tony frame need help mounting a gx390

[Jaundre46]

Hi guys, new to the forum. I recently bought a oval track kart with a 100 cc pcr engine but the piston and crank is damaged the chassis looks similar to a tony kart frame but I'm unsure, anyways I thought of buying a new engine for the cart saw on the internet that the gx390 looks like a fun and powerful engine, so I found a clone engine and im buying it the end of the month. the problem I'm having is that I don't know how I'm going to fit the engine to the chassis, and the other problem is the sprocket on the axle won't line up with the engine. any advice will be appreciated. or if anyone has done thus before and can help me on this cart it wold be great
thanks in advance

 

[firemanjim]

There was another guy wanting to do the same thing, recently. Someone posted a link to a small jackshaft kit that allows the use of a 4 stroke on a 2 stroke chassis. Wheniget a minute, I'll look for that link. In the meantime, try searching "4 stroke on a 2 stroke chassis" , here on the forum...
O, nice kart!

 

[Jaundre46]

It's probably the my post on my introduction I also asked the same question their and I thought of maybe putting it in the general section, I might get more info but then the guys gave me allot of info on my introduction post, Im now thinking of scrapping the whole four stroke thing maybe and try to get a 2 stroke engine with a centrifugal clutch. thanks for your reply buddy i appreciate it

 

[anderkart]

Burris makes a (small block) 4-cycle jackshaft motormount kit that would bolt right on your kart and allow you to keep your axle sprocket on the outside:

But due to space limitations of larger sized/Big Block engines like the GX390, the the driver sprocket must remain on the inside when installing their Big Block kit. So for an angled crossbar chassis like yours, you could install a smaller diameter axle sprocket (like shifterkarts use) inside of your axle bearings. Then use compound jackshaft gearing to compensate your gear ratio.

Here's the link to both of their jackshaft motormount models:
https://id3528.securedata.net/test.burrisracing.com/merchantmanager/index.php?cPath=103_105

Here's a link to their jackshaft gearing calculator:
https://id3528.securedata.net/test....roduct_info.php?cPath=103_110&products_id=412

The top pic shows a 6.5h hp engine with their small block, 15-degree jackshaft motormount:

The bottom pic shows how the sprockets must be installed on their Big Block kit:

 

[Jaundre46]

Ander kart thanks for the info, sorry for my late reply was a bit busy... got me a new engine decided on a four stroke 150cc manual bike engine got it for a bargain, I bought the woke bike and stripped it for the engine, also took a few mount of the frame to use on the gokart got it mounted yesterday and mad the shifter aswell. Just need to sort out the exhaust and the sprocket holder as the original sprocket for the bike does not fit.

 

[firemanjim]

You're going to be FLYING with that power plant!!

 

[Jaundre46]

You're going to be FLYING with that power plant!!

Thanks buddy i hope so just need to sort out the wiring because I plugged all the wiring and cdi on to the engine and connected the battery but the starter solenoid just clicks and doesn't turn the engine over. Don't know what I'm doing wrong, because when I kick start the engine it fires right up but when I engage it into first gear it dies, I think something is wrong on a safety switch on the neutral or something....

 

[firemanjim]

Yeah, I think the neutral safety switch is screwing with you.... Disconnect it. It works on a negative ground system. It's located just above and to the right of the shifter. Remove the cover, and you will see 1 (maybe 2 )wires coming out the side.....
EDIT
No. It's not the neutral safety switch. It IS a safety switch though.....

 

[J_Walker]

is there a reason you can't take the slip-on off the original bike, and just use the pipe for now? just flip it upside down so its going over the engine?

a clicking solenoid could just be a dead battery, that's what happens on most motorcycles ive ever touched that has that problem.


also for the putting it in gear, its most likely your kickstand safety switch is some how activated.

 

[Jaundre46]

Yeah, I think the neutral safety switch is screwing with you.... Disconnect it. It works on a negative ground system. It's located just above and to the right of the shifter. Remove the cover, and you will see 1 (maybe 2 )wires coming out the side.....
EDIT
No. It's not the neutral safety switch. It IS a safety switch though.....

Their is a few wires coming out the side of the engine with 2 plugs conecting to the wiring harness.. I'll try I and sort it out tonight got the battery on charge again...

 

[Jaundre46]

is there a reason you can't take the slip-on off the original bike, and just use the pipe for now? just flip it upside down so its going over the engine?

a clicking solenoid could just be a dead battery, that's what happens on most motorcycles ive ever touched that has that problem.


also for the putting it in gear, its most likely your kickstand safety switch is some how activated.

I did put the pipe on upside down but it is not a slip on it is a full length pipe, I'm thinking of cutting it and adding some pipe to lengthen the exhaust so that it can be mounted properly...

I checked the kickstand for a switch but their is nothing I'll check again tonight I think something is plugged in wrong

 

[J_Walker]

I did put the pipe on upside down but it is not a slip on it is a full length pipe, I'm thinking of cutting it and adding some pipe to lengthen the exhaust so that it can be mounted properly...

I checked the kickstand for a switch but their is nothing I'll check again tonight I think something is plugged in wrong

well its more of a button.. but it may not have one.

 

[Attackofthisclone]

Just slide the sprocket over.....

 

[OzFab]

Have another look at the frame, he can't simply "slide the sprocket over", there's a steel bar in the way...

 

[Jaundre46]

I managed to get the engine started last night with the electric start, I forgot to give the engine itself a direct earth to the battery.... stupid of me haha!

As for the sprocket I'm going to take out the small piece of crossbar that's in the way, the axle is already at the engineers to make me a new key way in the axle and put new bearings on the axle and make a new sprocket holder so that I can use the original motorcycle sprocket and he will make me some other sprocket sizes aswell later...

just need to get a fuel pump, and I got n small cracking in my tank that I need fixing(I got glue devil for it) don't know what you guys would recommend using to fix the crack. and last is the rear brakes need bleeding and I need to sort our the exhaust.

 

[anderkart]

As for the sprocket I'm going to take out the small piece of crossbar that's in the way, the axle is already at the engineers to make me a new key way in the axle and put new bearings on the axle and make a new sprocket holder so that I can use the original motorcycle sprocket and he will make me some other sprocket sizes aswell later...

You don't need to cut the frame to fit that large sprocket that came on your motorcycle. The reason is your karts rear tires are a lot smaller diameter than the motorcycles.

Racekarts with motorcycle engines use smaller diameter axle sprockets, like typically around 25 to 30 teeth like this shifterkart has:
(click on the pic to view a larger image. Notice that kart has an angled crossbar, just like your frame

 

[Jaundre46]

You don't need to cut the frame to fit that large sprocket that came on your motorcycle. The reason is your karts rear tires are a lot smaller diameter than the motorcycles.

Racekarts with motorcycle engines use smaller diameter axle sprockets, like typically around 25 to 30 teeth like this shifterkart has:
(click on the pic to view a larger image. Notice that kart has an angled crossbar, just like your frame

I see, but I positioned my engine so that the sprocket lines up between those 2 bars because my seat was in the way... I'll take a pic from the rear once I get the axle back

 

[anderkart]

Its pretty common to move seats over by bending the rear seat struts, then drill new holes in the front of the seat to line up with the front mounts.