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Engine Mods [message #217336] Thu, 08 July 2010 22:49 Go to next message
SPAL is currently online SPAL  UNITED KINGDOM
Messages: 835
Registered: June 2009
Location: London
(7) 125 GP Winner
Hi All,

Been doing a bit of reading up on engine mods available to increase power output and would value opinions/comments on any works youv'e had done in the past.

Now, I know that power don't come cheep, but it appears that certain mods offer better say " hp per £" than others and whilst I'm probably not going to end up doing any internal engine mods to my current project I figured its ok to discuss.

Appears that mods include:

Replace exhaust (to free up whats already there)
Airbox mods (to improve airflow , I guess)
Reprofile Cams ( to ????)
Head gasflowing (to improve airflow, I guess)
High Compression Pistons ( to (God knows)
Skim Head
Lighten & Balanced Con Rods
Lighten & Balance Crankshaft

Theres probably other stuff,

Don't know if theres a logical way that each of these would be done together, ie ( don't do 1 without also doing 3,5,) for example.

Your thoughts appriciated

SPal
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Re: Engine Mods [message #217337 is a reply to message #217336] Thu, 08 July 2010 22:53 Go to previous messageGo to next message
andy_scouser is currently offline andy_scouser  UNITED KINGDOM
Messages: 3293
Registered: June 2003
Location: Liverpool
(11) MotoGP Podium Finisher
The cheapest bang per buck has to be to lower your gearing. ESP on an sp1 or 929
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Re: Engine Mods [message #217341 is a reply to message #217337] Thu, 08 July 2010 23:07 Go to previous messageGo to next message
SPAL is currently online SPAL  UNITED KINGDOM
Messages: 835
Registered: June 2009
Location: London
(7) 125 GP Winner
Hi andy,

Yeah agreed, but that don't increase bhp, surely, Confused just the way you use what youve already got.

SPal Grin
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Re: Engine Mods [message #217345 is a reply to message #217341] Thu, 08 July 2010 23:23 Go to previous messageGo to next message
DrMartin is currently offline DrMartin  UNITED KINGDOM
Messages: 4746
Registered: January 2004
Location: Boredsville
(13) MotoGP Champion
I dropped my gearing. 1 up on the back sprocket + 1 down on the front. I figured I didn't need 165 top end but could do with nippier acceleration and it felt good Thumbs Up

As for all those other mods you've listed some are cheaper than others but my view is that what ever you gain in bhp you will lose somewhere else, either in long-term reliability / engine life or in useability: eg higher top end but lose torque at the bottom end, or unstable low speed riding etc. All fine if it's only on the track but not so handy on a road bike.
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Re: Engine Mods [message #217347 is a reply to message #217341] Thu, 08 July 2010 23:26 Go to previous messageGo to next message
drew70 is currently offline drew70  UNITED KINGDOM
Messages: 1508
Registered: January 2007
Location: Edinburgh
(8) 250 GP Racer
It depends what you want to spend really, as Andy says the old gearing trick will certainly liven her up a bit.
If you go down the cams route that ain't as expensive as you might think. I got mine done for the 600 by Kent Cams it cost £275 ish and that included adjustable gears Grin
If you get them done i wouldn't skim head. Light cleanup on the inlet ports, ignition advancer and a good bit time on setting up with dyno will probably be enough.
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Re: Engine Mods [message #217348 is a reply to message #217347] Thu, 08 July 2010 23:29 Go to previous messageGo to next message
andy_scouser is currently offline andy_scouser  UNITED KINGDOM
Messages: 3293
Registered: June 2003
Location: Liverpool
(11) MotoGP Podium Finisher
Exhaust and any air flow mods must be done first I'd imagine. Full system rather than can. Gearing gives the same as more power but lowers top end. Also a benefit of bringing gears closer together so you can more easily keep in the sweet spot
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Re: Engine Mods [message #217350 is a reply to message #217336] Thu, 08 July 2010 23:37 Go to previous messageGo to next message
DrMartin is currently offline DrMartin  UNITED KINGDOM
Messages: 4746
Registered: January 2004
Location: Boredsville
(13) MotoGP Champion
Or have a word with these guys Twisted Evil Thumbs Up

http://www.noswizard.com/
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Re: Engine Mods [message #217351 is a reply to message #217350] Fri, 09 July 2010 00:15 Go to previous messageGo to next message
andy_scouser is currently offline andy_scouser  UNITED KINGDOM
Messages: 3293
Registered: June 2003
Location: Liverpool
(11) MotoGP Podium Finisher
Now your talking doc
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Re: Engine Mods [message #217352 is a reply to message #217351] Fri, 09 July 2010 00:15 Go to previous messageGo to next message
andy_scouser is currently offline andy_scouser  UNITED KINGDOM
Messages: 3293
Registered: June 2003
Location: Liverpool
(11) MotoGP Podium Finisher
Drew. Do cams give all over torque? What's the draw backs?
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Re: Engine Mods [message #217358 is a reply to message #217352] Fri, 09 July 2010 08:30 Go to previous messageGo to next message
drew70 is currently offline drew70  UNITED KINGDOM
Messages: 1508
Registered: January 2007
Location: Edinburgh
(8) 250 GP Racer
Andy im not sure about the torque if it has improved but the bike pulls like a train from low rpm right up to red line.
Not any draw backs really, it still idles like a std bike so nice and smooth. There will be increased wear with higher forces going on with the valves getting pushed harder and open for longer. The only other thing was shimming the bugger, i had to enlist the help of an engine builder to make the right sizes for me as the shim sizes std were all about 2.00mm and went up to 2.85-3.00mm with the re-profiled cams. Thumbs Up
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Re: Engine Mods [message #217359 is a reply to message #217336] Fri, 09 July 2010 08:34 Go to previous messageGo to next message
Swiss T  UNITED KINGDOM
Messages: 5166
Registered: February 2004
Location: Sunny Stockport
(14) Eddie Lawson
Spal

I would just restore her to original spec. She will never have the kick of a modern sports machine no matter what you do or spend.

Long term reliability & value will be better if you keep her as original as possible.

My 893 is original apart from a dynojet kit [120 main jet instead of 115], K&N air filter & race can. The power delivery is very different to the newer bikes I have ridden; it has little then "bang", it goes mental & gives you all its got; great fun.

By the way, I have since learned what may have been the problem with the rebound adjuster on the forks; something to do with a nut being the wrong way round; I have a link if you need it.
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Re: Engine Mods [message #217367 is a reply to message #217359] Fri, 09 July 2010 10:30 Go to previous messageGo to next message
SP2 Riley is currently online SP2 Riley  UNITED KINGDOM
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Registered: January 2008
Location: peterborough
(11) MotoGP Podium Finisher
Swiss T wrote on Fri, 09 July 2010 08:34
Spal

I would just restore her to original spec. She will never have the kick of a modern sports machine no matter what you do or spend.

Long term reliability & value will be better if you keep her as original as possible.

My 893 is original apart from a dynojet kit [120 main jet instead of 115], K&N air filter & race can. The power delivery is very different to the newer bikes I have ridden; it has little then "bang", it goes mental & gives you all its got; great fun.

By the way, I have since learned what may have been the problem with the rebound adjuster on the forks; something to do with a nut being the wrong way round; I have a link if you need it.



agree with all of that Thumbs Up

if you mess with it it will be worth fook all Thumb Down
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Re: Engine Mods [message #217368 is a reply to message #217336] Fri, 09 July 2010 10:44 Go to previous messageGo to next message
Kakugo is currently offline Kakugo  ITALY
Messages: 3370
Registered: August 2003
Location: Lugdunon
(11) MotoGP Podium Finisher
The dirtiest cheapest way to increase power is to run oxygenated fuel. Without ANY other mod you are bound to see an increase of 3-5 bhp depending on engine and fuel.
Of course there are a number of drawbacks. Oxygenated fuel is ferociously expensive and, as much as Nutec, Elf etc say their latest products are much more stable than they used to be, they still requires careful handling. No, you are not going to be blown to Mars in a green explosion if you use a drop more than needed, but you will need to drain and flush the whole fuel system thoroughly with regular unleaded after each use. Cannot let it sit in the tank between trackdays or you'll end up with a large repair bill. No Finger
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Re: Engine Mods [message #217384 is a reply to message #217368] Fri, 09 July 2010 14:03 Go to previous messageGo to next message
cbrgaz is currently offline cbrgaz  UNITED KINGDOM
Messages: 619
Registered: June 2004
Location: Mostly at work
(6) 125 GP Racer
Early blades respond best to 4 things........k&n filter, dynojet kit, full race exhaust system and ignition advancer.
If you need more power after that then get the cylinder head gas flowed.
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Re: Engine Mods [message #217394 is a reply to message #217384] Fri, 09 July 2010 15:03 Go to previous messageGo to next message
SPAL is currently online SPAL  UNITED KINGDOM
Messages: 835
Registered: June 2009
Location: London
(7) 125 GP Winner
Hi All,

Wasn't really considering any internal mods for this engine, just now started playing about with engine I realised its a whole subject that I know nothing about.

Just looking for info, no definitive purpose.

SPal
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Re: Engine Mods [message #217395 is a reply to message #217359] Fri, 09 July 2010 15:06 Go to previous messageGo to next message
SPAL is currently online SPAL  UNITED KINGDOM
Messages: 835
Registered: June 2009
Location: London
(7) 125 GP Winner
Hi Swiss,

Adjusters fine cause 1 of my ones was u/s and 1 of the new ones u/s, so built up 1 set of good forks with bits from both.

THink its a bit more than just a nut cause the brass screw (rebound) i think is siezed on both adjusters.

Thanks once again.

SPal
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Re: Engine Mods [message #217461 is a reply to message #217384] Fri, 09 July 2010 23:00 Go to previous messageGo to next message
Pipe is currently offline Pipe  UNITED KINGDOM
Messages: 9472
Registered: June 2003
Location: Mainly Unit 4 but sometim...
(20) Michael Doohan
cbrgaz wrote on Fri, 09 July 2010 14:03
Early blades respond best to 4 things........k&n filter, dynojet kit, full race exhaust system and ignition advancer.
If you need more power after that then get the cylinder head gas flowed.


Thumbs Up Absolutely Gaz smile
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Re: Engine Mods [message #217500 is a reply to message #217336] Sat, 10 July 2010 09:57 Go to previous messageGo to next message
Quazi is currently offline Quazi  UNITED KINGDOM
Messages: 10668
Registered: March 2004
Location: Hiding behind Hadrian's W...
(21) Valentino Rossi
I honestly wouldn't bother.




You will not get what you're looking for out of that engine, you'd be better off getting a different bike.
Just rebuild it as a cleaned up example of an early blade.

The only thing I would bother doing, would be to smooth out the inlet and exhaust ports with a porting kit, you don't have to do anything drastic to them just smooth them out get rid of the casting defects of spots and ridges.

I do it to every engine I take apart, works a treat, but you have to know what you're doing and it takes time. smile
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Re: Engine Mods [message #217523 is a reply to message #217500] Sat, 10 July 2010 21:56 Go to previous messageGo to next message
SPAL is currently online SPAL  UNITED KINGDOM
Messages: 835
Registered: June 2009
Location: London
(7) 125 GP Winner
Hi All,

A SINCERE APOLOGY

I have mislead you! Whilst some of you may have read some of my posts and thought at various stages "does he know what he's doing" the real truth of the matter is :

I am a complete COCK who although working on a tightish budget for a refurb, is actually thinking of turning it into a 500 brake horse power misile that will be ridden to the next motogp title.

FFS give me a little credit, I just wanted some info, I've never done internal engine mods and the subject interests me.

Some of you guys have obviously involved yourselves in these subjects to a lesser or greater degree and I was looking for your experiences / opinions on the various mods I named in my origional post.

Just for the record:

" I have no plans to complete or attempt any of the following modifications to this 93 blade"

1 NOS conversion
2 High compression pistons
3 Head skimming
4 Crank Balancing
5 Con Rod Balancing
6 Turbo charging
7 Converting to run on economy 7
8 wtf

Hope that clarifies:

SPal Laugh
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Re: Engine Mods [message #217534 is a reply to message #217336] Sat, 10 July 2010 22:40 Go to previous messageGo to previous message
Quazi is currently offline Quazi  UNITED KINGDOM
Messages: 10668
Registered: March 2004
Location: Hiding behind Hadrian's W...
(21) Valentino Rossi
Thank fuck for that, I dn't think my heart would have taken it. Laugh
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