MX 360 compression.

[pryor]

I have a real nice 72 yamaha MX 360 that I hardly ride because of how hard it is to kick over, it always starts third kick and always kicks back on the second, it didn't come with a compression release and a webco one won't clear the pipe. What I am thinking about is to try two cylinder base gaskets. has any one tried this? I'm not worried about performance this thing has a real nasty power hit that could be mellowed a bit.

 

[thorman75]

Putting in 2 base gaskets will lower compression(slightly) but also raises port timing(harder hit) I'm wondering if a RT 360 Enduro has a thicker head gasket. Might want to check into that.

 

[ZOMBIE666]

a thicker gasket should work well enough, i had a beat to hell rt360 when i was 14, was NEVER able to kick start it. had to push start it everytime. once it started it was a bad ass bike. one day i was out putting around, stalled it at the bottom of a ravine. 10 years later, it's still there (most of it anyway)

 

[pryor]

The head on the enduro is different to lower compression, the heads won't swap because of the cross over pipe on the MX. I don't want to have the head cut or make any mods that can't be easily put back. If I can find an extra head for it I will have it opened up but the 72 MX is different than other years and hard to find. For now I'll just leave it home or it may end up in a ravine somewhere to. I think thats wy this bike is like new if it doesn't hurt you starting it it will riding it.

 

[Matt Fisher]

I remember talking to Cometic about gaskets, the guy mentioned they could make custom thickness gaskets if I needed them. Maybe have them whip up a thicker head gasket?

 

[fatboy570]

Pryor,have you found a compression release yet? My vintage sponsor bought a 74 MX 360 for frame and suspension parts for my 73 MX 250, and I think it has the complete compression release still on the head. I would have to do some looking, but I think its all there, if the 72 and 74 will interchange

 

[pryor]

Thanks Fat boy 570, but the 72 is one of a kind and doesn't have a built in comp release, I have a webco comp release that screws in the head but the pipe on a 72 crosses over left to right and will hit the comp release. I started riding it a lot lately after rejeting, new reeds ,and set timing, it doesn't kick back as bad, if I wear good boots and man up a little I can git through a day of riding. thanks again fat boy and I have some 73-74 mx motor parts if any body needs them. :cool:

 

[fatboy570]

What all motor parts have you got? I could also use some chain adjusters for my 73 MX 250

 

[pryor]

Fat boy, I have two motors that came with a bunch of parts the one motor I was told was a 74 mx 250 is missing the head and a few other parts but mostly complete,.I'm not sure what the other motor is it's missing the top end and is newer and larger ccs. I can check the numbers on the one to make sure it's a mx 250. I also have two DT parts bikes one a 74 250 and a 75 360 don't know if chain adjusters are the same. I really only like the 68-71 yamahas so I have no real use for this stuff it kinda just followed me home.

 

[pryor]

Just checked numbers ones a 73 mx 250 and one is a 73 mx 360 the 250 is missing head, ign. and sprocket cover the piston looks good but bore is worn out, someone tried to put an intake off a different bike on it looks like reed cage is junk and possible new holes drilled in cyl. the 360 motor is full of dirt and missing covers, top end, and ign.

 

[fatboy570]

Id say the chain adjusters will interchange. What would you want for them, plus shipping? I can give you my mobile number if you like, I think Ive figured out my adjuster problem, but it never hurts to have extras. Last year I had to swipe a set from an MX 360 parts bike to use on a 77 XT 500 I was racing at the time, but Im all out now. Thanks

 

[pryor]

Fat boy pay the shipping and I will send you a set, better they get used than rot away or go to the scrap man.

 

[fatboy570]

Sounds good. I sent you an email with my phone number, I really appreciate the help