Engine detonation

scottieh
Financial
Financial
Posts: 796
Joined: Wed Mar 30, 2011 3:58 am
What Bike or Bikes Do You Own?: 1988 XT600Z 3AJ
1987 XT600Z 1VJ
1985 XT 600
1980 TT500
1980 XT250
2001 KTM 300XC
Previously Owned Bikes: 1982 XT550
1981 TT250
1989 Yamaha Virago 750
1994 DR650
1980 Suzuki GR650
1997 KLR 250
1986 Honda Spree
Location: Salt Lake City

Re: Engine detonation

Post by scottieh »

steveloomis wrote:The very best to you on your trip.... Sounds like fun....

Yeah, from what I've read on RR's, fuel can get pretty scarce in some countries and you have to resort to buying from people along the road out of glass jugs etc. No telling what you get. Better be able to run on very poor quality fuel and a good running stock XT should do fine.
Glass bottles are if you're lucky. I was buying out of plastic milk jugs in one place in the Baja.

Here, actually, minus the jerry cans. (not my picture)

Image
scottieh
Financial
Financial
Posts: 796
Joined: Wed Mar 30, 2011 3:58 am
What Bike or Bikes Do You Own?: 1988 XT600Z 3AJ
1987 XT600Z 1VJ
1985 XT 600
1980 TT500
1980 XT250
2001 KTM 300XC
Previously Owned Bikes: 1982 XT550
1981 TT250
1989 Yamaha Virago 750
1994 DR650
1980 Suzuki GR650
1997 KLR 250
1986 Honda Spree
Location: Salt Lake City

Re: Engine detonation

Post by scottieh »

Had some good light last night while cruising the city giving the bike a workout

Image

Image

It idles roughly right now and pulses at less than a quarter throttle. I think the carb intake boots at the cylinder are leaking. There's a certain amount of gasket sealant poking out the sides of the boot that troubles me. I'll try spraying starter fluid around the boots and seeing how idle is affected. Seems to run fine past quarter throttle.
drumnagorrach
On the ladder
On the ladder
Posts: 92
Joined: Fri Apr 22, 2016 8:35 pm
What Bike or Bikes Do You Own?: Ducati S2R 1000
Previously Owned Bikes: Guzzi T3 Cali ,Cali 3 and Sport 1100. BMW R100/7 and R90S. Various Triumphs ( Meridan) .
Lots of Yamaha DT's 175-400,Suzuki PE 250, and SP370.And a very early XT500 ,it's engine no's had three zero's in front of the last three no's ( can't remember what they were ).
Location: Scotland

Re: Engine detonation

Post by drumnagorrach »

steveloomis wrote:Jets hard to come by, USA models needle jet are not adjustable, at least easily. No extra grooves. Can large carbon buildup cause detonation due to hot spots? With compression as low as it is, If it were mine, I'd pull it down and have a look after doing the oil in the cylinder test.
6Sigma jet kit , I have one fitted to my XT here in Scotland , it sorted my white plug . They are located in Phoenix AZ,fairly local to you .
ActionManMelb
Founding Member
Founding Member
Posts: 1052
Joined: Thu Mar 31, 2011 7:50 am
Location: Melbourne, Australia

Re: Engine detonation

Post by ActionManMelb »

It idles roughly right now and pulses at less than a quarter throttle.
Signs of an air leak and lean mixture. You are on the right track. :star:
"Don't worry," he said, "things could be worse ........."
So I stopped worrying and lo and behold, things did get worse!
Jens Eskildsen
No Gold Stars Yet
No Gold Stars Yet
Posts: 43
Joined: Fri Apr 08, 2011 6:47 pm
Location: Denmark

Re: Engine detonation

Post by Jens Eskildsen »

scottieh wrote: except that the air screw was set to four and a quarter turns out from bottom! I reinstalled it as i found it but yesterday's ride was full of popping and a hot engine so today I adjusted the air screw in about a turn or so and got it to mostly stop popping. Runs much cooler too. But there's still a fair amount of pinging especially under acceleration around 50mph.
Its a fuelscrew, by tightening it you just made the bike leaner, not richer.
Post Reply