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Discussion Starter · #1 ·
i have a 73 bonnie and brought it as a non running bike, well i finally got it running and when i took the amal carbs apart i saw that it had 180 main jets, the parts book calls for 210 main jets and i got some 210 jets and installed them. my question is do you think the 210's are too big, the bike has shorty mufflers on it. it idles ok but seems to bog down and quit on take off, ive played with the clip setting and i think that i have a carbaration problem.
 

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Hi Tigercub,

You're right, the 72 workshop manual states 180 size mains but my parts catalogue (71) says 190s. Given that the single carb bikes run 230 mains I guess that 210 is a bit too large for twin carbs. I think that the pre OIL bikes had 190s fitted (what air filters are you running?) I too have bought shortie pipes but I've not yet finished the bike to try it. (I've bought 190s)

Webby
 

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Firstly, what have you got, T120 orT140?
If you don`t specify the model or engine number, you`ll find buying spares very expensive, because you will have a box of stuff that`s no good.
Right, the 1973 (650) T120 should have 180 main jets.
The `73 (750) T140 should have 210 main jets.
The `72 (650) T120R OIF should have 190 main jets.
Hope this helps:)
 

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Discussion Starter · #4 ·
it's a 750, i have'nt installed the filters yet i want to work the bugs out first. the bike came with k&n filters.it must have been running on the 180's at one time but like i said it was a non running bike when i got it.are the 210's to big.
 

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Discussion Starter · #5 ·
i got the bike running,put the air filters on and it runs good till it gets to about 3000 rpm. would this be the clip position, i have the clip at its lowest setting.
 

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Put the old jets back in, change the needle clip to the middle position, and try again.

start with brand new spark plugs and do a "plug chop" on a nearby open highway; run it up through the gears to about 4,500 RPM and hold it there in 3rd for a couple of minutes, then snap off the throttle, pull in the clutch and kill the engine. Pull over and yank the spark plugs and have a look (you did remember to bring a plug wrench and shop rag in your back pocket, right?)

Black - raise clip (lower needle)
Grey / Tan - leave it alone
White - lower clip (raise needle)
 

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Firstly, what have you got, T120 orT140?
If you don`t specify the model or engine number, you`ll find buying spares very expensive, because you will have a box of stuff that`s no good.
Right, the 1973 (650) T120 should have 180 main jets.
The `73 (750) T140 should have 210 main jets.
The `72 (650) T120R OIF should have 190 main jets.
Hope this helps:)
Bugger!...Forgot to ask the obvious, thanks Caulky :)
Webby
 
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