Nice to see it all coming together Mike.
Let me know when you fancy a track day and I'll come along with you.
Modified Kr-1s Freshen up
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A bit more progress-
I've fitted the overbored carbs that I have had sitting in the garage for about 3 years.
These are some standard Kr-1s pwk 28's that have been offset bored to 29.5mm (the biggest you can go).
I actually spent the time to clean them out and set them up properly;- set float heights, balanced the throttles etc. - something I had never got round to doing before . It started 1st kick, something it never did before........
I've had to take a bit of a guess at jetting* as there is not a lot of information around about this modification. I'm going to take it out for a spin tomorrow to see how it goes.
Wish me luck!
Mike
*Unless I'm remembering my physics all wrong, the larger bore will mean the air is travelling more slowly over the jets- this means I will need larger jets (I think).
The engine is a Graham File tune with Tz pistons. It runs on premix.
I've gone up from 40 to 42 pilot jets and from 140 to 142 main jets with a 99 needle.
I've fitted the overbored carbs that I have had sitting in the garage for about 3 years.
These are some standard Kr-1s pwk 28's that have been offset bored to 29.5mm (the biggest you can go).
I actually spent the time to clean them out and set them up properly;- set float heights, balanced the throttles etc. - something I had never got round to doing before . It started 1st kick, something it never did before........
I've had to take a bit of a guess at jetting* as there is not a lot of information around about this modification. I'm going to take it out for a spin tomorrow to see how it goes.
Wish me luck!
Mike
*Unless I'm remembering my physics all wrong, the larger bore will mean the air is travelling more slowly over the jets- this means I will need larger jets (I think).
The engine is a Graham File tune with Tz pistons. It runs on premix.
I've gone up from 40 to 42 pilot jets and from 140 to 142 main jets with a 99 needle.
Need Break down cover? P.m. me.
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Some truth in that Garye345 - once mine are really clean it makes me reluctant to use them in the way it was intended.garye345 wrote:Looking good Mike.
Dont bother cleaning it matey,it'll only get mucky if you do .
Keep it usable and enjoy !
If it takes more than 2strokes then your just playing at it..
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Well, I just took it out for a spin.
F**k Me, what a difference.
It picks up much more readily from low revs and starts coming on strong at around 7k. There is a bit of a flat spot at around 8k but after that it just takes off, screaming up to an indicated 11.5k before tailing off. Before it was always a bit laboured getting above 10k, so I used to short shift a lot.
Not any more , it is there in an instant, pulling much harder than it ever used too.
The problem is, I can't be sure what has caused this transformation, because I have changed three things at once.
1. It could be the fact the carbs have actually been set up properly (I reckon that has improved the starting and low down pull)
2. It could be the extra flow of the 29.5mm carbs (could explain the better top end)
3. Or it could be the Gibson exhausts.
Or it could be a combination of all three.
All I know is that I am well chuffed!
F**k Me, what a difference.
It picks up much more readily from low revs and starts coming on strong at around 7k. There is a bit of a flat spot at around 8k but after that it just takes off, screaming up to an indicated 11.5k before tailing off. Before it was always a bit laboured getting above 10k, so I used to short shift a lot.
Not any more , it is there in an instant, pulling much harder than it ever used too.
The problem is, I can't be sure what has caused this transformation, because I have changed three things at once.
1. It could be the fact the carbs have actually been set up properly (I reckon that has improved the starting and low down pull)
2. It could be the extra flow of the 29.5mm carbs (could explain the better top end)
3. Or it could be the Gibson exhausts.
Or it could be a combination of all three.
All I know is that I am well chuffed!
Need Break down cover? P.m. me.