Topic: CB 750 Project 1 - Rides Well but a few tweaks needed

[timbo750]

Have been for a couple rides now. Just local so I can check on things when I get back, a total 38 miles so far and no oil leaks. Did however have a fuel leak out an over flow after about 5min sitting, it was the first time I hadn't turned the fuel off after grtting of the bike.

The clutch seems a bit sticky after its been idling for a bit and struggles to find neutral. It will find neutral when you first pull up.

I am not sure about how noisy these things are supposed to be, I have read about them being a bit noisy at rattle and Jeff comented on that as well, all the chains are all new, I will reset the cam chain tensioner but there isn't much I can do about the primary chain.

There also seems to be a bit of tappet niose at iddle but again not sure how much is normal.

I don't think the carbs are still quite right. It doesn't always return to a consistent idle and occasionally crackles and pops at idle. The exhaust system has what I would call a straight through baffle and has a nice note but would be giving very back pressure which might be part of the problem.  It crackles a lot when down shifting.

Out today for its longest ride, meeting up a few from the club and heading down to TT motorcycles annual BBQ.

[Terry in Australia]

Don't be too worried Tim, they do rattle a bit, and it's better to have too much valve clearance than not enough. If it quietens down a tad when you pull the clutch in, that's normal, and usually means that your carbs need to be synched, although even when they're spot on, it's still gonna rattle a little. As long as it doesn't rattle as loud as a Ducati with a dry clutch conversion, it's fine..........

[timbo750]

Thanks Terry, definitely  not like a Ducati thank god.

The popping at idle is starting to get annoying and the longer you ride it the higher the idle gets until it hangs around 2200-2300 rpm.
I  have a minor oil leak which I think is coming from the oil filter, I am planning on doing an early oil change so will also replace all the o-rings.

I haven't had it around any real twisties yet but so far really happy with the ride both solo and 2 up. It was worth spending the money on the Ikons. Also gave it blast through a couple of gears from the lights and pulls nice to 7000rpm.

I  also now have a leaking back tyre, will first change the valve before taking it a tyre joint. I also want to change sprockets, its doing approx 4400 rpm at 60mph in top.

[CBJoe]

Thanks Terry, definitely  not like a Ducati thank god.

The popping at idle is starting to get annoying and the longer you ride it the higher the idle gets until it hangs around 2200-2300 rpm.
I  have a minor oil leak which I think is coming from the oil filter, I am planning on doing an early oil change so will also replace all the o-rings.

I haven't had it around any real twisties yet but so far really happy with the ride both solo and 2 up. It was worth spending the money on the Ikons. Also gave it blast through a couple of gears from the lights and pulls nice to 7000rpm.

I  also now have a leaking back tyre, will first change the valve before taking it a tyre joint. I also want to change sprockets, its doing approx 4400 rpm at 60mph in top.

Haven't gone back to see what your setup is...but does the idle creep up as the bike comes to operating temp?  Or is this a 20 - 30 minute thing?  Maybe a lean condition at Idle. The popping could be due to exhaust leaks at the muffler connections.  Make sure they are good and tight.

Have you checked the plugs?

Cheers, Joe

[timbo750]

Joe
The idle would be about a 20min thing, the exhaust is good fit but is only a slip on. I haven't checked the plugs yet but will do during the week.

[seanbarney41]

Timbo, these bikes will roll at 8000 rpm all day long, so 4400 at sixty is fine.  They dont have any low end torque, its all high rpm horsepower.  16, 17 or 18 tooth fronts with a 48 tooth rear all work good.  (have a 50 tooth rear made if you like to do the occasional wheelie)  Get used to it. 

[timbo750]

I have spent more time on a VFR  than any other bike and loved the torque but I do like the way this revs so far.

[SOHC4 Cafe Racer Fan]

I have spent more time on a VFR  than any other bike and loved the torque but I do like the way this revs so far.

The sound of a V4 is something else. 

[Terry in Australia]

Yep, I put my minty 1996 VFR750 Into storage in December, I really should sell it as I'm too old and fat to use it as it was designed, but that V4 howl at max RPM's is hard to get out of my system......

[timbo750]

I had a black 95 with an Omrae carbon muffler, coming down the  steep parts at the back of Mt Glorious I was told that small flames would pop out the exhaust.

[Terry in Australia]

Ah Mt Glorious, one of my favourite rides when I lived in Ferny Hills was from home to Mt Nebo, across to Mt Glorious and back, I had a Ducati 900SS back then, and apart from parts continually falling off it, it was a great ride......

[timbo750]

My wife brother lives at Mt Nebo but not a bike rider. The road across there has been resurfaced in recent years and quite smooth. I also like the road over Mt Mee and then on to Maleny.

[Terry in Australia]

Well don't ride your CB750 like you did on your VFR, they're not as agile around corners!

[SOHC4 Cafe Racer Fan]

Well don't ride your CB750 like you did on your VFR, they're not as agile around corners!

That's an understatement! 

[timbo750]

And rest assured I do not want to verify that the hard way.

[timbo750]

Got out for decent ride yesterday,  went up around the Dandenong's and I am quite happy with it overall so far. The suspension is great and the breaks work well. The engine revs well and pulls hard, took it out to 7k a couple of times. The idle is still too high when its wrmed up and idle screew is off the stop and it still pops at idle once warn also. If I load up the engine in gear with the brake on it will lower the idle for a short while with less popping. I think the popping is either a carb over fuelling at idle, ignition misfire at idle or a valve not seating correctly.

[Terry in Australia]

Are any of the slide rods bent slightly Tim? I remember that Jeff was shaking his head trying to make the slides return when he backed the throttle off? Do you have a spare set of carbs in that pile of stuff you bought? Cheers, Terry.  

[timbo750]

I had issues too with the return when I first got it running. I have other carbs but they all need work. Are suggesting maybe just changing the shaft?

[Terry in Australia]

Nah, I reckon you should clean up another set and chuck them on mate, if your cables aren't binding, that problem will probably go away. Cheers, Terry.

[timbo750]

Ok. Might try and set up a small soda blaster, should clean things up a bit easier.

[Terry in Australia]

Good idea Tim, don't take the slides out of the new set, just give them a clean and chuck them on. Cheers, Terry.

[timbo750]

It's got a heap of dried up fuel crap in the bowls. Was going to strip them down just to make sure nothing is blocked.

[Terry in Australia]

Yeah, understood mate, but not much need to remove the slides, just drop the bowls, remove the idle screws, clean all of the jets and internal circuits with carb cleaner and compressed air, bench sync them, and shove them on, good to go. Cheers, Terry.  

[timbo750]

Have been out for a few rides now and have a few things that need sorting. I had a couple of things come loose on one ride, nothing too major, the tach cable came out of the tacho and the large chrome nut on the head stem cam loose and fell off but everything else seems good.

The clutch lever is not set at the right angle. The flat bar I am using I got with the bike and drilled the holes necessary to get the stock controls fitted with hidden wires, it would now seem that the clutch is rotated too far up on the bars and after a while riding it actually hurts to pull the clutch. But as I don't want to take too much out of the bars I will try and get another, maybe this time pre-drilled.

Also I am not liking the way the rear feels at the moment, the Ikons are set on the softest spring preload and the dampner on 1, time for some trial and error.

Now going to give it an oil change and check the tappets. I also have another set of carbs that I have started cleaning but the jets will need replacing as well.

[Terry in Australia]

Yeah, when I took a peek at your bike the one thing I didn't like was those wide flat bars Tim, a set of low Euro bars would be more comfy and easier on your wrists too.

You don't need to drill and slot the bars unless you just want to keep the wiring super tidy, just get your dremel tool out and grind some meat out of the switch blocks to make some room for the cables to pass through. Cheers, Terry.