HondaCB650

Mechanic went back into bike to tighten engine block bolts to stop a leak, then suddenly the engine is knocking. They're telling me that that is how it sometimes happens. Idk. They were screwing me from the get go and at this point I can't tell fact from fiction. Anyway, they're offering to replace the engine and cover the labor. So far only finding iffy replacements with a lot of miles and then a good looking low mileage 92' CB750. So I'm wondering if it's possible to swap this engine in and if so how much difficult it would be.

If you can weld, you can make anything fit. I'm not saying it won't bolt right in, I just have no experience with such things.

juntjoo wrote:Mechanic went back into bike to tighten engine block bolts to stop a leak.

If you want to have a tight engine, you have to clean surfaces carefully before reinstall and follow the stepwise torque schemes with a small enough torque bolt. Try tightening bolts at a CB650 head cover or head to stop a leak from outside will usually just scrap some threads and require some more helicoils.

Is this again the Harley guys you reported in viewtopic.php?f=3&t=14692 ?
Anyway my impression is something really bad is going one there. For whatever reason.

Basically one could make everything fit (and I bet it would not just be done with the engine) but this effort makes no sense if you just want to have a bike that runs. Moreover, if you would these guys let try that, you quite certainly will end up with a scrap frame, too.

Sorry but from my point of view you either find someone that really has some idea of old CB's, learn doing it in a proper way yourself or better forget about old bikes as quick as possible.

Volker_P wrote:

juntjoo wrote:Mechanic went back into bike to tighten engine block bolts to stop a leak.

If you want to have a tight engine, you have to clean surfaces carefully before reinstall and follow the stepwise torque schemes with a small enough torque bolt. Try tightening bolts at a CB650 head cover or head to stop a leak from outside will usually just scrap some threads and require some more helicoils.

Is this again the Harley guys you reported in viewtopic.php?f=3&t=14692 ?
Anyway my impression is something really bad is going one there. For whatever reason.

Basically one could make everything fit (and I bet it would not just be done with the engine) but this effort makes no sense if you just want to have a bike that runs. Moreover, if you would these guys let try that, you quite certainly will end up with a scrap frame, too.

Sorry but from my point of view you either find someone that really has some idea of old CB's, learn doing it in a proper way yourself or better forget about old bikes as quick as possible.

You're right. Yes, same guys. I've already brought it to another mechanic a couple towns away who specialize in old bikes.

Good idea.
Now someone at the Harley shop lost a bet.