From standard air box to foam air filter

[kejj]

So I'm thinking of ditching the air box and filter and put a modern foam filter in place.

Ramiar, K&N och similar.

I will need to up jet of what I understand. But does anyone happen to know how much they had to go when switchin?

Currently I'm on a 200cc SIL stage 4 engine, jetex carb with 50 choke, 50 starter jet and a 123 Main jet plus a scoot RS sport exhaust (that copy thingy)

Any good tips?

[joey]

...fit 30mm dellorto & evergreen filter.....hope you have replaced indian big end bearing...?

[joolz]

Not wishing to start an argument (well perhaps )

Is this 'replace the bearings on a SIL' a load of old bollox? (NOT aimed at ^^^^^ I have heard it a lot)

The reason I ask is this.... I am a Stress Analyst (Mech Eng) by profession and see a fair few bits of mechanical tech (including bearings) lol

Do you realise how difficult it actually is to buy s**t bearings?
If the above is to be believed then SIL must go out of their way to do this and the cost saving would be negligible in practice. Why on earth would they do it?

I do Finite Element Analysis for a living (FEA)... now SIL also have FEA tech in house (from their webshite) ... This is NOT the tech of penny pinching engineering noobs (its state of the art stuff).
TBH I would guess that a new SIL unit would/should be far better than any 30 year old Itallian motor with its slack tollerances/manufacturing methods etc even when new.

However I have NOTHING to back this up and I know some of you lot have loads of practical experience in this matter.

I am wondering (and hoping LOL) that the 'dodgy bearings thing' is an ancient throwback to the days when SIL were a little more slapdash than they are today.

Anyone got ACTUAL experience blowing up SIL bearings on a new engine (say in the last couple of years)?

Ta mi dears

Julian


PS Sorry for the hijack dude

PS I am about to 'upgrade mine to a Mikuni carb + foam filter + ScootRS exhaust (on SIL bearings )

[goldeneye]

hello julian.like you say, you"ve no experience . indian bearings are mainly given shite press on the lambretta front, because the big end bearings on SIL, and LML for that matter, seem to be made of cheese. ive had a couple of SIL cranks sieze solid on the big end, and have changed about five LML cranks for the same reason on peoples scooters. well documented, other forum members have seen first hand the damaged cranks, and the consequent bodywork damage from riders having an "off" due to the engine locking up . iv"e no problem with indian parts "fit for use", indeed, i ran an SIL GP200(standard) as my only transport for quite a few years. it may be hard to make a shite bearing, but it can be hard to make a bearing fit the conrod/crank web/crank pin application/combination, as some later SIL cranks show. they are used for low revving town use in india, not rally use like over here. anything over 3000rpm isnt heard of in lucknow. SIL have done a batch of japenese bearing cranks, especially for UK use. maybe they can answer your question a in more depth.

[kejj]

Staying of the bearing discussion (I'm changing it when it siezes)
I've no wish to upgrade or trim anything, I'm quite happy with the standard carb and if the jetex breaks I'll by a new one for 25£ http://bit.ly/9YJrHn
If I'll upgrade the carb then I feel that I'm going down the "upgrade/trim" lane. I like it easy and standard mostly.
Now, I've changed my rusty old 60s tank with a new stainless one. I've washed and cleaned it thoroughly and installed it. It is a few inches bigger and that makes it difficult to fit the air box in again. Plus I've heard that a foam filter breathes better.

So back to my question (maybe the dealers using this forum can answer to this) what sizes of jets should I by and try out when changing to foam air filter?

Best

[joolz]

Firstly Kejj sorry for the hijack ...

And thanks goldeneye for a great reply.....

So we are talking about the crank as opposed to all the bearings? (I have heard people saying 'replace the lot')..
Swapping the crank is not such a massive job, as you know (although one I havent done for 20+ years ).

The only experience I have of blowing up a crank was on an Italian SX200 in about 1985 -- not fun!

Back to filters....

I bought one of these jobbies http://scootrs.com/moreinfo.cfm?Product_ID=579
Goes on the standard hose (or so they say) ... Not fitted yet

Carry on

[soulsurfer]

Cam Lam Breathe Easy/Tino/Evergreen filter seem to be the best for our engines these days.

[dapper]

Sorry to jump in on the thread hijacking, but read somewhere that when some cranks are put together, swarf is left in around the bearing. Can't remember if it was this or another forum, but the guy said that he always flushes the bearing out before then oiling it, and he was surprised at what came out. May have some bearing on the thread

[joolz]

May have some bearing on the thread

Shamefull

really shamefull