[bjs14]

New to the Vulcan forums, hello everyone. Bought a new to me project, 01 Kawasaki vulcan 800 with "no compression in the front cylinder." I don't claim to be a mechanic by any means, but it interest me and I figured, what better way to learn, plus I got it cheap. I first went to pop out the spark plugs and noticed the front one was broken off in the head. Must be hard to get a compression reading if you cant screw anything in the spark plug hole. So I figure I'm going to have to drill it out, so I should start pulling the engine. Got the engine out. Take off the valve cover, everything looks okay. I decide to turn the engine over to see if everything is working, seems fine. Remove the rocker assembly and cam and take it off the chain to pull the head.

Looks like I'll need a new head with some valves and a piston.

Now my question is, How bad is the cylinder jug? Can I get away with reusing it after using one of those hones that attach to a drill or would it be better to find a used jug as well?

On an side note, the oil looked clean and I couldn't see any metal shavings and I found the head of the exhaust valve in the exhaust, so I'm hoping not to much got past the piston and in the bottom end. I will eventually pull the side cases and check to make certain and give it a good clean, but I am hoping to not split the bottom end. I guess time will tell. All help is appreciated!

 

[btom]

this sounds like the valve rockers were riding tight on shims at Top Dead Center and the front cylinder head got fried from excessive head, classic example of not checking valve shim clearances on all valves every 6,000 miles or 10,000 km. You might have to split the case and do a deep dive inspection on internals, dunno, I've not done that before but I'm a cautious type of person and if that were my motor I'd do a complete inner inspection first, to see if there's anything else going on

 

[bjs14]

Yeah I will be going deeper to make sure. The good news is I found all the pieces. The bike has nearly 40k on it, and I'm assuming the valves have never been checked. But I also want to keep it as cheap as possible that's why I would like to reuse that cylinder jug if it is still safe to do so

 

[btom]

there might be that used dropped valve shim still in there, or it might have ended up on top of the damaged piston

 

[bjs14]

All shims, retainers, and caps are accounted for

 

[btom]

Oh good you found that shim, and for the cylinder jug, there's no guarantee on the good condition of purchasing any used jugs, so I would be tempted to try to repair/reuse what you have, it couldn't do any harm

 

[JohnnyV]

The head can likely be saved. The valve seats will need to be machined/replaced. What I would do is smooth the chamber with a port job first, then cut the seats. The cylinder is pretty bad. A ball hone isn't going to be enough. It looks like you can buy used jugs on Ebay for $50 USD so it's likely going to cost more to have that one machined than just buying a used one and running a ball hone. You'll need new rings. I would order the jug before you order the piston so you know the ID of the cylinder. Most likely its 0.000 but there is a chance it might be something like .0010 where you would need to order a corresponding piston and rings. I'd check the rod but your crank/bearings are probably okay. There is a chance that the rod is bent but even if it is that doesn't mean it won't run. I've had a bent rod in an Isuzu for 30k miles that I still drive.

 

[RB 32504]

I agree with Johnny. Except that I would likely just replace the rod. That piston was hitting pretty hard it looks like. So you’re in it for… new seats, port job, new or use jug in good condition, piston, rings, rod. Take a very close look at the chain and sprocket. Did it skip a tooth? Chain stretched bad enough to replace?

 

[btom]

I am lucky that when I bought my '05 800 that the previous owner kept maintenance records so I could see in the Owners Manual when he last did a valve shim clearance check, keeping maintenance records is necessary I think

 

[MotoMedic1]

Hi BJ,

• Your going to get a lot of opinions on this. So here's mine:
  • The cylinder head is junk. I believe it's junk because the circumference of one of the exhaust valve seats is straight. The other seat has just as deep gouges in it. The amount of cutting it would take to reseat a valve on these seats would exceed the small shim gap limit (too tight) after installing a new valve. A used head in good shape may come with valves installed that are in useable condition.
  • The cylinder would have to be measured to determine cut depth necessary to remove gouge and scoring. If the cut depth would exceed minimum wall thickness then you need a new cylinder. IF it could be cut then BOTH cylinders would require the same bore. Bigger bore requires different pistons and associated parts (x2) and head gaskets. A used cylinder likely won't need bored. A used cylinder could easily be honed and probably use an OEM zero over piston. Measurements will determine what is necessary.
  • The piston is holed. That piece of forged Aluminum is in the engine. Aluminum is soft but can still cause damage. Your engine has a removable oil screen at the bottom. Make sure you remove it and do a search for the aluminum chunk. If you don't see it there then you will be opening the cases.
  • You may consider looking for a good used engine. Machine work these days is VERY expensive. Good machine shops are charging over $100/hr. for the kind of work you would need.
  • Reusing a bent rod....Whether or not the rod is bent is something you need to discover. If it is, it should be replaced. And if it's bent then the top main bearing is probably flat. The main bearing is designed to fail BEFORE the rod. So it would be a good idea to examine them. It takes a lot to bend a rod. But when they do you need to examine everything to which it was connected.
  • Why did exhaust valves stay open too long in order for the piston to hit them is a question you will need to answer before reusing this valve train. Did the cam chain jump and retard the cam timing? If so, how or why? Since both valves look like they were equally damaged I would guess that the cam drove them into the piston. So that means the cam was late (retarded) in closing.
• You have a project on your hands. The satisfaction of rebuilding an engine is almost immeasurable. The reason I still have my '01 GSXR600 is because of this feeling. I bought the bike with 28k on it for $475. Rebuilt the beat to crap engine with parts from ebay. Total parts under $400 which included a used crankshaft. It has 42k (41868) miles on it today.

 

[bjs14]

Appreciate all the replies. Good stuff. I was shopping around looking for parts and found another guy thats selling an 800 with a shifter shaft that's pushing in and has a dented tank for 300 bucks. So I may just pick that bike up as a good parts bike and see if I can make it work between the 2