Search found 813 matches

by MK
Sun Mar 24, 2024 4:53 pm
Forum: Chassis, Brakes & Suspension
Topic: RD350B
Replies: 2
Views: 73

Re: RD350B

I'd throw in using Koso RX1 / 2 units as they come close to what you're after: https://www.caferacerwebshop.com/de/rx2nr-snelheidsmeter-toerenteller-en-schakel-alarm.html They come with a manual and you can get several additional sensors like CHT https://www.caferacerwebshop.com/de/10mm-cilinderkop-...
by MK
Sat Mar 16, 2024 7:52 am
Forum: For Sale
Topic: RZ350 adjustable power valve contoller
Replies: 12
Views: 802

Re: RZ350 adjustable power valve contoller

Here's an example on how you determine the optimal open/close rpm. Simulate or dyno with PV closed, then with PV open. Usually you'd pick the point where performance starts to drop with PV closed and have it fully open a few 100 rpm before top performance. Voila, that's your transition rpms to start...
by MK
Thu Mar 07, 2024 5:30 am
Forum: For Sale
Topic: RZ350 adjustable power valve contoller
Replies: 12
Views: 802

Re: RZ350 adjustable power valve contoller

FYI: If you have such a device, try curve 14 (6000-8550) for stock'ish engines. That's been confirmed by quite a lot people to be the best compromise. For higher revving engines (modified+pipes) , something like 6k - 9-9 5 k was more appropriate. If you want to do this on your own, here's the how-to...
by MK
Mon Feb 12, 2024 4:24 pm
Forum: Electrical & Wiring
Topic: Gauges question.
Replies: 2
Views: 223

Re: Gauges question.

I'd have them laser cut from foam plate with the right thickness. Check out for maker projects around your place. In our town they'd offer such services here: https://makerspace-bs.de/lasercutter/ As an alternative there's always professional laser cutting services like these guys: https://www.cutwo...
by MK
Sun Jan 28, 2024 5:07 pm
Forum: Custom Projects - Other Bikes
Topic: Pitbike Supermoto
Replies: 5
Views: 682

Re: Pitbike Supermoto

Thanks mate, glad you like it :-) I wouldn't call that racing, it's only track days with like-minded people. In some cases even two-stroke meetings. Unfortunately age is already striking. In the last years I lost some seconds on my favorite Kart track If you haven't already found it, check out some ...
by MK
Sat Jan 27, 2024 5:00 pm
Forum: Engines
Topic: +4mm crank gains
Replies: 30
Views: 2074

Re: +4mm crank gains

The dip at 8.5k could be cured a bit by more ignition advance in that range.
And fiddling a bit with the PV fully open rpm. Try 9 - 9.25 k.
by MK
Sat Jan 27, 2024 4:55 pm
Forum: Custom Projects - Other Bikes
Topic: Pitbike Supermoto
Replies: 5
Views: 682

Re: Pitbike Supermoto

It turned out to be a super fun ride. Especially indoors during winter time. I do track days on a monthly base then. For outdoors I upgraded the engine to a 4 valve 155cc Daytona but it's still kinda small breasted. https://i.postimg.cc/9FPRt5D5/IMG-6210.jpg https://i.postimg.cc/rsNVWTQf/IMG-2827.jpg
by MK
Tue Nov 28, 2023 7:12 am
Forum: Engines
Topic: +4mm crank gains
Replies: 30
Views: 2074

Re: +4mm crank gains

I've been busy with other important things in live, so the 2016 version would be still available, if it weren't for my printing shop closing down a month ago. Honestly I was too lazy to source another one, yet. The 500 manual is available for download here: https://www.rd350lc.de/downloads/MK-Dokume...
by MK
Thu Nov 23, 2023 11:22 am
Forum: Engines
Topic: +4 crank on a mildly modified pv engine
Replies: 16
Views: 1881

Re: +4 crank on a mildly modified pv engine

I went the easiest path and simple had the head machined some 0.5-1 mm bigger than the bore size.
That saved dowel pins but still avoided piston to head collision.
by MK
Tue Nov 21, 2023 9:04 am
Forum: Engines
Topic: +4mm crank gains
Replies: 30
Views: 2074

Re: +4mm crank gains

- Enlange exhaust port down -2mm to match piston top at BDC (very small gains, might not be worth it) - Keep transfer ports as they are (I cant find any good gains modifying them) I once ran engmod sims that showed around 1.5-2 HP gains when matching the lower transfer port edges to the new piston ...
by MK
Thu Nov 16, 2023 5:25 pm
Forum: Engines
Topic: +4mm crank gains
Replies: 30
Views: 2074

Re: +4mm crank gains

Try something like 16-18 deg @ 9000 and fully open PV @ 8k
by MK
Tue Nov 07, 2023 12:52 pm
Forum: Engines
Topic: +4mm crank gains
Replies: 30
Views: 2074

Re: +4mm crank gains

by MK
Thu Oct 12, 2023 7:50 am
Forum: Engines
Topic: Motor Doesn't Rev-Up
Replies: 10
Views: 768

Re: Motor Doesn't Rev-Up

PS: I had one customer bike that had similar symptoms and here it turned out the main air jets were clogged. Owner insisted carbs had been cleaned, but after removing the brass ball in the carb belly you couldn't see through. Cleaning made it better, but not perfect. So he ended up with a pair of us...
by MK
Tue Oct 10, 2023 7:16 am
Forum: Engines
Topic: Motor Doesn't Rev-Up
Replies: 10
Views: 768

Re: Motor Doesn't Rev-Up

From the symptoms: Left right carb slide exchanged?
Slide cutaway must point towards air filter side.
by MK
Tue Jul 25, 2023 3:41 pm
Forum: Engines
Topic: Any high mileage RZ’s out there ?
Replies: 7
Views: 636

Re: Any high mileage RZ’s out there ?

Since 1987 I've done around 230.000 km on my RD. If something had a defect, I repaired or replaced it. (As there's virtually no original part left, you can call that cheating.) For unmolested engines piston life is some 20.000 km, cranks around 50.000. Lifespan is significantly reduced with pipes re...