Andy wrote:Here's how you can save yourself time, hassle, and money...
- HRC delimiter: not required - do the wiresplice
- Zeeltronic: not required* - the standard PGM-III is good for in excess of 70hp
- High compression: DON'T DO IT! - the NSR doesn't need, or like it!
Stock MC21 is 7.4:1. The above TT-F3 motor ran the HRC spec 7.9:1 and pump unleaded. No need to go wild with compression ratios on the NSR. It will just hit an RPM brick wall and detonate. You'll note there is no need to rev the knackers off of them either. Even the TT-F3 makes peak power below 12,000rpm.
Check the new crank is true. They're never as round as you would hope/expect, even from Honda. We true ours beyond HRC spec, and you can feel the difference through the footrests and less harsh over-rev. The motor will be significantly smoother with a well built crank!
*Programmable ignitions are more likely to be useful with 300 conversions, where they seem to respond more to tweaking the RC Valve and ignition timing.
Thanks heaps for your time Andy.
I will be in touch at some stage about a professional build from you guys but at the moment, I'll use your below info to complete this one.
Re: Delimiter - The wire splice has been done successfully.
Re: Zeeltronic - ok, this is good to know. My only concern here is the reliability of a 23yo PGM over time. Understanding it can hold up to 70HP; is reliability there and are these reprogrammable? I've seen some 'suggestions' these can if blown. I'll keep an eye out for a spare I guess...
Re: Compression - Ok, good to know. I'm not too mechanically minded, more logical.
So staying with the OEM Internals (Rods, Pistons) would maintain the compression, so this is the way to go I assume you're saying? If so, make sense. Maybe some new OEM pistons then as part of the build??
Re: The Crank. Really good to know - especially about the about ensuring it is true. My non-mechanical mind would think that from Honda it would have already been ready to go yet can understand the need to measure to ensure a perfect rotation to get the most out of the engine. Not sure what the actual HRC Specs are for a crank or how to go about that but, I'll ensure the webs on the side are like for like so there is no variation in the rotation.
Re the 300 conversions/Ignition - That's my next project
https://www.facebook.com/93NSR250RSPRebuild/photos/pcb.1733964240180399/1733964106847079/?type=3&theater
Thanks very much for your time Andy.
Cheers
Popes
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