SOHC.co.uk Forums > CB750
Clutch rattle
Graeme77:
Ill have a check and see how the primary chain adjuster is. Might pull the cam chain tensioner too, make sure its all working ok.
Its about as loud as the exhaust on tickover. Tick over at about 1200-1500rpm, but only had it running untill its just ok of choke, no longer really.
Engine has done 33000 but was rebuilt not too long ago. I have reciets for all the bits, including a cam chain i think.
I have a new chain in some spares but dont know if its cam or primary.
In a way, i'd quite like it to be the primary chain, would give me an excuse to pull the engine apart. I always at least take the head of any old vehicles i buy, just to have a look and see if all is well.
Thanks, ill report back if i have any questions or interesting updates.
K2-K6:
They usually make more of a "rustle" sound if all in good order and much less clattering if that makes sense.
I've known a couple of these in the past that were thrashed beyond belief and they still sounded ok which suggests if you've got any major noise then it's possibly worth investigating if general set-up can't improve it.
They will sound noisier on choke if they are hunting around so need to be properly warmed to clearly judge but they never sound really smooth/whiney like a Kawasaki Z900 for example.
If you've got a lot of transmission backlash you'll be able to get some idea of it by rolling it back and forth in gear with the motor off, it shouldn't really travel that far (assume chain is adjusted well).
Graeme77:
I played around some more this evening and it does sound like a chain.
I took the cam chain tensioner of and its fine. Not that far out when adjusted either so the cam chain should be fine.
Was looking at the carb air screws and the two cylinders which havent blued the exhausts (different subject i know) wernt set properly.
Ill get some gauges, or make some, to balance the carbs later.
Checked timing with a gun (electronic ignition) and its fine.
Im sure i can here a slight clutch rattle, and the main rattle. It does sound like a chain so next step i think is to remove the sump plate and measure the adjuster.
It doesnt like idling under 1000rpm so i think the carbs are deffo out of balance. If i hold it at around 1750rpm the main rattle goes but it doesnt go when just reved. Again, sounds like a chain to me.
Doesnt seem to be any backlash in the transmission. Ive been pushing it in gear to get it at the right point for setting the cam chain tension. The engine had stopped on 2/3, in 1st gear i pushed it to turn it over to 1/4 (no kickstarter). It was TDC on no.4 so pushed it forward more to get it up to no.1.
This only ended up with the bike maybe 1 foot further forward if that makes sense. Pushing the bike forward/backwards in gear to turn the engine has imediate effect.
The engine sounds very sweet, just with an extra added rattle :)
Ill probably pull the exhaust and check the primary chain tomorrow eve so ill let you know what i find.
Unfortunately i cant take it for a run to get it properly warm as i am still waiting for a date for my final test to get my full license :(
Trying to get the bike ready for when im legal.
Graeme77:
Any reason why i cant use a sincle vacuum gauge to tune my carbs?
I have 2, an old snail type, and a 'ball in tube' type.
I used them to balance my cars (sidevalve ford on twin SU's and a zephyr 6 on triple SU's).
Sold the cars but still have the balancers.
Why do i need 4 gauges?
I know adjusting one carb effects the vacuum at the others, but its not too hard to do.
I have pod filters so can i run the bike without the filters and balance the carbs with the one vacuum gauge?
I assume the reason for the proper type of gauges using the proper carb connectors is so you can do this with the air box still attached?
I guess it will run well enough with no air filters to balance the carbs?
Bryanj:
Believe me when i say after 30+ years of doing the job one gauge just dont cut it!
Yamaha used to supply one gauge with a rotary valve to select cylinders and that was a real pain in the A*se to use as well
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version