New to this site

jstewart
Posts: 17
Joined: Wed Jun 09, 2021 3:30 pm

Re: New to this site

Post by jstewart »

srankin I don't want to ruffle any feathers here. Should I be posting on another forum??

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srankin
Posts: 351
Joined: Fri Jul 14, 2017 8:45 pm
Location: Spencerport, NY USA

Re: New to this site

Post by srankin »

Don't worry about what forum to post on, LOL, just be aware, they're some rabid R90S fanatics out there who believe strongly in the purity of the R90S bike.

No one but me has mentioned it so, maybe I am a jerk? LOL

Better fit would be the "Classics" part of the forums. Enjoy the riding happy Fourth of July. St.
Owner of a 84, R80RT and 78, R100RS

MikeL46
Posts: 141
Joined: Fri Jan 01, 2016 1:58 pm

Re: New to this site

Post by MikeL46 »

In the Muscle Car world vehicles like that are called clones. Not a real XYZ, but exactly like an XYZ.

I like the term and nobody is offended by the desire to emulate a cherished design.

Mike
67 R50/2 w/R100 engine/trans and Ural Sidecar
69 R60/2 76 R90S 78 R100RS
70 Triumph w/Spirit Eagle Sidecar

jstewart
Posts: 17
Joined: Wed Jun 09, 2021 3:30 pm

Re: New to this site

Post by jstewart »

Have not been on here for a while so some updates:
1. 1000cc Siedelbrock kit finally came in.
2. 38mm carbs are here.
3. Conversion back to R90s bars or the nearest thing we could find is complete.
4. Conversion back to R90s switchgear and choke lever is done.
5. New ignition for dual plugs is here as well as coils.
6. Transmission thrust clearance was corrected as well as bearings replaced.
7. Crank clearances and thrust were checked and crank re-assembled in cases.
8. Rods were checked and were less than 1 gram of each other.
9. Rod bearings were replaced.
10.Heads were sent off for dual plugging, flow testing, new OEM seats for methanol fuel.
11.44mm intake valves installed in heads.
12.re-use 40mm exhaust valves with new seats.
13. Checked crank & lightened flywheel balance & they were perfect from previous owner.

The holdup has been getting parts particularly the OEM valve seats from Germany.

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cbclemmens
Posts: 24
Joined: Sun Apr 25, 2021 2:21 pm
Location: Apollo, PA

Re: New to this site

Post by cbclemmens »

You can calculate the compression ratio by measuring the compression with a regular compression gauge and dividing by atmospheric pressure (14.7 psi). For example, my R 75/5 has 160 psi compression, i.e. 160/14.7 = 10.88:1.

Craig

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schrader7032
Posts: 7868
Joined: Fri Oct 27, 2006 3:00 am
Location: San Antonio, TX

Re: New to this site

Post by schrader7032 »

Seems like a lot of compression on that R75/5!! I've been using a rule of thumb for computing things like that. Starting the compression ratio, such as 9.0:1 for the R75/5, I add 1.0 for the atmosphere then multiply by 14.7. So a 9.0:1 compression ratio is about 147 psi compression. If you have the compression results, one can work backwards.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

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