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View Full Version : Questionable oil pressure to head? Need some advice, motor started to lock up...



Velislide
12-11-2016, 09:52 PM
Awhile back I redid the entire top end of a 200M I picked up. Motor was all really clean inside, sat for a long time, cam bushing was semi-seized onto the camshaft. I could turn it by hand, but very stiff and couldn't get the bushing off. Thought maybe from sitting for so long? Not sure. Anyways, I put in a new cam from a XR200R, new oem bushing, had the head all redone with new valve guides and valves all cleaned up, jug was cleaned up like new and bored, honed. New wiseco piston, 87 200X Carb w/ 118 main, and 40 slow jet, etc.

I pulled both clutches and cleaned out some grit from the clutch discs deteriorating. Cleaned out the cases on clutch side and mag side like new, and everything looked great. Oil pump looked like new, and the two o-rings are perfect. I thought maybe the motor had originally seized the original cam due to oil pressure, but doesn't look like anything was wrong.

Anyways, ran great after assembly, can't test oil pressure at head since both heads I have, the oil test bolt is snapped off. Was with a friend looking at some guy selling some atc motors and parts, and everyone of his heads had those bolts snapped off too. Common I guess? But took it for a ride, first day, for maybe 2 hours, ran great. At points I was definitely on the gas to get up some hills. Day two, maybe 15 minutes into a ride, took it down a road and had it wide open to see how it would go, and it really wanted to bog at full throttle, and would just die if kept wide open. After some cranking would fire back up, was guessing too rich, as my exaust seems to be pretty plugged up too, so that's not helping. Get going again, and a few minutes later it starts to die again, shuts down. Go to crank it, and the electric starter could barely crank the motor over. Figured the cam maybe starting to sieze? Or could the forged Wiseco be cold seizing on me? Figured it would have to be warmed up by then, though it was snowing out.

Kind of stuck and not sure what direction to go. Was thinking of using compressed air through the oil ports with the oil pump off? Not sure what could be in there blocking the oil flow. Also, can I use a different head with this jug? Not sure if the machining for the cam journals would be perfect, with an unmatched head and jug? Would like to be able to test my oil pressure at the head. At this point, no idea what caused it to start to sieze. After sitting for awhile, it cranked easy and fired right up.

fabiodriven
12-11-2016, 10:18 PM
Did you use any RTV or anything on the top end during assembly? I've seen people RTV the oil supply shut before.

Velislide
12-11-2016, 10:21 PM
Only RTV I used was on the valve cover, upper half of the head where they mate. And was pretty careful. Should I pull the upper half and take a look?

barnett468
12-11-2016, 10:26 PM
how do you know it is not a weak battery or weak starter motor?

how much clearance did the piston have?

get the broken off bolt out of the head if you want to check oil pressure.

the fact that it turned over easier again after it cooled eliminates the cam from being the cause of this prob but it does not mean that the cam and journals are not f'd up.

if you plan to take it apart anyway then that is the thing to do first instead of guessing what the prob might be.



PREVIOUS KAWASAKI INTERNATIONAL R & D PROJECT ENGINEER AND ATV DEPARTMENT SUPERVISOR
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Velislide
12-11-2016, 10:37 PM
It's a brand new battery and starter motor is like new. After letting it cool down, it cranked perfectly fine. As far as the oil passageways, they were all very, very clean in the jug and head, when I assembled it. Not sure how far I would have to tear down things, to figure this out. Can the head gasket be reused? Or will I have to replace it for sure, if I pop the head off. Not sure how picky these little motors are.

Dirtcrasher
12-11-2016, 11:29 PM
All head gaskets are picky. This fun we have is filled with expenses...

83ATC185
12-12-2016, 09:09 AM
I have successfully reused the MLS honda gasket before but YMMV...you mentioned you had it apart, the little rubber plug in the top of the head that directs oil to the cam could've went awol? :wondering

yaegerb
12-12-2016, 11:29 AM
If you can start it, get it to idle and pull one of the valve caps to see oil misting inside of the rocker box. Or pull the rocker box and investigate the oil passages if you don't want to start it again for fear of seizing. When you say RTV...are you talking about the stuff you buy at autozone...like black permatex High Temp RTV? If so, throw that crap in the trash, go and pick up some 1211 threebond or Yamabond and skim coat the surfaces. You don't need a ton to do the job right.

Velislide
12-12-2016, 06:47 PM
Yep used High temp black RTV. Ordered a new gasket for the clutch case side, so once that come's, I'll pull the rocker cap and record a video in there and see what's happening. The little funny shaped rubber plug is in the head, made sure of that when assembling it.