87 Suzuki Quadrunner 250 topend problem.

Phonce · 10-29-2009, 10:17 PM

Hi , I am new to this site, so HI everyone. I did some work on the topend of my Suzuki 1987 250 ATV ( ring job) and it's not getting any oil to the Camshaft and valves, What do you think I may have done wrong . Do the oil get to the head by the rotation of the timing chain ???. The engine runs rough when used for a while and I took the valve adjusting caps off and there isn't any oil getting up there. If the timing chain sliders weren't in the proper place , could this be the problem???.

*DirtDemon* · 10-30-2009, 02:13 AM

I would start by checking the oil pump. Then all the oil passages and depending on what your machine uses, a hollow knock pin, or a transfer tube to get oil from the crankcase to the head. There should also be oil gallies in the rocker shafts, they must be lined up with the gallies in the head so that oil can flow through. If you don't have a manual, get one. I don't think the chain slides should effect oil transfer, but if you are unsure if you have them in right, I would double check to make sure they are in right.

Phonce · 10-30-2009, 08:55 AM

Hi Josh , thanks for the comeback. The only place where oil can pass is the space where the chain connects to the camshaft. the camshaft has three oil holes of which one was blocked so I redrilled them a little larger and the cam heated up and snapped off. when I took it apart it didn't have any oil on the head and the cam had a blue tinge on it.The cam oilholes can only line up according to the setting of the timing. As for the oil pump, I don't know how it has any connection to the valve head since there isn't any tubes or openings leading to it. This is a mystery Charlie Brown LOL.

Phonce · 10-30-2009, 11:08 PM

I don't see a tube to transfer the oil , what is a knock pin please?.

*DirtDemon* · 11-02-2009, 08:52 PM

A hollow knock pin is basically a line up dowel that goes around a cylinder or head stud leaving a space around the circumfrence the stud. Not only does it help keep things lined up properly, but they also allow oil passage between the crankcase and head by allowing oil to pass along the stud through the cylinder. Do you have a manual for this machine?

Phonce · 11-02-2009, 10:18 PM

Thanks for the info , I do have a service manuel but I havent come across anything about the oil passage to the head yet but I did find the oil passage on the rocker arm part and replaced the cam. the oil passage isn't plugged but I did check the screen filter at the base of the engine , it was completely plugged off. I started the machine and let it run for two or three minutes( after adjusting the valves) with both valve setting caps off and it still isn't oiling. I don.t this machine has been pumping oil since I bought it used 3 yrs ago LOL. Is it possible the pump may be damaged after not pumping so long?.

*DirtDemon* · 11-02-2009, 11:32 PM

It is very possible that the pump has been damaged from being run dry. Also, there is a gear that drives the oil pump and a small pin that works in the same manner as a woodruff key, it is possible that the gear is loose or damaged, or the pin could be broken or missing. I would definately inspect the oil pump and the parts that drive it to make sure everything is working ok.

Phonce · 11-03-2009, 12:24 AM

I will be checking these things in the morning, I was hoping to have it ready for Moose hunting tomorrow but I guess thats how things go sometime. Well, all I can say is thanks again. I'll let you know what I find tomorrow>.

Phonce · 11-04-2009, 11:08 PM

Hi Josh, I found the problem, A while back I replaced the secondary clutch and made a new gasket and failed to punch out one hole , the one which leads to the valve head. The pump had quite a bit of rough surfaces which I fixed by planeing with very fine sandpaper lain on my tablesaw top, the clogged screen probably caused the wear. The engine hasn't been running well and I blamed it on the top end problem but it still doesn't idle smooth. It starts easy but it hisitates when I use the throttle and sometimes it shuts off. When idling it speeds up and slows down , I checked the gasket which links the carb. to the head and it's ok. It certainly seems to be the carb , I changed the pump already.

*DirtDemon* · 11-05-2009, 02:24 AM

Sounds like you may just need to clean the carb. Take it COMPLETELY apart and clean every single thing well. Take special care with any rubber diaphragms that may be in there, you don't want to damage them. If you find one that is damaged, replace it, that may be your problem. Also, make sure that every passage and vent line is clear. If you find some places that you can't reach with a tool to clean, use compressed air. Refer to the repair manual for fuel screw and float settings, then tune as necessary once you get it running again. You may also want to check the fuel lines, any filters if there are any, and the petcock. Make sure you use fresh fuel. Good luck.