[Adrian II]

I don't know why people have to fit casquette headlamps to non-casquette models, the latter look better IMHO.

Funnily enough, I'll shortly be sending off a set of Superstar/Lightning fork yokes to Allan for a Redditch twin project. This sort of thing (only red).



A.

[Super45]

At a guess given the engine was thrown together with 2nd hand piston which had been filed down to fit I'd say it may have been in a bump at some stage in its life and put back together with what was available, thankfully no sign of frame damage 

Personally I'm of the opposite view and do like a casquette on the bullet and it's older and scaled down 250 cousins it's just the ungodly clocks and idiot lights on top that spoil it.

I do like a clean headlight less yoke look on a scrambler but  what was wrong with a single smart looking speedo nestled between the headlight clamps for the superstar with a few lights in the middle if that?

Down to cost I imagine...

Do we know who made the speedo set up for RE back in the day as Know doubt bought in?

[stinkwheel]

Pretty much all Brit bikes used Smiths Chronometrics. You can still buy them new but they are very expensive, even used. Even broken. Also a lot of reproductions/fakes out there.

[Adrian II]

The casquette headlamp only came in from 1954 AFTER the Bullet had already been in production for several years. The Superstar did look perfectly OK, but I think people were so used to the casquette by then that it was kind of stuck there. Many of the Indian-badged Bullet and twin cylinder derivatives sold in the USA kept the separate headlamp, so did the Fury and the export versions of the 750 Interceptor.

Genuine chronometric Smiths speedometers are not rare but people want money for them. Probably best to get a knackered but salvageable one and get it professionally repaired, making sure it's re-calibrated correctly for whatever size tyre is on the wheel where the 2:1 speedo drive lives, I think a 1550 or 1548 calibration code is close, side trip and plain bezel if possible for external mounting. You can buy totally refurbished Chronometrics outright, though I'd suggest any Indian Bullet has to be a keeper if you're willing to spend "a not insignificant amount" on that sort of thing.

A.

[Super45]

true forget out the US bikes.

I'll stick with what I've  got for now, spent enough time messing about getting the wiring to work in the casquette and a new headlamp to be spending more money on it.

first job is to get the carb set up to a reasonable state then MOT so I can test and set it up correctly  depending if it will pass with the 20 year old tyres on it or not. 

[Super45]

Right  bit of an update, resealed the head and barrel and had it running today, got it warmed up and had a go with the various slides I’ve bought. And found there’s still a leak from the barrel/tappet cover.

I reset the needle to the middle of the 3 notches so it’s on a standard setting for testing.

Firstly the number 2 slide has slight ( and I mean very slight) bit of corrosion making it ever so slightly too big to get into the carb so I’ll fish out my autosol when I can lay my hands on it before I try it again .

3.5 slide fitted and idle re- adjusted idle mixture, ended up with 2.0 turns out, at this stage when blipping and a pull up the street it’s slightly more  responsive but not massively, adding some choke and testing it when blipping made it pull a bit better up the road again.

Slide 4.0 fitted, this gave the best pull when pulling away after tweaking the idle screw I was able to pull away cleanly with no flat spot.

Issue is with this one the engine idles way too High at about 1500rpm ( cables ok) so it’s above the flat spot.

tried to lower the idle speed per the manual  but it had become very sensitive to adjustment  so it would only take a slight tweak for the idle to drop quickly and die, unsure with this being the largest cut out of the choke slide is too big so effect it’s on choke all the time or not will need to take the carb top and look further.

[SteveThackery]

[quote author=Super45 link=topic=36970.msg482478#msg482478 date=1720283065

Issue is with this one the engine idles way too High at about 1500rpm ( cables ok) so it’s above the flat spot.

tried to lower the idle speed per the manual  but it had become very sensitive to adjustment  so it would only take a slight tweak for the idle to drop quickly and die, unsure with this being the largest cut out of the choke slide is too big so effect it’s on choke all the time or not will need to take the carb top and look further.
[/quote]

Slide 4 is awfully weak. Sounds like you've got the idle mixture really rich to compensate.

Setting up the 928 is quite a ball ache because the idle mixture screw also operates as an idle speed control (it bleeds more or less air in, thus working a bit like a throttle). So the idle mixture control, the idle speed control and the cutaway all interact to influence the mixture just off idle, in the famous Concentric Flat Spot.

I'd be looking at a #3 slide, middle needle position, and then spending some time getting a really nice idle when it's hot.  Once there you can richen the idle slightly (remember to screw in the idle speed screw to compensate) and see if that helps squash the flat spot.

[stinkwheel]

Slide 4.0 fitted, this gave the best pull when pulling away after tweaking the idle screw I was able to pull away cleanly with no flat spot.

Issue is with this one the engine idles way too High at about 1500rpm ( cables ok) so it’s above the flat spot.

tried to lower the idle speed per the manual  but it had become very sensitive to adjustment  so it would only take a slight tweak for the idle to drop quickly and die, unsure with this being the largest cut out of the choke slide is too big so effect it’s on choke all the time or not will need to take the carb top and look further.

Now try dropping the needle a notch.

[Super45]

[quote author=Super45 link=topic=36970.msg482478#msg482478 date=1720283065

Issue is with this one the engine idles way too High at about 1500rpm ( cables ok) so it’s above the flat spot.

tried to lower the idle speed per the manual  but it had become very sensitive to adjustment  so it would only take a slight tweak for the idle to drop quickly and die, unsure with this being the largest cut out of the choke slide is too big so effect it’s on choke all the time or not will need to take the carb top and look further.


Slide 4 is awfully weak. Sounds like you've got the idle mixture really rich to compensate.

Setting up the 928 is quite a ball ache because the idle mixture screw also operates as an idle speed control (it bleeds more or less air in, thus working a bit like a throttle). So the idle mixture control, the idle speed control and the cutaway all interact to influence the mixture just off idle, in the famous Concentric Flat Spot.

I'd be looking at a #3 slide, middle needle position, and then spending some time getting a really nice idle when it's hot.  Once there you can richen the idle slightly (remember to screw in the idle speed screw to compensate) and see if that helps squash the flat spot.

That was the starting point with how the carb was delivered, didn’t make a difference where the pilot air crew or the slide screw were put it still have the flat spot to the point of cutting out when trying to accelerate off idle

[Super45]

Now try dropping the needle a notch.

Roger Wilco. 👍🏻

[Super45]

Now try dropping the needle a notch.

4 slide fitted and dropped the needle a notch.

Rich idle 1.5 out on pilot air screw to get it to idle on its ,

Idle rises fluctuates on its own to above what was set initially once the slide has been put in and sort of settled on a fast uneven idle. 

Wd40 tested no air leaks and still has the flat spot.

[stinkwheel]

Oh well, worth a try. I thought dropping the needle might keep it off the main jet/needle jet for a bit longer at lower rpm. Cost nothing to try anyway.

Just as something to try, it might be worth physically looking at the throttle slide when it's on idle with the air filter removed to see what it's doing. i suspect you'll be able to see it directly or with the aid of a mirror and torch. Just before I finally had enough of the amal on my 350 and put the mikcarb back on, I noticed it seemed to "hang up" on the idle at times. I put this down to wear on the throttle and carb body making it not always return to the stop properly, maybe the vacuum through the carb canting the slide forwards slightly. Possibly even an odd venturi effect lifting it a little. When I think on it, it may have always done this to some extent but it became much more of a problem when I started doing trials work which often involves giving it a small sniff of throttle then coming reliably off it again.

It would be interesting to see, I'd probably do it by marking the slide with a marker pen at the fully closed position then seeing if it returns to this position when the throttle is blipped or if it's hanging up slightly off fully closed in the carb body, or maybe even rocking or fluttering up and down slightly with the induction pulses.

Another thing I've found over the years is most motorbikes idle much better if they have at least some exhaust resistance/back pressure. This holds true for my japanese DOHC V4 (which gets a baffle fitted once a year for the ride to the MOT and back and is noticeably less prone to stalling when moving off from cold with the baffle fitted) as much as it does with my bullets. If you have a totally wide-open exhaust, it might be worth experimenting with putting a small baffle in it?

[SteveThackery]

I'm going to offer the same advice I give to everyone else wrestling with the crappy Concentric Mk1: dump the useless bloody thing in the recycling bin and fit a Mikuni.

By the way, maybe you missed it earlier - if you want to keep trying with the Amal for a bit longer, the first thing you should do is fit the #3 slide. #4 is way too weak, in my experience. I promise it will improve (but not cure) the off-idle flat spot.

[Super45]

Oh well, worth a try. I thought dropping the needle might keep it off the main jet/needle jet for a bit longer at lower rpm. Cost nothing to try anyway.

Just as something to try, it might be worth physically looking at the throttle slide when it's on idle with the air filter removed to see what it's doing. i suspect you'll be able to see it directly or with the aid of a mirror and torch. Just before I finally had enough of the amal on my 350 and put the mikcarb back on, I noticed it seemed to "hang up" on the idle at times. I put this down to wear on the throttle and carb body making it not always return to the stop properly, maybe the vacuum through the carb canting the slide forwards slightly. Possibly even an odd venturi effect lifting it a little. When I think on it, it may have always done this to some extent but it became much more of a problem when I started doing trials work which often involves giving it a small sniff of throttle then coming reliably off it again.

It would be interesting to see, I'd probably do it by marking the slide with a marker pen at the fully closed position then seeing if it returns to this position when the throttle is blipped or if it's hanging up slightly off fully closed in the carb body, or maybe even rocking or fluttering up and down slightly with the induction pulses.

Another thing I've found over the years is most motorbikes idle much better if they have at least some exhaust resistance/back pressure. This holds true for my japanese DOHC V4 (which gets a baffle fitted once a year for the ride to the MOT and back and is noticeably less prone to stalling when moving off from cold with the baffle fitted) as much as it does with my bullets. If you have a totally wide-open exhaust, it might be worth experimenting with putting a small baffle in it?

Will give it a try worth a go cheers.

[Super45]

I'm going to offer the same advice I give to everyone else wrestling with the crappy Concentric Mk1: dump the useless bloody thing in the recycling bin and fit a Mikuni.

By the way, maybe you missed it earlier - if you want to keep trying with the Amal for a bit longer, the first thing you should do is fit the #3 slide. #4 is way too weak, in my experience. I promise it will improve (but not cure) the off-idle flat spot.

It’s an expensive bin filler which is why I’m persevering!

I’m yet to try my 2.5 as it needs a good clean up as it’s a tight fit in the carb due to very minor corrosion so that will tried also as the 3 slide is what it came with and gives a good idle off the batt so will try that also running slightly richer as I think it was about 2.5-3 turns out on the mixture screw so will run it the opposite way for a try. With a 1.5 turn out as a starting point