Just fitted a free-flow filter and a free-flowing exhaust system to my -83 TR-1 only to find out it goes too lean on 1/3 to full throttle. Can these strange Hitachi things be tuned richer anyhow or do I need to get new jets?

Sorry dude, no help from me. I'm looking for the same fix as i done the same thing. Powerfilters and open exhaust. Starts fine, idle's nice but at higher throttle the engine seems to hold back and makes a lot of noise (big bangs and stuff), sounds kinda fun but it's not the smooth ride it should be.

As far as i know there should be a way to adjust a pilotscrew somewhere but the manual and fishes i found aro no help at all.

So if anyone can halp us out....???

OmeJozz

OK gents here's the problem - CV carbs are sesitive to inlet manfold vacuum which you've both changed when you changed the exhaust. One says it goes lean the other says pops & bangs. What is happening is that the slides are hanging up & even flutering due to a lets say a difference in the vacuum compared to standard.Now 99/100 the new pipes willhave reduced the manifold vacuum & therefore there is not enough suck to raise the slide to where the motor needs it. In the bottom of the slides there is a hole which is the calibration for vacuum to lift the slide. Simple equation - lower manifold vacuum needs bigger hole to lift the slide. Enlarge the holes in .05mm steps until you achieve full throttle under load. Usually there is no need to move the needle setting as the fuelling requirement has not changed markedly under part throttle. It is wise though to check the plug colour under full throttle conditions
Usual disclaimers - you should go carefully & not rush out & burn a hole in a piston!Keep looking at plug colours.
Greg

Hi,  
I had the same problem with mine

I'm running a '83 TR1 with a standard air filter, standard jets and settings and Jama headers with reverse-cone megaphones

I'd stripped and cleaned the carbs, fitted new diaphragms, jets, needles, air screws and float needles
I've junked the mixture control valve (as its function is purely for emission control, not smooth running)
It would start ok but took a bit to warm up
on small throttle openings it would miss and sputter and on closing the throttle it would spit and bang

Haynes and other manuals don't give a setting for the pilot air screw
I read somewhere 3 turns out, and somewhere else 4 turns
I tried both but it was no better.

I found an interesting article about setting Hitachi carbs here http://www.drpiston.com/hitachicarbs.html
So at Dr Pistons suggestion I got a Gunson Colortune
What a marvelous tool!  
I found the air screws needed to be 5 turns out on the front cyl and 5.25 turns on the rear cyl
the old lass now runs sweet as a nut! Thanx Doc!  

Get a colortune - takes all the guesswork out of air screw settings - u should be able to find one on ebay for around £25
For replacement diaphragms and carb rebuild kits NRP Carbs in Manchester are the dogz danglers
http://www.nrp-carbs.co.uk/

I also had trouble getting the carbs to synchronise
I found it was due to the roller on the throttle linkage being worn causing slack in the linkage so the throttles were opening out of synch
Of course, replacement rollers are no longer available - thanx Yamaha  
However CMS in the Netherlands stock many discontinued parts including the roller at 6.50euro http://www.cmsnl.com/products/roller_4x71426700/

I found CMS after I'd engineered my own fix   I got a minature ball bearing - cost about £2, 16x8x5 I think it was from memory - best to check  
The bearing wasn't quite as wide as the original roller so i shimmed it with a 8mm washer either side
A dab of bearing fit on the pin holds it in place
It works a treat!
I've finally got the rotten carbs to synch and get this - thanx to colortune NO popping and banging on the overrun!  
lol life is good! :-D