CR750 Running (or not running!) issues

[K2-K6]

Agree that you've ideally to change the float level to match the others first to eliminate that difference.

As you state,  move the float toward the main carb body to raise the fuel level. The fuel reaches the same level "on the float" so wherever you place the float when the fuel valve is closed,  then the level will follow. Assume it's the same float,  no leaks, and same length needle shutoff valve.

As Dave says though,  an air leak at exhaust port area will often give popping on overrun.

[philward]

Update on running issue as per previous posts - thought it might generically help forum members, Floats all re-set and sealed the exhaust/head joints on the exhausts. Popping moved to different cylinder! Thought I'd re-balance carbs as I had had carbs off.
Discovered the fault by mistake as I was setting up bike for carb balancing. Took the tank off and instead off filling remote petrol tank (I use when running bike with tank off) from petrol can, thought I would hang the remote tank of the main tank tap so that I could drain some petrol into remote while I was setting up the vac guages. Turned the tap to reserve and got on with vac guages. When I went back to the tanks, hardly any petrol in remote tank as the tap was 'dribbling' petrol out. Turned the tap to normal on and the the petrol flowed freely. As I have been running the bike on reserve due to keeping a minimum amount of petrol in the tank (as if you remember, I was waiting for leaking replica CR750 tap to be repaired by guy who makes them and wanted minimum petrol to drain when re-fitting), this was probably the problem - and the movement of the popping randomly to different cylinders as different float chambers are deprived of fuel.
The tap I have on is the one off a cr250 motocross bike that the tank manufacturer recommends and fits (due to hole centre dimension) - its an aftermarket tap.
So if you are fitting replica taps to any of your bikes/projects, check the fuel flow to avoid any set up issues!

[Rozabikes Tim]

Simplest of things. Hope that bottoms it for you. Remember on a race motor I ran, we welded a second tap into tank, each feeding 2 carbs, as it was a thirsty beast!!

[philward]

More snagging advice needed please! Only a minor issue but irritating. I have a discreet rear light that tucks under the seat hump that includes LED indicators - front indicators are flush fitting (on fairing) with ordinary bulbs. Lithium battery with Electrex narrow race alternator.
Problem is the indicators flash normally without engine running (battery voltage 12.6v) but when engine running the indicators flash fast (battery voltage 13.6v)
From memory, I originally bought an LED specific flasher relay but to double check, I have just bought another LED friendly relay and it now flashes fast with or without engine running!
Is it the combination of ordinary bulbs and LED bulbs that is causing the problem?
Electrical genius' help required please

[hairygit]

Most of the led specific flasher unit I have seen flash at 90 flashes per minute, which is faster than our old bikes did originally. The law says between 60 and 120 flashes per minute, and 90 is smack in the middle of that. Because they are solid state, they continue at the same rate even if a bulb blows, unlike the old bi metal strip type.

Sent from my X6pro using Tapatalk

[philward]

Most of the led specific flasher unit I have seen flash at 90 flashes per minute, which is faster than our old bikes did originally. The law says between 60 and 120 flashes per minute, and 90 is smack in the middle of that. Because they are solid state, they continue at the same rate even if a bulb blows, unlike the old bi metal strip type.

Sent from my X6pro using Tapatalk

But why the difference in the flash rates with and without engine running Hairy?

[hairygit]

Solid state relays rely on clean secure earth's, often an engine running, the vibration will improve the engine to frame earth connection, but many other factors come into play. For example, what voltage are you getting at the power feed and earth that actually enter the flasher unit? Also dirt in the contacts of the indicator switch on the handlebars or the wires from that switch to where it joins the main loom? Maybe removing the old flasher unit and installing the new one has cleaned crud out of a connection and improved continuity, to name just a couple of suspects.

Sent from my X6pro using Tapatalk

[philward]

I'll check those points but everything is new - ie, new switches, loom, relay, lights in fact everything except metal work