Well, I'll start a little thread here as I need POWER, I know I've said in the past I don't but that may have been a lie, Elegy (Dave Reynolds) on his rocket ship of an RGV250 vj23 passed me down Park Straight at Cadwell, and pulled about 5 yards between Park and Barn which basically covers 80% of the tricky bit of Cadwell Park (pick out the corners here), he then breezed passed 4 400's and pulled about 50 yards on me between Barn and Coppice, it took me 2 laps to get passed one of those 400's, even so I had to put a horrid block pass on him and by then I couldn't even see the other 3!

So, a limp plan is afoot to improve it's earth shattering 53bhp (GT dyno proven no less). Watch this space, like me it won't be going anywhere fast
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i take it were on about your 28 fontyyy can you not go down the pgm2/3 route and ditch the pgm 4 and loom and the flywheel for 18/21 hrc items ?

Could do, but it's a relatively tiny improvement and there's an HRC '28 flywheel which is smaller and lighter than anything else anyway.
And I like the PGMIV

My bike dyno'd at 9 horse lower than it has in the past, that's just wear and tear, anything up around the 65 bhp mark would be good and about a 25% improvement on what I've got now. That's only 3 bhp more than it's made in the past.
I think there's a line to draw between power and longevity and (of course) what I can actually use, Dan (Gecko Racing)'s '28 absolutely flys, it's probably the fastest thing out there but even when it does stay togeather it's going to want a rebuild after a trackday or meet.

+ all RS stuff except the cases is legal in F250 if you want to spend a fortune on engines and maintainence.

And either are a rather boring know to work route.
I know of a source for good copies of the HRC '28 ram air box, there's VHM heads to try as well as different fuels, 010 (and other) cards etc. I'd rather have a play with that sort of stuff.

I think keep the porting fairly stock, try and keep ring life nice and long so I can get plenty of practice in without worrying about it.
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Is avgas legal in the f250 ? if it is as you said you can run VHM heads with avgas inserts

Hi, interested in what you are saying about HRC cards etc but i do think a 9hp loss due to wear and tear is a bit excessive. My TZ250 even with worn rings only lost possibly 3bhp and that was pushing out approx 75bhp.

Surely your 25% loss must be due to other issues not just wear and tear.

With regard to Avgas i used to run it when i raced with Derby Pheonix and no one complained because i was never fighting for the lead. If it gives a reliable engine then go for it. Of course you could source the BP track day fuel at 102 octaine which is available at petrol stations near some race tracks!!!

http://www.bp.com/genericsection.do?categoryId=6621&contentId=7017179
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MC21 300
Aprilia RS250 track bike

t3racing wrote:a 9hp loss due to wear and tear is a bit excessive. My TZ250 even with worn rings only lost possibly 3bhp and that was pushing out approx 75bhp.

The level of power is irrelevent, you ever swap a fresh top end for a 15 y/o one that you then did 1/2 dozen track days and 20 races on?
The bike made 62 bhp 2 years ago, then made 53 on the same dyno recently.

There's nothing "wrong" with it (if you don't mind struggling to pass flyweight 13 y/o's on 125's), it's done a track day and 5 race days since then, but it is worn out and jetted rather safely.
Andy guessed at 10 bhp down, he wasn't too far off.
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So are you saying you have not replaced the pistons/rings in two years of racing and track days?
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MC21 300
Aprilia RS250 track bike

Yes
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Blimey your a brave man, just goes to show these bikes can be thrashed and abused!!!!
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MC21 300
Aprilia RS250 track bike

Yeah, if they are (previously) set up well, run standard compression, and good quality oil!

Fontyyy's route is hardly recommended, but he does conform well to all of the above! I believe he doesn't over-rev it a lot either. (12,000rpm max., but peak is a good 800rpm or so lower, so no need to rev it much more.)

It's a shame you don't re-ring it a little more often Fontyyy, as 62~63 from an MC28 is undeniably good... in fact, probably the best we've ever seen, including 300's, and with your experience gained over the last year or more racing, I am sure you would place better with full power. (Or at least have a chance to!)
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NSR-WORLD.COM

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Andy wrote:I believe he doesn't over-rev it a lot either. (12,000rpm max., but peak is a good 800rpm or so lower, so no need to rev it much more.)

Only when I miss a gear

I didn't really plan it this way, I've got a complete dry clutch engine sat here needing a rebuild, as well as the motor in the racebike, as well as about half a dozen barrels lying around.
It's just the way it worked out, a couple of seizures, a couple of 2nd hand barrels, a couple of cold months thinking "I should get on rebuilding that really" and before you know it the season's started again.....
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The 18 top end might be a good route.
Stephen is selling some 18 barrels,pgm 2 and loom.
Even Dan has junked the PGM 4 as you know.
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The PGM IV is definately not an issue, with the correct card its as good as a HRC pgm. My track bike makes good power and is using a PGMIV.

I was however considering taking the PGM off my MC21 with the loom and putting it on my track bike so as to free up the PGM for a future rebuild of the MC28SP. Then again its probably almost beyond a rebuild and it will be cheaper just to go to fastline and buy a 28SP.

Sounds like new pistons and rings should be the first thing on the shopping list to me Fontyyy!
Maybe a full engine strip with new crank seals etc! I would personally spend my money on refreshing and setting up what you have got to give yourself a good starting point before I spent it on VHM heads etc.
Mind you what do I know, my 21 with fresh rings only gave 59 bhp

nsr.wayne wrote:Even Dan has junked the PGM 4 as you know.

No he hasn't, his race bike runs a PGMIV and 030 card.
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