Port timing

[Stoneman]

Ive read a lot of info from Jaguars website and have used a lot of it in the build im doing for my son

I thought I might share some of my finding and get some thought on direction

you are probably all aware of the info so I might just jump in and post some screen shots of where I'm at

this has been done on Super Hawk R80

Crank balancing

I managed some time for on the ports
I haven't altered anything as yet other than cleaned everything up

I used auto cad a inserted and traced the ports

If all is correct i think the timing looks pretty good.

Talking to jaguar i have been able to also begin making his performance CDI
i know this has been a little controversial at times but its looking pretty good
This is Version 6 released this year i believe
first lot of boards should be here next week with the parts

going to run with this Coil

not wanting to start any arguments, just share thoughts

 

[Stoneman]

Boards arrived

Very happy with them

 

[Stoneman]

As it turns out with my porting it seems my transfers are a little high

So for the fix it it’s either square off my transfers, as they taper towards to top of the cylinder or raise the exhaust port and port it for around the 10,000 rpm mark.
I’m wondering though if I’m measuring from the top of the taper for port duration or maybe half of the taper if that makes sense
Does the taper make a difference to duration?

Given I’ve balanced the crank I’m sort of keen to see what I can get out of it with just pipe work and a decent carb (mikuni vm18) after porting

Any way mounts nearly done so i guess it’s on to a bit of R&D

 

[Street Ryderz]

As it turns out with my porting it seems my transfers are a little high

So for the fix it it’s either square off my transfers, as they taper towards to top of the cylinder or raise the exhaust port and port it for around the 10,000 rpm mark.
I’m wondering though if I’m measuring from the top of the taper for port duration or maybe half of the taper if that makes sense
Does the taper make a difference to duration?

Given I’ve balanced the crank I’m sort of keen to see what I can get out of it with just pipe work and a decent carb (mikuni vm18) after porting

Any way mounts nearly done so i guess it’s on to a bit of R&D

The taper can be squared or angled into the port (transfer) when the top of the ring drops past the highest point of the window (some are angled or eyebrowed) it's considered open and the start of duration because the pressure from down stroke alows passage it at that point.Getting a good blow by fig means you have to raise the exhaust port timming some simply because you cant lower the transfers.But that doesnt mean that it's for higher rpm or the 10,000 mark since the stock port timming can hit 11,000 rpm maybe more when set up properly,You said it yourself when you tune the pipe you can control or even effectivly cap your rpm. If you stage your pipe to hit at 8,500 and it has a 2,000 rpm band width it peaks at 10,500 after that it will run out some but not make any more power so by 11,500 your done.Now staging the pipe that late in the range is not for street use IMO and wont really be possible with Jags cdi anyway as it only goes to around 9,000 witch is great on the street and means you would stage the pipe for 6,000-7,000 rpm if you want it at the top.So you can raise the exhaust port timming upto 1.5mm before effecting torque(no loss) to get a higher blow down fig and not really changing the top rpm it's better suited to high rpm but doesn't nesisarly create it.

 

[gary55]

Ive read a lot of info from Jaguars website and have used a lot of it in the build im doing for my son

I thought I might share some of my finding and get some thought on direction

you are probably all aware of the info so I might just jump in and post some screen shots of where I'm at

this has been done on Super Hawk R80

Crank balancing

View attachment 79769 View attachment 79770

I managed some time for on the ports
I haven't altered anything as yet other than cleaned everything up
View attachment 79771

I used auto cad a inserted and traced the ports
View attachment 79775

If all is correct i think the timing looks pretty good.

Talking to jaguar i have been able to also begin making his performance CDI
i know this has been a little controversial at times but its looking pretty good
This is Version 6 released this year i believe
first lot of boards should be here next week with the parts

View attachment 79772 View attachment 79773
going to run with this Coil
View attachment 79774

not wanting to start any arguments, just share thoughts

On the port map, does each small square represent 2mm? What I'm getting from this is 28mm down to top of exhaust, 32mm down to top of transfer, with 14.5mm x 12mm transfer window and exhaust at 21mm x 15mm. This is just me. I would raise the exhaust port 1mm to get 5mm of blow down and widen it 1mm on each side. Then just the regular cleaning of the transfers without removing the lip in them on the exhaust side. This is on the current engines I am using cause they have high enough compression to begin with so I'm not to worried about the low end torque. Looks like your having some fun. Cool stuff.

 

[gary55]

I remember when you first got it, and what wonderful luck you had with everything being just perfect.

 

[Stoneman]

On the port map, does each small square represent 2mm? What I'm getting from this is 28mm down to top of exhaust, 32mm down to top of transfer, with 14.5mm x 12mm transfer window and exhaust at 21mm x 15mm. This is just me. I would raise the exhaust port 1mm to get 5mm of blow down and widen it 1mm on each side. Then just the regular cleaning of the transfers without removing the lip in them on the exhaust side. This is on the current engines I am using cause they have high enough compression to begin with so I'm not to worried about the low end torque. Looks like your having some fun. Cool stuff.

Each line is 1mm

Yes I plan on raising the exhaust

 

[Stoneman]

I remember when you first got it, and what wonderful luck you had with everything being just perfect.

It’s been a long process

Haha, I know!
It takes a little getting your head around it all because all parts are different
I’ve learnt to be carful ordering parts now I know the difference
The simple fact is they are all different and that makes it all the more challenging in a way

But it’s coming a long nice....fingers crossed
The main problem I had was the rear mount getting it mounted with the rear sproket mount and being off set to the standard mount

I’ve spent a lot of time with learning milling and lathe techniques along with a few other things

But I’m getting there

 

[Stoneman]

The taper can be squared or angled into the port (transfer) when the top of the ring drops past the highest point of the window (some are angled or eyebrowed) it's considered open and the start of duration because the pressure from down stroke alows passage it at that point.Getting a good blow by fig means you have to raise the exhaust port timming some simply because you cant lower the transfers.But that doesnt mean that it's for higher rpm or the 10,000 mark since the stock port timming can hit 11,000 rpm maybe more when set up properly,You said it yourself when you tune the pipe you can control or even effectivly cap your rpm. If you stage your pipe to hit at 8,500 and it has a 2,000 rpm band width it peaks at 10,500 after that it will run out some but not make any more power so by 11,500 your done.Now staging the pipe that late in the range is not for street use IMO and wont really be possible with Jags cdi anyway as it only goes to around 9,000 witch is great on the street and means you would stage the pipe for 6,000-7,000 rpm if you want it at the top.So you can raise the exhaust port timming upto 1.5mm before effecting torque(no loss) to get a higher blow down fig and not really changing the top rpm it's better suited to high rpm but doesn't nesisarly create it.

Thanks SR

I’m more talking peek power around the 10,000

I was given the idea of squaring the transfers with JB weld not actually increasing the area
This I learnt should give me a faster in take charge but not really understanding what that means. I’m thinking it’s less charge being lost during compression or back pressure into the case on the up stroke?

I’m thinking of raising the exhaust duration to around 160-165
I believe that can make good use of the power, I have to work out the measurements yet
TBH I’m still confirming what I’m thinking

I believe the version 6 cdi is good upto 10,000 rpm and couldn’t be tested past that, so could probably be happy reaching higher
He has a bit of a right up on his web page about it

Sorry for all the edits

 

[6blueoval9]

Thanks SR

I’m more talking peek power around the 10,000

I was given the idea of squaring the transfers with JB weld not actually increasing the area
This I learnt should give me a faster in take charge but not really understanding what that means. I’m thinking it’s less charge being lost during compression or back pressure into the case on the up stroke?

I’m thinking of raising the exhaust duration to around 160-165
I believe that can make good use of the power, I have to work out the measurements yet
TBH I’m still confirming what I’m thinking

I believe the version 6 cdi is good upto 10,000 rpm and couldn’t be tested past that, so could probably be happy reaching higher
He has a bit of a right up on his web page about it

Sorry for all the edits

On the transfer ports in the cylinder the angles are a bit off on the side closest to the exhaust ports...You Lose about 30% of your mixture being sucked right out of the exhaust port.

You ultimately want the entire charge being directed to the intake side of the combustion chamber.