How about all my modding/tuning questions in one thread?!

[Bron-Yr-Aur]

Hey to all, and a preemptive 'thank you' if you have the patience for reading this. I don't want to keep posting thread after thread, so I'll try to get it all in here.

1) I've just completed the installation of my new-to-me CR's (if you plug the FCR's, be forewarned that I already know they're the cat's meow, they're just not in my budget right now ) The bike was very hard to start. I know absolutely nothing of the CR's or their nature. I don't even know if the choke should be up or down to engage it. Anyhow, I turned the petcock on, gave the throttle a few good twists to fill the bowls, and started turning her over. With the choke up, right from the start she sounded like she wanted to catch, but only while the starter was engaged. I probably hit it 30 times, but couldn't get it to go. I started to smell gas, so I put the trickle charger on (not because it was slowing, just because I wanted to make sure) and went in to eat dinner. Came out, and the same thing for about 10 tries, with choke in varying positions. Finally, with it all the way down (off, I assume?) she started to sputter a little beyond me pushing the starter. About another 8-10 tries and she got going. Running a little rough in low rpms (unlike the stock cvk's). After about a minute, I gave her a couple stout revs, she smoothed out nicely, then settled into a nice idle. Question: how can I prevent this horribly difficult process? I got the carbs from Easy, so I totally trust the jetting, at least as a baseline until I can tweak them for my bike. He was running a similar setup, at similar altitude and temps. Could this problem be timing issues due to losing the TPS? Suggestions?

2) I pulled my cam cover tonight, prepping her for the 790 cams. Do I need the thick red assembly lubricant that I've used on car motors before when installing the cams, or will my synthetic oil suffice? Do I have to change the oil, at $12/qt with only 600 miles on it? I also remember somewhere in a post that someone pulled the whole oil tube assembly in one piece. Am I remembering that correctly? Any experiences to share? Also, do cams directly affect jetting? (Will 790 cams automatically necessitate fattening up the mixture?)

3) After reading some posts on the 790 vs. 813's, I realized that it had never occurred to me that a stock 865 tune will possibly really limit the gains of the cams. I have the Procom and have not played with any of my maps (that's for another day) Are there any stock maps on the box that will be better suited to the 865 with the 790 cams? And I'm wondering, since I've lost the TPS, what is the timing advance at WOT on a stock tune? Without a TPS, will this affect the way I want to tune the bike? (i.e. do I need to be extra careful of anything dangerous, like burning something up?) Has anyone learned anything of the pre-programmed settings on the Procom? As a point of reference, I'm one of the minority in that, before my CDI took a dump on me, I was one of the very few who experienced 0 HP gains with the reprogrammed igniter. My bike seems to have been making optimal power on the stock tune, at least at WOT. But I'm not sure if those rules apply now, after changing cams and carbs. And I don't know if the factory tune on the Procom truly emulates a stock Triumph tune, as Procom says.

Ok thanks again guys. I posted like this because I'm doing everything at once. I don't know if that's the best way, since if something isn't quite right, it would be easier to isolate had I done it in stages. But I suffered a dirt bike accident a few weeks ago (shattered my patella and chipped my femur) so I have spare time and no hope of riding for at least another month. Figured this would be a good time to get the bigger projects out of the way. Plus, it's gonna be way more fun the next time I ride the bike (provided it starts!)

Right on. Kick out the jams...

[killian101]

about the CR's: Ive been told, they are really hard to tune. I was lucky enough to have some guys who know what they where doing. But, there is far too little info out there for these carbs. Maybe the good folks over at BC or bellacorse can put together a good video on how to tune this carbs.

Once you get the basic jetting down, your bike should turn over with zero problems. But every bike is different, so you may need to rejet depending on your setup The lost of the TPS? Not sure, im work through that issue now...check the idle and you may want to invest a new petcock too. once you get the jetting sorted, you never need the chock...you bike should just start and warm up in a few minutes.

[beemerrich]

1) starting - my bike starts in the summer without the enrichener on and by giving a small amount of throttle. in the winter, I use the enrichener but have to open the throttle some to get it to light off. you'll need to find the formula for your bike since how the air screw (idle mixture) is set will have a significant affect on the starting dance.

BTW, the choke isn't a choke, but an enrichener. It dumps more fuel into the carb throat to richen the mixture for cold starting. It the bike doesn't fire off with the enrichener on/opening the throttle some, then the starting condition is too rich and you need to close the enrichener/open the throttle a little on the next attempt to start. I find that partial enrichener positions on my carbs are not a good thing...either all on or all off for it to do anything predictable.

2) I've done 2 cam swaps - one without assembly lube (your 790 cams) and one with the lube since it came with the cams (813 cams). I guess it probably is better to use it, but it ain't the end of the world if you don't.

Don't bother changing the oil unless you think a bunch of swarf got in while doing the cam swap.

The 790 cams, if anything, will make your jetting go rich - so no worries.

3) I've not had the tuneable procom, but the earlier generation was within 1/2 RWHP of the pieman massaged stock ignitor specifically set up for 790 cams/extra advance/8500 rpm limiter. The absence of the TPS has no downside, so that's a non-issue.

Regards,

--Rich

[Bron-Yr-Aur]

Thanks Rich, very helpful post. I feel like such a newb with these carbs. I didn't even have an idea on which way to go. I know that many times, hard starts in the cold means too lean, but I ruled that out when I started smelling fuel. (Not to mention that, due to freaky weather, it was actually in the 60's last eve) Thanks for the advice on the all-or-nothing scenario with the enricher. I know touching the throttle is a no-no with the stock cvk's, but these flat slides are a different beast that I know are going to take some getting use to. I'm glad I can give it a little gas with these. That'll give me a little more control over how it starts. I think the next time I start it, I'll leave the enricher down and try just controlling it with the throttle.

As for hard to tune, I'm not too worried about that. My a/f gauge I'm sure will help out tremendously on that. In all of this, I guess my main concerns are just being pointed in the right direction, that's all.

[mikeinva]

You dont need the tps but the procom has less timing at start up then a stock box and with out the tps hooked up you have alittle more timing at start up.wot it wont do anything because with no tps it acks just like with the tps at wot it advances with rpm only.You may need to add some timing at start up to make it light up better .None of the down loadable maps will do that,but you can make a custom map pretty easy.I wonder if I could email you one ,that should work.I would use the setting for the older 790s I think its #1 on the screw switch,The stock 790 map runs better then the stock 865 map.

[Bron-Yr-Aur]

Originally Posted by mikeinva

You dont need the tps but the procom has less timing at start up then a stock box and with out the tps hooked up you have alittle more timing at start up.wot it wont do anything because with no tps it acks just like with the tps at wot it advances with rpm only.You may need to add some timing at start up to make it light up better .None of the down loadable maps will do that,but you can make a custom map pretty easy.I wonder if I could email you one ,that should work.I would use the setting for the older 790s I think its #1 on the screw switch,The stock 790 map runs better then the stock 865 map.

Excellent. Thanks Mike. I'm hoping to possibly start messing with the mapping in the next 2 weeks. I would have been installing the cams today, but I'm a little stuck with the whole making-a-tool-for-the-sprung-gear issue. Once I get those in and the bike back together, I'll try that setting (I think you're right about #1) and then contact you about custom maps after that. Like I said earlier, I won't be doing much riding til around Jan. Hopefully there will be some days like today! 67°

I just wish my butt could tell the difference in 2 hp, because I hate to be spending $ on Dyno runs. Especially since I have no idea where any are around these parts.

[killian101]

Originally Posted by mikeinva

You dont need the tps but the procom has less timing at start up then a stock box and with out the tps hooked up you have alittle more timing at start up.wot it wont do anything because with no tps it acks just like with the tps at wot it advances with rpm only.You may need to add some timing at start up to make it light up better .None of the down loadable maps will do that,but you can make a custom map pretty easy.I wonder if I could email you one ,that should work.I would use the setting for the older 790s I think its #1 on the screw switch,The stock 790 map runs better then the stock 865 map.

You can can email a map in a zip file if you want...

[Bron-Yr-Aur]

Well, I haven't tried to start it again since I've had it apart, but I'll be doing it in the next couple of days.

I just finished installing the cams tonight. I was a little surprised at how hard it was to find the shims. (Thanks local Kawi/Honda dealer, only $4 ea.) With only .05 mm increments, it was hard to get in the middle of the tolerance range on a couple.

Opinions please: better to go towards the tight or loose if I couldn't get in the middle? On one of my exhaust valve shims, it was pretty tight on the smallest gap. But the next smaller on the feeler was loose. Should I plan on checking my valves again in the next 1,000 miles or so? Assuming they'll get tighter? Now that I've done it, it won't be a big deal to do it again since I know what to expect.

Btw I found a way to fab a locking pin for the cams, and both pins costed less than a penny I used aluminum pop rivets. That way a lathe wasn't necessary, only a bench belt sander for the soft aluminum.

And one more question. Since its been pretty cold here and I've been having the cold start problems, and I now have new cams, would it be a good idea to take a heat gun and slowly heat the carbs before my next start? Seems like if the carbs are warm, it should start right up. It can't be good for the starter to keep cranking and cranking like I did last time

[grzegorz]

Got CR carbs too and there is not real problem with starting bike in any weather...when is cold I do open "enricher " but maybe for 2 turns(it never runs with it open), I been advised to change slow jet just after carbs went on bike and I did it but cant remember what number(about 4 years ago)
about procom...had one but never made it work properly and read many opinions that their ignitor doesn't like TPS disconnected....maybe someone can make map which will work ..I'm not that good........my original ignitor never went south but after Procom adventure I decided tu buy second hand unit of ebay sent to Pieman for remapping and can't be more happy.....even got dyno back to back with two ignitors and difference in mid range is huge
my opinion about CRS....as you know there is not much info about them but I really like them ....acces to needle 2 bolts ,acces to main jet 1 sump bolt ..with few tools in my pocket I can change jet in few minutes on lay bay as I did recently trying to set A/F ratio...

[mikeinva]

send me a pm if you want i will give you my phone number .