'84 Venture rear head removal.

[xntriklytwzted]

I was recently gifted two Venture's, an '84, and an '85, from a family member just before his passing.

 

I'm hoping to have the one he was primarily working on up and running in the spring.

 

Problem is, it needs a new rear head.

 

Is there anyone out there that can POSITIVELY say if the rear head can be removed while the engine is still in the frame? Looks like a pretty darn close fit, and I'd just like to have my plan of attack down.

 

As a side note? I've read here, in various places, that there were some head gasket differences. A three-piece, single, etc.... Is there one specific brand I should look for? Suggestions there?

 

Thanks everyone!

[OrlinEngh]

You can get the rear head off while still in the bike, I have done it on a 84 and a 87 it is alittle tight to get to a couple of the bolts but not to bad.

 

Orlin

[xntriklytwzted]

Orlin,

 

Thank you soooooooooooooooo much!

 

You've made my month!

 

Does the engine have to be sagged/loosened?

 

I'll give a back story....

 

I've been collecting/wrenching on bikes for a long time now, and anyone who knows me, knows that if it has two wheels and a motor, I want it!

 

Back in October I got a phone call from my brother-in-law. He was in town (well, state) helping his brother, Mark, and family make his final arrangements. He'd fought for years, but the cancer had spread, and he wasn't given long.

 

I was told Mark had a couple bikes, that none of his kids wanted to mess with, and if I could come with the trailer, they were mine, free of charge. All he could tell me was that they were bigger old Yamaha's.

 

I arrived in short order.

 

What I left with was a trailer, an an SUV, FULL of two Ventures, all parts, and some spares. I was told one had been a parts bike for the other, and that one had been running recently.

 

I noticed that the right rear plug had a pressure gauge hanging out of it ( I got the gauge and a brand new sync tool as well). But he said it had run, free is free, and I saw the look in Marks eyes that was one of dispair for never having got to ride either of them, sadness to see them go, but a little hope that something would be made of them.

 

Tinkering around, within a week, I had the primary bike running, still on the trailer. I sent a video to Mark, whom I was told was ELATED to see it, really raised his spirits.

 

There was a problem though, that right rear cylinder WOULD NOT fire. Spark, check. Compression, check. Fuel, well it was getting the same start fluid the others were.

 

I did notice that the throttle slide wasn't opening as it should though. A quick hand-over-the mouth of the carb revealed very little vacuum.

 

Hmmm, maybe there's a clog in the intake boot.

 

Pulled the carbs. Nope, no clog. NOT GOOD.

 

Rolled motor over with carbs off, and watched in horror as the valves didn't budge a bit.

 

Pulled cam cover and found that the cam was snapped, right under the carrier.

 

Both valves compressed easily, though one just wouldn't seat fully. We're talking just barely not seating (grain of sand type clearance).

 

Could I slap a cam in it? Yeah, but I already have a leaky valve. It could very well possibly be bent (not sure if this is an interference engine). Replacing the cam would mean messing with all the valve shims which will be worn all different. And most importantly, what shape is that piston in if that valve's been stuck open, or cam snapped and allowed that valve to slap the piston just enough to crack it.

 

I'd rather pull the head, check the piston, replace with a used head who's cams/valves match, and are known to be good.

 

Its been too cold lately to work on it, but it's looking like a thaw is on the way, and I was hoping to pull that head and have it replaced by late April. If not a whole lot sooner.

 

I see now, it's very do-able.

 

I really want this bike tip top by Late spring, early summer.

 

Thanks again for all your help!

[pmelah]

sounds like your on your way to having a good running bike keep us posted oh you know the rules no pics it did not happen

[OrlinEngh]

I didnt have to loosen the engine, sounds like you have plenty of parts to get it back up and on the road again, enjoy they are alot of fun to ride.

Orlin

[xntriklytwzted]

I'm stayin away from using the parts bike as, well a parts bike. It's complete, and eventually i wouldn't mind building a funky classic bobber out of it, or a cafe. Who knows. I know the engine turns freely, it complete, and I have a title. That's a good start.

 

Not sure what I'll do with the 84 (bad head). I MAY re-gift to another family member.

 

I can't, in good conscience, profit from them. I feel like I was entrusted with them (it).

 

Am I correct about the head gasket stuff? Was there a certain brand/type I should use?

[xntriklytwzted]

Orlin was spot on. Head can be removed with engine in bike. I left the gas tank on as well, which makes getting to the cam chain tensioner bolts a little tight. I also only loosened the exhaust rather than removing it totally. Aside from the tensioner bolts, the only thing that gave me trouble was the front cam chain guide, it takes some finagling to get it past a piece of the frame. I'm pretty sure I bent it a hair, hopefully I get the correct arch back in it for re-assembly. Thanks again!

 

 

Sent from my iPhone using Tapatalk

[xntriklytwzted]

http://img.tapatalk.com/d/14/02/21/he9u3aru.jpg

 

Appears as though I'll also be honing at least one of the rear cylinders as well.

 

http://img.tapatalk.com/d/14/02/21/ymepeju7.jpg

 

 

Sent from my iPhone using Tapatalk

[bongobobny]

Well, if you have it down that far, you may as well go all the way and pull the engine, split the casing, and do all 4 cylinders. While it's apart, do the 2nd gear fix if it hasn't already been done. The 83, 84 and early 85 had a 2nd gear issue whereas it will pop out of gear under hard acceleration.

 

Now if you really want a quick 1st gen, get yourself a set of 1200 VMax heads and cams, they pretty much bolt right on...

[frankd]

See if you can find new piston rings before you pull it apart. For the 1200, they aren't available from Yamaha any more. If you go into a cooperative dealer, he can look online if any other dealers have them in stock. Then you can call and buy them from that dealer. For the 1300, rings are still available, but they are expensive.

 

Frank D.

[xntriklytwzted]

Couple issues with re-install of this new head...

 

I can't seem to figure out how to set the cams, and in true idiot fashion I didn't mark anything while I was taking the old cams off for reference later.

 

The manual's pictures are pretty grainy and the directions aren't the greatest.

 

After installing the cams, and all caps minus intake and exhaust 2, do I then remove the cam sprocket bolts allowing them to "freewheel"?

 

Which marks on the right side of the cams do i align with the cam cap marks..... the hole that's drilled all the way through the cam as seen looking at the cam from the side of the bike, or the tiny little holes drilled into the top of the cam end as seen from above?

 

If it's the ones viewed from ABOVE.... on my intake cam I actually have several....

 

a little clarification on this plz

 

thanks guys

[icebrrg3rd]

Here's a few pics that might help.

 

Pic #1 shows the two different size "dots". Use the smaller one for the rear cylinders. (IIRC, the cam is the same for front & back, that's why there are 2 marks)

Pic #2 shows the timing marks on the flywheel. They line up to the cover (see pic #3)

Pic #3 shows the access covers you can remove if you don't have the side cover off. The smaller one is where you'd line up the marks.

 

Also remember that the crankshaft rotates twice (2x) for every one (1x) rotation of the camshaft. So you need to know where the front cylinder's cam is in relation to the rear cam. Hate to have them out of sync. Don't have my manual with me here to point out specifics.

 

If you need more info, just ask.

 

-Andrew

Edited June 25, 2014 by icebrrg3rd