XT600E wont go over 140 km ??? Help !!
 

Hi , I have a 91 XT600E done 40,000 + Km . It runs well pulls like a school boy! It will get up to 130 km and after a loooong strait I can get to 140 km !:confused1: I am running 16 frt and 45 tooth rear ?? , I have gone over everything I can think of from dyno tuning carbs dialing in cam free flow exhaust fitted a better coil . I have not been able to ride an other XT600E to compare,Am I expecting too much ?? How do your XTs go ? I,m not after a race bike but a bit more go would be useful in all the gears:D so if you can let me know that would help. Thanks :mchappy:

Original its 15/45 and top speed marked as 148km/h. Maybe you need to buy a R1 if you like riding from 140-280km/h ;)

:welcome:to Horizons
Looking at your problem.... it is not a problem!
130 Km/hr is already 80.778mph so... you are already achieving over the prescribed max speed limit in NZ :nono: tsk tsk tsk

It's a 23-year old air cooled single dual purpose. Exactly how fast do you think it should go?

Use the right tool for the right job.

Go 15 in front or 47 in the rear, it should help a bit.

Then he will get lower top speed, with the gearing he has its suppose to give more than 140 so its low. Maybe take a compression test on engine.

Speed?
 

If you want to go fast, 16 or 17 front, 42 back, but then don't take it on a dirt road in the mountains.

Maybe 8th gear is missing....

Ha Ha ! Thanks guys , I know its not a race bike but it just seams to run out of go a bit earlier than I thought it would of ? Top speed is just an indication of what it will do in the lower gears and who dosn't want a bit more go?:thumbup1: I just wanted to know if thats all it should have, or if your similar bikes have a bit more go than mine, but it sounds like thats all I should expect from the old girl and I love riding it :mchappy:

Well i dont think its ok, with your 16 in front you should gain about 5-6km/h, and if yours stall at 130 its to early. Check your engine compression and your carbs diaphragm. If its taking in air true the rubber it will give you slow riding on high rpm.

Thanks . I checked the comp and got 150 PSI ?

Its good, have you notice if bike stalls when you get high rpm? Remove carb and check everything, included the needle filter inside. When my diphragm was not working i felt like i had half power on high rpm, i recomend change anyway when rubber is over 20years old its not smooth anymore.

140km/h is only 5700rpm on stock gearing. He will be able to rev higher with the bigger rear sprocket for added top speed, without being anywhere near the revlimiter.

Its different from bike to bike, a xt350 pulls to just about redline when stock, and need a smaller rear og bigger front, as it runs out of revs before the power is gone.

I never do high rpm on the XT to get high speed, this engine last longest on low rpm on al gears. If you set the 47 back you get about 8km/h less than with standard 45. And that is on 6500rpm.

MY 90 will do 100 mph. I had to switch to air pods and 135 mains in both carbs and raise slide needles all the way up. The biggest problem is the ignition timing. My 86 has a max advance of 36 degrees vs the 28 max in the 90. With the same air box and jetting changes the 86 will leave the 90 in the dust and has a top end over 100 mph. You willing to avoid deep water crossings, clean the air filter often and drop your mpg to 45 to go 100 mph? you cant have everything. thumpthump

I can hear a boom boom boom BANG coming on!doh

I hope I dont hear the boom boom Bang :censored: I just like the thump thump thump ! . About the diaphragm,the 91 models sold in new Zealand dont have diaphragms so I can rule that one out . And I would rather be able to ride over two hundred miles on a tank of gas than do over a hundred miles an hour for a short while.The perfect lambda settings when it was on the dyno are 0.85 ish through out the rev range (near perfect) . So will a 86 CDI plug into a 90 model ?? I advanced the pick ups a bit by slotting the holes and it felt a bit stronger pulling out of the corners ! I,m sure the 86 models would of had a better cam profile due to smog emissions etc but I have not seen one ? Thanks guys bier

Ok, what did they use instead of diaphragm? You have pict?

An 86 ignition box will not work in a 90 . Totally different system. However, I am talking with Wieltronic and they said they could load the 86 map into a unit for a 90. You have to provide the map. They also sell a kit with their unit so you can load 2 maps of your design and provide a bar mounted switch. Steve Loomis sent me a picture of an 86 map on ADV and I am going to see if Wieltronic can load it in a box for my 90. With the mods I mentioned before you go about 100 miles before you hit reserve. I need a bigger tank.

At 6000 rpms with 47 sprocket, you will go faster than 5700rpm with 45 sprocket.

I dont ride at high revs, bet hes asking about top speed, not cruising speed or whats best for the bike.

My bike is closing in on 150.000km, I ride with everything from 13/47 to 16/45 depending on the task.

No you wont, 5980prm with 15/45 gives you 147km/h, 15/47 give you 139km/h at 5980rpm if you go down to 43 it will give you higher speed 152km/h.

I know that at the same rpm, he will go faster with a smaller rear, but that wasnt what I wrote.

I wrote that a +2 rear sprocket will add 300 rpm to get to the same speed as the stock 45. But if he cant rev out in 5th gear,the engine will struggle even more to rev with a smaller rear, reducing topspeed. This is very noticable when going uphill. So tats why he needs to go the other way, if he reall wants higher top speed. If it rev'ed close to redline, a smaller rear would be better.

I added the 1990 xt600 on gearingcommander :innocent:

His problem seems to be that he cant rev muvh past where the engine has the most torque, so to me the gearing must be too tall.

I use 16/45 for daily use, to keep my revs down when cruising, but it doesnt give me better topspeed, or better mpg as you need to rev out the gears slightly more, as they're "further apart"

Thanks for that . I think the gearing I have feels good , I dont really want to rev high all the time , but just the way it wont rev out when there is no time to change up ( when in the windy stuff )makes me think theres a problem ? Its proberly time for a freshen up . Maybe a over size piston ?. Has any one here put a big bore piston into theirs with out a hot cam and heavy valve springs etc etc and did it go much better ??

With a compression of 150psi the engine is as good as new and dont think thats the problem, question is do the engine get enough fuel/mixture and is it correct.

air fuel mixture is near perfect according to the dyno testing ,so its not that ? I shal injoy whats left of our summer and look further into it in the colder weeks :mchappy:

Cold???:palm: If you had dyno, what hp did it give you? And what about that diaphragm in the carb, how is yours built up without this?

My '80's carbs don't have diaphragms , the "90's do , maybe they use the older carbs down there? They simply rely on the piston of the slide to be close fitting to the cap bore, not the best design .

I think he is simply out of power for the too high gearing. I have several XT's and they are not powerhouses that can pull any gearing wanted. I run 15/40 in 2 and that is about all they can handle while still being able to pull fully(just barely with a small headwind @ 65mph). At most I could go down to 38 rear but headwinds would limit topend.

The advance will probably make a huge difference in the upper rpm's.

For more power a high comp piston/mild porting and big headpipe with can will get quite a bit more oomph . A better set of carbs will also greatly improve performance with some tank range loss.


TURBO !!!!

The dyno didn't have a HP gauge ? so I cant answer that one ? On the night I had mine on the dyno my mate put his SRX 600 on and it hit the rev limiter in top gear !. He didn't even know it had a rev limiter :confused1:. Where my bike in top gear as we wound up the resistance on the dyno my motor wound down and down ... we could have stalled it if we wound it on more ! It sounds similar power to JJRIDERS So maybe its normal thats good to hear , IIts hard for me to know as I have never riden another XT 600 and My 450 Sherco with 14 48 gearing will do 160 km so I expected a bit more ompf , but I would rather be on the XT for real long rides :mchappy: Horses for courses . Cheers guys bier

Hey beagle can you post pict of your carb?

Ya pics, it would be interesting to see if they put the older (or at least to the US) carbs in the e-starts down there. I don't think the carbs would cause the hp loss actually might be opposite, the boots may be smaller id than the older models, I think the US '90's bikes had a bit less hp than the '89 and older ones ,part of that because of smaller boots. I think.

Hi guys I will need to take the fuel tank off to get a photo and have not had a chance . But I did find one thing ! Every now and then I could smell fuel in my shed and I was looking into it yesterday and I found the small fuel line from the fuel bowl of the main carb to the bottom of the secondary carb had a small crack and when I touched it fuel would leak out , so I guess when secondary carb was open it would have sucked in some air ? ? So after I replaced it I went for a thrash and it was pulling a bit better ! still wouldn't go over 140 but it got there faster,:thumbup1: witch is what I like to feel.

This is quite interesting. The XT6 has nice torque but is not really that powerful. I did uncork (exhaust, snorkel) my 2000 XT600E and expected a big change in performance (that is usually the case with corked up engines) but got nothing.



The headers are pretty big, so maybe the long intake “hoses” are the limiting factor? For example, the XR650L had to fulfill the same regulations, has similar low state of tune (compression 8.3:1?) but has way more power/torque after uncorking.

Replacing the stock carbs with Keihin cr31's will improve your motors performance, you'll actually be able to accelerate when in 5th gear and wishing you had a 6th . Mike :funmeterno:

And the price is only?

The price is ??? How fast do you want to go ??? :funmeteryes:

Mikuni BSR33 x2 - Raptor 660

Well the old girl is back on the road :mchappy: After being board out to 620cc valve grind, port out the head, new 5th gears and all the bearings etc etc she running sweet . Still wont go over 140 km but it gets there respectively it has heaps more pull from down low:thumbup1: sounds like I need to change the carbs if l want it to go better up top end ? so if you start to hear a bit of a wine in top gear ! stop riding it, as bits of steel from 5th gear will be pumped around in your oil :thumbdown: LOL its not a good look . Its good to feel the thump thump thump again :mchappy:

I noticed you've got a relatively high fairing mounted on your bike in addition to a top box. At 140 kmh the wind resistance at the front would be massive. The top box most likely adds suction at the rear, like a vans rear end. Maybe that could account for the lack in the last 8-10 kmh at the top? Have you tried uninstalling it and see how big of a difference it makes?

Cost of the Keihin cr31's about 400us then add 300 for a dyno tune. The cost is high, but the results are substantial. Mike

I havent tryed it without the screen etc but now l know how it is to have that big screen l dont want to go back to streching my arms , I know l want the best of both worlds :confused1: but l just want a bit more go ! can anyone tell me dose a mid 80s tt600 cam fit my 91 xt600 and are the cam lobes on the tt600 a bit more sharp looking ? Thanks :mchappy:

Hahahaha