`78 cafe-inspired build thread

[GoRacers]

The shift forks will drop out after you remove the shift fork shaft. the shift drum does not need to come out necessarily. However, if you find you need to remove yours, it can also be removed without splitting the cases.

So I can get both gear shafts, the forks, and the drum out without splitting?

[GRom4232]

Where would I be able to snag seats like these?

[Gallaecus]

Where would I be able to snag seats like these?

yes especially the red bike...

is that a modified sportster seat ????

[GoRacers]

Got the drive axle and gears out last night.

The dogs on 5th that mate with 2nd have definitely already had the "dremmel" fix done.....but I don't think it was done right. The dogs are SEVERELY back cut (dovetailed), I don't think it's possible for them to mate on a flat surface with the slots in 2nd gear.

I also don't think the gears are installed 100% correctly on the axle. Looking at the diagram now (don't have the parts with me), I feel like there may have been a circlip missing on my transmission between 5th and 2nd. I can't remember right now, I'll check that also when I clean the parts up.

I didn't see anything I didn't like about 5th gear or the inside of the casing on the drive axle....what else should I look for that causes the 5th-gear grinding noise (very light) on the freeway? I'm more concerned about this than the 2nd gear issue...

I'll take some pics after I degrease and clean up all the parts so I can better inspect them.

[81xsproject]

Noted. I set then to the spec in the manual, don't remember what it is off the top of my head.

That's good. As you already noted it ran great at that setting 25.7mm. I did a series of TESTS a long time ago and IIRC there was little to no difference in the floating height of plastic vs brass when measured at their respective measuring points.

[trbig]

Got the drive axle and gears out last night.

The dogs on 5th that mate with 2nd have definitely already had the "dremmel" fix done.....but I don't think it was done right. The dogs are SEVERELY back cut (dovetailed), I don't think it's possible for them to mate on a flat surface with the slots in 2nd gear.

I also don't think the gears are installed 100% correctly on the axle. Looking at the diagram now (don't have the parts with me), I feel like there may have been a circlip missing on my transmission between 5th and 2nd. I can't remember right now, I'll check that also when I clean the parts up.

I didn't see anything I didn't like about 5th gear or the inside of the casing on the drive axle....what else should I look for that causes the 5th-gear grinding noise (very light) on the freeway? I'm more concerned about this than the 2nd gear issue...

I'll take some pics after I degrease and clean up all the parts so I can better inspect them.

Yup, if that big circlip is missing between 2nd and 5th, it will let 2nd get too close to 5th and do what you were describing.

[DGXSER]

The dogs on 5th that mate with 2nd have definitely already had the "dremmel" fix done.....but I don't think it was done right. The dogs are SEVERELY back cut (dovetailed), I don't think it's possible for them to mate on a flat surface with the slots in 2nd gear.

What you want to look for is the edge of the dogs to be fairly sharp corner, not rounded off in a curve shape in section view, from the side of the gear. The issue that causes the slipping is when the edge of the gear gets rounded it tends to slide out of the slot. For the gears to work properly, you want a slight back cut on the slots of 2nd gear as well as the back cut on the dogs of 5th gear.

I also don't think the gears are installed 100% correctly on the axle. Looking at the diagram now (don't have the parts with me), I feel like there may have been a circlip missing on my transmission between 5th and 2nd. I can't remember right now, I'll check that also when I clean the parts up.

From the factory, 2nd gear sits against the collar on the countershaft, and there is a washer between the gear and the cir-clip that holds it in place on the shaft. The cir-clip is on the 5th gear side. A common "fix" to add to the dremmel work on the gears themselves, is to install the washer on the backside of 2nd gear, moving it closer to 5th gear, letting the cir-clip side directly against the gear. (there has been many a debate on if the ger riding against the cir-clip is a good idea or not, no clear answer really, judgement call.

I didn't see anything I didn't like about 5th gear or the inside of the casing on the drive axle....what else should I look for that causes the 5th-gear grinding noise (very light) on the freeway? I'm more concerned about this than the 2nd gear issue...

I'll take some pics after I degrease and clean up all the parts so I can better inspect them.

Look a the shift fork that was on 5th gear, see how it looks on both sides.

[DGXSER]

That's good. As you already noted it ran great at that setting 25.7mm. I did a series of TESTS a long time ago and IIRC there was little to no difference in the floating height of plastic vs brass when measured at their respective measuring points.

AHHH-HAHH!!!! I was just messing with a set of 78-79 carbs with the XV920 float valves (Viton tipped) with plastic floats. Had them set at the "plastic" float height of 23 mm and the carbs were WAY rich. I set them down to 24 mm no real improvement. Bike went form topping out at 4-5k to maybe 6k. I now have them at the 25.7 mm setting, need to get them on my bike for testing. Honestly not been to motivated as I did not expect results, but this gives me alot of hope. Definitely test them by Saturday.

[GoRacers]

5th gear dogs...



Slots on 2nd gear...



Seems that 5th gear was contacting its shift fork...


5th gear has irregular chamfers all the way around the edge, makes sense since it was contacting the fork...


I can't tell with my eyes whether the fork itself is bent, they don't have a very uniform/precise shape to them to begin with. I am replacing the forks with the ones coming with my parts transmission.



My main question is how 5th touched the fork. Is it only possible with a bent shift fork?

I checked again, and it looks like the gears were installed correctly, along with the circlips and washers.

[DGXSER]

Ok, so 2nd gear was in place along with its proper circ-clip. As I mentioned in your other thread, looks like someone had second gear slipping issues and stood on the shift lever to hold the gear in place, causing the grinding on the shift fork you see.

Given the tightness of all the gears and such in the case, the decreased width of the shift fork where the gear rides, MAY allow for 5th gear wheel, when in 5th gear, to move further toward the engine case than designed. Based upon the wear on the case side of the gear, it would appear it has.

And yes, someone went WAY overboard on the lsope of the "dovetailing"! Interestingly enough, it does nto appear they put any slope on the slots in 2nd gear. If you look at the tech tip on the dremmel repair, it shows how it is the combination of both gears being back-cut that forces them to pull together and resolves the slipping issue. Only cutting one does not really solve the problem.

Sounds like your on the correct path with the new gears and fork(s). I would check the fork on 4th gear as well, and back-cut the "new" 1st, 4th, 2nd, and 5th gears if they have not been done yet.

[WMarshy]

Question to the transmission gurus...

Well, the fork that drives 5th also drives 2nd gear and problems usually start with 2nd... is it possible to bend the fork trying to keep it in 2nd gear to the point it contacts 5th like you are seeing...?

[DGXSER]

Marshy, we just had a pretty in depth discussion in his 5th gear issue thread on how the transmission works. 2nd gear never moves, but the shift fork shown slides 5th gear on the countershaft toward 2nd gear so its dogs interlock with the slots in 2nd gear. Looking at his second gear, you can see the scraping of 5th gear dogs sliding out of the slots and across the face of 2nd gear.

If someone holds their foot on the shift lever, it can keep the shift drum from rotating the little bit required to let the shift fork drift over so 5th gear dogs can slip out of the slots...at least until the dogs get REALLY rounded off, and until the gear eats the face off the shift fork as shown here, so it can move as needed to skip out. The PO of Banshee had done it with both 2nd and 1st gears......



If you look in his first two pictures, you see the slot between where the gear teeth end, and the "plate" ring the dogs are on. That slot is where the shift fork sits, it pushes toward the dogs when shifting into 2nd gear, and it pushes away from the dogs when shifting into 5th gear.

When you figure that the amount of material in contct when the dogs are in the slots is less than 1/4", bent is a relative term on the shift fork. with the wear shown on the fork, 5th gear could slide that little bit closer to the engine case when in 5th gear. How close is it to the case in 5th to start with? I never really measured it or paid attention, so I can't say if the wear shown is enough movement to allow contact. But obviously from the last picture, 5th gear has been rubbing abnormally against something on that side.

The last picture shows the side of 5th gear that faces the engine case on the shifter side. With the opposing wear pattern on the gear, it is even possible the countershaft bearing on that side is damaged. Hard to say for sure. Just some things to think about and check out.

[GoRacers]

Marshy, we just had a pretty in depth discussion in his 5th gear issue thread on how the transmission works. 2nd gear never moves, but the shift fork shown slides 5th gear on the countershaft toward 2nd gear so its dogs interlock with the slots in 2nd gear. Looking at his second gear, you can see the scraping of 5th gear dogs sliding out of the slots and across the face of 2nd gear.

If someone holds their foot on the shift lever, it can keep the shift drum from rotating the little bit required to let the shift fork drift over so 5th gear dogs can slip out of the slots...at least until the dogs get REALLY rounded off, and until the gear eats the face off the shift fork as shown here, so it can move as needed to skip out. The PO of Banshee had done it with both 2nd and 1st gears......



If you look in his first two pictures, you see the slot between where the gear teeth end, and the "plate" ring the dogs are on. That slot is where the shift fork sits, it pushes toward the dogs when shifting into 2nd gear, and it pushes away from the dogs when shifting into 5th gear.

When you figure that the amount of material in contct when the dogs are in the slots is less than 1/4", bent is a relative term on the shift fork. with the wear shown on the fork, 5th gear could slide that little bit closer to the engine case when in 5th gear. How close is it to the case in 5th to start with? I never really measured it or paid attention, so I can't say if the wear shown is enough movement to allow contact. But obviously from the last picture, 5th gear has been rubbing abnormally against something on that side.

The last picture shows the side of 5th gear that faces the engine case on the shifter side. With the opposing wear pattern on the gear, it is even possible the countershaft bearing on that side is damaged. Hard to say for sure. Just some things to think about and check out.

I'll check that bearing that sits next to 5th again, but I don't remember seeing anything abnormal about it when I pulled it out.

The parts transmission I bought from Andreas has already been modified, so I may not have to do anything but reinstall them and go.

[xs11lover]

Where would I be able to snag seats like these?

Buy em and make them fit......sorry it's not an easy answer.

[GoRacers]

More transmission talk going on here...
http://www.xs11.com/forum/showthread...981#post388981