Quirks of Mikuni/Solex's and Webers

[GeeB]

Still not right. Checked everything and put back together again and checked timing which was quite far advanced. Running better and no pinging still running rich though. I am mechanically challenged so hope this doesn't sound too dumb. When i screw all of the mixture screws all the way in the car keeps on running no sign of stalling. Does the fuel somehow do a bypass? It also seems to want to idle about 1500 rpm at running temp, is this right ?

[allencr]

Yes, seating the idle mixture screw/adjustment should Always stop the engine!! If it doesn't, the idle jet is too large/rich, or the carb is F'd up.
Throttles syncronized, left & right butterfly/plate and front & back carb??
1500 is too high and it is starting to run off the main circuit besides the
idle circuit, but even at that speed I think it should shut down.

[Steve M]

Worn butterflies, or large butterflies on a small engine with large cams and poorly tuned can result in the engine idling on its slow, or pilot jets.
We've got that problem with the 18RG using big cams and 44mm carbies.

Chances are that isf you can't get the idle below 1500 the carbiesw are not balanced or your butterflies are worn.
If this is the case, (especially where worn) you're likely to idle on the pilot jets.

[jeffro ra28]

Is there a descent type of soft mounts you can buy for these carbies?
I have looked around and all i can find is crap house plates with O-rings. Are these any good? What are you using?

i think the harmonics of the 8500rpm it turns isnt doing the venturies (coming loose) and swishing up the fuel. So i need some good soft mounts! Any idea's?

[Billzilla]

Is there a descent type of soft mounts you can buy for these carbies?
I have looked around and all i can find is crap house plates with O-rings. Are these any good? What are you using?

i think the harmonics of the 8500rpm it turns isnt doing the venturies (coming loose) and swishing up the fuel. So i need some good soft mounts! Any idea's?

Yeah the usual O-rings will work fine.
Just do them up so they crush a little and the carbies can move around a little, say, 5mm or so at the air-cleaner end.

[jeffro ra28]

Hey bill.
Can you explain the 5mm at the air cleaner end?

Cheers btw.

[jeffro ra28]

oh ya ok i think i get what your saying now duh

So im geussing some nyloc nuts would be apropriate in this case?

[jeffro ra28]

Also, Would anyone have the correct part number for a 40mm solex gasket kit?

[Billzilla]

oh ya ok i think i get what your saying now duh

So im geussing some nyloc nuts would be apropriate in this case?

Yep, fresh nyloc nuts are the go. Just make sure you can wiggle the end of the carbies up/down a total of about 5mm with your fingers as that's soft enough.

[joey]

Is there a descent type of soft mounts you can buy for these carbies?
I have looked around and all i can find is crap house plates with O-rings. Are these any good? What are you using?

i think the harmonics of the 8500rpm it turns isnt doing the venturies (coming loose) and swishing up the fuel. So i need some good soft mounts! Any idea's?

I'm using the redline o-ring style ones for about 7-8months now and havnt had a loose venturi to date so i'd say they're a safe bet.

[Billzilla]

Erm, just wondering if it's worthwhile making this thread a sticky?
Pop it in the tech section or something like that. Lots of good stuff from many people here.

[Rodger]

jeffro,

Mikuni/Solex gasket kit suitable for the S5 Solex typically found on the 2T-G is:

Z70-1044

It comes up as a 44mm kit because the 40mm kits are for Type R.

I have stocks of these kits and they are very very rare to find suppliers.

Redline's part number for the softmount kit is:

52-110K

These kits have all parts to do one Solex/Weber/Dellorto so two kits are needed.

Any Auto parts store with a Redline range can order them in. I could get these in if you have trouble.

Regards

Rodger

[GeeB]

Jet holders coming loose again, will soft mount kit help here also or is this simply a case of regular checks.Will previous owners screwdriver damage to jets affect function its enough to stop a couple of the tubes sliding out. Also how do you determine if the right size jets are in there.

[jeffro ra28]

Pretty sure soft mounts are designed to minimise fuel swish. There is a chemical in fuel which boils at 32 C and when its swished up, the surface friction from it shaking against the carbies causes it to boil and sends fumes into the engine. Just like when you shake up te fuel can for the mower and it tries to blow the lid off! Should also help stop things coming lose to id imagine.

[Rodger]

Hi GeeB,

A softmount kit may help stop jets coming loose. However I do not use softmounts on my engines both in competition and street use and have yet to have Jet Block Assemblies come loose.

Make sure when you re-tighten them that you remove them completely first. Then remove the Main Air Jet and install the Jet Block back in with a very large flat blade screwdriver. Seat the Jet Block firmly, then screw on the Air Jet.

The idea is not to use the Air Jet to tighten down the Jet Block.

Damage to the Air Jet is always caused by a too small screwdriver or as I say above. As long as no brass chips have fallen into the block or main body and there is no damage to the metering hole then they will be ok. Perhaps they can be cleaned up of dags with a fine file.

If there is significant damage to one or two slots then this will affect tuning. Mind you, you would have to be chasing that last 0.0001kw and 0.001 sec lap time to see any difference.

Regards

Rodger