[n.devdath]

Originally Posted by akshay4587

You got 30kmpl with K&N because of Lean AF ratio.
if you want K&N to perform,get a bigger carb(not necessary) and bigger jets,and then go about tuning.

I dont want it to perform. I only want FE, hence the question and the background. Is it ok to revert back to it or will it have any adverse affect on the engine?

[akshay4587]

Originally Posted by n.devdath

I dont want it to perform. I only want FE, hence the question and the background. Is it ok to revert back to it or will it have any adverse affect on the engine?

Do not revert to K&N without upjetting.
due to lean AF ratio,engine will heat up more,which may lead to damage.

[n.devdath]

Originally Posted by akshay4587

Do not revert to K&N without upjetting.
due to lean AF ratio,engine will heat up more,which may lead to damage.

So, do you mean to say that the FE figures I m getting are acceptable the way they are?? 25-26 in the city and 26-27 on the highways at a constant speed of 80kmph?

[desideep]

i would say around 30 ish on the sane riding like 50-60 are nice and the highway runs could see around 28 for a normal tuned CI engine

[jingaboysr]

25-27 for a CI 350 engine for constant 80ish speeds is a bit less, you should be getting a tad above 30 ideally.

Check if your air filter is clogged and also analyze the spark plug to see if you are running too rich.

[n.devdath]

Originally Posted by jingaboysr

25-27 for a CI 350 engine for constant 80ish speeds is a bit less, you should be getting a tad above 30 ideally.

Check if your air filter is clogged and also analyze the spark plug to see if you are running too rich.

Checked Sir, air filter replaced 500kms ago and spark plug too checked. Also checked it for fuel leaks elsewhere. Just some wicking near the fuel tap, that is all.

[abhimanyuargal]

Originally Posted by akshay4587

You got 30kmpl with K&N because of Lean AF ratio.
if you want K&N to perform,get a bigger carb(not necessary) and bigger jets,and then go about tuning.

so is it better to go in for a bigger carb instead of just bigger main and pilot jets? will the 500's carb fit on a 350?

[shan2129]

^^ i would suggest you not to go for the 500 carb.( VM28 on standard 500 ), you can try a bigger carb of any other models if you can fit it. You can always try on bigger jets.

Regards

[abhimanyuargal]

Originally Posted by shan2129

^^ i would suggest you not to go for the 500 carb.( VM28 on standard 500 ), you can try a bigger carb of any other models if you can fit it. You can always try on bigger jets.

Regards

okay thanks for that tip. but any suggestions for a bigger carb that'll fit? and if not then what size jets should i use?

[shan2129]

i tried a lot to fit a bigger carb., the only thing about STD 350 is that it runs better with stock carb and bigger jets. I got myself 40 and 105 size jets. tuned it and re-tuned it, now my bull runs good. I also tried the VM28 that comes with 60-135, but that didnt work out that well. The first time i tried the VM28 my 350 rocketed away, but then it slowed down as the fuel mixture was not burning and was sedimenting residue on the plug.

So run big jets or if you know a mech that can fit a VM28 on your bike, that would do the trick.

[jingaboysr]

[quote=shan2129;1986540 I got myself 40 and 105 size jets. tuned it and re-tuned it, now my bull runs good. I also tried the VM28 that comes with 60-135, but that didnt work out that well. [/QUOTE]

VM28 comes with 25 size pilot jet and 110 size main jet.

60 -135 on a VM28?? That would be too rich unless you have a free flow setup. Is 60 really the size of the pilot jet?

[shan2129]

yep, i was shocked to see myself. but 60 is the pilot jet in VM28. i will try to find the manual i got with the carb.

[bradhey]

Originally Posted by shan2129

i tried a lot to fit a bigger carb., the only thing about STD 350 is that it runs better with stock carb and bigger jets. I got myself 40 and 105 size jets. tuned it and re-tuned it, now my bull runs good. I also tried the VM28 that comes with 60-135, but that didnt work out that well. The first time i tried the VM28 my 350 rocketed away, but then it slowed down as the fuel mixture was not burning and was sedimenting residue on the plug.

So run big jets or if you know a mech that can fit a VM28 on your bike, that would do the trick.

Can you confirm if these are original mikuni jets you got on your bike. And have you done any other modifications (like exhaust, air filter) on your 350. How many turns is the air screw open from fully closed position. Thanks

[shan2129]

@bradhey : Yeah, i have the original jets. I have the RE original Short bottle. I bought a K&N but didnt install it yet as i was planning to go for a goldstar, but then postponed my plans. I would suggest you search for pete-snidal manual on the internet and download it. It can also be bought online for almost 1k. It explains the perfect tuning and maintenence setup. Every bike has a different ratio that suits the overall running scenario. ( weather and altitude conditions do matter ). Just to answer your question, my air screw is almost 4 turns from fully closed position.

[Hog Head]

I have been following this thread with interest and there seems to be a lack of knowledge on how to hot rod a RE. It is really very simple:

You cannot have fuel economy, and performance so pick the one you want and tune it accordingly. If FE is your goal leave it alone as it is jetted for FE and not performance from the factory.

At the simplest level, an engine is a pump - moving more air in and out = more power. The easiest way to do this, and the biggest bang for your Rp on a Bullet is to rejet the very lean carb, add a free flow filter, and fit an efficent pipe. A bigger main jet alone will not suffice and at a minimum you need a pilot and needle jet as well. A new slide is nice if you can get one.

Hitchocks have some very good recommendations for jetting combos on page 12 of their catalogue. The Micarb takes the same jets as a VM series Mikuni.

That gets more air in now you need to get it out. A megaphone silencer will offer the most performance, but may be a bit loud for some. A Goldstar would be second choice but not as good as the megaphone for outright performance. One thing usually not discussed in India is tuning the length of the header pipe to take advantage of wave reversion to extract gas at high RPMs'. The stock header length is fine for a stock bike but as you add compression and vary the cam timing you will want to shorten this up

The Bullet is so restricted on moving air that it responds well to this mod.
Lets call the mods so far a stage 1.

After that you need to open up the engine for stage 2 mods, and you better know what you are doing and be prepared to pay. The Bullet head casting is crap to say the least and a good pocket port job and 3 angle valve grind will do wonders. Do not be temped to hog material out of the intake tract as it is too large as it is, which results in too low a flow velocity for optimum performance. If your budget allows, fit a 2mm larger inlet valve.

Since you are in the head, a set of lighter Samarat rockers would reduce reciprocating mass. Be very aware that the stock Samarat offering leaves a lot to be desired and you will want to bolt it up and hone to spec before fitting. Since you will be revving it more, you may question the quality of the pushrod adjusting nut - Hitchocks makes a quality replacement

With the head work the stock carb will now be lacking, and depending on how much head work you do, a 30 or 32mm carb would be appropriate. - I went for a Mukini 32mm TM flat slide with my head work and cams but this is a lot of carb for most bikes.

This is about the limit for a warmed over budget RE.


One could try to re-phase the cams but the compression must be increased to 8.5 or 130 psi cranking pressure to make this work, which will shortly result in a blown bottom end, and all the other good stuff in the following paragraph. There is really no way around this design problem with the RE engine. If you are not prepared to buy a new bottom end, then stop at the Stage 2 simple head work.

Stage 3 involves compression and cams which leads to failure of the stock bottom due both to the pressure and the new ability to rev. The stock case bearings are very poor and needs to be replaced with quality imported SKF bearings. You will also need a roller big end from Alpha, steel rod, and high compression piston. All this now requires balancing of the crank. The additional compression causes more heat, so you need an alloy cylinder as well. Lets not forget the crappy clutch that now will not hold the power so a new one from Barnett is called for. The points ignition and the crappy mechanical advance will not cut it either so you are now in the market for either a Boyer micro digital or Pazon unit. Do not be tempted to fit the RE ignition module as you are still stuck with the traditional (did I say crappy again) advance mechanism
As you can see this is getting complicated and expensive very fast.



Do not trust the metallurgy in the stock aluminium rod in a HiPo engine, and typically a 300 USD steel rod from Carillio is the weapon of choice. ACE in the USA is developing a new aluminium NASCAR style rod with a shell bearing and removable end cap. The big advantage is that the expensive Alpha roller will not be required. I am in line for one of these c/w his new piston and rebalanced crank assembly and will report once I have it in hand and installed.

The ultimate engine mod IMHO is the ACE 535 Fireball package from the USA. This is a very special head by Joe Mondello, lightweight 535 piston, cams, Carillio rod, blueprinted alloy barrel, and Mikuni TM 32 on a custom manifold. Designed to work as a package and expected to push 40 rear wheel HP on the dyno. Buy it if you can afford it as there is nothing that flows better.

Good luck with the mods and finding someone that know what he is doing - I do my own work for this very reason.

As always, YMMV