Forum

[Elvis]

Hai am Elvis, I own a 1992 350 bullet. Crank of 10.5kgs, mikcarb carburettor, basic air filters and all them basic components.
I was hoping to give it a little upgrade. Would an Amal carb and a performance air filter be any good?
Am open to all suggestions.

[stinkwheel]

In my experience a louder pipe and freer filter is a useful upgrade if you set the carb up to suit.



Also in my experience/oppinion, an amal carb is not so much an upgrade as a pain in the arse. Latchy starting and idling a speciality with a quick-wear carb body and slide. To the extent that I intend to swap mine out for a mikcarb again. Unfortunately I now have a tuned, gasflowed head and so feel I ought to use a larger than specified mikcarb which will need dialling in to suit with no real baseline to work from.



A standard size mikcarb on standard head however is a very known quantity, almost lego motorcycle tuning. With A filter and B exhaust you use X jets, Y needle position and Z slide. http://accessories.hitchcocksmotorcycle ... ttor-parts



I think a set of balanced samrat rockers is a good upgrade. Massively reduces the reciprocating mass of the valvetrain.



Standard pistons are made of elephant dung mixed with melted down rupees but a forged upgrade is an expensive investment.

[PeteF]

I'm with stinkwheel, switching to an Amal will not bring any more horses.
Free flow filter and exhaust will help a bit.
Retarding the inlet valve timing will also help a bit. CLICK HERE
Samrat rockers? Yes, probably.
I've been trying to warm up my 350 for years now but I DON'T want to spoil that nice soft feel the engine has. You CAN make them go fast but it will change the characteristics of the engine and then you might as well just get a 500.

[vince]

Hi, india bullets are overgeared at 5.2 which is closer to 500 gearing. Nearly every british 350 was geared much lower around 5.8 Redditch bullets were at 5.67 so fit a 15t gearbox sprocket if you want a bit more response. Vince

[John R]

Sounds right.
I think the biggest difference without going for hotter cams etc. is a free flowing exhaust + bigger jets- our hosts will advise. Free flowing filter makes some difference but not that much.
I have an Amal Mk. 1 concentric fitted, the deluxe version that isn't supposed to wear out its slide so quickly; I usually have a bell mouth, just for the look of it, which probably doesn't help. My bike (1989 350) is going like a bomb at the moment because the workshop at Sammy Miller's Museum set it up for me.
But like others, I don't necessarily think Amals are better than Mikarbs. Years ago, I swapped to an Amal. It took a while to get the bike running OK so I was satisfied with it, and I rode it around with the Amal for a while. Then someone knocked it off its stand and bust the brake lever so I had to fit a new one and new twist grip I didn't have the right cable for the Amal so I refitted the Mikarb. Guess what? it went faster! To be honest, they both work in much the same way so jetting etc. is everything.

[Elvis]

So I already have the free flowing exhaust in place. Will definitely try with bigger jets and samrat rockers and the free flow air filter.
And is a silent engine ever a possibility with our motorcycles??

[PeteF]

Another thing that makes the 350 a lot more "rideable" is a close ratio conversion. It gets rid of the big jump in ratios between 3rd and top. 3rd then becomes a much more usable gear and you then don't need to change the final drive ratio. This means you can chug around the lanes in top with less revs (if that's your thing)

[Presto]

I agree with PeteF (again!) - the close ratio gears are a big improvement. A number of owners seem of the opinion that this is the best tuning mod they have fitted to a 350.

[Wheaters]

My 2004 350 Bullet Electra, which I bought about 18 months ago, is used for chugging around the back lanes plus a bit of non-metalled surface road exploration.

Earlier this year I removed the cylinder head to have the exhaust valve seat replaced with one not made from cheese and decided to check the inlet port for gas flow. It was really poor; there were adverse steps between the carb outlet, the spacers, the gaskets and the port itself. All now cleaned up and gas flowed using mainly hand tools. I also discarded the original air intake system and filter (all the rubbers were completely shot) and replaced it with a cone gauze type; slightly bigger jets and a richer slide fitted to compensate.

The other mod I did was to lighten the rocker assemblies using my bench and hand grinders and fine files. I guess I'm just too tight-wadded to buy the Samrat ones and it was easy to lose a lot of the reciprocating mass.

I gained 10 mph on the speedo, possibly about 7 or 8 mph in real life.

I am thinking that I could do with lowering the gearing for better control at low speeds. I recently read that these Indian home market bikes have taller gearing than the UK ones so as the bike could do with a new chain I might fit a "shorter" 15T front sprocket at the same time.

[Wheaters]

Oh yes, thanks Vince for the info on the gearing!