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which carby is better

18K views 46 replies 22 participants last post by  Bekk 
#1 ·
ok guys need some input please i have zen esp full ported 30.5 motor comes with Walbro WT-813 High-Performance Carburetor which has no choke how hard are they to start with no choke , or am i better off swapping it over for a Walbro WT-668 Carburetor
which has an internal choke im running a standard 26 fulie at the moment but have the zen to put in when i feel ready
thanks for all the help
pete
 
#6 ·
Stick with the 813 mate. Awesome carb and if looked after will start day in day out.
People that don't like them have know idea.


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#8 · (Edited)
+1 from me. Stick with the 813 matey. great carby. All you need to do is give it a few Squarts on the trigger and she now fires first or second pull.
The 813HP has an accelerator-Pump which eliminates any BOG and you can fine tune the engine Much better
 
#10 ·
People have mixed opinions on 813 carbs, some like them some don't. Back to back performance difference between 668/813 is very minimum. I've never had a problem with 813, but the 990 will be my next carb. Best carb yet IMO
 
#12 ·
Not really, people have it in there head that because the 813 has an accelerator pump it has to be better. I've run a 668/813 back to back on a 6.5hp ccracing engine with no noticeable difference at all.
 
#14 ·
Except that a test should involve multiple tanks of gas. Should it not?

I don't think your cc racing motor had anymore than 2 tanks through it before it **** itself.

What a test!

Lmao.


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#20 ·
Even a single weber will do nicely those are mean carbies
 
#21 · (Edited)
I'm one of those people that have "no idea" except when it came to getting rid of my 813, due to having too many problems with it, and replacing it with a 990. Thanks to Homers tuning help during the Sept meet at Luddenham my 29cc Zen with Samba 4410 pipe is running sweet.
 
#26 ·
love the pic MM lol

813 - love or hate em.
668 - no performance difference compared to the 813 and you get a choke for easy starts. Each to their own but.
990 - NFI but I'll look into it
 
#28 ·
The 990 is an 813 without the accelerator pump. So no more flogged out throttle shafts.

I have been testing this now for a month or so and have found it to be the same performance as the 813. A little harder to start with a spot on tune, but richen the low speed a 1/4 for start, then set it back and it is sweet as. I have been using the 5T in the sand and by now usually the 813 is beginining to show signs of throttle shaft wear. Nothing to note so far on the 990.

Hope this sorts it for you
 
#29 ·
Hi there

As I am new, is there a listing or thread which details the differences between all the models of carb.
Just thought such a listing might help people like myself understand carbs abit better.
 
#30 ·
im thinking of trying the 813 on a 4WD FG Baja, im not familiar with this throttle shaft wear, how quickly does it wear and is it just the shaft that wears or the carby body?
 
#34 ·
the mix screws on the 990 also feel more positve than the 813. I always found the low needle on the 813 to be quite innacurate. like it has a deadband when you move it. I've heard of people swapping the 813 mixture screws for 668 ones.
 
#36 ·
bloody hell that thing is very impressive! what engine are you running?
 
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