New member from UK

[Mohawk]

I've had my ZZR250 for 7 years now, I bought it as a winter bike & its been used slightly in the winter whilst I reworked my VFR800 each winter.

This year there was not much that needed doing to the VFR so I decided to treat the 250

Current mods include KR1-S Front forks/wheel/brakes & an Ohlins shock from the later Ninja 250R.

This winter has replaced the KR1-S fork internals with a combination of VFR & VTR1000 fork cartridges/valves/springs & fresh oil. Plus replacing the forever seizing Tokico calipers with CBR929 Nissin ones

The latest has been to replace the swingarm with a FR1-S alloy one & a Honda VTR250 17" rear wheel to match the front, with custom wheel spacers, plus a 48 toth rear sprocket by super sprox & that need a 110link X-ring chain to allow for the larger sprocket & 15mm longer swingarm. This does not lengthen the wheel base as the KR1-S forks shortened the front by a similar amount, as well as giving a steeper rake angle & shorter trail. Combined with teh Ohlins shock I expect the handling to be awesome now, its was much better than standard as was.

I've also converted the coils to CoP units from a CBR600RR, works great, reduces weight & frees up space for ram air ducts !
I have added an oil cooler to the head feed. thank you Kawasaki for the external oil feed line
I also have a complete clutch from the newer model which I believe will fit & cure thehorrible clutch knock that the older engines are famous for at idle due to the plastic buffers they are fitted with that compress & leave the basket loose.

I've also just had a spare cylinder re-seleeved & bored to 66mm to make a 282cc big bore engine. I just picked this up today, so will be a while before I have time to rebuild the engine, but hoping for around 40HP, with some other mods I have planned.

More in the threads section as I get round to it.

[cbinker]

welcome.

[HoneyBadgerRy]

Originally Posted by Mohawk

I've also just had a spare cylinder re-seleeved & bored to 66mm to make a 282cc big bore engine. I just picked this up today, so will be a while before I have time to rebuild the engine, but hoping for around 40HP, with some other mods I have planned.

Those are some cool mods. What Pistons are you planning on using in your 66mm build? I am looking forward to hearing more from you and your bike.

[allanoue]

Chris
You will fit right in, half our members have the same first name as you.

[csmith12]

Welcome Chris!

Somebody has been busy...

[Mohawk]

Originally Posted by HoneyBadgerRy

Those are some cool mods. What Pistons are you planning on using in your 66mm build? I am looking forward to hearing more from you and your bike.

Thanks all.

The pistons will be ZX6R ART ones, as in the stock ZX6R ones, they are close to the stock 250's weight, but I'll balance them & loose some weight to get them the same as the 250's as required. I'll run 2x base gaskets to avoid compression issues.

[HoneyBadgerRy]

Originally Posted by Mohawk

The pistons will be ZX6R ART ones, as in the stock ZX6R ones, they are close to the stock 250's weight, but I'll balance them & loose some weight to get them the same as the 250's as required. I'll run 2x base gaskets to avoid compression issues.

What year is your bike? I believe the base gaskets are thin aluminium fiberglass layered gaskets, so I doubt you will gain much clearance by running two. You could try to get a custom copper gasket, but personally I would rather just do a little DIY porting to the combustion chamber and the pistons to avoid clearance issues and try to get as much compression as possible, unless its so much that E85 detonates. If you do that route though, you might find problems with ignition and fueling. You already have cop's, but I have no idea how powerful of a spark they run. For fueling might want to look into a fuel pump, or go EFI (If there is a probblem, which there might not be).

[Mohawk]

Bike is a 2001 model. I'll make a custom gasket if required.

Well my calculations are as follows for compression ratios

bore - radius - stroke -area mm - cc - CR - head cc (calculated from std CR)
62.00 31.00 41.20 3017.54 124.32 12.50 10.81
64.00 32.00 41.20 3215.36 132.47 13.25 10.81
66.00 33.00 41.20 3419.46 140.88 14.03 10.81

So 14.03-1 static compression. I've not got round to calculating the dynamic ratios yet, which is ultimately what determines if it will work.

I've not stripped one of these engines yet, so no idea what the base gasket is made of or its thickness. Like wise until I do a comparison of the pistons, no idea if the fit in the combustion will need to be modified. But I'll cross that bridge when I get to it.

I'm sure the CoP's are up to the job, been used on other high comp engines with no issues. The timing is not that advanced on these engines, so should also be fine, if in needs delayed, then I'll adjust the pick up.

[HoneyBadgerRy]

Originally Posted by Mohawk

The timing is not that advanced on these engines, so should also be fine, if in needs delayed, then I'll adjust the pick up.

Good luck with that, It is not impossible, you could machine your own keystone, and find a way to pull the flywheel. However, you would be better off with an entrons kit, or a microsquirt. I am currently unaware of anybody how adjusted the pickup to adjust ignition timing.

[taz]

welcome chris

[DEFY]

Welcome

[CaliGrrl]

Welcome!

[snot]

Welcome

[Snake]

Hello and welcome!