CDI improvement

[tomski]

In lookin at the motorcyclenews.com review of the steamer, they state
"If you want to give the Triumph Tiger even more pep you can fit the CDI and cams from a Speed Triple, Daytona or Trident of a similar vintage"

I wonder what happens when the CDI is swapped (without the cams)..is that an option with any benefits?

Any views?

[MtheTiger]

I doubt it.
The camshape & ingition timing given off by the sensor when the timingplate spins around determines the power (along with the compression ratio).
The CDI merely translates the sensor output to a pulse input to the coils.

I could B wrong though so any additions/corrections to my opinion?

[CoolHandLuke]

You need both.

It is highly likely the CDI will work at low revs, but when you twist the throttle the timing will be thrown off due to the differences in advance firing at higher speeds.

The power differences come from the cams which adjust when the valves open and how long they stay open for.  I would imagine the gearing would be different, but I will get back on that.

[JetdocX]

Additionally, the Daytona and Speed Trip have higher rev limits and forged crankshafts to handle the extra revs.

[CoolHandLuke]

All the 900 carb engines have the same primary drive ratio of 1.75 (105/60).

All the 900 carb engines have the same gearing:

Code Select Expand

1st: 2.733 (41/15)
2nd: 1.947 (37/19)
3rd: 1.545 (34/22)
4th: 1.291 (31/24)
5th: 1.154 (30/26)
6th: 1.074 (29/27)
Valve Timings....


Trophy 900 (85 PS versions)
Trident 900 (85 PS versions)
Sprint 900 (85 PS versions)
Thunderbird Sport 900 (83 PS@8500rpm, 76.0Nm@6500rpm)
Thunderbird Adventurer 900 (83 PS@8000rpm, 82.0Nm@6000rpm)
Tiger 900 (85 PS@8000rpm, 82.0Nm@6000rpm)

Code Select Expand

 Inlet: open = 1 degrees BTDC, close = 30 degree ABDC, duration = 211 degrees, valve lift = 7.1mm
Exhaust: open = 28 degrees BBDC, close = 2 degrees ATDC, duration = 210 degrees, valve lift = 7.0mm


Trophy 900 (98 PS@9000rpm, 83.0Nm@6500rpm)
Daytona 750, 900
Speed Triple 900 (99 PS@9000rpm, 80.0Nm@6750rpm)
Trident 750, 900
Sprint 900 (98 PS@9500rpm, 78.3Nm@6500)

Code Select Expand

 Inlet: open = 21 degrees BTDC, close = 50 degree ABDC, duration = 251 degrees, valve lift = 8.9mm
Exhaust: open = 51 degrees BBDC, close = 25 degrees ATDC, duration = 256 degrees, valve lift = 8.6mm


Daytona Super 3 (114 PS@9500rpm, 81.4Nm@6000rpm)

Code Select Expand

 Inlet: open = 27 degrees BTDC, close = 55 degree ABDC, duration = 262 degrees, valve lift = 9.4mm
Exhaust: open = 54 degrees BBDC, close = 28 degrees ATDC, duration = 262 degrees, valve lift = 9.3mm

Ignition Timings & Compression Ratio....


Trophy 900, Daytona 900, Speed Triple, Trident/Sprint 900:

Code Select Expand

Idle: 5 degrees BTDC@1000rpm, Max. Advance: 26 degrees@6500rpm
Electronic Rev Limiter: 9700rpm
Compression Ratio: 10.6:1


Daytona Super 3:

Code Select Expand

Idle: 5 degrees BTDC@1000rpm, Max. Advance: 26 degrees@6500rpm
Electronic Rev Limiter: 9700rpm
Compression Ratio: 12:1


Tiger 900:

Code Select Expand

Idle: 5 degrees BTDC@1000rpm, Max. Advance: 29 degrees@6500rpm
Electronic Rev Limiter: 8750rpm
Compression Ratio: 10.6:1


Thunderbird Sport 900, Thunderbird Adventurer:

Code Select Expand

Idle: 5 degrees BTDC@1000rpm, Max. Advance: 30 degrees@6500rpm
Electronic Rev Limiter: 8750rpm
Compression Ratio: 10.0:1


Daytona 750, Trident 750:

Code Select Expand

Idle: 5 degrees BTDC@1000rpm, Max. Advance: 35 degrees @6500rpm
Electronic Rev Limiter: 11000rpm
Compression Ratio: 11.0:1


Notes

(Updated to include cam lift).

Usually, models prior to 1998 will have Mikuni whilst 1998 and beyond have Keihin.

[tomski]

Thank you all, you are truly a fountain of knowledge :)

[CoolHandLuke]

Looking at the comparisons, if I were ever to consider changing the CDI, it would be for the Trophy.

[CoolHandLuke]

Additionally, the Daytona and Speed Trip have higher rev limits and forged crankshafts to handle the extra revs.

There is no need to as all the early 900 3 cyclinder engines share the same crank, part number: 1200400-T0301.

[BruKen]

please define early..... 92-98?

[CoolHandLuke]

please define early..... 92-98?

This statement only applies to carb models.  Depending on the model, the 1st and last year are model specific.  For tigers, it would be 93 - 98.

[KillaHedgeHog]

I haven't included valve lift, as that is covered by the cam change.  Engines were released with Mikuni or Keihin carbs.  Usually, models prior to 1998 will have Mikuni whilst 1998 and beyond have Keihin.

Quick question on Cam Shafts...  Do the early Tiger and Trident engines have the same amount of lift and only differ in duration, or does the higher power engine also have more lift?

I only ask as I have two engines; ones the original tiger engine, and one was sold to me as a Trident engine... but both have cams with the some amount of lift (lobe base diameter and max lob height is the same).  I already have a CDI unit to match the trident engine, but now wonder if both my engines are from Tigers!?!

[CoolHandLuke]

I haven't included valve lift, as that is covered by the cam change.  Engines were released with Mikuni or Keihin carbs.  Usually, models prior to 1998 will have Mikuni whilst 1998 and beyond have Keihin.

Quick question on Cam Shafts...  Do the early Tiger and Trident engines have the same amount of lift and only differ in duration, or does the higher power engine also have more lift?

I only ask as I have two engines; ones the original tiger engine, and one was sold to me as a Trident engine... but both have cams with the some amount of lift (lobe base diameter and max lob height is the same).  I already have a CDI unit to match the trident engine, but now wonder if both my engines are from Tigers!?!

Hi, and welcome aboard.

If you are 100% sure that the cams are the same then the engine could be one of  the 85PS engine versions and not the 98PS version of the Trident. Or, as you say, it could be a Tiger engine.

The Tiger and the 85PS versions of the cams had the following lift:

In: 7.1mm
Ex: 7.0mm

All the 98PS engines had the following lift:

In: 8.9mm
Ex: 8.6mm

As far as I know, the 85PS versions of the Trident/Trophy/etc were only for the California market.  If anyone knows any different, could they let me know?

[KillaHedgeHog]

If you are 100% sure that the cams are the same then the engine could be one of  the 85PS engine versions and not the 98PS version of the Trident. Or, as you say, it could be a Tiger engine.

The Tiger and the 85PS versions of the cams had the following lift:

In: 7.1mm
Ex: 7.0mm

All the 98PS engines had the following lift:

In: 8.9mm
Ex: 8.6mm

As far as I know, the 85PS versions of the Trident/Trophy/etc were only for the California market.  If anyone knows any different, could they let me know?

I have verniered them up and they seem to measure exactly the same base diameter and max lobe height, but it's obviously quite hard to measure the timing with basic measuring implements!

I have some T595 cams coming, which I only bought as they were dirt cheap on ebay!  Can the font of all knowledge give me any clues as to whether these are the same as the trident 98PS engines?

[CoolHandLuke]

I have verniered them up and they seem to measure exactly the same base diameter and max lobe height, but it's obviously quite hard to measure the timing with basic measuring implements!

I have some T595 cams coming, which I only bought as they were dirt cheap on ebay!  Can the font of all knowledge give me any clues as to whether these are the same as the trident 98PS engines?

I can't find anything online.  I'll have to check a workshop manual tomorrow and get back to you.

[KillaHedgeHog]

I have some T595 cams coming, which I only bought as they were dirt cheap on ebay!  Can the font of all knowledge give me any clues as to whether these are the same as the trident 98PS engines?

I can't find anything online.  I'll have to check a workshop manual tomorrow and get back to you.

Thanks, I appreciate the help. :)

I have been looking at photos of an open T595 engine, and comparing them to what mine looked like in bits (lots of bits!), and internally they look very similar... I also wonder if the wet liners and pistons from the 955 engine would pop straight in?  Now that would be a neat conversion!