ways to test carb flow.....

Judotrip · Posted: June 22, 2007, 12:00 pm Post subject: ways to test carb flow.....

I was wondering if there was any other way to test the fuel flow to the engine besides the ole spark plug inspection after the bike starts to falter...

I replaced my rotor and the bike was running like a champ for two rides. I started it up and it was running real rough with no power.... It doesn't sound like it is missing, and starts fine with the choke pulled out. When the bike is warmed up and the choke is pushed in it's idle goes downhill until it dies. It does stay running with the choke pulled out to the first position, but it is not good to run it like this...

I did a plug check, and one looked good and the other was dirty black....

Any suggestions, before I go rebuilding my carbs....
THanks,
Judo

INXS650 · 650Rider Supporter Joined: Mar 22, 2007 Posts: 645

Does sound like a carb problem if one plug is black. Pull em off and clean em up.

jimdi · 650Rider Supporter Joined: Oct 27, 2005 Posts: 512

Yeh - I just had the same problem -
Had the carbs tuned to perfection - new parts etc. Ran great for 6 months. The other day - went for a long ride - and mine started the same baloney.
Pulled the plugs and they were carboned up.
Put on my "backup" set of carbs and the bike ran fine again.
So - I must have got a clogged jet or passage in my main carbs -
So it's cleaning time!
Imagine you have the same problem.

xsjohn · Last edited by xsjohn on January 2, 2008, 10:18 am; edited 1 time in total

If that cylinder is running rich (colder) you can tell with a infared thermometer.....the BP7ES or autolite 63 can take richer mixtures I found out and run cooler.......And stay clean a bunch longer.......

John

jimdi · 650Rider Supporter Joined: Oct 27, 2005 Posts: 512

Yeh - I am not saying to run at 22 - just that on both my 81's 34's with plastic floats (not brass) -
22 puts you right up to the lip of the bowl with fuel (with good needles)
23 gives you the 1mm space the book calls for.
As I said - I have noticed no adverse effect when I ran 24 before either. - It just leaves the fluel level lower than what the book calls for.

As far as my carbs...
Just put on my "backup" carbs they run fine at 2.25 out -
Carbs I did have on ran fine at 1.75 out (2 was too rich) -

I think I will just leave may backup carbs on - I have rebuilt both sets - and I can find no reason for the difference.

I will tell you with the backups on - I am on the edge of a wheely if I hit it too hard!

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