KR1S race bike-work to finish!

Show us that box of bits in your shed!
Post Reply
Woodsy
Light Smoker
Posts: 47
Joined: Wed Nov 09, 2011 9:39 am

KR1S race bike-work to finish!

Post by Woodsy » Tue May 29, 2018 10:29 pm

I’m pretty far through rebuilding my race KR1S, and I’m getting the chassis back together at the moment. Which is where I’m after any help / advice on a few things...
But first, a brief summary of the bike. I got it about 7 years back from a guy that had raced it with some mates as a team. It’s been pretty thoughtfully built, with solid blocks welded in place of the for standard cast footrest mounts on the frame, tzr250 frame mounted choke lever, Mark Jordan fettled barrels and cylinders (very tidy by the way!) and TZ silencers. It had been left to rot for a few years, and so I’ve stripped everything back to basics for a return to track, both trackdays and perhaps racing at my advanced years! Rebuilt crank (by BDK), replated barrels, all new bearings throughout, new 2nd gear and selector forks, replated forks, etc.
I’d like to modify the loom to remove the lighting, horn and ignition switch: question is, does anyone have a wiring diagram of what to modify/ remove from the loom?

SP_BOTT
Oil Injector
Posts: 697
Joined: Sun Sep 30, 2007 5:59 pm

Re: KR1S race bike-work to finish!

Post by SP_BOTT » Wed May 30, 2018 7:38 am

Do you need to go that far? Everything just unplugs from the loom, i think that's how i'd do it anyway, and shrinkwrap the connectors if worried about water ingress. But they're not that well protected in the first place.
How much was a crank rebuild, as BDK are reasonably close to me, what sort of turnaround, as they can be 'quite busy' at times.

Woodsy
Light Smoker
Posts: 47
Joined: Wed Nov 09, 2011 9:39 am

Re: KR1S race bike-work to finish!

Post by Woodsy » Wed May 30, 2018 11:05 pm

Thanks for the thoughts on the loom-the main points I’m hoping for advice on is making the kill switch the only ignition switch (ie losing the ignition barrel), and short circuiting the clutch/sidestand switch.
BDK were about 2-3 weeks turnaround from memory. 8)

Woodsy
Light Smoker
Posts: 47
Joined: Wed Nov 09, 2011 9:39 am

Re: KR1S race bike-work to finish!

Post by Woodsy » Tue Jun 05, 2018 8:28 pm

Looks like I’m on my own with the loom then... :lol:
Any advice from the racers about brake pads? I’m running standard discs for now and hope to do at least one of the TwoStroke GP rounds...

Woodsy
Light Smoker
Posts: 47
Joined: Wed Nov 09, 2011 9:39 am

Re: KR1S race bike-work to finish!

Post by Woodsy » Tue Jun 23, 2020 11:41 am

After a looooong time away from this post, I thought it time for an update!

Long story short, first ride at Mallory (for the Festival of 1000 Bikes) last July saw me ignoring the temperatures and seizing on my second lap. It nipped up as I was turning into the lake Esses at around 70, so I had my first closed throttle highside. I wouldn’t recommend it to anyone...

So after a rebuild, setup session at Krazy Katt dyno, lapping the head and cylinders and a fresh set of pistons, it had its first bedding in track session at Bedford yesterday. Decent turn of speed (from the bike), possible warped front disc (vibration increases with speed), and probably water pump lip seal damaged as moisture visible in oil sight glass.

Pics to follow...

maccas
Oil Injector
Posts: 855
Joined: Mon Sep 07, 2009 8:33 pm
Location: east yorkshire

Re: KR1S race bike-work to finish!

Post by maccas » Wed Jun 24, 2020 1:47 pm

How'd it get on on James' dyno? Did you crack 60hp?

Sounds like a decent bike!

Dan

Woodsy
Light Smoker
Posts: 47
Joined: Wed Nov 09, 2011 9:39 am

Re: KR1S race bike-work to finish!

Post by Woodsy » Tue Feb 23, 2021 9:44 pm

Thanks for the message Dan, and sorry for the enormous delay replying!

Sadly didn’t break 56 bhp - James thoughts were the pipes weee holding it back, as it fairly abruptly stopped at 11k.

Been a few more mods since which I’m near finishing... I’ve cleaned up the transfer entrance, opening them up to match the cases. Also rebuilt the engine as I used an inferior silicone sealant which had started to break down on contact with the gearbox oil! Think this was both allowing gearbox oil into the RH primary case and air, hence running lean as the revs built, according to James’ afm. Now rebuilt with 3Bond, and I’ve actually put the final clutch friction plate in the correct position; I could not understand why it would not disengage cleanly until I checked a photo pre rebuild!! Should be a marked improvement...

Next is getting the inserts for one of Jan’s heads machined to suit the TZ250 26J pistons I’m going to run. Mitakas are really poor at the moment, as the gudgeon pin holes had started to elongate / stretch after only around 40 mins running! Be careful of them...

So lots going on, and I’m hoping to get on track at Bedford Autodrome early April.

maccas
Oil Injector
Posts: 855
Joined: Mon Sep 07, 2009 8:33 pm
Location: east yorkshire

Re: KR1S race bike-work to finish!

Post by maccas » Wed Feb 24, 2021 2:12 pm

56 on James's dyno is pretty good to be honest. Which pipes are you running? Are you running a zeeltronic?

Dan

Woodsy
Light Smoker
Posts: 47
Joined: Wed Nov 09, 2011 9:39 am

Re: KR1S race bike-work to finish!

Post by Woodsy » Mon Mar 01, 2021 3:22 pm

Hi Dan-that’s good to know. MJ showed me some of his curves, and mine looked pretty weak in terms of torque and overrev.
The pipes were Huxleys, and I’m going to run stock pipes with TZ silencers next.

I do have a Zeeltronic which I’ll fit once I’ve adjusted the cutout time; Boruk suggested increasing it, as I was not getting a spark when I tried it last year. Any suggestions around this would be much appreciated to resolve it as I’d like to get away from the stock ignition and CDI woes!

Cheers,
Al

Post Reply