Jockey Journal Forum banner
1 - 19 of 19 Posts

·
Registered
Joined
·
33 Posts
Discussion Starter · #1 ·
hello there..i was wondering what carburators people use when they change from 650cc to 750cc?i just finished rebuilding my t110 1960 from sludge trap to top due unfortunate bearing failure and changed cylinder to morgo big bore kit 750cc...i have fairly new amal concentricks 930 that i used on 650cc and they were fine for it but would it make big difference if i change the carbs to say amal mark 2 or 34 mm mikuni flatslides???i have both ready to go..so what you fellas think???

Timppa
 

·
Registered
Joined
·
3,691 Posts
I say stay with the Amals, In my opinion the Amals are way easier to tune and have better low RPM torque, The Japanese carbs can be made to run better at top end but they are a lot harder to get tuned in,
Nothing wrong with 2-930 Amals on a 750 engine.
 

·
Registered
Joined
·
76 Posts
My 76 T140 (750cc) came from the factory with Amal 930's. You may have to adjust the jets but I would guess they will do just fine.

I also think the mark1 concentrics look better than the mark 2 or the mikunis.
 

·
Registered
Joined
·
243 Posts
I don't think you can go very wrong with any of your 3 choices.I like them all,but I've found the mikuni TM's(flatslides)tho more difficult to set up,can give you throttle response that make them worth the trouble. Since you say you have all three,why don't you start with the mark 1's, go to the mark2's, then the Miks and give us a comparo here on JJ. I run a pair off 36mm TM's on my T-140 Hot Rod and I think they are the best carbs I've ever run. Let us know. Jack
 

·
Registered
Joined
·
171 Posts
This is a thread drift and I apologize but the title may make it work for somebody.

The Las Vegas Craigslist has a guy selling a complete Morgo 750 kit that gets cheaper and cheaper. About $250 Dollars now.

NFI, just hope it helps somebody....
 

·
Registered
Joined
·
6 Posts
sorry to steal your thread but im in the same boat, but im wanting to run a single flat slide any idea what size, mikuni tm's of course. I was thinking one 36 but if jack adams is running two then one may not be enough
 

·
Registered
Joined
·
706 Posts
I'm running two 930's on my Morgo-kitted 750--runs great! I just looked in the 750 manual and used the same main jet as the later 750s.

Regarding the Mikuni question, for a street bike I'd run one 34mm rather than a 36, simply because the cylinders are not drawing fuel simultaneously, so the 34 will provide plenty of juice. Also, the smaller diameter of the 34 will give better response due to the faster flow. Heck, a 32 Mic would probably work even better.
 

·
Registered
Joined
·
33 Posts
Discussion Starter · #9 ·
thanx for the replys fellas...i give all 3 a go and be sure to share the results in jj...here is a shitty cellphone foto of the engine...

Timppa
 

Attachments

·
Registered
Joined
·
2,012 Posts
I was gonna do 34mm Mikuni VM but i was advised to go with 32MM on a mostly stock 750. The jets had to be changed out to get it set up right. Works great now.
 

·
Registered
Joined
·
794 Posts
I was gonna do 34mm Mikuni VM but i was advised to go with 32MM on a mostly stock 750. The jets had to be changed out to get it set up right. Works great now.
I am running 32mm Mikunis on my '68 750 and 51065 cams...weren't too bad to tune...1-2 kicks everytime....no issues here.... an engine builder buddy of mine crunched numbers and advised against the 34mm's, said 32mm's were borderline too big.
 

·
Registered
Joined
·
3,691 Posts
Single 930 concentric works fine on a stock 750, 270 main .106 needle is a good place to start
TR7 came that way from the factory, 750 c/c single Amal 930 , good simple easy to maintain bike.
 

·
Registered
Joined
·
172 Posts
What kind of performance would you get running 2 932 on a Morgo kit with stock cams?
Wish I could afford Dyno time. I suppose you could make an educated guess....

Stock T120 quoted as 45-46bhp @ 6500 depending on what book or brochure you are reading.
Stock T140 quoted as 46-50 bhp @ 7000. I think 50 is a little optimistic, maybe on a first production UK jetted bike before they were de tuned, I think 44 is a more realistic figure
Stock TR7 34-46 bhp.

So a T120 with T120 cams R Radius cam followers, displacing 750cc, twin carb in a reasonable state of tune 49-to mid to low 50's would be my guess.

I know there is a guy in the UK who turns out reliable 70bhp T140's. That's pushing the modern Bonneville's !

The really funny thing is... I've done the poor mans cam swap on a couple of T140's, but only ever one TR7, but man did that thing go afterwards (or did there just seem to be more improvement on a Tiger over a Bonneville because the Tiger was a bit of a slug to start with ?)

These are the things that keep me awake at night
 
1 - 19 of 19 Posts
Top