Okay setup?

[Stevie W]

After trying to keep up with my friends TS1 I decided that I need to give my Indian GP200 a bit of a boost. I don't want to go racing about but want to just have more torque and a bit more top end. To achieve this I have bought the following Rapido 225 kit, AF 48mm clubman exhaust, 30mm Dellorto phbh along with a Tameni crank , Koyo bearings and Rolf seals.
What's the consensus on this setup and are there any tips which might get the best out of it.

[Blaginit]

All ways have it set up on a dyno it will save u a lot of expense and grief cheep at about £70 better than a seize or holed piston give u that little piece of mind it's running ok all the best mate on your project

[CHRIS in MARGATE]

Now I disagree. Not for the sake of confrontation or argument; that is not the intention.
The components sound fine and you should ensure that your timing is strobed correctly (whole chapter of debate that is). Jet it up so it is on the rich side at all points throughout the throttle range. You might foul a couple of plugs to begin with. Get some miles on it and get it almost run in and THEN if you are still looking for a printout to wave at your friends in the pub (sorry being facetious ) by all means for peace of mind get it dynoed.
Just my opinion from experience so don't send me a bill for a new piston !

[coaster]

Sitting on the fence a bit, Chris's approach is great if you have the time and experience to set it up by ear. A GOOD dyno operator with Lambretta experience will be able to pinpoint any problems such as weak spots in the carburation which could take even an experienced mechanic to sort out by roadside adjustments. The Rapido is a solid kit and can be reliable if set up correctly. Make sure there is at sufficient piston to bore clearance and that the rings are gapped correctly. Assemble carefully using sticky's book and be sure to do a leak down test and you will have a solid base to build on.

[Meds]

I had a similar set up running gp200 19/46 gearing and a BGM clubman, it would climb great but topped out at 70mph(GPS), it wasn't pleasant to ride with standard 150's as the jetting wasn't right at the bottom/mid range.
It's been through quite a few iterations since then.
I'm thinking about trying a SSC taffspeed copy if I can get one.

[Rich Oswald]

Is it a 225 Classic or 225 Race? Imo that set up will be fine for the classic but if it's a race version then I don't think you will get the best from it with the 48mm Clubman.

Rich'

[paul213]

If its not built yet check bore to piston clearance (.0035 to .004") and compression ratio , chamfer the port edges . other than that build it and enjoy

[Stevie W]

Is it a 225 Classic or 225 Race? Imo that set up will be fine for the classic but if it's a race version then I don't think you will get the best from it with the 48mm Clubman.

Rich'

There is no classic rapido 225 only a race kit but it does have a choice of pistons. I chose the skirted (cheaper one) which changes the port timing slightly making it easier to set up.

[Stevie W]

Thanks for the advice guys, it looks as though I made a reasonable choice with a good bang for the buck ratio. I'll certainly take on board what you have said and report back when I've done the job.

[Rich Oswald]

Is it a 225 Classic or 225 Race? Imo that set up will be fine for the classic but if it's a race version then I don't think you will get the best from it with the 48mm Clubman.

Rich'

There is no classic rapido 225 only a race kit but it does have a choice of pistons. I chose the skirted (cheaper one) which changes the port timing slightly making it easier to set up.

Maybe there isn't now but there used to be as I bought one from AF.

[Warkton Tornado No.1]

After trying to keep up with my friends TS1 I decided that I need to give my Indian GP200 a bit of a boost. I don't want to go racing about but want to just have more torque and a bit more top end. To achieve this I have bought the following Rapido 225 kit, AF 48mm clubman exhaust, 30mm Dellorto phbh along with a Tameni crank , Koyo bearings and Rolf seals.
What's the consensus on this setup and are there any tips which might get the best out of it.

I hope you chose a long stroke crank as that is one of the easiest ways to soften the Rapido's standard state of tune, IMO....

[Meds]

Interesting comment about the long stroke crank,How would you set it up with the long stroke crank?
I was thinking about a 60x110 rod in mine which means 4mm longer at TDC and 2mm longer at BDC (over a standard 58x107).

[Warkton Tornado No.1]

Interesting comment about the long stroke crank,How would you set it up with the long stroke crank?
I was thinking about a 60x110 rod in mine which means 4mm longer at TDC and 2mm longer at BDC (over a standard 58x107).

Stating the obvious, perhaps, but juggling with base packers with the intention of bringing down the transfer duration is the aim.

A by-product will be the reduction in exhaust duration.

Dependent upon the piston selected (Suzuki TS250 works for me, though Kawasaki H2’s are available, meaning a re-bore) will mean that there then is the opportunity to also have a say on what inlet duration is achieved. If going the Suzuki route, opt for a rod, even if it's longer (no bad thing*) that will suit the Suzuki Ø18 mm wrist pin, though I use caps as I already had the crank (61 mm stroke)

Personally, I’d rather opt for a Japanese bike piston any day over the standard issue, & in any case, they are very affordable compared to others...

* I gave up any pre-occupation with keeping high primary compression (along with stupidly small tailpipes) long ago when engines wouldn't rev out or over rev

[Meds]

I dont know much about this so stating the obvious is a big help .
Im only playing with this to get an Idea what needs doing and wheather I want to.
Fitting a small packer (say 1.5mm) to reduce the exhaust and transfer timing means increasing the head gasket to 2.5mm, which seems a lot to me but may be perfectly acceptable?
inlet duration isnt a problem as I have a reed fitted with a TS1 piston, this cleaned up the lumpy bottom end really well

[Warkton Tornado No.1]

I dont know much about this so stating the obvious is a big help .
Im only playing with this to get an Idea what needs doing and wheather I want to.
Fitting a small packer (say 1.5mm) to reduce the exhaust and transfer timing means increasing the head gasket to 2.5mm, which seems a lot to me but may be perfectly acceptable?
inlet duration isnt a problem as I have a reed fitted with a TS1 piston, this cleaned up the lumpy bottom end really well

Dependent upon how much land exists above the piston top ring will have an influence upon what packing goes on the base, because you want to avoid a head gasket @ all costs, IMHO. Better to get the cylinder head machined so that the squish band is further in.

However, I'm a bit lost as to why there needs to be 1.5 mm base & 2.5 mm head packing which equates to 4 mm if you were considering a stroke increase to 60 mm as that is only 2 mm variation from 58 mm...

Now that you've revealed that you have a reed valve, the inlet is not a worry if you are juggling to obtain softer port timings.

Out of interest, what reed valve have you fitted?

[Meds]

LTH reed, cost me 4 MPH top end, made the scooter much more rideable round town.
I have a PM25 on it at present so it great on A roads where we can keep up revs but not great up hills
On the plus side fuel consumption is great.
I'm looking at trying to smooth it all out and I have a bit of a plan.
1. Return to a low/mid power exhaust
2. Tame the port timings ( it would have been simpler buying a less aggressively tuned barrel, but I have it now)

As to the packers, my calculations are as follows, taking the datum as the crank center as this is a known fixed point ( and removes the unknown in casing machining) to the top of the piston
58x107, 39mm piston. 60x110,39mm piston
TDC: 107+39 +29 =175mm. 110+39+30 = 179mm difference 4mm (3mm extra rod length+1mm extra crank throw)
BDC: 107+39-29 =117mm. 110+39-30= 119mm difference 2mm (3mm extra rod length- 1mm extra crank throw )


Based on my current set up as the start point, to get the piston at the same position WRT to the ports I need to
lift the barrel 2mm at BDC (using a packer)
At TDC I would need a further 2mm

So if I wanted to reduce the port timings, I would have to have to move the piston up the cylinder at BDC by reducing the size of the base packer.
As the extra length required at TDC is fixed at 4mm, what ever I take off the bottom I need to add to the top maintaining the 4mm.
Alternatively the use of a 58/110 Set up
TDC 39+110+29=178mm
BDC 39+110+29= 120 mm
seems much gentler method and allows a bit more scope to reduce the size of the base packer, but there must be a down side with the 58/110 rod?

I have tried to show all of my assumptions, reasoning and calcs to identify if there is a flaw in my logic

what I need is to do is work out what can be done reasonably, my biggest issue is having a big head gasket.
Or do I just live with it and enjoy the quirks.

[Warkton Tornado No.1]

LTH reed, cost me 4 MPH top end, made the scooter much more rideable round town.
I have a PM25 on it at present so it great on A roads where we can keep up revs but not great up hills
On the plus side fuel consumption is great.
I'm looking at trying to smooth it all out and I have a bit of a plan.
1. Return to a low/mid power exhaust
2. Tame the port timings ( it would have been simpler buying a less aggressively tuned barrel, but I have it now)

As to the packers, my calculations are as follows, taking the datum as the crank center as this is a known fixed point ( and removes the unknown in casing machining) to the top of the piston
58x107, 39mm piston. 60x110,39mm piston
TDC: 107+39 +29 =175mm. 110+39+30 = 179mm difference 4mm (3mm extra rod length+1mm extra crank throw)
BDC: 107+39-29 =117mm. 110+39-30= 119mm difference 2mm (3mm extra rod length- 1mm extra crank throw )


Based on my current set up as the start point, to get the piston at the same position WRT to the ports I need to
lift the barrel 2mm at BDC (using a packer)
At TDC I would need a further 2mm

So if I wanted to reduce the port timings, I would have to have to move the piston up the cylinder at BDC by reducing the size of the base packer.
As the extra length required at TDC is fixed at 4mm, what ever I take off the bottom I need to add to the top maintaining the 4mm.
Alternatively the use of a 58/110 Set up
TDC 39+110+29=178mm
BDC 39+110+29= 120 mm
seems much gentler method and allows a bit more scope to reduce the size of the base packer, but there must be a down side with the 58/110 rod?

I have tried to show all of my assumptions, reasoning and calcs to identify if there is a flaw in my logic

what I need is to do is work out what can be done reasonably, my biggest issue is having a big head gasket.
Or do I just live with it and enjoy the quirks.

Thanks for the additional information but I’m not sure that I was firing on all cylinders earlier (excuse the pun)

Presuming that the base of the exhaust & transfer ports are 58 mm down from the top of the barrel.

Crank centre to BDC = 39 + 107 - (58/2) = 146 – 29 = 117

Crank centre to BDC = 39 + 110 - (60/2) = 149 – 30 = 119

Maintaining the exhaust & transfer ports being level with the crown @ BDC would, indeed, need a 2 mm packer.

Crank centre to TDC = 39 + 107 + (58/2) = 146 + 29 = 175

Crank centre to TDC = 39 + 110 + (60/2) = 149 + 30 = 179

Of course, I can see that you are correct having set out the geometry myself in that you need an extra 2 mm @ the top which is best done by scooping it out of the head. Chances are the squish you are using is not @ its optimum, so you may find you can machine less than 2 mm out.

However, what that will do is reduce both transfer & exhaust duration as mentioned previously.

That can be calculated if you have the port heights...

What you may find is that you might be able to add a little to the base packing (say, 0.5 mm) so the piston goes to just below the exhaust & transfer ports to allow even less material to be scooped out of the head, but you really need to build the engine to check that out.

[Meds]

Thanks for that.
I agree it needs to be built to set it up correctly and allow for all of the tolerances,
now I know it's feasible and my calcs are ok a decent starting position.
Now comes the hard bit.
Setting what timing I need then making it happen.
I might go for a 58/110 crank as it seems to give more scope on the bottom with less issues around the head.
I will probably get it ball park using packers and gaskets then sort it out next winter to optimise

[Warkton Tornado No.1]

Thanks for that.
I agree it needs to be built to set it up correctly and allow for all of the tolerances,
now I know it's feasible and my calcs are ok a decent starting position.
Now comes the hard bit.
Setting what timing I need then making it happen.
I might go for a 58/110 crank as it seems to give more scope on the bottom with less issues around the head.
I will probably get it ball park using packers and gaskets then sort it out next winter to optimise

Hmmm.

If you're going to the trouble of re-rodding, it might be not much more hassle to source a bigger stroke crank with a longer rod fitted, say, a 116 mm or more....

Only my opinion, mind.

I don't know what's about, but the 61 mm stroke cranks were very affordable a while back. Perhaps stock has dried up...

[Meds]

It comes down to cost/hassle
If I rod to 116 then I need a new piston as well
If I go 60/110 I'm worried about the head, assuming 1-1.5mm base packer to lower the ports, which is the main reason I'm doing this, I will need a 2.5-3mm head gasket to set it up
I need to cost it out and find out what's best. I want to try and do this so if it all goes wrong, I can put it back where I started.
Lots to consider, I'm now starting to get a grip on why conrod conversions were/are so popular.