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Sil crank... stage 4 200 ?

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Sil crank... stage 4 200 ?

Postby Lockman69 » Sun May 26, 2019 6:37 pm

Has anybody had any luck using the standard Sil 200 crank?

I have always binned the standard crank or had the rod and bearing replaced... but my son has got a brand new engine that he wants to run with a big carb and expansion... money’s tight so the temptation is to keep the existing crank and bearings, hence my question... any opinions welcomed

Cheers
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Re: Sil crank... stage 4 200 ?

Postby al pushpak » Sun May 26, 2019 7:29 pm

Hmmmm... it could be ok to run it with that set up but I think it was AF Rayspeed that stated that std Sil cranks are fine on a std set up but seeing as it's a stage 4 then I would class it as a mild tune, I know you said funds are tight but for the sake of about £80 for a better quality rod & bearing replacement I think for peace of mind it would be worth doing ;)
Last edited by al pushpak on Tue May 28, 2019 7:09 pm, edited 1 time in total.
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Re: Sil crank... stage 4 200 ?

Postby Dazts1 » Sun May 26, 2019 7:31 pm

Defo don’t do that. I don’t think I’ve heard of one that hasn’t failed before 1500m. Your webs will be fine to use just new rod and bearing. This will be your cheapest option if money’s tight. And you’ll end up with a mint crank. Pm sent.
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Re: Sil crank... stage 4 200 ?

Postby gaz_powell » Sun May 26, 2019 7:45 pm

If its a genuine brand new SIL engine as a minimum you should;
Up rate the crank - use the SIL webs with a decent rod kit
Change the stretchy Rolon chain
Change the crank seals to Rolf or Corteco
Change the needle roller bearings on the cluster and endplate to decent INA
Check the end plate float
Redo timing
All the above from experience.
Never had any issue with the other roller bearings fitted
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Re: Sil crank... stage 4 200 ?

Postby dickie » Sun May 26, 2019 8:17 pm

And the front sprocket 2 piece bolt for single piece one.
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Re: Sil crank... stage 4 200 ?

Postby Lockman69 » Sun May 26, 2019 10:17 pm

Thanks Guys... the bank of dad to the rescue....again :D
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Re: Sil crank... stage 4 200 ?

Postby missing lynx » Sun May 26, 2019 10:29 pm

I ran Rapido 225 on a sil engine for about 5000 mile the only thing I replaced was the hub bearing the chain chain guide and bronze bush in the clutch and upgraded clutch in those miles
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Re: Sil crank... stage 4 200 ?

Postby dickie » Sun May 26, 2019 10:47 pm

missing lynx wrote:I ran Rapido 225 on a sil engine for about 5000 mile the only thing I replaced was the hub bearing the chain chain guide and bronze bush in the clutch and upgraded clutch in those miles

My grandad smoked 40 woodbines a day and lived to be 84.
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Re: Sil crank... stage 4 200 ?

Postby Scooterslag » Mon May 27, 2019 1:32 am

I had chiselspeed replace the shite SIL bearing for a decent make a couple of years ago , can't remember the cost (old age kicking in :) ) but it wasn't big coin. I think the SIL conrod is fine in a standardish motor - its normally the crappy bearing which falls apart or welds itself together. Might be worth giving Chisels a call. Paul
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Re: Sil crank... stage 4 200 ?

Postby ULC Soulagent » Mon May 27, 2019 3:48 pm

dickie wrote:
missing lynx wrote:I ran Rapido 225 on a sil engine for about 5000 mile the only thing I replaced was the hub bearing the chain chain guide and bronze bush in the clutch and upgraded clutch in those miles

My grandad smoked 40 woodbines a day and lived to be 84.

:lol: :lol: :lol:
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Re: Sil crank... stage 4 200 ?

Postby missing lynx » Mon May 27, 2019 7:42 pm

I'm only tell my personal experience! I use to ride the scooter hard 2s up I've got a mate doing the same at the moment and he's clocking up the miles with no issue with a SIL crank and I know plenty of guys who have forked out on expensive cranks only for them to twist on them !!
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Re: Sil crank... stage 4 200 ?

Postby dickie » Mon May 27, 2019 9:15 pm

I'm not mocking you (well maybe a little) but just pointing out that lack of evidence is not evidence of non existence.

What you're saying is data, and useful but it isn't the only story.

Sorry if I seemed like I was taking the piss.
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Re: Sil crank... stage 4 200 ?

Postby missing lynx » Mon May 27, 2019 9:37 pm

Fare enough but how many people that have commented have had a Sil crank let go on them or how many have ditched a Sil crank to have the "better" crank twist on them ?
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Re: Sil crank... stage 4 200 ?

Postby dickie » Tue May 28, 2019 5:45 am

missing lynx wrote:Fare enough but how many people that have commented have had a Sil crank let go on them or how many have ditched a Sil crank to have the "better" crank twist on them ?

You could well be right. In all honesty, I have never used a standard crank. Every motor I've ever had has come to me as needing complete rebuild. I've used SIL cranks in a couple but with Yamaha 110 rods and new bearings. So, personally, I have zero experience. I'm only taking the word of people with more experience than me.
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Re: Sil crank... stage 4 200 ?

Postby MickYork » Tue May 28, 2019 7:28 am

Indian bearings are hit and miss. Some seem very good quality others are very poor. What's the bearing in a SIL crank ? You don't know ?
For £50 +/- in the heart of the engine i think it's a no-brainer.
Better to have a quality known part rather than a part that may be ok...or not (especially if you intend putting in some decent miles).
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Re: Sil crank... stage 4 200 ?

Postby gaz_powell » Tue May 28, 2019 8:28 am

If you compare the standard SIL big end end bearing to any other decent type say even NRB, you would think twice about using them.
I love SIL webs and use them all the time in high powered motors but wouldn't trust a standard one even in a standard motor.
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Re: Sil crank... stage 4 200 ?

Postby Adam_Winstone » Tue May 28, 2019 9:21 am

^... Agree 100%. Original Indian crank bearings have a history of failing, often only lasting for the running in period. No, not all, with some working perfectly well for the lifetime of the intended service, bit the rate of failure is a real concern.

I've not had one fail but I have stripped one out that was blued, with the bearing rollers absolutely shot.

Crank failure was one off the biggest issues when dealers were selling new SIL assembled GPs and the reason why dealers like RS used to immediately strip new machines and put a more reliable crank in, otherwise machines were coming back during the warranty period.

The web's are great, the rods not good but the bearings are rubbish.
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Re: Sil crank... stage 4 200 ?

Postby Bofs » Tue May 28, 2019 4:37 pm

A mate of mine bought a Resurrection Scooter restored GP200, guess what. Big end welded itself up after less than 500 miles. Follow the general consensus and change it.
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Re: Sil crank... stage 4 200 ?

Postby dscscotty » Tue May 28, 2019 6:32 pm

Please take notice of the advice regarding Indian crankshaft bearings, they break, I have the facility to strip and build my own cranks and regularly see failures of which the damage can be catastrophic, Indian webs whilst not pretty are a very tight pin fit and a good base for quite a high spec crankshaft. yes the rods are ok for standardish 10bhp ish motors if fitted with a decent big end bearing, but is it really worth it. There are some good cranks out there and there are some poor cranks out there, many look good but have a low web/pin fit, causing twisting/alignment issues. Don't take a chance, get it uprated!
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Re: Sil crank... stage 4 200 ?

Postby Warkton Tornado No.1 » Wed May 29, 2019 12:05 pm

dscscotty wrote:Please take notice of the advice regarding Indian crankshaft bearings, they break, I have the facility to strip and build my own cranks and regularly see failures of which the damage can be catastrophic, Indian webs whilst not pretty are a very tight pin fit and a good base for quite a high spec crankshaft. yes the rods are ok for standardish 10bhp ish motors if fitted with a decent big end bearing, but is it really worth it. There are some good cranks out there and there are some poor cranks out there, many look good but have a low web/pin fit, causing twisting/alignment issues. Don't take a chance, get it uprated!


Do you happen to judge the fit of the pin in the webs by the force required? The reason that I ask is that I have an hydraulic press that I have yet to put into use, as it requires rebuild, but I have no gauge with it. Do you always weld as a matter of course, rely on fit (dependent upon force) or use any type of Loctite?

Don't worry! I'm never going to be a competitor to you, but I would like to have a go @ a crank or two.Any good advice welcome! TYIA :D
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