spacer plate querry
Moderators: oldjapanesebikes, H2RICK, diamondj, Suzsmokeyallan
-
- Novice racer
- Posts: 947
- Joined: Sun Aug 23, 2009 7:59 pm
- Country: USA
- Suzuki 2-Strokes: gt750
- Location: HOUSTON USA
spacer plate querry
i have seen lots of info for porting of buffalo jugs but i wondered about using a spacer plate under the jugs and skimming the head the size of the plate to get the compression back towhere i started , i see that the porting is of slightly different dims but both seem to move metal from the cylinder in the same dirrection, and would be a realtively easy fix.
your thoughts are appreciated,
thanks mark
your thoughts are appreciated,
thanks mark
She will never be pretty but hoping she will be a fun ride.
1973 SUZUKI GT750K.=SOLD
yamaha speedtwinn 100 barn find =SOLD
1x 1973 kawasaki H1 (restored)
1x 1973 kawasaki H1 (basket case) =SOLD
1982 HONDA CB900F =SOLD
1982 YAMAHA RD350LC.
1985 RZ350N
1973 SUZUKI GT750K.=SOLD
yamaha speedtwinn 100 barn find =SOLD
1x 1973 kawasaki H1 (restored)
1x 1973 kawasaki H1 (basket case) =SOLD
1982 HONDA CB900F =SOLD
1982 YAMAHA RD350LC.
1985 RZ350N
-
- AMA Superbike
- Posts: 1769
- Joined: Tue Oct 14, 2008 6:47 pm
- Location: Blythewood, SC, USA
I used 74 jugs, with a 2.25mm plate, and additional base gasket on mine. We milled the top of the cylinder 3mm, and installed the stock head. With 34mm VM carbs, K&N filters, and JEMCO pipes, I got 80 HP on the rear wheel.
Lane
Lane
If you stroke it more than twice; you're playing with it.
Too many bikes, too much time, ENOUGH SPACE, FINALLY! Never enough money.........
Too many bikes, too much time, ENOUGH SPACE, FINALLY! Never enough money.........
-
- To the on ramp
- Posts: 362
- Joined: Fri Mar 06, 2009 12:18 am
- Location: Calgary, Canada
Lane.
When you did the lift plate conversion, did you leave the porting alone, or did you drop the exhaust and intake ports to match? What jetting did you use on those 34's to get them to work. My hotrod needs to go to the next level. I have a lift plate, and the 34's. Any info would be greatly appreciated.
Thanks. Fred
When you did the lift plate conversion, did you leave the porting alone, or did you drop the exhaust and intake ports to match? What jetting did you use on those 34's to get them to work. My hotrod needs to go to the next level. I have a lift plate, and the 34's. Any info would be greatly appreciated.
Thanks. Fred
Suzuki GT 750s
Ducati 750 GTs
2007 Duc 1000 GT (the clone)
2002 V Strom 1000 (lives again)
Suzuki RE5s
CBXs (18 cylinders, 72 valves)
Ducati 750 GTs
2007 Duc 1000 GT (the clone)
2002 V Strom 1000 (lives again)
Suzuki RE5s
CBXs (18 cylinders, 72 valves)
-
- Novice racer
- Posts: 947
- Joined: Sun Aug 23, 2009 7:59 pm
- Country: USA
- Suzuki 2-Strokes: gt750
- Location: HOUSTON USA
74 jugs
hey lane ,what was the reason for using the74 jugs was it available to you or for the upgrade from that year ,talking of that have you seen the juds and pistons etc on ebay #290361557988 i thought worth it just for the wiesco pistons alone. or is the UKNOWN "PROFFESIONAL " a warning.
mark.
mark.
She will never be pretty but hoping she will be a fun ride.
1973 SUZUKI GT750K.=SOLD
yamaha speedtwinn 100 barn find =SOLD
1x 1973 kawasaki H1 (restored)
1x 1973 kawasaki H1 (basket case) =SOLD
1982 HONDA CB900F =SOLD
1982 YAMAHA RD350LC.
1985 RZ350N
1973 SUZUKI GT750K.=SOLD
yamaha speedtwinn 100 barn find =SOLD
1x 1973 kawasaki H1 (restored)
1x 1973 kawasaki H1 (basket case) =SOLD
1982 HONDA CB900F =SOLD
1982 YAMAHA RD350LC.
1985 RZ350N
-
- AMA Superbike
- Posts: 1769
- Joined: Tue Oct 14, 2008 6:47 pm
- Location: Blythewood, SC, USA
OOPS! I'm sorry guys, I used 75 jugs. With the lift, I'm close to TR specs. The best I can remember, I have 30 pilots, 3.5 slides (3.0 would probably be better) and about 200 mains. I can't remember what needle jets or needles are in there....whatever they had when I got them (came off an H2).
I matched the exhaust ports to the piston tops at the bottom of the stroke and cleaned up the transfers and intakes, and milled 2.5mm off the rear piston skirts, which left the intake timing almost the same (it was a guess that worked!)
Lane
I matched the exhaust ports to the piston tops at the bottom of the stroke and cleaned up the transfers and intakes, and milled 2.5mm off the rear piston skirts, which left the intake timing almost the same (it was a guess that worked!)
Lane
If you stroke it more than twice; you're playing with it.
Too many bikes, too much time, ENOUGH SPACE, FINALLY! Never enough money.........
Too many bikes, too much time, ENOUGH SPACE, FINALLY! Never enough money.........
- tz375
- Moto GP
- Posts: 6206
- Joined: Mon Nov 03, 2008 10:47 am
- Location: Illinois
The reason that spacer plates became popular was with racers who found that when they tried to raise the exhaust to TR specs, they broke through into the water jacket.
Exhaust height measured down from the top are:
J/K/L: 42.5mm
M/A/B: 40.0mm
TR750: 32.0/30.5mm depending on which article you read!
The roof can be raised to around 35.5 or 36.0 on a good casting (doesn't matter what year), but that's still way short of the TR, but add in a 4mm spacer plus extra gasket and it's getting close. It would also be hard to ride on the street.
Transfers are interesting:
Early J: 51.5mm
J-B: 53.0mm
TR750: 49.0mm
Using a spacer and no other porting increases all the duration times but leaves the same blowdown which is a nice simple way to push the overall powerband upwards.
The only way to know for sure whether more or less blowdown would be beneficial would be to try different timings and see the effect, but for a street motor you want to avoid increasing that too much.
So the simple fix is a spacer plate and just clean up the floors of the ports and maybe lower the intake floor just enough to clean it up. too much intake duration will hurt bottom end torque badly.
Lane has sensibly reduced his intake duration slightly.
For a race motor it's a different story and big HP requires wide ports ad they lead to other problems so choose wisely.
Lane's formula clearly works well.
BTW, try not to follow too many old school articles. For example 3mm off the head is said to be safe - It is not.
Exhaust height measured down from the top are:
J/K/L: 42.5mm
M/A/B: 40.0mm
TR750: 32.0/30.5mm depending on which article you read!
The roof can be raised to around 35.5 or 36.0 on a good casting (doesn't matter what year), but that's still way short of the TR, but add in a 4mm spacer plus extra gasket and it's getting close. It would also be hard to ride on the street.
Transfers are interesting:
Early J: 51.5mm
J-B: 53.0mm
TR750: 49.0mm
Using a spacer and no other porting increases all the duration times but leaves the same blowdown which is a nice simple way to push the overall powerband upwards.
The only way to know for sure whether more or less blowdown would be beneficial would be to try different timings and see the effect, but for a street motor you want to avoid increasing that too much.
So the simple fix is a spacer plate and just clean up the floors of the ports and maybe lower the intake floor just enough to clean it up. too much intake duration will hurt bottom end torque badly.
Lane has sensibly reduced his intake duration slightly.
For a race motor it's a different story and big HP requires wide ports ad they lead to other problems so choose wisely.
Lane's formula clearly works well.
BTW, try not to follow too many old school articles. For example 3mm off the head is said to be safe - It is not.
-
- AMA Superbike
- Posts: 1769
- Joined: Tue Oct 14, 2008 6:47 pm
- Location: Blythewood, SC, USA
Truthfully, my engine was a guess. I looked at what others had done (including the factory) and sorta picked what I thought would work for me. I got lucky. If I could lower the weight, I would really have something....maybe this winter.
Lane
Lane
If you stroke it more than twice; you're playing with it.
Too many bikes, too much time, ENOUGH SPACE, FINALLY! Never enough money.........
Too many bikes, too much time, ENOUGH SPACE, FINALLY! Never enough money.........
-
- Novice racer
- Posts: 947
- Joined: Sun Aug 23, 2009 7:59 pm
- Country: USA
- Suzuki 2-Strokes: gt750
- Location: HOUSTON USA
many thanks
many thanks to all.
loads to digest and look at over the winter.
methinks i will get a spare set of jugs to experiment on when i come to it.
cheers mark.
loads to digest and look at over the winter.
methinks i will get a spare set of jugs to experiment on when i come to it.
cheers mark.
She will never be pretty but hoping she will be a fun ride.
1973 SUZUKI GT750K.=SOLD
yamaha speedtwinn 100 barn find =SOLD
1x 1973 kawasaki H1 (restored)
1x 1973 kawasaki H1 (basket case) =SOLD
1982 HONDA CB900F =SOLD
1982 YAMAHA RD350LC.
1985 RZ350N
1973 SUZUKI GT750K.=SOLD
yamaha speedtwinn 100 barn find =SOLD
1x 1973 kawasaki H1 (restored)
1x 1973 kawasaki H1 (basket case) =SOLD
1982 HONDA CB900F =SOLD
1982 YAMAHA RD350LC.
1985 RZ350N
- Suzsmokeyallan
- Moto GP
- Posts: 4326
- Joined: Fri Oct 24, 2008 9:11 am
- Location: Mostly Barbados, sometimes Florida and western Canada
- Contact:
Richard if you post up all the Buffalo and TR barrel specs for all the years in one message it can be made into a sticky.
Two strokes, its just that simple.
69 Suz U70
69 Suz T500
72 Suz GT750 cafe
74 Suz TS250
74 Suz GTXVR project
75 Suz RE5
75 Suz GT750
76 Suz TS400
76 Suz GT750
81 Suz GSX1100
86 Suz RG500x2
88 Hon CR500
93 Hon CBR900RR
98 Suz GSF1200x3
15 Kaw Ninja H2
69 Suz U70
69 Suz T500
72 Suz GT750 cafe
74 Suz TS250
74 Suz GTXVR project
75 Suz RE5
75 Suz GT750
76 Suz TS400
76 Suz GT750
81 Suz GSX1100
86 Suz RG500x2
88 Hon CR500
93 Hon CBR900RR
98 Suz GSF1200x3
15 Kaw Ninja H2
- tz375
- Moto GP
- Posts: 6206
- Joined: Mon Nov 03, 2008 10:47 am
- Location: Illinois
Mark,
When you work out what you want to do, you could do worse that to contact Eric (Zookie) board owner around here or Bill Trippe in Illinois, both oh whom are good with a porting tool.
I use Bill Trippe because he's close and we use different software to work out what we want and then asymptote towards an optimal solution.
Scott Clough of SCR is another racer who makes his living tuning 2 strokes. I only know of one that he did and it was OK. Lanes makes more power with the same pipes!!!! OK so Lane has bigger carbs, and maybe he just got lucky, but then again, I like lucky people.
You could port the barrels yourself, but I try not to because they are too easy to screw up
When you work out what you want to do, you could do worse that to contact Eric (Zookie) board owner around here or Bill Trippe in Illinois, both oh whom are good with a porting tool.
I use Bill Trippe because he's close and we use different software to work out what we want and then asymptote towards an optimal solution.
Scott Clough of SCR is another racer who makes his living tuning 2 strokes. I only know of one that he did and it was OK. Lanes makes more power with the same pipes!!!! OK so Lane has bigger carbs, and maybe he just got lucky, but then again, I like lucky people.
You could port the barrels yourself, but I try not to because they are too easy to screw up
-
- Novice racer
- Posts: 947
- Joined: Sun Aug 23, 2009 7:59 pm
- Country: USA
- Suzuki 2-Strokes: gt750
- Location: HOUSTON USA
thanks
thanks i will probably ask zooke when i am ready to go ahead.
i am thinkin i want to have one standard bike and one to make into a cafe racer styley but i am getting ahead of myself.
thanks again.mark
i am thinkin i want to have one standard bike and one to make into a cafe racer styley but i am getting ahead of myself.
thanks again.mark
She will never be pretty but hoping she will be a fun ride.
1973 SUZUKI GT750K.=SOLD
yamaha speedtwinn 100 barn find =SOLD
1x 1973 kawasaki H1 (restored)
1x 1973 kawasaki H1 (basket case) =SOLD
1982 HONDA CB900F =SOLD
1982 YAMAHA RD350LC.
1985 RZ350N
1973 SUZUKI GT750K.=SOLD
yamaha speedtwinn 100 barn find =SOLD
1x 1973 kawasaki H1 (restored)
1x 1973 kawasaki H1 (basket case) =SOLD
1982 HONDA CB900F =SOLD
1982 YAMAHA RD350LC.
1985 RZ350N
- water cooled
- Yeah Man, the Interstate
- Posts: 704
- Joined: Thu Oct 23, 2008 3:23 pm
- Country: USA
- Suzuki 2-Strokes: 1974 Suzuki GT750
- Location: Medina OH