Honda Motorcycles - FireBlades.org banner

1 - 20 of 27 Posts

·
Registered
Joined
·
28 Posts
Discussion Starter #1
Hello everyone, i am new to the site and this is my first post. I just bought a 94 blade for a very low price because of a strange sound its making in what seems like the front of the engine. I am on a mission to fix it and have a nice running bike. I have searched the forums and found some suggestions but i wanted to get some more opinions.
Here's what i'm working with.....
The bike starts just fine, idles great, no smoke, no sounds. If you rev the bike up in neutral, around 4000 rpms you can hear funny knocking (sounds like a wood stick smacking the engine). Its not very loud when in neutral, but when i am riding in gear it seems to be a lot louder. It starts right around 3500 rpms and doesnt go away until i let off the throttle. Power seems to be ok, i haven't really got on it because of fear of doing more damage.
Is this the sign of cam chain or something more serious?
Thanks......
 

·
Registered
Joined
·
1,628 Posts
:welcome: CAM CHAIN OR TENSIONER, depending on the miles the bike has, if it's over 20,000 mile, it might be both....

or it could be an exhaust leak from one of the head pipes.
 

·
Registered
Joined
·
28 Posts
Discussion Starter #3
Thanks for the quick reply, im going to start taking it apart Monday to try to find the root of the problem. I will go for the cam chain and tensionor first. thanks for the help.
 

·
Registered
Joined
·
28 Posts
Discussion Starter #4 (Edited)
ok, the engine is out and i got as far as removing the bottom end. the bike slips out of second and i found some worn dogs and worn shift fork. i found some copper metal shavings in the oil pan. i dont know if this is from the source of the knocking or what. the cam chain seems really tight. i did find a unusual mark on the bottom of one of the cylinders. its a chunk of metal missing, i dont know if the crank is hitting it or is it possible that the piston sleeve is slamming down to make the knocking sound. i've never heard of a sleeve coming loose. i'll post pics, please let me know what you think. (the pics were taken looking from the bottom of the 1st cylinder....notice the chunk of metal missing)
 

·
Super Moderator
Joined
·
32,034 Posts
ok, the engine is out and i got as far as removing the bottom end. the bike slips out of second and i found some worn dogs and worn shift fork. i found some copper metal shavings in the oil pan. i dont know if this is from the source of the knocking or what. the cam chain seems really tight. i did find a unusual mark on the bottom of one of the cylinders. its a chunk of metal missing, i dont know if the crank is hitting it or is it possible that the piston sleeve is slamming down to make the knocking sound. i've never heard of a sleeve coming loose. i'll post pics, please let me know what you think. (the pics were taken looking from the bottom of the 1st cylinder....notice the chunk of metal missing)
That looks to me like it's broken a rod at some time.
If a new rod was put in without measuring the oil clearance or if the journal is damaged that might explain the noise.
Definately inspect the rod journals while you're in there.
 

·
Registered
Joined
·
1,628 Posts
turn the rotating mass slowly and look to see if there are any clunks in the rotation, as far as the shavings, that worries me, you might be up for a rebuild or new motor.....
 

·
Registered
Joined
·
28 Posts
Discussion Starter #7
thanks for the suggestions, i'm gonna go further into the motor tonight, so i'll let you guys know what i find. if all else fails, i might just have to slap a different motor in there. what years will be a direct fit, and what is the easiest way to find one?
 

·
Registered
Joined
·
1,787 Posts
Check rod and main bearings and also check crank for being straight. If no major problems I would suggest that rebuilding would be reasonable.
 

·
Super Moderator
Joined
·
32,034 Posts
thanks for the suggestions, i'm gonna go further into the motor tonight, so i'll let you guys know what i find. if all else fails, i might just have to slap a different motor in there. what years will be a direct fit, and what is the easiest way to find one?
If it did break a rod you might see minor damage to the top and bottom of the piston, the bore, the combustion chamber and the valves. The piston and valves would most likely have been replaced though. It's even possible that cylinder has been over-bored to repair any damage so measure it carefully.
I believe '92-'95 are exactly the same engines.
'96-'99 are the 918 engine but I believe they bolt straight in still.
I think the 919 Hornet right through to '07 is also an option.
The Hornet is injected so you could also consider a complete harness/ECU/instrument cluster swap and have injection as well :)
 

·
Super Moderator
Joined
·
32,034 Posts
Check rod and main bearings and also check crank for being straight. If no major problems I would suggest that rebuilding would be reasonable.
I'd always prefer to rebuild than replace.
 

·
Registered
Joined
·
28 Posts
Discussion Starter #11
well i think i found the problem, i should have noticed it right away when i took the bottom end off. i have a bad bearing on the 3rd rod, i can wiggle the piston rod on the crank, it roughed up the crank a little. can i get this smoothed out, or am i lookin at a new crank?
 

·
Super Moderator
Joined
·
32,034 Posts
well i think i found the problem, i should have noticed it right away when i took the bottom end off. i have a bad bearing on the 3rd rod, i can wiggle the piston rod on the crank, it roughed up the crank a little. can i get this smoothed out, or am i lookin at a new crank?
Only the crank repairer can tell you if it can be repaired.
Is it blued as well or just scored?
Be sure to measure all bearing clearances to ensure you have good oil pressure. Any one bearing only needs to be a few thou loose and it will reduce pressure throughout the rest of the engine.
 
  • Like
Reactions: ghbzorro

·
Registered
Joined
·
1,787 Posts
Only the crank repairer can tell you if it can be repaired.
Is it blued as well or just scored?
Be sure to measure all bearing clearances to ensure you have good oil pressure. Any one bearing only needs to be a few thou loose and it will reduce pressure throughout the rest of the engine.
:plus1:
 

·
Registered
Joined
·
28 Posts
Discussion Starter #14
its not blue, its the same color as the others. when i run my finger across it you can feel it is a little rougher then normal.
 

·
Super Moderator
Joined
·
32,034 Posts
its not blue, its the same color as the others. when i run my finger across it you can feel it is a little rougher then normal.
It sounds repairable then but it'll depend on how much metal needs to be ground away to smooth it out and whether an over-size bearing is available.
Otherwise it might be possible to metal spray it and grind it back to stock size.
Get it to a crank shop.
 

·
Registered
Joined
·
28 Posts
Discussion Starter #16
i found a guy on craigslist that will sell me the crank, pistons, rods, and bearings and bottom case for $150. came out of a running 94. so if all goes well, this could be the best news i've got all week.
 

·
Super Moderator
Joined
·
32,034 Posts
i found a guy on craigslist that will sell me the crank, pistons, rods, and bearings and bottom case for $150. came out of a running 94. so if all goes well, this could be the best news i've got all week.
Bottom case?
If you mean the bottom half of the crankcase _set_ be aware that making two unrelated crankcase halves work can be a big job. They are sold as a matched set for good reason.
 

·
Registered
Joined
·
28 Posts
Discussion Starter #18
ok, well my case is fine, so i'll probably just use that. i basically just need the crank, 1 bearing, and 1 rod.....those should fit right in mine, correct?
 

·
Super Moderator
Joined
·
32,034 Posts
ok, well my case is fine, so i'll probably just use that. i basically just need the crank, 1 bearing, and 1 rod.....those should fit right in mine, correct?
I assume you mean you'll order a new bearing for the rod you're replacing?
The rod bearing is matched from the rod to the crank so that one is fine.
You will need to order new bearings for the other rods and the mains to match your case and crank and rod codes or by measuring everything up.
The fact that case codes are only stamped on one case of the set means that you don't know what bearings fit the other case when you mix cases.
 

·
Registered
Joined
·
28 Posts
Discussion Starter #20
ok, so if i get the crank, and all the rods, and all the bearings out of a different engine those will work or wont work.
 
1 - 20 of 27 Posts
Top