Clanking sound low rpm
 

ok well last week accidentally dropped to 1st gear at hwy speed and over revd the engine pretty hard. no noticeable performance issue, but this weekend i noticed a clanking or tapping or lite knocking type of sound at low rpm and low temp (not loud either, i just notice bc i'm privy to MY bike). not sure if the over rev caused the issue or just coincidental timing. i had several peeps and mechs listen. at first myself and someone else thought it was a valve knocking, another thought it piston slap, and a knowledgeable buddy/mech thinks it a carb issue. couple others said just ignore it and ride til it gets worse or breaks [Fthat]. the sound is MOST noticeable with a cold/cooler engine at around 2200 rpm. as engine warms it is not as pronounced. also not nearly as pronounced when revving engine up nor when riding, except for when i'm at lower speed turning an easy corner and the engine braking between 2-3k rpm makes it sound a bit more. also miles are at 19k, fresh 10-40w synthetic oil, and no maintenance of valve adjustment as long as i've owned bike which is since 11k miles. any thoughts or suggestions?

Have you verified if its both cylinders or just one? The noise IS comming from the head portion of the engine or case area? It runs and starts normal? No compression issues? Do you have Manual Cam Chain Tensioners or stock? If anything, pull the valve cover from which the noise is noticable and do a valve adjustment check. Im kinda new the the bike my self, but if it was me thats where I would start. Look for anything in the top end as well if / when you decide to pull the Valve Cover.

have you always done synthetic oil changes or is this your first time changing the oil with synthetic?

@squid the sound IS coming from rear cylinder top end. runs and starts normal. no compression issue as i can tell, still strong pull. stop cam chain tensioner. although someone suggested today to check plugs bc he said sounded like a misfire, but i dont believe thats what causing the clanking sound. really think its a valve, but honda dealer quoted me 5 hrs @ $390 for valve adjustments. cant afford that.

@merckid yes always synthetic

without knowing where you are, I would say that is a high price just to check valves. Even if they have to shim them that seems a bit high. It may be worth your while to pull the valve cover and check the tension of the cam chain. You can check the valve clearances at the same time and save yourself nearly $400.00 It's easy and not all that time consuming, and you'll know your bike better.

I doubt that the bike is misfiring due to the fact that it still pulls hard, unless cruising at around 2200 RPM it runs rough. You could always do it your self. The shop manual is on here, if you have some mechanical skills its pretty straight forward to check them. Replacing the shims would be different, but if you find out which valve or valves they are you could cut the cost of labor down.

twist beat me to it.

haha thx guys. i am mechanically inclined, however im def NOT a mechanic. i CAN do the simple stuff i.e. bleed brakes, change pads, change wheels and tires, etc; but as far as digging into the motor i dont know my way around very well. but if someone was to show me i could easily reproduce the work. i'll check out the manual, problem with manual is that i cannot ask it questions for answers.
@twist how would o know the proper tension? same as checking belt tension on my chevy?

@squid in gears 1/2 the engines runs fine at 2200 rpm, but in gears 3/4/5/6 it struggles in the higher gears, each progressively more struggle, which i assume is typical of any manual vehicle.

someone did suggest i just go ahead and buy an aftermarket manual tensioner, but i honestly dont wanna spend any more money than necessary right now- in between jobs. is it really worth it to do that? to do a tune up, what would be suggested i start with or do that is reasonable with finances? i dont mind spending some money if it'll really help, but want it to be reasonable.

what is .020 needle, 48 pilots, PAIRectomy, and CARBectomy?

The .020 needle and 48 pilots are in reference to the carburetor set up for aftermarket pipes that was written up by 8541hawk, the PAIRectomy and CARBectomy are removing all the emissions equipment that comes on the bike. If you use the 'search' you can find out how to remove these. you will only have to worry about removing the CARB system if your bike is a California model.

@squid ah i see, ok thx. i'm in Hou, Tx

No worries. As far as the chain tension goes It should have very little deflection (2 mm or less) atleast thats what use when I did my manual CCT's.

YouTube is a great resource for learning how to fix just about everything. I don't find too many videos about the SuperHawk, but there are plenty of other carb'd V2 Honda videos like the RC-51 etc.....

By deflection do you mean play in the chain vertically or stretch of the chain? If you mean the play, or slack, 2mm is over tightened, it should be closer to 8mm (or 1/4").

To answer about changing to manual tensioners, it is the common consensus that manual tensioners should be the first work done to the bike. Others that have never had a failure of the OEM part may disagree, but those who have had to rebuild their heads far out number them. You can make your own from the stock cct with a few tools and around $5 in hardware if money is tight, just know that you will need to drill and tap new threads, so a drill press is crucial.

I pulled the valve cover and checked the rear valve clearances. They were within spec as best I could tell. When reassembling (and I sure hope I did it properly with the camshaft timing) I noticed the front side of cam chain guide slapped the housing and made closely the sound I was hearing. I wish I knew before disassembling what I know now bc I would've checked the slack in the cam chain. I'm wondering if the chain skipped when I accidentally downshifted to 1st gear at 75mph and abruptly over revved the engine. Maybe the stock CCTs were allowing too much slack in chain. It's hard knowing if I'm taking apart engine properly when I've never done anything like it before.

From best I could tell slack was built up on the front side of rear cylinder causing the chain the hit the chain guard and the guard would slap against the housing. Clanking sound is gone. Thx to 7moore7 for the phone call and giving me instruction and photos when I needed it most. And thx to everyone else on the forum that helped as well.