1978 DT175 - No Clutch

Ok,

So i bought this bike a while back and have started working on it.

The first issue was no spark, managed to solve that one with a new coil, it now starts, runs and stalls out, might have to pull the carb again. Seems that as soon as I push the choke in it stalls, might just have to warm up more before I turn it off.

One thing though is I can't use the clutch. I have adjusted the lever and cable adjustments as much as possible and still nothing.

What should be my next check. I was going to pull the cover and try to adjust from there, not sure if i should pull the clutch and check plate thickness.

Any other suggestions, the bike had sat for many years before I bought it.

Thanks,

What do you mean when you say you can't use the clutch? It won't disengage? If that is the case, it is stuck like they love to do. So: put in in first or second gear, pull in the clutch lever, then rock it back and forth until it suddenly comes unstuck. In extreme cases, you have to pull the clutch cover, loosen the screws holding the springs in tension, and go from there. They really like to stick, always have. Running a good grade of made for two stroke transmission oil usually helps a lot. Don't bother until you get done sorting everything. Don't run car oil in the transmission, just motorcycle oil. look for JASO MA on the spec, it is for wet clutches.

The idle passages love to crud up, as well as the pilot jet. Use compressed air and spray carb cleaner, it will come clean sooner or later. Don't stick metallic objects in the jets.

Yeah, when I pull the clutch lever in the clutch won't disengage. I will try your tip of just rocking the bike for a while to see if it comes loose.

Not sure what the guy before me ran in it, again this bike sat for a long time, I will put the proper oil in.

The friction plates "bond" for lack of a better term, to the metal ones. Even overnight. But sitting is the worst. If you pull the clutch cover, be sure to bleed the Autolube pump afterwards. It is the small phillips screw at the top face of the pump, usually has one of those red fiber washers for a gasket. Be sure there is no air in it. You can even start the engine, let it idle, pull the screw, then hold back the cam pulley that the cable attaches to, towards the pump body. That will allow max stroke of the pump. If it is an early enough pump, it has a while nylon wheel on the opposite side from the cable pulley. Just turn it by hand in the direction of the arrow cast onto it, hold in the pulley like I said above, and see if any bubbles come out of the pump. If the pin that engages the cam face of the pulley is tight, and there are no bubbles, and you use quality synthetic injector oil like BelRay Si7, Autolube works great and not only do you use less oil, the engine both runs better and longer. Pre-mix is right for only max load, too much oil for everything else. Be sure the pin I spoke about is tight in the pump body. If it falls out, the pump doesn't work because the cam can follow the pump plunger and limit it's stroke. You will note at wide open throttle, the cam on the pulley allows the cam to move away from the end plate on the pump plunger. That is how it varies the stroke according to load. Plus, the faster th engine runs, the faster the pump pumps. Great, simp,e, well engineered system. Tight pin, no air bubbles, and good oil is all you need.

The newer bikes don't seem to do the clutch thing, so they changed something.

My MX 175 had the same problem. The PO told me the plates were sticking due to the bike setting for a while. That was BS. My problem was with the pushrod assembly. If your clutch and cable are adjusted to the max., and your clutch assembly is lubed look for problems in the pushrod area. I had to replace a small ball bearing between two pushrods to fix my bike

My MX 175 had the same problem. The PO told me the plates were sticking due to the bike setting for a while. That was BS. My problem was with the pushrod assembly. If your clutch and cable are adjusted to the max., and your clutch assembly is lubed look for problems in the pushrod area. I had to replace a small ball bearing between two pushrods to fix my bike

Not to begin a contest: I merely pointed out this has been a problem with Yamahas for years, although it may not be his problem, as it wasn't yours. Yamaha even used funny looking V shaped rings over the clutch hub between the steel plates to correct it, but it didn't; we ended up throwing them away: they cause the clutch to slip under certain conditions. The ball bearings are used as throwout bearings, some of the other Yamaha models use two, one at each end of the pushrod. By the time the ball goes, all portions of the system should be changed: pushrod(s) everything.

What happens is the ball bearing falls out when someone has it apart and the don't notice it falling out. they reassemble and No clutch. Luckily my Dt Clutch is behaving but I also made sure the Ball was there while I was replacing the Main seals.

True enough. When you worked on them professionally, it seems like everyone would check, but I can see why they wouldn't. They also don't like to bleed autolube pumps, then say Autolube is no good, needs to be removed, and run pre-mix. I'd take a properly set up Autolube system any day over premix. I know that in competition bikes, every ounce counts, and convenience isn't on the list. But for everything else....

Most people should consult a parts list before they assume anything.

I plan on converting my MX back to an auto lube system, got all the parts on ebay!

I used to work on the old Yamaha's quite a bit (thats one reason I just bought and restored my Dt as a commuter Bike) I have always had good luck with Autolube on my street Yamaha's. (R5B and RZ 350)

True enough. When you worked on them professionally, it seems like everyone would check, but I can see why they wouldn't. They also don't like to bleed autolube pumps, then say Autolube is no good, needs to be removed, and run pre-mix. I'd take a properly set up Autolube system any day over premix. I know that in competition bikes, every ounce counts, and convenience isn't on the list. But for everything else....

Most people should consult a parts list before they assume anything.

I had a R5C when it was a new bike. I wish I still had it. Of all the motorcycles I've owned, that's the one that I can't remember where it went. I want a R5 rolling chassis and a Banshee engine with Modern suspension and wheels/brakes. What a hoot that would be. Great for storming mountain roads, which we have plenty of.

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