442cc kit changes

Forum rules
Please can you post items for sale or wanted in the correct For Sale section. Items / bikes for sale here will be removed without warning. Reasons for this are in the FAQ. Thanks
User avatar
Drunkn Munky
Site Supporter
Site Supporter
Reactions:
Posts: 10328
Joined: Thu May 01, 2008 9:37 am
Bike owned: NC30 MC21 TZR FZR GSXR RG MITO
Location: Kent
Re: 442cc kit changes

Post by Drunkn Munky » Fri Mar 13, 2015 10:15 am

Omega do or did some proper +1mm pistons, lighter than je and stock pistons. There the ones I'd go for.

User avatar
Variablevalves suck
Site Supporter
Site Supporter
Reactions:
Posts: 2608
Joined: Sat Jan 24, 2009 10:52 am
Bike owned: GSXR Carb o'ring kits supplied
Location: Stoke-on-trent
Re: 442cc kit changes

Post by Variablevalves suck » Fri Mar 13, 2015 10:54 am

Don't know if Omega ever did a gixer one, may be able to fit a ZXR one with a little work.

You can help the weight of the JE set by using FZR wrist pins as these are tapered on the inside to save weight where as JE pins are bored parallel and very heavy.

User avatar
Drunkn Munky
Site Supporter
Site Supporter
Reactions:
Posts: 10328
Joined: Thu May 01, 2008 9:37 am
Bike owned: NC30 MC21 TZR FZR GSXR RG MITO
Location: Kent
Re: 442cc kit changes

Post by Drunkn Munky » Fri Mar 13, 2015 11:16 am

Lol ignore everything ive said i thought we were on about NC's :oops:

CHR15
Settled in member
Reactions:
Posts: 127
Joined: Sun Aug 12, 2012 12:02 am
Bike owned: GK73A
Re: 442cc kit changes

Post by CHR15 » Mon Mar 16, 2015 10:41 pm

stripes1976 wrote:Biggest gains I found was swapping the crank.

to what if you dont mind me asking?

User avatar
Variablevalves suck
Site Supporter
Site Supporter
Reactions:
Posts: 2608
Joined: Sat Jan 24, 2009 10:52 am
Bike owned: GSXR Carb o'ring kits supplied
Location: Stoke-on-trent
Re: 442cc kit changes

Post by Variablevalves suck » Mon Mar 16, 2015 11:23 pm

There's potential to fit the early gsxr4 crank from the 51, its longer stroke and smaller bore so would stroke the motor.

Some problems.
15 mm wrist pin.
Different taper on end - could be an easy fix due to inside out flywheel, it had Sam style.
Different clutch that may or may not swap over and could have way off primary gearing.

CHR15
Settled in member
Reactions:
Posts: 127
Joined: Sun Aug 12, 2012 12:02 am
Bike owned: GK73A
Re: 442cc kit changes

Post by CHR15 » Tue Mar 17, 2015 12:10 am

Theres a bloke in stoke splitting a 71b motor.

See if he gets back to me about the crank.

Are the big ends the same od as the 73a crank?

User avatar
Variablevalves suck
Site Supporter
Site Supporter
Reactions:
Posts: 2608
Joined: Sat Jan 24, 2009 10:52 am
Bike owned: GSXR Carb o'ring kits supplied
Location: Stoke-on-trent
Re: 442cc kit changes

Post by Variablevalves suck » Tue Mar 17, 2015 8:25 am

Ye sorry mate i should have said 71 not 51.

it has the same mains but you would have to find a conrod that was of the correct length with a 15mm wrist pin as it has 14mm pins.
might have enough meat to machine out but its that long since i looked at them that i cannot remember.

I think the biggest problem will be the clutch, take a look at the workshop manual to see the differences.

I will try and get you more info as i looked into it about 10 years ago.

User avatar
Variablevalves suck
Site Supporter
Site Supporter
Reactions:
Posts: 2608
Joined: Sat Jan 24, 2009 10:52 am
Bike owned: GSXR Carb o'ring kits supplied
Location: Stoke-on-trent
Re: 442cc kit changes

Post by Variablevalves suck » Tue Mar 17, 2015 8:34 am


CHR15
Settled in member
Reactions:
Posts: 127
Joined: Sun Aug 12, 2012 12:02 am
Bike owned: GK73A
Re: 442cc kit changes

Post by CHR15 » Tue Mar 17, 2015 8:33 pm

so,

use 71b rods, with the little ends re-sized to 16mm. that's easy enough to do.

im not bothered about modifying either ends of the crank, thats piss easy.

the primary drive gear seems to be the sticking point.

i presume the centre to centre distance between the input shaft and crank on the 71b is different from the 73a.

and as the drive gears are different profiles and sizes it makes it a bit tricky.

i do enjoy a challenge.


i'm collecting a 71b bottom end on thursday so we'll see how it pans out.

User avatar
Variablevalves suck
Site Supporter
Site Supporter
Reactions:
Posts: 2608
Joined: Sat Jan 24, 2009 10:52 am
Bike owned: GSXR Carb o'ring kits supplied
Location: Stoke-on-trent
Re: 442cc kit changes

Post by Variablevalves suck » Tue Mar 17, 2015 11:09 pm

Its been along time mate but on re reading I'm sure Bart had problems fitting the clutch primary in the casing or something,
Think the primary gears were bigger diameters.
Soon see if you getting a motor.

Some more info.
bearing. ( 2x shells ).


Part number 12229-43400-0G0.

83-86 GSX550

83-86 GS550 EF ES3 SE SF SG S3 (USA)

84 GSX500

87 GSXR400R


Post Reply