1997 Evo loses power

[nascar7613]

1997 Road King, stock Evo 80" engine. The wrist pin retaining ring had broken, the wrist pin shifted and took out the rear cylinder and piston. Replaced the cylinder, piston, rings, wrist pin on the rear cylinder. Cleaned the metal shavings out of the engine as much as possible, such as removing the oil pump and cleaning it, blowing thru the oil lines, ect. Ran the bike about 20 miles and changed the oil again. The motor is quiet and runs fine when I first start out, but when the bike gets fully warmed up, after about 20 minutes, I can hear some engine noise, it has a serious loss of power and the oil light comes on at idle. There is more heat coming off the engine then there should be. It must be loss of oil pressure, but I'm not sure what is causing it.

 

[Jack Klarich]

Do a compression test first, clean the overhead tappet screen, use a master gauge @ the oil pump what do you read? If you have NO pressure or very very low pull that pump off and inspect and clean out all passages, check gears and replace seal and new keys. The pinion gear drives the oil pump, I have seen the shafts seize up tho it is rare, you may want to pull the cone off and check in there also

 

[nascar7613]

Thanks for your reply. I have pulled the oil pump apart, everything looks ok. I replaced the keys and seals with a James gasket oil pump kit. There was quite a bit of metallic residue in the oil even after changing it twice. I wonder if the oil loses it's viscosity charicteristics if it has metallic residue in it after it comes up to full tempurature. The bike runs and sounds great until it gets fully warmed up. Would a high volume oil pump help the problem, or is there something else causing the oil pressure loss.

 

[Jack Klarich]

There may be some metal thrown thru the engine you cannot see, it could be blocking oil going to the tappets? Recheck the overhead tappet screen do you find any trash here?

 

[Fastlinnie]

I would say if you remove that rear cylinder you will see that the piston is trying to gauld up.Most likely the rear rod has too much side play from wear that's why the wrist pin lock came out and it will again. Bottom end needs rebuilt .