KR-1S.co.uk Forum

Thought I would start a thread on Dyno runs as George (username NZKR1) has asked me to post his result.

Engine is KR-1 with the exhaust and KIPS ports modified to match a KR-1S, KR-1S pipes, head skimmed 0.54mm and a 1mm base gasket (basically lifts the ports about 0.6mm). Slight increase in compression due to head skimming. The bike is on avgas and runs 35mm carbs off an SP with a modified airbox.

Dyno type is unknown but the engine as a stock KR-1 made 52hp so a healthy 8hp gain over stock.

Ok my best as of Nov 2007



Flowed and filled cases.
KIPS and main exhaust up 1mm, KIPS are about 3mm wider
Transfers up 1mm, main transfer nearest exhaust tidied up, rear transfer significantly wider (ring webs between main transfer and boost port about 2mm thick) runs TZ pistons with ring groove in the boost port. Barrels matched to the cases, KIPS ports matched to the power valves. Head matched to TZ piston domes, Barrels shortened 2mm and strengthened to run 3TC pistons, V-Force 3 reed blocks.
Lomas pipes, 35mm carbs, running airfilter in a modified standard airbox, air feed from over the rad, rad dropped to allow feed.

Reading on a Dynopro dyno where a stock KR1S makes 50hp. Bonneville bike made 56hp. This engine at 64hp is 14hp (28%) up on a stock KR-1S engine.
Engine is 14hp up on a stock KR-1S

As a comparison a stock KR-1S, the Bonneville bike which was basically flowed cases, porting pretty standard (Falconman has the barrels and head - think he used them to set the 250-PP record at El Mirage) and my old race motor before I went over to Lomas pipes and changed the barrel spec.

wow mark, that power curve (or rather line!!) is incredible!!! power is significantly improved throughout by quite a good margin. ie 5hp up at 8k is just the beggining. i bet that bike will be awesome. this is exactly what i love about the kr. easily the oldest in terms of concept on a f250 grid but also one of the best motors out there (except maybe for the vj23) but a 6k the 23 should be!!

Thats some improvement there mark! =D>

Looking good there Mark. I'll post mine up in the new year after the rebuild.

If anybody says a KR has less midrange than an RGV point them at this graph.

Best RGV I have seen published v my last KR motor (both measured on the same dyno)
To be fair to the RGV the blue curve was as started - red is as sorted - virtually standard motor - heads and arrow pipes (I think - I am well impressed with it). My engine is as per my earlier post black curves tuned to the nuts....

My dyno results Graham File tune , Jolly Moto Pipes , modified air box ,PWK 35 carbs ,Zeeltronic Ignition and power valve controller , Shell V Power pump fuel , Moto Tassinari V Force reed blocks.

There pretty good curves MJ, the torque is nice and flat for about 3000rpm and the power curve is a 45deg line upwards.Which IME ads up to and 'electric' feel. They just keep accelerating.
satarn I think your PV opens to fast to early and you have no advance after peak either:?:

Your through the gears run shows the big gap between first and second.

Satarn,

Thats a good curve but I agree that it look like the PV open too early. To set the up do two runs one with them open one shut. You want the valves to open at the point where the two curves overlap.

Considering thats with JollyMoto pipes you have good overrun but I would love to see the bike running with Lomas pipes and compare the difference.