Suzuki Club UK

The bogging will be that you’ve dropped it to 8*, that’s what the book says but as mentioned in my previous post most of us run 10* as they run better.

Cheers Scottie, I guessed that might have been the case but thought I would try it just in case. I'll stick it back to 10 and go from there.

Hi Larry
Do you mean that the piston 'flutters' up and down slightly ?
10w40 should stop piston flutter unless the damper/damper spring is worn or perhaps the incorrect damper/spring for that particular SU carb is fitted ,I believe there are different types of damper and spring for different models of SU ?

Yes, flutters up and down but like you say, only slightly. Give me a day or so and I'll get a video to show you what I mean. Thanks

As it happens I have a spare SU belonging to a friend, I'll compare and see if they have similar play.

So I've compared the pistons and mine looks to be ok wear wise, compared with another used one at least. I'll get a video later.

I've also bought a pressure gauge for checking fuel and vacuum. Fuel pressure measuring at just over 4psi at 12.6v and as high as 5 when engine on and blipping throttle. I'm gonna buy a regulator to trim it back to between 2 and 3 psi, see if that makes a difference.

Also gonna whip the cam cover off and double check valve clearances, as I've noticed it's a little tappety.

If you are checking the tappets it might be worth getting some Loctite. Those screws get loose very easily!

Valve clearances checked and all ok. I haven't added locktite as I didn't need to change any, but point noted for next time. Thanks

Doing some googling and came across this forum thread, same engine and same issues, unfortunately the guy never confirmed if he found a fix.

https://forum.retro-rides.org/thread/20 ... p-su-hif44

Rather than order a pressure regulator to go with the cheap pump I have, I've decided to buy a better quality pump that puts out a slightly lower pressure.
https://www.ebay.co.uk/itm/FUEL-PUMP-EL ... 890.l49292

Should have it by the weekend, will wait and see what that does.

Have also put timing back to 10 btdc now.

**Edit**:
I forgot to mention, I've now added the proper SU dashpot oil also

Huco fuel pump fitted. Made a bracket to hang it off the back of the intake manifold so it's tucked in out of the way against the bulkhead.

Only had time to give it a very quick run but it looks to be an improvement. Need to get it proper hot to be certain.

Pump seems like a good quality unit. It must have a built in regulator as it only kicks in when it needs to. It barely runs at idle but ticks away much faster when holding the throttle open.

Hopefully that's cured it. Very tidy engine bay there!