Scorpa - Engine Query

[dgshannon]

I'm goana run it at 60:1 or 62.5:1 with TTS and possibly optimax. I really hope that helps the knocking, as otherwise i love it.

<{POST_SNAPBACK}>

Forget the 50, 60 or 62.5:1, as it is overkill. Get yourself some fresh, quality, fuel and a good synthetic oil. I am sure that the Castrol is fine, but as with dfwilson, all my experience has been with Motul. I have owned 3 different SY250, and run each of them at 80:1 using Motul. For fuel, I would mix premium pump gas, with 114 octane racing fuel, at a 50:50 ratio. Mixing in racing fuel is not a necessity, but the increased octane does help prevent knock.

Prior to the Scorpas, I had two different Montesa, and a Beta. In these I ran Silkolene, but also at 80:1. With quality synthetic oil, you just don't need the high oil content you have been suggesting. Remember, that as you take oil content out of the mix, you are adding fuel in to replace it. This alone makes the the mixture more rich. Don't start moving the carb needle to a richer setting, until you have fresh fuel and a proper premix ratio.

[barrybaines]

I emailed Scorpa and they said i should run 2.5% oil..... what is that as a ratio.

IMHO I would go with the opinion of the manufacturers of the bike could be worth getting Yamahas` opinion on the matter though

[nitjay - hrc]

Shannon, whilst your views are obviously welcome, here in the Uk we basically get the choice between 95 or 98Ron Fuel Scorpa Reccommend 95Ron but im going to use Optimax @ 98Ron for at first just see how she likes it, i read on a french forums (in french) Scorpa saying something about running 1.5% oil at 98 fuel the only reason that Scorpa recommend such a strange fuel ratio (40:1) is because the engine is off a motorcross bike, hence that giant kickstart level (which is labelled kickstart incase you didnt know)

My dad reckons 50:1 i reckon 60-65:1 Scorpa reckon 40:1 other recommend 70:1 +

next time im getting a fourstroke !

Ive asked Birkett but he hasnt answered my email yet.

Edited March 14, 2006 by Nitjay - HRC

[steveo]

I think you will find that pretty much all the engines have this idle knock,some more than others.

Have had each Sy250 since 2001 an have had this characteristic as part of the deal.

Have used Motul 800 at 100;1 in the first three bikes 2001,2002 and 2003 with no problems.

The most annoying thing I found in using this oil was it quickly gummed up the exhaust,which in turn changed the crisp sweet exhaust note to a more doughy restricted blat.This was due to the low revs mostly used by the machine in the way I practiced.Just does not get hot enough to burn the oil

The seals of the middle resonator unit where the header pipe and rear muffler enter and exit were seeping unburnt oil residue continually.

To put your finger into the rear exhaust hole would give a black wet oily result.

The other thing I would mention is I would replace the spark plug every three months and always it came out as black and sooty as ....

Over the last two years,again with new bikes at the star of each season, I still premix premium (98) unleaded at 100;1 but am now using Motorex 2T Speedmix-Low smoke.

The difference is dramatic.

All the above problems have been eliminated and the motor stays crisp and sweet.

To now stick your finger in the exhaust there is only a light black soot ,no wet oil residue.

It may be worth looking at the condition of the oil build up in your exhaust system to see how it looks.

The whirring noise when you release the clutch is the gears.

My 2004 bike sounded like a Formula I.

The bikes that really sang a song with gears were the Aprillas in the early 90's.

I agree with DLS dont go changing needle heights till you have tried these suggestions.

The other thing that does come to mind is has the needle height setting been altered from its standard setting by the previous owner?

[feetupfun]

Also i know Betas do it, but do any of your Scorpa's Whine?

<{POST_SNAPBACK}>

Hi Nitjay

The whining noise is just one of the good reasons to have the Yamaha engined Scorpa. The whining sound you are hearing is produced by the straight cut primary (crankshaft to clutch) drive gears. It is usually loudest just as the clutch is engaging under load. Many other bikes have angled gear teeth in the primary drive to prevent this noise. I personally reckon the sound is very cool because it means that the crankshaft and gearbox is free of axial loading and less of the motor power is being lost in that part of the transmission. There is absolutely nothing to worry about from this noise. The motor in the SY250 is actually quite mild as far as primary drive noise is concerned. My 1976 KT250 has the standard straight cut primary drive gears in perfect condition and is so loud that spectators can clearly hear the whining as I ride past.

If you are seriously into the mechanical noises of your bike, do this noise test: Warm the engine up fully and ensure the clutch plates have let go. With the bike stopped and motor idling, listen carefully as you shift into neutral. There should be a change in noise (gears rattling but nothing to worry about). Again listen carefully as you then pull in the clutch. There should be another change (clutch plates rattling and again nothing to worry about). You sound like just the guy to enjoy that sort of thing. You aren't the only one into motor noises. One of my favourite videos is a local club production which has a great sound track including the primary drive whine from a Yamaha TY250Z (same engine as yours) and a KT250 as they ride past in sections.

[nitjay - hrc]

Thanks so much for all your help, you have settled any fears i had over problems with the bike!

The knock iam talking about is pretty much the same as the one coming from the bike in this video *****CLICK ME***** Except mine is slightly deeper and a little quieter.

On closer inspection of the exhaust, there isnt any goo in there, but a sort of thickish layer of dry soot however the exhaust note is nice and mellow and doesnt pop, the previous owner was running the bike at 50:1 on TTS.

Thanks loads for all your help, i cant wait to get out on this machine and test it in the sections! (unfortunately that might not be for over a month!!!)

by the way, i new i had heard the whiring somewhere else other than Betas, from the Climber ive been riding whilst i was waiting for my new bike!

Edited March 15, 2006 by Nitjay - HRC

[dgshannon]

To put your finger into the rear exhaust hole would give a black wet oily result.

<{POST_SNAPBACK}>

I once knew a girl like that.

[jools]

Nitjay, I have an 06 sy250 which is my first scorpa aswell. I've found when you start it from cold the engine does knock a bit but it quietens down as it warms. the dealer i got it from said not to ride it straight away from cold but leave it for 10 - 15 mins ticking over on the kick stand. Also i run it on ipone samouri at 80ml to 5 litres of shell optimax.

I would be very surprised if you had engine problems. i rode mine yesterday at a road trial, with some sections you had to really thrash the bike and the fan came on twice!! does'nt pink or anything, superb, enjoy it!!!

[nitjay - hrc]

If your o6 one sounds like that, then thats great (from my p.o.v) because it means theres nothing wrong with mine! I cant wait to trial it, i still havent been able to ride it properly yet!

Ill just have to not thrash it when i warm it up, give it a bit of time before i go flying into any sections!

Thanks!

[boofont]

the only reason that Scorpa recommend such a strange fuel ratio (40:1) is because the engine is off a motorcross bike, hence that giant kickstart level (which is labelled kickstart incase you didnt know)

<{POST_SNAPBACK}>

What motorcross bike is that then? Never seen any TYZ's getting raced around my local track that's for sure!

[downunder]

Boo

YZ250 but I think they used different rings

Guess what I just got ....and it doesn't need anything trick to make it look schmick!

I like 50:1 with Motul 800 and 98 octane, who cares about a little smoke !

You know the old addage...... Where there is smoke there is fire!

Edited March 27, 2006 by downunder

[essex rider]

Beautiful Bike, Love the triple clamps and the new colours. Add some carbon or kevlar fork and exhaust protectors and it will look super trick

[nitjay - hrc]

Has anyone got a rear exhaust guard, do they look anygood? birketts got one but at

[dfwilson]

Has anyone got a rear exhaust guard, do they look anygood? birketts got one but at

[nitjay - hrc]

Ive been having a little play on my bike this morning, and listening to it and inspecting it (perfectionist at work) I wish i could just ride it and forget, but until im in a proper trial i wont be able to.

It hasnt been even started for a month, and i started it up (took about 2 kicks with choke on) it took a while for me to be able to turn the choke off without it stalling, but i expected this as it hasnt been run for ages. When it was ready i just rode it round in some figure of eights, and going through the gears a little. I wanted to test my slow action throttle all worked properly. When i put it away after about 10-15 mins of running i noticed the fan had come on, i just wondered if this was right as i hadn't exactly been thrashing it about.

Ive still got the same fuel i had in it which is regular 95 with Silkolene oil at about 50:1 and i could still hear the knocking sound, but once it warmed up it was definately better, and i could only hear it loudly when i put my ear to the cylinder. I just wondered how i knew when it was pinking (as it was loudest on the climbdown from higher revs) and when it was other things.

Also on this, ive been following the IWTC and i am sure that the 06 Sherco makes the exact same noise, ive noticed it in nearly every round i have watched that the sherco has been in.

Im sorry to ask so many questions, but im still learning about mechanical things, and i love to be able to diagnose everything! If anyone could shed some light it would be much appreciated.

i was also suprised how much of a difference a slow action throttle made to the feel of the bike, theres no immediate slam of power, which is pefect for me as i dont ride steps.

Edited April 13, 2006 by Nitjay - HRC