Howdy, bringing back an R5 from the dead.

[m in sc]

ues, hone them lightly and see if there is any pitting afterwards. if not, you are good to go. 

[RD4140]

Dear Diary -

Well, everything's back together. The transmission was easier than I expected, everything looked pretty good and spun smoothly but I put in new seals just because. It seems to click through all the gears up and down as expected. The only boo boo I made was forgetting to put the little nipples on the crankshaft bearings down into their grooves on reassembly. I pulled it back apart and made sure I got that right. It kinda dimpled the bearing surface but I cleaned that up so I think no harm done.

However, the top ends been a bit of a PITA/head scratcher. I didn't change anything in there, but put in new gaskets when installing. I know i got everything back in, there's no parts left over. Everything got torqued down per the manual.

But I'm only getting 65 psi compression in the cylinders. Thats cold, both dry and oiled. I suspect my test gauge might be crap, so I've ordered another one. I wasn't able to test it before disassembly because it was stored outdoors with no carbs or plugs, so the cylinders got some crap in them and I wasn't game to make it spin before cleaning it all out.

I had a spare complete R5 motor that I haven't fiddled with and it also had exactly 65 psi compression. I'm guessing my gauge poops its pants around 65 psi. I'm a gambling man but don't like the odds of two unrelated motors being so similar.

Anyway, I'm not going to fuss with it right now, I'd rather get the ignition, timing and electronics done and circle back to the cylinders. I don't have a garage so I rent a workspace in a friends garage. I realise that potentially I'll have to pull it all part again if I need new rings or top end work, but I can do that during summer when it's sunny out and can work on it in my yard again without freezing me nuts off.

Anyway, thats it for now.

[pidjones]

A common compression test mistake is not holding the throttle wide open.

[RD4140]

Yah I tried "everything" (that I could think of). Throttle wide open, carbs on, carbs off etc. the tester adaptor and seals not being tight enough, a leak in a fitting etc. I've think I've ticked off most of the rookie mistakes.

[RD4140]

Hi - I have questions:

Can anyone recommend an easy to find 2-stroke oil (will be running pre-mix), and also a gear oil? Located west coast USA so no fancy english stuff. I see most people say 10W40 for the g/b but is there anything particularly recommendable?
Also anyone want to guess what size jets / carb settings I'll need for an 1970 R5 with DG pipes and Y-boot with K&N Filter, running pre-mix??
With the vape ignition system installed and sparking nicely, I'm getting pretty close to baby's first kick over.

Still chasing down a few extra PSI compression but I'm still suspecting it's my dumb tester, so I'm going to forge ahead while saving for a better one.

Thanks 

[SoCal250]

Uh oh, an oil question!
I can guarantee that you're going to get as many different oil suggestions as there are replies. Here are MY preferences:
2T oil: Motul 710. All my bikes are injected, but this oil is for both injected and pre-mix applications.
Transmission: BelRay Gearsaver 80w
Both are available at most bike shops, including Cycle Gear.

[RD4140]

Uh oh, an oil question!
I can guarantee that you're going to get as many different oil suggestions as there are replies. Here are MY preferences:
2T oil: Motul 710. All my bikes are injected, but this oil is for both injected and pre-mix applications.
Transmission: BelRay Gearsaver 80w
Both are available at most bike shops, including Cycle Gear.

Yeah, I read that whole ass oil thread and came out even less sure of what to use.
I like your suggestions, I've been running Motul in all my bikes and never had a problem so I'll stick with that.

Thanks.

[Mgmark]

I've used Motul 710 with no trouble. I use the 800 for the premix only bikes, and 510 for injector oil if I can find it.

[dgorms]

Motul 710..............

[SoCal250]

and when you're pouring it in, the bottle still reads "OIL" 

[RD4140]

Has anyone else with an R5 had any issues with gasket profile on the clutch cover?
Mine has a section where it goes outward, leaving only a very small section to sandwich ..

I had a slight weep from this area, and suspect it might have extruded out when torqued down.

Are some gasket brands better than others? This is from NE Brand.
Also, has anyone got away with using Loctite 515 or 587 on this cover (or any liquid gasket maker)? I used them alot in industrial applications and never have a problem but not sure if it will work for this application. 

[RDryan]

Hmm that's interesting as I can see in the pic it's not quite lining up. They say you really shouldn't have to use something like loctite as you asked about but when I did mine I used some Yamabond that I had from splitting the cases and reassembly. I had it and the previous owner had used it and I just felt like it would fill in any gaps and what would it hurt? ...actually worked quite well and I was able to take the cover off when I needed to service a slipping clutch and reattach. I stuck the gasket with the Yamabond on the clutch cover. Although I'm not sure what maker's gasket I used, it was a much better line up of case/gasket/clutch cover on a 75' rd250. So sorry I can't be more helpful there. If you don't wanna spring for another gasket from say Economy Cycles( a forum sponsor) my suggestion is that it looks to me like you could snip the gasket on the other side of that bolt hole where your finger is in the pic then it will line up at that area shown and yeah just use what you feel comfortable with on one side of the gasket to get it to stick...I bet that would work just fine) but maybe better to just get a better fitting gasket.

[pdxjim]

I'll pop in here to say I use BRP(Bombardier) XPS Snowmobile/PWC oil from the Polaris shop down the end of SE Division St at the river.

Last time I bought it was $40/gallon, and it's full synth and smells good and is designed for premix or injection systems.

Gear oil I use Rotella T5/T6. It's great stuff and available cheap(ish) and any autoparts store and even cheaper at Walmart (but fcuk walmart).

[RD4140]

Dear Diary,

I finally got the chance to roll the bike outside and give it a kick.
This is pretty much straight out the box and bolted together. Junkyard bike/motor + vape ignition + DG's. From here I guess I'm going to concentrate on learning to tune it up. You can probably hear it don't sound spot on, so I welcome any input. I think I'm running 150 main and 30 pilot in the carbs, but I'll have to check I actually made that change.

I'm pretty happy that this old junkyard dog has a second chance at life.

I have a laundry list of parts I need but really need a petcock if anyones got a spare laying around they want to flip. I need to get some exhaust gaskets too it seems, not sure how I missed that.

[m in sc]

sounds pretty decent but again, its dead cold, will sound better warmed up.  good start!