mr72's '92 project - "Renegade"

[mr72]

Got the tires swapped today. Sport demon / pilot street radial combo is now on the Bonneville and the shinko 705s are on the GS. Zip tie method worked well.

Man, do the 705s handle differently! Bike feels squirmy and wobbly. I put 32 psi to start, thinking I need less in the front and more in the rear. Might try as high as 36 in the rear and down to 30 front. Anyone have ideas? Other forums suggest these tires on a v Strom would be like 39-41 psi for street riding, but I imagine my GS probably weighs 100lb less than a DL650.

Oh and I broke the rear brake line on the Triumph while changing tires. So the GS will be my main ride for the next couple of weeks until I get the Bonnie fixed. Still $20 for don't used brake lines is less than 10% of what I would have paid to change the tires.

[cbrfxr67]

Pics no worky,... but I always go 35-42 I think you schooled me before on that but I still do it

[mr72]

Put a hockey puck under the side stand and it sure does stand up a lot better. I think with the lowering of the forks in the triples, bigger tires, and longer rear shock, the stock side stand is not just a little bit too short, but way too short. So this weekend one plan will be to put a big washer to shim it so it doesn't flex and then fabricate a foot pad from a hockey puck to give me not only some more lift but a better ability to park it in grass or gravel.

Pumped up the tires to 41 R and 37 F. with these round profile tall tires and that high pressure it just feels light as a feather. Parking that bike is a joy. Will get to ride it a bit today before the cold front shows up for Weds/Thurs.

[ShowBizWolf]

I think I know exactly what flex you're talking about when it comes to the side stand and increased bike height. It made me think there was something worn or bent at first!! I tried a few different size washers and even the thinnest one I could find barely fit. I hope you have better luck than I did.

I decided to buy a stock side stand off eBay ($10 free ship) and lengthen it. I hope to have it done and put on by this weekend and update my thread. The puck trick works well too, it's what I've been doing for a while now.

I can't see the pics either, they just show up as a gray circle with a while dash in the middle Maybe when I get to work I'll be able to see them on those computers!

[mr72]

Alright.

So I made a side stand riser from a hockey puck, will install tomorrow.

And I have been using the GS since last weekend when I broke the rear brake line on the Triumph, which included my bi-weekly coffee run through some pretty fantastic roads today. I ran with the new tire pressure, 37F 41R, and it was fantastic. New tires, WIN! The bike is a delight!

[mr72]

Here we go.

Threading the holes in the bottom of the side stand foot to add the spacer, M6 tap:



Formerly hockey puck rubber spacer installed:



Bike parked with new side stand extension:



I endeavored to make a similar spacer for my Triumph, since it also has longer than stock shocks in the rear and winds up being too tall. But the problem there is a) I don't want to drill holes in the stand and b) due to the shape of the foot, there's no kind of clamp arrangement I could come up with. I may experiment with some adhesive. I have had a set of hockey pucks stuck to the bump stop perches on my Jeep axle with Gorilla Glue for a few years now, they are holding up fine, but I am not sure I can expect such duty on a side stand. Maybe Liquid Nails? I mean, if it falls off, then so what? I still have the stock length side stand then.

Speaking of the Bonneville, it is amazing how night and day it is vs. the GS now. And that was the plan all along.

Next up, I still need to do some paint and permanently mount the rear brake reservoir. I bought a bushing that might work on the rear brake, I'll try it while I have it apart to paint. And I bought a pair of plastic tool boxes with the intent of turning them into panniers on the GS but I am still working out how to mount them without going too crazy.

[cbrfxr67]

Really looking good mr!

[mr72]

thanks! I also found a giant oil leak in the GS. I actually think it's the cam cover gasket, and I have a new one here. Need to swap it. I just hate taking the tank off. Might do an oil change and also change the left engine case gasket while I'm at it. It's not a bad enough leak to cause the oil level to change much, but it does get oil on my boots and pant legs, and I don't like that at all.

[profile_deleted]

Great looking bike.  It's got that "utilitarian, all business" thing going on... love it!     

[mr72]

Thanks Bruce.

Trying to make this like the compact SUV of motorcycles. Goes on all roads, including the abundant Central TX gravel county roads and paved backroads that haven't had maintenance done in a half century. Should stay upright on extended road construction sites with graded road base. Something I can ride down to the river bank or lake shore if I want. Being simple to repair and lightweight is a bonus.

My parents have property out in Llano county that's part of a subdivided ranch. To get there from my house requires a long ride on a US highway with 70mph speed limit over probably 30 out of the 50 miles, then into 20+ miles of poorly maintained rough county roads with some serious low water crossings that often require 4wd to get through if it has been raining recently. Then 11-12 miles of actual gravel county road with ruts and washboard surface. The goal was to make the GS into a bike that would get there and back, plus be usable on the roads around their place. I think it is basically there now.

It's probably not as good as a more modern, purpose built adventure bike in this class like a CB500X, but I already owned the GS. The GS is a lot lighter than a CB500X with similar power, and even lighter than a Versys 300 with more power. The BMW G 310 GS and the new KTM 390 Adventure are both closer in weight to my GS with similar power, but I'm really not into a single, and of course I'd have to spend $5K+ on one. I imagine any of these "real" adv bikes will be better off road than my GS and with fuel injection they are more fuel efficient, but they are all water cooled which I frankly think is a liability on something you are taking down gravel roads at speed. With a little tinkering I got the GS500 close to where I want it and now if I want to spend $5K on another motorcycle, I can get something different, such as a VanVan AND a 150-180cc Vespa.

[profile_deleted]

The BMW G 310 GS and the new KTM 390 Adventure are both closer in weight to my GS with similar power, but I'm really not into a single, and of course I'd have to spend $5K+ on one.

I had a 310 GS for about three months... couldn't hold a candle to the "real" GS 500.  It was a nice bike but didn't have any personality... or enough "oomph" to get out of its own way...lol.  Ended up trading it for my "82 GS 450.

Still grooving on your GS... that is just one good looking bike.   

[mr72]

Got the brake-side fixes done. Painted the master-cylinder bracket (it was welded plain steel), added a shim in the brake lever pivot to remove some slack, and whipped up a bracket for the reservoir, attached with Gorilla Glue. Let's see how that holds up!



I'm still trying to figure out how to mount my bar end mirrors. I know, I know, you're not supposed to use bar end mirrors on a "dirt" bike. But these are ultra cheap and if one breaks due to a fall, so what? $16 to replace, and all the time the bike is not falling down, I can see 100% better.

And I need to fix that oil leak, but I have a good idea what it is.

Still considering beefing up the shifter mount. If this Gorilla-Glue bracket holds well enough on the rear brake reservoir, I might just use the same technique to add reinforcement to the shifter plate.

The truth is, this GS is ready to ride and I'm anxious to go out and get some gravel under the tires.

[profile_deleted]

Not that I am not optimistic about the gorilla glue. But you could always run a metal bracket down from the air box mounting bolt which is what I did on one of my bikes.  In my mind I am just picturing the "coming loose during a ride, flopping over and hitting the rear wheel and all hell breaking loose" kind of scenario...lol. 

[mr72]

Yes that is precisely what I had intended to do, but I figured I'd give this a try. But I can easily make a bracket just like that. It would require a longer hose on my bike, due to the location of the master cylinder.

[mr72]

Rode around a lot on Saturday, and the bike crackles and kind of sputters when revving above about 8500 rpm. Also checking my fuel economy, with the 125 jets I was getting about 50-52 mpg and I only got about 42mpg on the last tank running the 127.5 jets. I'm beginning to think I went the wrong way on jets. I might go back to 122.5s and shim the needle to try to get rid of the off-idle hesitation. Bike is definitely not running right above 8K and even though my first impression after swapping the jets was that it was better, longer-term testing doesn't bear it out. Confirmation bias I guess.

So the carbs are coming back off. Might go ahead and swap the float bowl gaskets while I'm at it since at least one looks like it's leaking. And while the tank is off, I suppose I should put the new cam cover gasket on that's been in my garage for over a year waiting to go on.

Glad I have two bikes to ride.

[mr72]

Did some stuff.

First, the good. My math told me that I had raised the rear end about 7 mm higher than I raised the front with the tire change. The jittery handling confirmed this to me. So I went ahead and lowered the forks into the triples another 7mm or so, now the top of the fork legs are basically flush with the actual triple, not the clamp assy that's on top of the triple as before. They are probably 20mm lower than stock. Considering I have a longer rear shock as well as bigger rear tire I figure this was in order. The bike is a little less jittery but the handling still does catch me off guard when coming off the uber-stable Triumph. I'll still call this a win.

Speaking of shocks and suspension, I am also beginning to think the rear end is underdamped. Fortunately that's adjustable on the Katana shock. Have to fool with it.

And with nearly no preload on either end, the ride is very soft even with the 0.90kg/mm springs. Again, comparing to the Triumph, it's like floating on a cloud.

I also beefed up the mount that holds the left footpeg assembly and shifter. I went ahead and drilled a hole in the frame at the forward end of the bracket and tapped it with an M6 tap. I used an M8 jam nut as a spacer and put a bolt through to cinch it down, using the original hole that was there to mount the shifter. I put another hole closer to the rear and tapped it with M8 tap and used a shoulder bolt to re-mount the shifter. After making a new longer rod it now shifts like it should. It's basically like a factory shifter. Let's call this a 100% win.

Also mounted some teeny bar end mirrors. After failing to figure a way to do it in the alloy bars with any normal mounting hardware for bar ends, I finally just pounded an M8 nut into the end of the handlebar and screwed them right in. Really cleans up the look of the bike by taking off those awful old mirrors.

I was determined to find the real cause of the high rpm sputtering and did some testing. After numerous runs up in first and second gear it's clear that it basically sputters at almost exactly 9500 rpm but runs awesome up to there. I tested this with the petcock on PRI to rule it out, same exact result. Plugs were medium brown. I think it may be running just a touch on the rich side but it runs very well right until 9500 rpm. I think it's likely ignition misbehaving, so I'll look into that.

So next up I'm going to get new coils, new wires, and new plugs. Then when I pull it all apart to swap those, I'll probably do the valve cover gasket and get rid of the last of the oil leaks.

[mr72]

Let's see. First the good: I installed my brake light flasher and set that up, it's working great. And after lowering the fork legs in the triples it seems to have settled down the handling just enough that it doesn't freak me out every time I ride it. Actually it's quite natural and just feels light weight.

I also whipped up a setup of sort of side racks to mount some cheap plastic tool boxes as sort of cheap hard side cases. Wanted to ride without the top case. But even though this was most of a Saturday project, I'm not happy with it. They just stick out way too much. I think I might just pull everything off and get a set of Tusk soft side panniers to put on.

OK, now the whole purpose of the weekend project was to fix what I have now found to be a 9500 rpm sputter. I can really only ride it to 9500 rpms in first and second gear during this sort of lock down, since the roads between my house and grocery stores etc. are max about 50mph speed limits. The bike runs awesome up to 9500 rpm and then like a switch it sputters and doesn't want to rev higher. I started by looking at the plugs, figuring maybe it was mixture even though it makes no sense for it to be mixture, and the plugs are light brown, just on the rich side of normal. But I got new ones anyway. I got the hunch that the problem was ignition, and I still think it might be. But I was willing to consider a vacuum leak even though that makes no sense considering the behavior is basically the same as it was before I pulled the carbs to swap in 127.5 jets, and I thoroughly checked the carbs then and was absolutely sure they were put in and together right.

Actually, following the timeline, and reading my own posts here, I remember that with the 125 jets it had some off-idle hesitation and would begin to break up at 8500 rpm and now with 127.5s it has no hesitation and doesn't begin to break down until 9500 rpm. So I am guessing the jetting getting bigger improved some problems. However, with stock airbox and stock-ish exhaust (shorty Yoshimura muffler on stock headers), I can't imagine that it needs bigger than 127.5 jets.

Anyway, thinking maybe there were issues with an ignition coil, I pulled the tank and checked the coils thoroughly. I actually crimped new 1/4" spade connectors on both coil wires on each coil, since there was some corrosion on the old ones. I noticed that the high-voltage side wiring was corroded on both sides under the insulation, which is not a good sign. I also inspected the vacuum line and it was all good, tested running the bike before I took it apart on both PRI and RUN to rule out fuel starvation (same behavior both ways), etc. I didn't pull the carbs. I put it all back together, and tried running it on the side stand since it was raining. It ran fine, and in neutral with no load it will rev freely to 12K rpms or more.

So I was optimistic that I'd fixed it, but no dice. On the road test ride reveals it still sputters or misses at 9500 rpm in 1st and 2nd gear. Probably in every gear if I had enough roadway to get it going that fast.

This is a confusing issue. The fact that it behaves essentially the same after tearing the carbs all the way down, swapping jets, checking everything, and putting it all back together, seems to indicate that it's unlikely the cause. Also there was a time when the bike ran >9500 rpm ok, but I can't identify what might have changed because I rarely revved it this high and didn't really notice this until after I switched to the 14t front sprocket.

But the fact that the problem moved from 8500 rpm to 9500 rpm when going up a jet size makes me think maybe it's still lean at WOT/high-rpm. Scratching my head, but given that I have a nearly open type muffler (it's like a 14.5" long straight-thru Yoshimura) AND exhaust wrap all the way to the muffler makes me think maybe I am really under-jetted for this setup. It would be at high rpm where the exhaust effects would show up the most.

Theory of wrapped headers changing performance characteristics is that by increasing the temperature of the exhaust throughout its path through the pipes, it reduces so-called "back pressure" (man I hate that term) and increases (in theory) exhaust velocity. It also raises the resonant frequency causing the torque peak to occur at a higher rpm, which will result in more total hp, in theory. But of course, the real question is, does this cause the air to flow over the jets faster or slower? Well, probably both, I would guess, depending on rpm. In any case, there has to be higher vacuum at high revs due to lower back pressure so the slides will come up further and create a chance for air to flow more slowly over the jet in addition to opening the jet all the way sooner. So, bigger jets? Worth a try.

EDIT: I ordered 132.5 jets...
Also I think I am going to find a way, while the airbox is off, straighten out the front edge so the intake boots go on straight. Heat gun, the right combo of C clamps and 2x4s, should flatten her right out. For the life of me I can't figure out why the airbox outlets are shaped like /  \  while the carb inlets are |  |  ... who designed this? Or did my airbox just get warped over time due to heat?

Thing is, if I can get rid of this miss and get it to run hard all the way to 11k rpm then this bike is going to be a beast.

[mr72]

I checked my parts box.

I have 122.5, 125, 127.5 and 142.5 jets in the box. The 142.5 have never been installed, was planned for pods which I never did.

After thinking about it a lot more yesterday and doing more research, I became convinced that I should jet up. Going from 125 to 127.5 moved the problem from 8500 rpm to 9500 rpm. So if this is true then going up to 130 jets should move the problem to 10,500 rpm? Maybe. Who knows. The world thinks we're not supposed to be riding anyway, and it rains all the time this month in Central TX, and this is not my primary bike, so I'm going to experiment.

I ordered 132.5 jets, to test my theory: the main jet affects mostly WOT and high-rpm running and has minimal effect on midrange/low-throttle cruise, and the combo of shorty/large-ID muffler and full exhaust wrap is having an exaggerated effect on exhaust flow rate compared with the normal "slip-on" expectation. I also ordered a UNI drop-in air filter which would also get along with the bigger jetting.

Also, I just today remembered that when the shop did the top-end rebuild, the mech said he was doing some "mild porting" and "cleanup" of the head, which I actually doubted was done but if so it would also affect jetting.

So in about a week these parts will arrive and I'll dig back in. Stay tuned! Meantime, maybe today I'll take the bikes down and clean them up, get some more pictures.

[The Buddha]

I checked my parts box.

I have 122.5, 125, 127.5 and 142.5 jets in the box. The 142.5 have never been installed, was planned for pods which I never did.

After thinking about it a lot more yesterday and doing more research, I became convinced that I should jet up. Going from 125 to 127.5 moved the problem from 8500 rpm to 9500 rpm. So if this is true then going up to 130 jets should move the problem to 10,500 rpm? Maybe. Who knows. The world thinks we're not supposed to be riding anyway, and it rains all the time this month in Central TX, and this is not my primary bike, so I'm going to experiment.

I ordered 132.5 jets, to test my theory: the main jet affects mostly WOT and high-rpm running and has minimal effect on midrange/low-throttle cruise, and the combo of shorty/large-ID muffler and full exhaust wrap is having an exaggerated effect on exhaust flow rate compared with the normal "slip-on" expectation. I also ordered a UNI drop-in air filter which would also get along with the bigger jetting.

Also, I just today remembered that when the shop did the top-end rebuild, the mech said he was doing some "mild porting" and "cleanup" of the head, which I actually doubted was done but if so it would also affect jetting.

So in about a week these parts will arrive and I'll dig back in. Stay tuned! Meantime, maybe today I'll take the bikes down and clean them up, get some more pictures.

Yea opening the ports will get a lower velocity at the same rpm. That would need larger jets. So a polish job on the head/ports will mean you can toss out the old jetting numbers. 132.5 is a good jump up - I'd jet it till you start losing power up top, then back down 1 step.
You may also need pilots and needles etc looked at, but get the mains right before jetting it lower down. Jetting needs to be done top down.
Jetting is dependent on throttle position - mark your grip and switch so you can tell 1/2 vs 3/4 vs 1/4 etc etc.

PS: Sorry, opening the ports will result in not much change in the velocity in the venturi of the carb. Increase in CC will result in an increase in the velocity, and the carb can flow a lot more than the head can. So smaller jets in that case over a stock bike. You sure it was worse with 125's ?

Cool.
Srinath.

[mr72]

Yes it was definitely worse with 125s. It had a hiccup at throttle opening from cruise and it sputtered at 8500 rpm. 127.5s and the hiccup is gone, it pulls hard and strong all the way up to 9500 and abruptly sputters [which is why I initially thought it felt like an ignition issue].

I just didn't consider the exhaust wrap might affect jetting but it was an oversight. Whatever porting may have been done also has to have some impact but likely mostly at only very high revs and full throttle. The reality is that with the original 16t sprocket and before I got my Triumph, my riding style almost never took me above 7k rpm and I wouldn't have noticed if it kicked over at high revs. It's only lately that I've paid attention to how it runs at high revs.