Search found 464 matches

by James P
Sat Aug 04, 2018 11:12 am
Forum: Engine
Topic: KMX oversized piston.
Replies: 7
Views: 351

Re: KMX oversized piston.

The 200 fits the 125 cases and the crank is the same 54.5mm part too. Its just stuff like the carb, radiator and clutch that are different, and I've got upgrades for all those ready too. The only problem is if I fit the 200 top end on this engine, the custom pipe I've got won't really work, and I'v...
by James P
Wed Jul 18, 2018 2:26 pm
Forum: Engine
Topic: KMX oversized piston.
Replies: 7
Views: 351

Re: KMX oversized piston.

a sleved one is always inferior, not matter how good the job has been done. because of the lesser heat dissipation between sleeve and cylinder. don't think it will matter much in one "underpowered" KMX though. Yes Jan - I agree. As you point out, the cooling "inferiority" of a sleeve may not be not...
by James P
Wed Jul 18, 2018 1:38 pm
Forum: Engine
Topic: Squish clearance and compression ratio - advice please!
Replies: 31
Views: 3058

Re: Squish clearance and compression ratio - advice please!

Please could someone tell me what the standard piston dome radius is... I'm not sure if you still need this info, but the dome radius of a standard piston is about 120mm. I found it difficult to measure with accuracy, as I could only use a profile gauge to get a trace of the dome profile, then comp...
by James P
Mon Jul 16, 2018 2:18 pm
Forum: Engine
Topic: KMX oversized piston.
Replies: 7
Views: 351

Re: KMX oversized piston.

You will have to add the cost of modifying the head to the cost of the bigger bore cyinder and piston unless you can do the work yourself, plus the cost of a non-standard head gasket if it isn't included with the 56 mm cylinder and piston. This may or may not be cheaper than finding a standard bore...
by James P
Fri Jun 15, 2018 11:55 am
Forum: Chit Chat
Topic: SP/F3 kit steering stopper
Replies: 5
Views: 499

Re: SP/F3 kit steering stopper

is all i have from a saved web page... can probably scale photo off parts sticker Thanks for that Danny - I have those same photos from when an SP or F3 kit was split up on Yahoo ages ago! I even put a bid on the steering stopper from that lot, but the price went higher than I thought it was worth ...
by James P
Sat Apr 14, 2018 8:59 am
Forum: KR250 Chat
Topic: KR250A custom for sale in Japan...
Replies: 2
Views: 510

KR250A custom for sale in Japan...

Saw this tidy KR250A for sale on Yahoo Auctions:

https://page.auctions.yahoo.co.jp/jp/auction/g263576977

Fitted with ZXR250C wheels and forks.

Regards,
James
by James P
Wed Apr 04, 2018 12:10 pm
Forum: Chit Chat
Topic: SP/F3 kit steering stopper
Replies: 5
Views: 499

SP/F3 kit steering stopper

This may be a long shot; Does anyone have the steering stopper from the 1988 SP/F3 kit (Part No.32085-1303)? I want to try to make one of these or something similar, but dimensions would be handy! I have taken most of the measurements directly from the frame to create something similar, but I would ...
by James P
Wed Apr 04, 2018 11:58 am
Forum: Chit Chat
Topic: Kr1 b1/b2 Rear wheel clip
Replies: 26
Views: 2023

Re: Kr1 b1/b2 Rear wheel clip

It seems that this happens often with a certaian person. I don't know why as I have never met him. But their seems to be a problem with him. I have a idea why he is the way he is Martin, Since your comments were made directly underneath my post, are you possibly referring to me...? What exactly do ...
by James P
Sat Mar 17, 2018 5:27 am
Forum: Chit Chat
Topic: Kr1 b1/b2 Rear wheel clip
Replies: 26
Views: 2023

Re: Kr1 b1/b2 Rear wheel clip

The rear axle nut thread is M16x1.5 isn't it (I haven't got mine on hand to confirm)?? If so, and you can't get hold of one of these special clips, you could try using a Lambretta engine pivot shaft nut. These are shallow M16x1.5 Nylock nuts (about 12mm tall in total), so shouldn't come off if they ...
by James P
Sat Mar 17, 2018 4:38 am
Forum: Engine
Topic: Balance shaft rebuild?
Replies: 6
Views: 636

Re: Balance shaft rebuild?

Joe439 wrote:
Fri Mar 16, 2018 5:58 pm
What seal and bearing to use on it.
Joe,

See my reply under a previous topic: http://kr-1s.co.uk/forum/viewtopic.php?f=1&t=13790

You could modify "normal" 6303-C3 bearings and you could also perhaps use a 23-47-7 seal with a 0.7mm spacer.

Let us know what you end up doing!

Regards,
James
by James P
Tue Aug 15, 2017 7:48 am
Forum: KR Bits and Bikes Wanted
Topic: Wanted Rear kr1s mudguard
Replies: 3
Views: 861

Re: Wanted Rear kr1s mudguard

Here are a couple from Japan if you can't find anything closer to home:

https://page.auctions.yahoo.co.jp/jp/auction/n224432701

https://page.auctions.yahoo.co.jp/jp/auction/m203252339

Regards,
James
by James P
Tue Aug 15, 2017 7:33 am
Forum: Engine
Topic: The engine will not start.
Replies: 9
Views: 1170

Re: The engine will not start.

for some time the engine starts cold very badly. after the start, it took a few seconds for both cylinders to run. with a warm engine, the engine starts normally. Dirk, Perhaps your bike has several different problems. Poor starting from cold could be a blocked starter jet or passage in one or both...
by James P
Sun Jul 02, 2017 10:14 am
Forum: Chit Chat
Topic: Rear Sprockets
Replies: 3
Views: 931

Re: Rear Sprockets

Contacted B and C Express about a Renthal rear sprocket for the KR1S and they said they haven't had them for 10 years now :shock: but can make one from a blank for about £44 :shock: I didn't realise they must be a unique fitment for the KR1S bikes ? A steel JT rear sprocket is £20 posted If you wan...
by James P
Sun Jul 02, 2017 9:28 am
Forum: Engine
Topic: 1mm skimmed head Squish Clearance Part two
Replies: 3
Views: 805

Re: 1mm skimmed head Squish Clearance Part two

...forgot to mention, if you're not already aware:

It will be a good idea to also measure the volumes of your combustion chambers (to calculate compression ratios), just to make sure your pistons won't melt!

Regards,
James
by James P
Sun Jul 02, 2017 9:22 am
Forum: Engine
Topic: 1mm skimmed head Squish Clearance Part two
Replies: 3
Views: 805

Re: 1mm skimmed head Squish Clearance Part two

To check the squish clearance, it will be best to check with the components you are actually going to use. Otherwise, there is a chance that the components you use for testing (i.e. conrods and pistons) may each be slightly shorter than "standard", while the components you actually use for the final...