300 kit on E bay

[tsmall]

Hi Yall! OK. I’ve been lurking for a while and just reading. I’ve read a bunch of post about modifying the 250. I understand I got what I got with this engine. I got my GZ for, well let’s say, part of the settlement! LOL! Most expensive GZ ever on this forum I’d bet!!!! I’m just playing with it. I want a bar hopper! I know there’s not much to get out of the 250, but I’ve hot rodded a Briggs and Stratton just to see what I could do to make my lawn mower run faster and piss off the neighbors. That being said, I’m doing a bobber out of it. A nice single seat for ME. One thing everyone forgets about is you get HP by also by reducing weight. Now, I have about $50.00 US so far into it for the drag bars and tail light. I’m going to weigh what I took off. This is what I am thinking about on what to do with the power plant. I like the look of that 300 cc kit and the cost is pretty low. I’m thinking that kit, about a bigger main jet, playing with the carb shimming and idle adjustment, a JC Whitney muffler that has a 1 3/8th reducer and working up the stock air box as suggested in this forum. I also want to a 130 front and a 150 rear tire. No fenders or rear frame rails. I like that comment about a 150 rear being like a 15 and 1/2th front sprocket! The one thing I haven’t been able to find is how does that E bay 300 kit work and fit up. If it’s a piece of sh*t, can someone let me know? If no one’s tried one yet, I’ll be the guinea pig! As a disclaimer, I got my ’67 BMW R50 side car rig and my ’75 R90S waiting for the money to get them back to where I like them, but this GZ is just the ticket to tinker with until the is alimony done. It’s a nut to drive with those drag bars! With no fenders, I figured out that it’s a good idea to get a set of goggles! Hahahahhahahahahaha!
http://s4.postimage.org/z5o3gtd7t/PICT0071.jpg (http://postimage.org/image/z5o3gtd7t/)

[lenkf]

Interesting mods. Looks like that bike will always be a bobber because it appears the frame has been sawn off. I suggest taping up the open ends to keep out water. I had to add a pad to my seat to drive it far and looks like you've removed all the cushion from your seat frame. I've seen this done before and the owner attached a cool spring seat on top of the original plastic seat frame. The large rear tire looks wicked cool and should lower RPM a bit at speed. I hope you keep going to create a finished looking bobber and look forward to future pics.

[tsmall]

Yep, the seat is stripped. I was thinking of just leaving the original mount and having it recovered. And yep, it's a one seater from now on. I have a friend who is going to fab me up some sort of sissy bar that will clean up the back end. I have found out that it doesn't take much to get torn up from the tires slinging various chucks of road debris so I'm thinking of using the original fenders and cutting the down. Seat and sissy bar first! I don't need fenders, although they are nicer than I originally gave them credit for LOL! Thanks for the words of encouragement.

[jonathan180iq]

Yeah, fenders come on bikes for a reason.
You can get a wicked rooster tail in the back, and a reverse rooster in the front, with any kind of debris or liquid on the ground.
I can't image what riding a bike like that would be like.
I wouldn't want to.

[tsmall]

Oh yeah Jonathan. I've seen pictures and show bikes so I thought I'd give it a try. Lesson learned. I won't travel far in with the stripped down look. I can have the front fender off with four bolts and I can fabricate a mount for the rear fender with four bolts. Trimmed up and fit right, I believe it’d look good with fenders too. It’ll be like two bikes in one. A convertible. I’m glad to read here, the forum, how to trim them. I figure that I can have some fenders when I venture out for a little cruz and can take them off if I get a hair and just want to a run to the store or....where ever! I really am surprised what can be done with these bikes for so little. Hell, I might like it better with fenders.

[tsmall]

OK. Going off topic with this thread so I'll start a new one when I do the fenders done up if I don't screw it up too bad. The motor kit will come later. I was just wondering if someone had done it yet. I'll be the guinea pig when I get what done with what I got. Thanks!

[jonathan180iq]

There isn't a kit that will work. Whatever you see on E-bay is crap.

If you prove us wrong, then we'll build a shrine in your honor.
But don't hold your breath.

[tsmall]

Much better Jonathan.

[trykemike]

Hello I read this excerpt from a gn250 rider ( same engine as gz 250 4 valve dual exhaust pipes )
check it out
http://www.kiwibiker.co.nz/forums/showt ... g-problems (http://www.kiwibiker.co.nz/forums/showthread.php/142622-Gn250-running-problems)

[trykemike]

Hello I just found another post re the 300 kit

http://www.bikechatforums.com/viewtopic.php?t=189648

[blaine]

That's very interesting.The ones that use it seem to like it.
:) :cool:

[tsmall]

Thanks trykemike. Good reading!

[greatmaul]

wow, those really are good recommendations. Now I'm interested, too.

And, they are still listed on ebay: http://www.ebay.com/itm/GN300-GN250-BIG-BORE-cylinder-Improve-performance-/140662917690?pt=UK_Motorcycle_Parts&hash=item20c029ca3a#ht_2558wt_932

Are we sure the gn250 top will bolt up with a gz250 bottom?

[Water Warrior 2]

wow, those really are good recommendations. Now I'm interested, too.

And, they are still listed on ebay: http://www.ebay.com/itm/GN300-GN250-BIG-BORE-cylinder-Improve-performance-/140662917690?pt=UK_Motorcycle_Parts&hash=item20c029ca3a#ht_2558wt_932

Are we sure the gn250 top will bolt up with a gz250 bottom?
Interesting kit for more displacement. Do a little research of part numbers for the gaskets on the GZ and GN. If the cylinder base gasket and head gasket are the same you might have a winner. Keep in mind this mod might be very expensive overall.
If it is just a R/R then go for it. The increase in hp and torque would be really sweet.

[greatmaul]

Ok, I looked up the PN for cylinder head gasket and base gasket, and they are the same, cross matched, for the gz250 and gn250

cylinder head gasket p/n: 11141-38201
cylinder base gasket p/n: 11241-38301

hopefully this will help someone else, because my mechanical skills are pretty rusty and I don't think I'd have any chance at doing this without a "how-to" complete with pictures that have red arrows drawn on them and things circled in yellow, along with a story line full of things like, "CAUTION: do not xxxxxxxx here or you will destroy the entire xxxxxxxx assembly."

[Water Warrior 2]

Ok, I looked up the PN for cylinder head gasket and base gasket, and they are the same, cross matched, for the gz250 and gn250

cylinder head gasket p/n: 11141-38201
cylinder base gasket p/n: 11241-38301

hopefully this will help someone else, because my mechanical skills are pretty rusty and I don't think I'd have any chance at doing this without a "how-to" complete with pictures that have red arrows drawn on them and things circled in yellow, along with a story line full of things like, "CAUTION: do not xxxxxxxx here or you will destroy the entire xxxxxxxx assembly."
Maybe hire a professional with knowledge and tools. It could be the best bet for a good mod without reliability issues if you mess up due to rust between the ears.