Head inlet nozzle question on a 72J

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Steve72J
Posts: 28
Joined: Fri May 18, 2018 1:25 pm

Head inlet nozzle question on a 72J

Post by Steve72J »

So my title says 1973 - the manufacture plate says 8/72 (VIN is GT750-25247). Engine serial number is 25639. Color is the red burgundy.

I You Tubed "1972 GT750" the other night and watched a dozen or so videos of 72's and all but one video shows a 2-bolt plate design mounted on the head intake port of each cylinder. Only one video had the nozzles cast with the heads.

Mine does not have the 2-bolt plates but has a nozzle as part of the head casting to accept a carburetor-to-head boot utilizing two "hose" clamps to affix the carburetor to the head.

Does anyone know about the dating of the nozzle design change ? Was it a mid year change, or a Asian/European/US location issue ?

My parts engine is 200 miles away and has the two bolt design but I think the engine serial number is a later model (but not sure).

Plan on seeing what it'll take to correct the title sometime this year
Steve72J
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Re: Head inlet nozzle question on a 72J

Post by Steve72J »

Found the answer here ... https://www.oldjapanesebikes.com/GT750_ ... de/page-61

"The carburetor mount was bolted to the engine during the early production and then switched to a spigot mount as was used on the 1973 models, starting at frame number 21134. The photo to the right is of the earlier bolted flange mount."
teazer
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Re: Head inlet nozzle question on a 72J

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lairdofsmoke
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Re: Head inlet nozzle question on a 72J

Post by lairdofsmoke »

Hi Steve 72J.
Does your tank etc look anything like this enclosed photo.
Ok this is an 73 USA ONLY colour, but I think some found their way to West Germany.
By the way the double disc was also listed as an optional extra on the J models, also find confusing is your remarks about the barrels carb mounts, having viewed two internet sites listed, makes me think this is either an extraordinary early K model or someone has changed the barrels over for a K set, for whatever reason. Only your piccies will help to confirm one way or the other.
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Cover of USA  "motor CYCLIST" mag Jan 1973
Cover of USA "motor CYCLIST" mag Jan 1973
On fragrant cloud
Faststeve
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Re: Head inlet nozzle question on a 72J

Post by Faststeve »

I didn't think any of the k model had bolt on carbs!!
From wot I know they was only on frist 6 months
Of the J model
Steve
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PaulD738
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Re: Head inlet nozzle question on a 72J

Post by PaulD738 »

My bike was a late 71J and had the cast intake stubbs with the rubber adapters on the barrels. I always thought it was only the L, M, A, B bikes that had the bolt on stubbs?
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Faststeve
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Re: Head inlet nozzle question on a 72J

Post by Faststeve »

Hi paul my J is a low number and it as bolt on
Carbs standard bike. I looked it up when I got it.
I think it's on old Japanese bike site
Steve
Faststeve
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Re: Head inlet nozzle question on a 72J

Post by Faststeve »

Yes Paul
Your bike is right same as my bike.
That's wot I call bolt on carbs flange
Sure only early J had this
The later JAnd K Had slip on flange
Steve
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