Hello all,

I've been reading this forum for a while now - great info. So about a month ago I was cut off on the highway and forced to lay down my 1991 Heritage Classic. She slid straight down the highway from about 80km/h to 0 without hitting anything (and so did I). Anyway the left side is pretty scrapped up and insurance is willing to fix all the damage (100% no fault). It's mostly just cosmetic stuff except my clutch linkage was pushed into my front cyclinder causing a decent gauge in one of the cooling fins. Insurance has agreed to replace the complete cyclinder and I understand from the shop that this comes in a cylinder/piston assembly. My question is if I only replace the front cyclinder without replacing the rear cyclinder and doing any other engine work am I asking for trouble down the road? The bike has about 90,000km on it so one cylinder would be running with 0km and one with 90K. The shop is suggesting that I, at the very least replace both cylinder and piston assemblies.

I've always been told that if you don't have to crack open an evolution engine don't. Should I just live with the cosmetic damage to the cylinder and not start tearing the engine apart? If I do go ahead with the repair should I also have the heads and crank looked at while the mechanic is in there?

Prior to the accident the bike ran like a clock - no oil burn, lots of power.

Thanks in advance for any suggestions and advice.

 

I didn't think you could buy a single cylinder. I thought they were only sold in pairs.

Cylinder piston assemblies? Never heard of that either.

If you can stomache the looks, I'd leave that motor intact, before I'd even consider swapping only one of the cylinders. That's insane.

Must have been the insurance people tell you that crap?

You are speaking in km, maybe they do stuff different where you are at?

 

Tough call. I hate things that don't match too. Good chance the engine will go another 55k so let them pay for the one and do the other out of pocket.
Choice two is basically live with it.
Ron

 

As long as I've be around these machines, if you're going to open one rocker-box/head/jug, do both.
If the bottom end is running fine, well, you know: if it ain't broke...
'91 was a good year for the Evo; the bean counters in Milwaukee learned their lessons from trying to cut back on certain areas of the engine in '89 (the cylinder studs would pull out, for instance) and let the wrenches to the talking.
Of course, like Faast Ed says, if you can stomache the cosmetic issue, go with it.
Yes, you can get cylinder and piston matched sets one jug at a time, but I still think it's best to do the pair (jugs are always nicer as a pair...). That way, when it's time to go back to do your top end, you'll be at it all at one time, vs, breaking the top end down twice as much (remove the fuel tank, intake, top mounts, etc.)
roll on
-L

 

Thanks all for the advice,

I talked to the shop today and we're going to replace both cylinder/piston assemblies. While they are doing the cyclinders I'm also going to have my valve seals done as a minimum. Once they have broken down the engine and completed an inspection we'll see if anything else needs to be done.

Originally, insurance was also going to replace the left saddle bag which has a bit of road rash, but i've convinced them to use the money for the bag ($500 replacement value) and put it toward the second cylinder replacement. I did not want to have one brand new saddlebag and one 18 year old saddlebag anyway - i'll live with the little bit of road rash as engine reliability is more important to me.

Funny note - my total cost of repairs is overtopping $8,000 for my 91 FLSTC and insurance is electing to repair rather than write-off (insured value $10,000). I don't understand insurance companies some times as salvage value alone should be around 3,000 !?!

go figure?

 

Thanks for the update!

Too bad you don't have a tc88. The cost of bigger jugs/pistons is around the same as stock jugs/pistons. I don't think they made the kit for evo's.

 

ed is right what you can do is look for a pair of stock evo cylinders and havee then cleaned up and new pistons to match. stock compression.
swap them in and leave it alone