GN250 Cafe Racer

**highace10** · 14th March 2013, 15:07

Got the cover, fitted nicely.

Also got the new main jets and thew in the 135. It idles nicely and revs well, haven't taken it for a ride yet. Maybe this afternoon.

**pondyrock** · 10th April 2013, 18:21

Originally Posted by JMSR

seat cut and shaved (much easier than anticipated), trial tank stripping (looks great most angles but dominates the bike side on, black tank ordered), new rear guard rear mounting bolt holes drilled to lift tail (in line and under original holes, close to the edge gives nice lift), guards and rear shock shrouds cut down, black tank and smaller indicators, new Cycleworks full exhaust system (moved the needle to richen it up to suit) and moved tail light back, removed centre dash between dials and lowered front end 38mm (attacking corners feels much better with this mod). LOTS more mods to come including full engine mods and hot carb. This is easily the most fun I've ever had with 3 weeks and $800!

Hey mate, do you have any more detials on how you cut down your seat like that? Looks great and would like to do the same to mine, including the shortening of the rear guard?

Cheers,

Matt

**highace10** · 10th April 2013, 20:09

All done. Running nicely now after a couple of small things.

:-)

**nzmikey** · 11th April 2013, 11:17

Originally Posted by highace10

Thought i would drop in and post a pic of my GN that is still in the works.

Still have a few things to do...main ones being:

Somehow changing the fork oil to a higher weight. Hopefully stiffen things up a bit

and get the damn thing going, especially after ive cut out the airbox. CV Carbs and pods dont mix apparently.

Ace

Are you running clip on's on that ? If not how the hell did ya do that ?

**JMSR** · 11th April 2013, 22:16

Highace that looks preeeeeeeeemo!!

Matt, Pulled the staples on the cover then used a wide flat handsaw for cutting the plastic and the foam. The plastic cuts easily with a sharp saw. I cut the back off to the molding for the rear mount, and drew a horizontal line from the bottom front corner along the side then cut it with the saw teeth flat along the line for a good straight cut. You'll be cutting through the foam at the same time so it'll act as a guide for the saw. I should also mention I have a 50mm ply spacer between the plastic and front mount hook which changes the profile a little and and matches the spacer under the back of the tank. Smooth of the edges with a sanding disc or block. Lay the saw flat on the lower part of the seat and slowly cut with broad strokes the top off the pillion section. Round off the corners of the foam. When putting the cover back on use the pattern as a guide. Instead of stapling I used M3x6 long self tappers with wide washers and pre-drilled a pattern of about 60 around the underside. This would allow for adjustments and future covers not to mention it's near impossible to staple that plastic! Good luck.

**ducatilover** · 11th April 2013, 22:55

I've got a normal staple gun from Bunnings, has done me about 5 seat covers and it managed fine when I did the GN seat chop last year

I better get around to finishing my GN. NOS piston for the DR600 motor in it arrived last week, so I might manage to get the motor done tomorrow.

**JMSR** · 12th April 2013, 07:32

Hmm I tried a good industrial staple gun but it must have been poos.

Wow exciting times with the GNs! I wish I could be as excited with mine but customs is dragging their heels on releasing my go faster bits. Grrr.

**ducatilover** · 12th April 2013, 11:20

Originally Posted by JMSR

Hmm I tried a good industrial staple gun but it must have been poos.

Wow exciting times with the GNs! I wish I could be as excited with mine but customs is dragging their heels on releasing my go faster bits. Grrr.

Are you using decent staples? I don't remember the brand mine are, but they're not el-cheapo ones, cheap ones just fold on themselves

What go-fast bits have you got yourself?

**pondyrock** · 12th April 2013, 17:57

Originally Posted by JMSR

Highace that looks preeeeeeeeemo!!

Matt, Pulled the staples on the cover then used a wide flat handsaw for cutting the plastic and the foam. The plastic cuts easily with a sharp saw. I cut the back off to the molding for the rear mount, and drew a horizontal line from the bottom front corner along the side then cut it with the saw teeth flat along the line for a good straight cut. You'll be cutting through the foam at the same time so it'll act as a guide for the saw. I should also mention I have a 50mm ply spacer between the plastic and front mount hook which changes the profile a little and and matches the spacer under the back of the tank. Smooth of the edges with a sanding disc or block. Lay the saw flat on the lower part of the seat and slowly cut with broad strokes the top off the pillion section. Round off the corners of the foam. When putting the cover back on use the pattern as a guide. Instead of stapling I used M3x6 long self tappers with wide washers and pre-drilled a pattern of about 60 around the underside. This would allow for adjustments and future covers not to mention it's near impossible to staple that plastic! Good luck.

Thanks for the write up. I'll give it a try, I like that you've actually cut away the plastic along the sides and the back making it shorter.

Did you just move your rear mudguard up and drill new holes to make it shorter?

**JMSR** · 13th April 2013, 08:00

300cc piston and barrel, hot cam and rockers from these guys http://www.xlitemoto.com/index.html. He's also just told me they're now dealing with 400cc kits.

Below, word for word, is the advert for the cam. Man I laughed! Then I saw the profile. Then I saw the graph. Then I sorted it.

The GN250 is painfully slow , no power at all , even GN400 was sluggish piece of s*#t, let alone GN250 , even GN125 feels faster , so if to make one Camshaft for this model , it better make it fast , or not make it at all :

this not a normal RACE cam , it put any RACE s#*t into shame , we not BS you .. look , lobes almost Square , so it has faster ramp then NASCAR , more duration then a GP bike , you not believe GP bikes not use big durations .. so it is for street , designed to work with stock head and valve train... should clear stock piston too .. check all clearances.

cylinder can be enlarged a lot on this model , we tried different sizes but valves too small , it run of steam at high rpm therefore Megaphone is a must for big CCs

can be taken to about 375 but only 300 kit mass produced , if you want one , its $150 for full kit , no case boring required .., others sizes never mass produced so not exist for sale , this model not popular in china because of high cost , so we can not mass produce any parts for it. either , will not do further experiments and testing on it.either ..

this cam is ONE OFF , sorry for high prices , only 1 part exists in the world , not mass produced ...

Matt, yep I just drilled new holes for the indicators. Under the existing ones there's a nice little clear area to drill. Be careful not to raise it too high, allow for the nearby crossbar. Then I just used masking tape from a chosen spot in the center of the guard below the tail light to just behind where you have just drilled to mark my cutting line to reshape the guard. A steady hand with a 1mm cutting disc on the grinder followed by a wide, coarse sanding block was all I used. I also drill holes for the new tail light under the old ones to make it lower and more horizontal. Zoom in on the previous pic and the two below as a guide.

**ducatilover** · 13th April 2013, 16:10

Please tell me that cam is some sort of joke?

**JMSR** · 13th April 2013, 17:31

Win or fail I'll be the one who found out

.

**ducatilover** · 14th April 2013, 21:29

I'll send you a free cam and assorted parts once you snap valves and springs, free but only if you video it. Or take pictures of it throwing small engine parts at somebody on a dyno

I'm going with, valve hit piston, bend valve, crack rocker (at the least) and possibly snap the guide (mine managed that)
Or it simply won't start

I'd also like what drugs that fella is on, so I can stay away from them lol

**JMSR** · 15th April 2013, 19:42

I'm not toooo worried

. I've had good advice from Dunedins finest bike mechanics and old boy bikers thanks to being a barber. Not to mention a couple of race engines for cars under my belt thanks to my Mech Eng degree and 12yrs machinery design. Throw in a brother in law who builds trail bikes for VMX including the old DRs. So as I say,I'm not toooo worried. Anyway Xlite have had the world record for 1/4mile 125cc 2 stroke at 10.6s!!!! So they shouldn't be slouches surely.

One thing that is interesting, and this all agreed upon after much deliberation and investigation, is the use of standard soft springs. How's that for twisting your noodle. It's what Xlite recommend. The bike mechs agree and I think it adds up so it's chocks away on this build for sure!