Not pulling from 100 - 110k's/hr

[Graeme]

I've come back for a run down the expressway & I noticed that iit's not puuling away from 110k's hr. It gets there OK, and seems to have plenty of power under that.

I had the top end* done up about 1600 k's ago. It shouldn't be showing tightness at that speed I wouldn't have thought???

I was also going to check the valve clearances. With the top end being reco'd, should they be the same ie. inlet 0.1mm outlet 0.2mm or perhaps as "new." Those clearances I don't have.

* This probably should be extremities done up  

EDIT: I did the fuel mixtures last weekend. I haven't balanced the carbies as Snowbum adises that you get everything else right first. but although it's idling a bit high, it seems OK.

[tvrla]

What are the symptoms when trying to accelerate from 110? Open the throttle and it bogs down? Will it go faster, just not quickly? Slower than expected?

There's really not much for me to go on - it could be lots of things like, low fuel level in the float bowls, plugged jets, weak spark, wrong ignition timing or who knows what else.

It's such a broad question, I can't give you a meaningful response. So adjust the valves and check the fuel level first. Then get back to us with what you find. Has fuel consumption been what you'd expect?

[nhmaf]

If you had top end/valve seat work  1600 km ago it is time to recheck/adjust the valve lash and check the torque on the head bolts anyway.   I'd do this first, and then we can take it from there.    Another common issue might be a torn, cracked, or misfitted carb diaphragm - if there is just a slight leak that may not show up at lower speeds/RPMS, but is more apparent at wider throttle openings/engine RPMs, which often work out to be somewhere around that 100 k/h mark..   But as wirespoke indicated, at the moment, there are many possibilities..

[Graeme]

 [smiley=dankk2.gif]

I'll do all that then. It's sluggish. Doesn't feel like it wants to do much; 'bit like me really.

Yep, re-torque the heads. All my life I've wanted to buy a torque wrench. Now I can.

I've just started to measure fuel consumption as of about last week.

[montmil]

Graeme,

Be sure to throughly review your shop manual for the correct procedures for re-torqing the heads. Perhaps deduct a couple pounds of force from the manual's specs.

And go gently into the world of the Torque Monster as there lies much pain for the virgin traveler.

[tvrla]

I've heard that the beam (the cheapest style) torque wrenches are the most accurate.

The second thing to know about torque wrenches is they're most accurate mid range. So in this case you'll want one with a max reading of 50 ft/lbs.

[Graeme]

Well, I went racing out & bought a Kingchrome 13.6Nm - 203.5 Nm. Imperial = 10 to 150 ft/lbs.

Interestingly, Wirespokes I did think that may have been the case but I wanted to get the job done today if I could fit it in.

This one has been cerified +/- 4% and the test certificate gives reading @150 actual = 151 ft/lbs reading. 30=30.9. Interestingly 100 = 100.

It looks like it's giving +4% - 0%. More accurate mid range. That would be expected, I guess.

Funny about torque wrenches, I've needed them in the past, but there's always a neighbor or a friend who has one & insists on coming around & using it for you. Like it's some sort of "power wand" and ownership by others in the tribe is not allowed.  

So, to get the more accurate readings in the Haynes, I'll have to ring one of the neighbors.  

[juliansr]

check your fuel filter!

[Session101]

check the carbs and your diaphragms are working properly

[airhead27]

Sounds like the same issue I had and it ended up the needle jets in my carbs were worn. Once I changed the needle jets engine ran like new. I can't remember how many kilometers but Bing does  recommend needle jets being changed

[wilcom]

I had an 1982  R80 that had similar problems every now and then. It ran fine except it wouldn't want to  pull that last 1000 RPM.

I'd adjust my valves and all was well until next time. Don't know if it was recession or if the 82 is prone to that, it was all before I thought much about all the things that could go wrong, I just rode them back then.

Around 1980 I climbed on my R90/6 in California and rode to Dallas to see the folks and that bike hadn't seen a wrench in 6 months other than checked the oil and air in the tires. Now,  with all the "lists"and hand wringing, I fear to leave for the market without a full tuneup!!!