The 50

[F5 Dave]

Ah, glad to see you have some conduit holding barrel down, first pic got me worried. I only run 196 ex on the 50 so don't get too carried away too soon.

[cotswold]

I would have loved to have that when I was racing my MB50. It's all about the piston though. The MB had 1.5 mm rings that used the clean tips off if you revved them much past 11. What are these? I ran RD pistons but it wasn't a simple conversion.

Ahhh, Hate it when people prophesy doom. Took the rings off the piston to do my port timings and I just went to put them back on to use this weekend and........

[Gigglebutton]

whats the hp with nitro

13hp and heaps of torque at 9k on the Nos but would not rev higher. Now I have the Ignitech I can retard it and hopefully rev to 13. Fuck yeh

[Gigglebutton]

The job for today was to measure where my ports are timing wise. The target was 80* ATDC for the exhaust and 118* ATDC for the transfers.
The cylinder had to be lifted to get 86 and 116, I used penny washers under the cylinder to achieve this.
The exhaust port needs raising and the cylinder needs a bit skimming off to get where I have been told I want to be.

How thick are the washers. I may have some ali sheet around the sane thickness

[F5 Dave]

Ahhh, Hate it when people prophesy doom. Took the rings off the piston to do my port timings and I just went to put them back on to use this weekend and........

Yeah I played that game way too many times. They're a bit shit like that. Power would drop off ESP as I ran one ring. Research a piston to run.

[cotswold]

Yeah I played that game way too many times. They're a bit shit like that. Power would drop off ESP as I ran one ring. Research a piston to run.

I am at 1mm over on this one 40mm, the AM6 pistons start at 40.3, they have a 12mm pin, do you know if the Honda can take another over bore?
There seems to be plenty of bore left and the AM6 pistons are readily available, Prox do one. Athena do a 40mm and 12mm pin but you have to give a blood sample to get on their customer list. ( who asks for your IRD number? )

[F5 Dave]

not sure about wc 50 Honda, the air cooled one had heaps of meat. Prox should be good.

[speedpro]

The Honda 100 will lose ring tips as well but over 14,000rpm. The power would get peaky but more or less same peak power on the dyno.

[cotswold]

Job for today was to make up a spacer for the reed block as it was too long to fit, I spotted a bolt on one from Japan and copied it as best I could with hand tools, it all seems to fit ok in the modified cylinder but not in the standard one....so I will have to take it apart and open it out a bit. Was hoping to avoid that for now.

[cotswold]

Quick rant, I rocked up to mxspares as they sell prox pistons, I ask them if they can get me a piston for an aprilia, I had the correct part number, is that an MX bike? No why, because we only sell MX pistons, but it's a prox part number and you sell prox pistons, only for MX bikes. I left angry.

[Bert]

Try a Yamaha jog 50, minarelli 50 (read Yamaha & aprilia) share the same piston as the AM6 engine..
Come in 10 or 12mm pin.

[F5 Dave]

Quick rant, I rocked up to mxspares as they sell prox pistons, I ask them if they can get me a piston for an aprilia, I had the correct part number, is that an MX bike? No why, because we only sell MX pistons, but it's a prox part number and you sell prox pistons, only for MX bikes. I left angry.

Maybe its part of thier distributorship agreement that they can take the MX side of the sales. Maybe.

[cotswold]

Maybe its part of thier distributorship agreement that they can take the MX side of the sales. Maybe.

the voice of reason, you could well be right but I worked in a bike shop and we always tried to get whatever the customer wanted or at least offered an alternative. Pissed me off so much I bought one off shore and it will be cheaper even with postage.

[cotswold]

I spent a little time unbolting bits that were not required. Next will be to take a grinder to the bits that are not bolted on.
I have fitted the 28mm carb but need to buy in some smaller jets as it seems to be running very rich, the smallest I had was a 97.5. I had to use the original reed block which was a pain, the original cylinder requires a decent amount of porting to get the big block to fit. Those PWK's are a bit different to work with, not sure I like it.

[F5 Dave]

Well there will be a Mikuni on deck in a couple of days. Think I'm running a 145 in my PWK, but its all relative to the engine & doesn't mean too much, heck I was on 280s on my old Mikuni non PJ flatslide.

Often you run similar or larger jetting than the bike it came off as there is less suction.

Often it is easier to tack weld on the threaded part of a bigger cage or some 12mm plate to extend a tiny 1/2 reedblock (like the MBs had) to fit a 4 petal reed then just devcon the gaps [edit seen spacer above]