for the predator 212 in the video desert rat linked) in order for the carb to toggle. I'm guessing something else is at work than just the springs at this point. Might explain why it was sold in the first place. I'll have to look into it more this weekend.

Currently with or without the biggest spring on it, and the spring from the third image attached to the throttle assembly base back to the governor arm, it idles with choke on. With choke off, it tries to slowly get up to full speed, but throttle still does absolutely nothing, as it in no way currently pulls on the governor arm (or pushes). Without something like reversing the carburetor toggle (making the current position the 'open' position, and setting up some sort of spring running from the frame up front back to the governor arm to keep it pulled closed without throttle), or swapping the throttle assembly 180 degrees and seeing if that isn't the issue, I'm out of ideas aside from just ripping the motor open to get some idea of why the governor isn't springing back. Could very well be damaged/removed for all I know.

@SAS289 the spring going to the exhaust housing was my own notion. I thought maybe it would help the throttle return, and it's far too big to really go anywhere else. I'm partially convinced it's not even to the bike at all, just some random part the prior owner wasn't sure where it came from, so it got put in the "mini bike parts box". The many joys of buying used things. I might just break down and buy a predator if this weekend proves fruitless. I know the motor can be fixed, but I need it running sooner than later for chores around the property, and those predators are cheap enough and what with the deal I got buying the bike from CL I can justify the quick fix. It'll give me time to properly look at the current motor and figure out what went wrong where.
 
#10
How far do you plan on going with modding this engine, if at all?

If you're willing to spend the money on a billet rod and a billet flywheel you could remove the governor completely. Add in some 18lb springs, a header and a 22mm Chikuni carb setup and you'd have a pretty stout little engine. Might as well add in a small cam and a flat top piston since you'll be inside the engine already.

Personally, I hate the governor and it gets fully removed from any engine I have and billet parts get installed.
 
#11
@Strigoi I'm not really interested in modding it since I'm not needing more top end. Obviously I'll do what's needed to get it working if it's not such a high price that buying a new motor becomes cheaper. I like tinkering to a degree but reverse engineering someone's mistakes is never fun. The reason for this bike, is to have a bike with relatively inexpensive replacement parts, that I can find at any store, hook a trailer to for hauling water/feed/seed/etc around the property. Sorta like those old tote gotes.

@desert rat I appreciate it. I'll take a peek this weekend since now I know I need to get a better understanding of thing. Once I strip everything down and check the setup of the governor arm, I'll know if I'm in over my head or not. Just a shame my work day leaves me very little for anything else once I'm home.

Anyone know where you can find the plastic chain cover for these things? I'm not crazy for how close my leg sits to the chain without anything to keep my pants from getting caught in it.
 

SAS289

Well-Known Member
#12
I should have seen this before but you are missing the throttle spring. It goes from the manual linkage to the governor arm.

With the engine off if you twist the throttle on the handlebar the governor arm does not move at all, correct?
 
#13
@SAS289 Correct. No action on the throttle end to the governor. I attached the spring in my pic 2, to the governor mimicking the picture 4 that Strigoi uploaded. From the governor to the plate of the throttle assembly, but it does nothing, since the governor arm naturally hangs back like that. Nothing pushes/pulls it AWAY from the linkage currently.
 
#15
@desert rat This is good info. I've only messed with things while it's off. when I power it, I only do so while on top of it since I don't want to witness a ghost rider. I think this weekend will yield results. Thanks again for clearing this up.

I picked up a predator 212cc motor since my local HF finally got them back in stock. At some point in the distant future, I'd like to fabricate my own frame for a bike, going for a heavier duty frame that's wider in case I want to put a 420cc in it.
 

SAS289

Well-Known Member
#17
That would work without the governor. Not so well governed. The small spring connected to the carb would defeat the startup function of the stock linkage plus governor setup.

Bottom line here is that if you have the governor and want to stay governed, duplicate the stock throttle linkage that these engines came with when new.
 
#19
Thanks for all the replies and assistance. I got it up and running finally, with the big breakthrough being from @desert rat 's tip about the governor and how it works. I linked the medium spring up to the governor arm, and back to the throttle assembly arm, not just to the base of it. Had to play around a little with what slot I had it in. First setup was too far on the spring, so it ran the second I took off the choke. Next setup seemed like more of the same, but after giving it throttle real fast and letting off, it seemed to work just fine afterwards. I'll lubricate some things, and make sure none of the springs are snagging on anything, but I consider that a success. Next thing to deal with is welding the left peg back on, getting a replacement gasket for the gas tank fill port, and finding/fabricating some type of cover over the chains.

PS: governor is there and works as it should.
 
Top